(msia) guide to sewer selection and installation (dec2006)_vc pipe pg17～

A Guide toSewer Selectionand Installation

ISSUE: 01REVISION: 0NOVEMBER 2006

A Guide toSewer Selectionand Installation

PED/SDQS/ST018/GLD/1106/001

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TABLE OF CONTENT

1.0 INTRODUCTION 1

1.1 Purpose of This Guide 11.2 Who Should Use This Guide 11.3 How to Use This Guide 1

2.0 SEWER PIPELINE - REGISTRATION AND APPROVAL 2

2.1 General 22.2 Pipes Submission and Evaluation 2

2.2.1 General 22.2.2 Submission Procedures 32.2.3 Evaluation Process 3

3.0 SEWER PIPELINE - SELECTION GUIDE 5

3.1 General 53.2 Selection Criteria 5

3.2.1 Material 63.2.2 Joint 63.2.3 Structural Design 73.2.4 Quality Assurance 7

3.3 Selection Process 73.3.1 Exclusions of Use Explanations 12

4.0 SEWER PIPELINE – MATERIAL SELECTION 15

4.1 Gravity Sewerage System 154.1.1 General 154.1.2 Definition 154.1.3 Precautions and Principal Applications of Sewerage Gravity

Pipeline System 15

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4.2 Vitrified Clay (VC) Pipe 174.2.1 Manufacture 184.2.2 Protective Coatings/Linings 204.2.3 Sizes/Classes 20

4.2.4 Joints 214.2.5 Fittings 224.2.6 Pipeline Hydraulic Design 244.2.7 Application of Pipes 25

4.3 Reinforced Concrete (RC) Pipe 264.3.1 Manufacture 274.3.2 Protective Coatings/Linings 284.3.3 Sizes/Classes 284.3.4 Joints 294.3.5 Fittings 314.3.6 Pipeline Hydraulic Design 324.3.7 Application of Pipes 33

4.4 Ductile Iron (DI) Pipe 344.4.1 Manufacture 354.4.2 Protective Coatings/Linings 374.4.3 Sizes/Classes 374.4.4 Joints 384.4.5 Fittings 404.4.6 Pipeline Hydraulic Design 414.4.7 Application of Pipes 42

4.5 Glass-fibre Reinforced Plastic (GRP) Pipe 434.5.1 Manufacture 444.5.2 Protective Coatings/Linings 454.5.3 Sizes/Classes 454.5.4 Joints 464.5.5 Fittings 474.5.6 Pipeline Hydraulic Design 484.5.7 Application of Pipes 49

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4.6 Profile Wall High Density Polyethylene (HDPE) Pipe 504.6.1 Manufacture 514.6.2 Protective Coatings/Linings 554.6.3 Sizes/Classes 554.6.4 Joints 554.6.5 Fittings 584.6.6 Pipeline Hydraulic Design 584.6.7 Application of Pipes 59

5.0 FORCE MAIN 63

5.1 General 635.1.1 Definition 635.1.2 Pipe Materials and Application Conditions 63

5.2 Ductile Iron (DI) Pipe 645.2.1 Manufacture 655.2.2 Protective Coatings/Linings 655.2.3 Sizes/Classes 655.2.4 Joints 655.2.5 Fittings 675.2.6 Pipeline Hydraulic Design 685.2.7 Application of Pipe 68

5.3 Steel Pipes 695.3.1 Manufacture 71

5.3.1.1 Mild Steel 715.3.1.2 Stainless Steel 72

5.3.2 Protective Coatings/Linings 725.3.2.1 Mild Steel 735.3.2.2 Stainless Steel 73

5.3.3 Sizes/Classes 725.3.4 Joints 745.3.5 Fittings 755.3.6 Pipeline Hydraulic Design 765.3.7 Application of Pipes 76

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5.4 Glass-fibre Reinforced Plastics (GRP) Pipe 775.4.1 Manufacture 785.4.2 Protective Coatings/Linings 785.4.3 Sizes/Classes 785.4.4 Joints 785.4.5 Fittings 805.4.6 Pipeline Hydraulic Design 805.4.7 Application of Pipes 81

5.5 Acrylonitrile Butadiene Styrene (ABS) Pipe 825.5.1 Manufacture 835.5.2 Protective Coatings/Linings 845.5.3 Sizes/Classes 845.5.4 Joints 855.5.5 Fittings 865.5.6 Pipeline Hydraulic Design 875.5.7 Application of Pipes 87

5.6 Solid Wall HDPE Pipe 885.6.1 Manufacture 895.6.2 Protective Coatings/Linings 905.6.3 Sizes/Classes 905.6.4 Joints 905.6.5 Fittings 925.6.6 Pipeline Hydraulic Design 925.6.7 Application of Pipes 93

6.0 VACUUM SEWERAGE SYSTEMS 94

6.1 General 946.2 Acrylonitrile Butadiene Styrene (ABS) Pipe 95

6.2.1 Manufacture 966.2.2 Protective Coatings/Linings 966.2.3 Sizes/Classes 966.2.4 Joints 976.2.5 Fittings 976.2.6 Pipeline Hydraulic Design 97

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6.3 Solid Wall HDPE Pipe 986.3.1 Manufacture 996.3.2 Protective Coatings/Linings 996.3.3 Sizes/Classes 996.3.4 Joints 996.3.5 Fittings 996.3.6 Pipeline Hydraulic Design 99

7.0 PIPE JACKING 100

7.1 General 1007.2 Vitrified Clay (VC) Pipe 101

7.2.1 Manufacture 1027.2.2 Protective Coatings/Linings 1027.2.3 Sizes/Classes 1027.2.4 Joints 1037.2.5 Pipeline Hydraulic Design 103

7.3 Reinforced Concrete (RC) Pipe 1047.3.1 Manufacture 1057.3.2 Protective Coatings/Linings 1057.3.3 Sizes/Classes 1057.3.4 Joints 1067.3.5 Pipeline Hydraulic Design 106

8.0 SEWER PIPELINE - DESIGN GUIDE 107

8.1 General 1078.2 Rigid Pipe 107

8.2.1 Vitrified Clay (VC) Pipe 1078.2.1.1 Pipeline Structural Design 1078.2.1.2 Pipeline Embedment 108

8.2.2 Reinforced Concrete (RC) Pipe 1108.2.2.1 Pipeline Structural Design 1108.2.2.2 Pipeline Embedment 111

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8.3 Flexible Pipe 1138.3.1 Flexible Pipeline Structural Design 1138.3.2 Flexible Pipeline Embedment 1148.3.3 DI Pipe 1168.3.4 GFRP Pipe 1178.3.5 Profile Wall HDPE Pipe 1188.3.6 ABS Pipe 1188.3.7 Steel Pipe 119

8.3.7.1 Pipeline Structural Design 1198.3.7.2 Pipeline Embedment 119

8.3.8 Solids Wall HDPE Pipe 1208.3.8.1 Pipeline Structural Design 1208.3.8.2 Pipeline Embedment 120

9.0 SEWER PIPELINE – TESTING GUIDE, SITE HANDLING ANDINSTALLATION 123

9.1 General 1239.2 Field Testing 123

9.2.1 General Pipeline Testing Guide 1249.2.2 Test for Straightness, Obstruction and Grade 1249.2.3 Low Pressure Air Test 1249.2.4 Hydrostatic Test 1249.2.5 High Pressure Water Test 1259.2.6 High Pressure Leakage Test 1259.2.7 Vacuum Test 1269.2.8 Infiltration Test 1269.2.9 CCTV Inspection 126

9.3 Factory Testing 1279.4 Site Handling and Installation Guide 128

9.4.1 Dos and Don’ts 128

9.5 Handling and Installation Practice 1339.5.1 Storage 1339.5.2 Excavation 1339.5.3 Pipe Cutting 1349.5.4 Pipe Jointing 1349.5.5 Pipe Inspection 135

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APPENDIX A : Checklist B

APPENDIX B : Product Details: Sewer Pipes and Fittings Form

APPENDIX C : Evaluation Criteria Form

APPENDIX D : Summary of Approved Suppliers/Manufacturers

LIST OF TABLES

Table 3.1 Type of Pipelines for Various Sewerage SystemsTable 3.2 Application of Various Types of Pipes in Sewerage SystemsTable 3.3 Limit on Use for Various Types of Pipes for Sewerage SystemsTable 3.4 Exclusion of UseTable 4.1 Gravity Sewer Pipeline Materials and ApplicationTable 4.2 Precautions and Principal Applications of Gravity Sewer Pipeline SystemTable 4.3 Summary of VC Pipes Design and Specifications for Gravity Sewerage SystemTable 4.4 Preferred Nominal Lengths of VC PipesTable 4.5 Crushing Strength (FN) in kN/m for Various Sizes of VC PipesTable 4.6 Allowable Angular Deflection of VC PipesTable 4.7 Colebrook-White Roughness Coefficient, kB BBsBBB for VC PipesTable 4.8 Various Pipeline Hydraulic Design Equations of VC Pipes for Gravity Sewerage SystemTable 4.9 Advantages and Disadvantages of VC PipesTable 4.10 Summary of RC Pipes Design and Specifications for Gravity Sewerage SystemTable 4.11 Crushing Test Loads of RC Pipes for Gravity Sewerage SystemTable 4.12 Allowable Angular Deflection of RC PipesTable 4.13 Colebrook-White Roughness Coefficient, kB BBsBBB for RC PipesTable 4.14 Various Pipeline Hydraulic Design Equations of RC Pipes for Gravity Sewerage SystemTable 4.15 Advantages and Disadvantages of RC PipeTable 4.16 Summary of Ductile Iron Pipes Design and Specifications for Gravity Sewerage SystemTable 4.17 HAC Lining Thickness of Various Sizes of DI PipesTable 4.18 Standard Pipe Lengths of Various Sizes of DI PipesTable 4.19 Allowable Angular Deflection of Jointing for DI PipesTable 4.20 Various Pipeline Hydraulic Design Equations of DI Pipes for Gravity Sewerage SystemTable 4.21 Advantages and Disadvantages of Ductile Iron PipesTable 4.22 Summary of GFRP Pipes Design and Specifications for Gravity Sewerage SystemTable 4.23 Nominal Sizes of GFRP PipesTable 4.24 Angular Deflection Limits Relative to the Nominal Size of the GFRP PipeworkTable 4.25 Methods of Hydraulic Design of GFRP PipeTable 4.26 Advantages and Disadvantages of GFRP PipeTable 4.27 Summary of Profile Wall HDPE Pipes Design and Specifications for Gravity Sewerage

SystemTable 4.28 Classifications of Profile Wall HDPE PipeTable 4.29 Colebrook-White Roughness Coefficients (kB BBsBBB) for Profile Wall HDPE PipeTable 4.30 Advantages and Disadvantages of Profile Wall HDPE PipeTable 4.31 Technical Comparison of Various Types of Pipe for Gravity Sewerage SystemTable 4.32 Summary of Comparison for Various Types of Pipe for Gravity Sewerage SystemTable 5.1 Pressure Sewer Pipe Materials and ApplicationTable 5.2 Summary of DI Pipes Design and Specifications for Force MainTable 5.3 Colebrook-White Roughness Coefficient, kB BBsBBB for DI PipesTable 5.4 Advantages and Disadvantages of DI Pipes for Force MainTable 5.5 Summary of Mild Steel Pipes Design and Specifications for Force MainTable 5.6 Summary of Stainless Steel Pipes Design and Specifications for Force MainTable 5.7 Colebrook-White Roughness Coefficient (kB BBsBBB) for Steel PipesTable 5.8 Advantages and Disadvantages of Steel PipesTable 5.9 Summary of GRP Pipe Design and Specifications for Force MainTable 5.10 Angular Deflection Limits Relative to the Nominal Size of GRP PipelinesTable 5.11 Colebrook-White Roughness Coefficient, kB BBsBBB for GRP PipesTable 5.12 Advantages and Disadvantages of GRP Pipes for Force MainTable 5.13 Summary of ABS Pipes Design and Specifications for Force MainTable 5.14 Dimensions of ABS for Force MainTable 5.15 Classifications of ABS Pipes for Force MainTable 5.16 Colebrook-White Roughness Coefficients (kB BBsBBB) of ABS PipesTable 5.17 Advantages and Disadvantages of ABS PipesTable 5.18 Summary of Solid Wall HDPE Pipe Design and Specifications for Force Main

Table 5.19 Colebrook-White Roughness Coefficient (ks) for Solid Wall HDPE PipesTable 5.20 Advantages and Disadvantages of Solid Wall HDPE PipeTable 6.1 Summary of ABS Pipes Design and Specifications for Vacuum Sewerage SystemTable 6.2 Dimensions Of Abs For Vacuum Sewerage SystemTable 6.3 Classifications of ABS Pipes for Vacuum Sewerage SystemTable 6.4 Summary of Solid Wall HDPE Pipe Design and Specifications for Vacuum Sewerage

SystemTable 7.1 Summary of VC Pipes Design and Specifications for Pipe JackingTable 7.2 Tolerance on Internal and External Diameter of VC Pipes for Pipe JackingTable 7.3 Allowable Angular Deflection of VC Pipes for Pipe JackingTable 7.4 Summary of RC Pipes Design and Specifications for Pipe JackingTable 7.5 Crushing Loads of RC Pipes for Jacking PipeTable 7.6 Minimum Angular Deflection and Straight Draw Joints of RC Pipes for Pipe JackingTable 8.1 Compositions of Fill Material for RC Pipeline EmbedmentTable 8.2 Bedding Factors for Working Dead Loads for Various Types of SupportTable 8.3 Typical Flexible Pipe MaterialsTable 8.4 Maximum Particle Size of Embedment Material for Flexible PipelineTable 8.5 Minimum Relative Compaction of Embedment Material for Flexible PipelineTable 8.6 Notations Applicable in the GuidelinesTable 8.7 Minimum Cover (H) for Flexible PipelineTable 8.8 Minimum Embedment Zone DimensionsTable 9.1 Summary of Field Testing for Sewer PipelinesTable 9.2 Summary of Factory Testing for Various Types of Sewer Pipe

LIST OF FIGURES

Figure 2.1 Flow Chart of Product Registration and Approval ProceduresFigure 3.1 Steps of Preliminary Selection of Sewer PipelineFigure 4.1 Types of VC PipesFigure 4.2 Typical Manufacturing Process for VC PipesFigure 4.3 Spigot Socket with Rubber ‘O’ Ring Joint for VC PipesFigure 4.4 Skid Type Sealing Joints for VC PipesFigure 4.5 Typical Range of Fittings for VC PipesFigure 4.6 Types of RC PipesFigure 4.7 Typical Flexible Joint of Spigot Socket RC PipesFigure 4.8 Typical Flexible Joint of Rebated/Ogee RC PipesFigure 4.9 Typical Double Spigot Joint with Collar of RC PipesFigure 4.10 Typical Range of Fittings for RC PipesFigure 4.11 Types of DI PipesFigure 4.12 Typical Manufacturing Process of Centrifugal Casting for DI PipesFigure 4.13 Typical Push in Joints for DI PipesFigure 4.14 Typical Self-anchoring Push-in Joint for DI PipesFigure 4.15 Typical Ranges of Flange for DI PipesFigure 4.16 Various Range of Fittings for DI PipesFigure 4.17 Typical Filament Wound GRP PipesFigure 4.18 Typical Centrifugally Cast GRP PipesFigure 4.19 Definition of Stiffness for GRP PipesFigure 4.20 Typical Integral Socket and Spigot Joint of GRP PipesFigure 4.21 Typical Loose Collar Joint of GRP PipesFigure 4.22 Typical Rigid Joints of GRP PipeFigure 4.23 Various Ranges of Fittings for GRP PipeFigure 4.24 Types of Profile Wall HDPE Pipe for Gravity SystemFigure 4.25 Various Forms of Profile Wall HDPE PipeFigure 4.26 Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes

(Option 1)Figure 4.27 Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes

(Option 2)Figure 4.28 Helical Pattern of Profile Wall HDPE PipeFigure 4.29 Typical Manufacturing Process of Annular Profile Wall HDPE PipeFigure 4.30 Annular Pattern of Profile Wall HDPE PipeFigure 4.31 Spigot Socket with Rubber Ring Seals Joint for Profile Wall HDPE PipesFigure 4.32 Typical Socket Fusion Welding for Profile Wall HDPE PipesFigure 4.33 Butt Weld Joint of Profile Wall HDPE PipeFigure 4.34 Butt Welded Joint of Spigot Socket Profile Wall HDPE PipeFigure 4.35 Flange Ends Joint of Profile Wall HDPE PipeFigure 4.36 Screwed Fittings for Jointing of Profile Wall HDPE PipeFigure 4.37 Plastic Fittings for Jointing of Profile Wall HDPE PipeFigure 4.38 Various Ranges of Fittings for Profile Wall HDPE Pipe for Gravity SystemFigure 5.1 Typical Bolted Mechanical Joint of DI Pipes for Force MainFigure 5.2 Typical Flange Adapters of DI Pipe for Force MainFigure 5.3 Typical Self-anchoring Flange Adapters of DI Pipe for Force MainFigure 5.4 Typical Self -anchoring Bolted Mechanical Joints of DI Pipe for Force MainFigure 5.5 Typical Slip-on Coupling for DI PipesFigure 5.6 Typical Self-anchoring Tie-bar Joints for DI PipesFigure 5.7 Additional Ranges of DI Fittings for Force MainFigure 5.8 Typical Manufacturing Process of Mild Steel Pipes for Force MainFigure 5.9 Typical Manufacturing Process for Stainless Steel Pipes for Force MainFigure 5.10 Butt-welded Joint Preparation of Steel PipesFigure 5.11 Sleeve Welded Joints of Steel PipesFigure 5.12 Slip-on Type Coupling of Steel PipesFigure 5.13 Threaded and Coupled Joints Recessed for Bitumen LiningFigure 5.14 Various Ranges of Fittings for Steel PipesFigure 5.15 Typical slip-on couplingFigure 5.16 Typical stepped slip-on coupling

Figure 5.17 Typical band couplingFigure 5.18 Typical flange adapterFigure 5.19 Typical flange jointsFigure 5.20 Various Ranges of DI Fittings for GFRP PipesFigure 5.21 Typical Manufacturing Process Flow of ABS PipesFigure 5.22 Types of ABS PipesFigure 5.23 Typical Spigot-socket with Solvent Cement Joint of ABS PipesFigure 5.24 Typical Spigot-socket with Elastomeric Seal Joint of ABS PipesFigure 5.25 Typical Stub Flange Joint for ABS PipesFigure 5.26 Various Ranges of Fittings for ABS PipesFigure 5.27 Typical Manufacturing Process of Solid Wall PE PipeFigure 5.28 Typical Butt Fusion Welding for Solid Wall HDPE PipesFigure 5.29 Butt Fusion Welding of Spigot socket Joints for Solid Wall HDPE PipesFigure 5.30 Typical Flange Joints of Solid Wall HDPE PipesFigure 5.31 Fabricated Fittings for Butt Fusion of Solid Wall HDPE PipesFigure 5.32 Stub End and MS Flange Fittings for Solid Wall HDPE PipesFigure 5.33 Plastics Compression Fittings for Solid Wall HDPE PipesFigure 6.1 Typical Spigot-socket with Solvent Cement Joint of ABS PipesFigure 6.2 Typical Stub Flange Joint for ABS PipesFigure 7.1 Type of VC Pipe for Pipe JackingFigure 7.2 Types of RC Pipes for Pipe JackingFigure 7.3 Typical Flexible Joint of Rebated/Ogee RC PipesFigure 7.4 Typical Double Spigot Joint with Collar of RC PipesFigure 8.1 Construction Method of Class ‘A’ BeddingFigure 8.2 Construction Method of Class ‘B’ BeddingFigure 8.3 Construction Method of Concrete EncasementFigure 8.4 Construction Method of Type H1 and Type H2 SupportFigure 8.5 Construction Method of Type H3 SupportFigure 8.6 Construction Method of Type HS SupportFigure 8.7 Terminology and Typical Construction of Pipe Support for Flexible PipelineFigure 9.1 Typical Field Pressure Test Equipment Layout

Section 1 Introduction

1.0 INTRODUCTION

1.1 Purpose of This Guide This Guide provides guidelines to material selection of sewers for appropriate application as well as some recommendation for proper pipe handling, installation and testing practices. It draws on a wide base of knowledge and experience from operators and manufacturers.

The Guide also contains reference information on pipe registration requirements and the approval status of the pipe manufacturers/suppliers. Product information such as pipe material, sizes and limitation on use of sewer pipes available in Malaysia and information on pipe handling, installation and testing are included in the Guide.

The Guide does not cover the installation of internal plumbing systems to buildings as these procedures are managed by Local Authorities.

1.2 Who Should Use This Guide This Guide is primarily for owners, developers, consulting engineers, manufacturers, suppliers and Public Authorities whose developments or products involved sewer pipes.

1.3 How to Use This Guide The information in this Guide is listed in five main categories described in the following sections:

• Sewer Pipeline - Registration & Approval Section 2.0

• Sewer Pipeline - Selection Guide Section 3.0

• Sewer Pipeline - Material Selection

- Gravity Sewerage System Section 4.0

- Force Main Section 5.0

- Vacuum Sewerage System Section 6.0

- Pipe Jacking Section 7.0

• Sewer Pipeline - Design Guide Section 8.0

• Sewer Pipeline - Testing Guide, Site Handling and Installation Section 9.0

A Guide to Sewer Selection and Installation 1 13th November 2006

Section 2 Sewer Pipeline - Registration and Approval

2.0 SEWER PIPELINE - REGISTRATION AND APPROVAL

2.1 General All manufacturers/suppliers must obtain approval from the Director General of Sewerage Services (DGSS) for the ranges of pipes, which they intend to supply to the sewerage industries in Malaysia.

2.2 Pipes Submission and Evaluation

2.2.1 General Flow chart of the sewer pipe submission and evaluation process is shown in Figure 2.1.

2.2.2 Submission Procedures The following are procedures for the preparation and submission of document to DGSS: 1. Obtain submission forms of

a. Checklist B (see Appendix A); and b. Product Details – Sewer Pipes and Fittings Form (see Appendix B) from DGSS offices or from the DGSS website at www.jpp.gov.my. Photocopies of the submission forms attached in this Guide are acceptable, however a confirmation shall be made with the relevant authority if there is any latest revision being issued.

2. Prepare a complete set of document as per Checklist B including company profile and

technical details of the products. All the submission documents shall be bound neatly. 3. Submit two (2) copies of the submission documents together with the Checklist B and the

Product Details – Sewer Pipes and Fittings Form to DGSS for evaluation. 4. The manufacturer/supplier will be notified on the status of evaluation within 1 month of the

date of submission received whether:

• Additional information/clarification may be requested;

The product has been approved with or without conditions; •

• The product has been rejected.

5. The manufacturer/supplier shall give the feedback on additional information/clarification requested within two (2) months; if not the DGSS will close the submission file and any respond after that will be considered as a new submission.

6. The manufacturer/supplier, whose product has been rejected, may appeal to the DGSS by providing valid reasons.

A Guide to Sewer Selection and Installation 13th November 2006

2


2.2.3 Evaluation Process The following are steps of evaluation adopted by the technical evaluation committee: 1. Check if the submission of the document contains all the necessary information for evaluation.

If not, the manufacturer will be requested to submit the outstanding information.

2. Evaluate the submission of the document based on a set of evaluation criteria as attached in Appendix C, the DGSS Guidelines and other relevant standards.

3. Notify the manufacturers/suppliers within 3 months of the date of submission received whether:

Further information/clarification is required; • • •

The product has been approved, with or without conditions; The product has been rejected.

4. Check if there were problems associated with the pipe/brand encountered at site.


3


Figure 2.1: Flow Chart of Product Registration and Approval Procedures

Notify the manufacturer/supplier that the submission's

rejected

Submission Satisfactory

Notify the manufacturer/supplier on

the approval granted

Yes

No DGSS Design Guidelines & Policy

DGSS Technical Committee evaluating the submission

Yes

Submission Complete?

Notify manufacturer/supplier No

Obtain Checklist B and Product ails-Sewer Pipes and Fittin

Form from DGSS Det gs

(Sample in Appendix A & B)

Prepare & submit two (2) complete sets of documents to DGSS

DGSS initial check Manufacturer/supplier

to complete the submission

Start

Evaluation Criteria (See Appendix C)

Related Reference Material


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Section 3 Sewer Pipeline - Selection Guide

3.0 SEWER PIPELINE - SELECTION GUIDE

3.1 General Within the past few decades there has been a growing choice of sewerage system. There is an increased range of materials available for sewerage applications and there may be significant economic advantages to a more informed approach to materials selection. New sewerage systems are being introduced as a result of the utilisation of various plastic materials while traditional systems are being improved to overcome deficiencies. A greater choice of sewerage systems means more sewer materials can be applicable. The selection of suitable pipe material for the sewerage system and particular application requires knowledge outside the normal training of the designer with some complex issues requiring specialist materials and structural knowledge. Handling, installation and testing methods could also vary for different pipe materials. An increasingly competitive market place has made it more difficult to formulate objective technical decisions on materials. Information from suppliers is fragmented and focuses on the advantages rather than the disadvantages of a particular material. The section provides a summary of necessary information to lead to the accurate selection of sewer pipeline system.

3.2 Selection Criteria The fundamental requirements of a piping selection for sewage conveyance system are:

• Availability of complete range of components to suit the system’s design, function and repair, e.g. where service connections are required, appropriate fittings must be available

• Achieving the specified design life within the specified level of maintenance. Specified design life may be for the length of time that a service is to be provided to an area of customers or shorter time if there is plan to renovate, upgrade or replace the piping system in future. The design life generally sought by authorities for most instances is at least 100 years with special circumstances permitting a shorter life.

Specified level of maintenance that would be desirable by most authorities at a minimum as

to require infrequent cleaning of silts and slimes. The design life, maintenance level and ranges of product form the basis for establishing criteria for selecting sewer material. The main criteria identified for the purposes of selecting sewer material are as follows:

Material; • • • •

Joint; Structural design; and Quality assurance.



3.2.1 Material Materials to be used in sewer pipe, fittings, elastomeric seals, pipe coatings and other accessories must have the following properties:

Good corrosion resistance at the internal wall to hydrogen sulphide and sulphuric acid produced in septic sewage, and any industrial discharges attacks;

•

• • • • •

• • •

•

• • • • • • • •

• • •

• • • •

• • • • • • •

External wall to remain chemically stable when exposed to aggressive soils and groundwater; Resist microbiological attack from the internal and external environment; Good resistance to abrasion caused by sewage flow and any maintenance cleaning; Remain sufficiently impermeable; Suitable for the site condition;

Factors to be taken into account in selecting materials should include:

The nature of the effluent and the possibility of chemical attack or mechanical damage; The nature of the ground conditions and the possibility of subsidence or chemical attack; The quality of workmanship which may be expected and the degree of supervision to be provided; Third party interference to the pipe surrounding.

3.2.2 Joint The pipe and fittings jointing systems and access chamber connections need to have the following characteristics:

Able to be consistently constructed in the specified manner under field conditions; Resist groundwater infiltration; Resist sewage exfiltration; Resist root intrusion; Resist pullout for an elastomeric sealing joint; Have sufficient tensile, shear and bending strength for welded joints; Not cause excessive snagging and fouling; Not significantly affect the hydraulic flow roughness, through mismatching of surfaces and joint gap; Not impede routine maintenance operations; Resistance to damage due expansion; and Able to joint two pipes of different materials.

For elastomeric sealing joints, such performance is required for one and a combination of configurations that are possible with the joints such as:

Axial displacement (minimum insertion of spigot); Axial deflection (relative deflection of one pipe length to adjoining pipe length); Ring misalignment (shear); Ring ovalisation (for flexible pipe);

The elastomer properties affecting long term sealing performance are:

Hardness; Rate of compression; Stress relaxation; Water absorption; Resistance to ageing; Resistance to chemicals; and Resistance to microbiological deterioration.



3.2.3 Structural Design The selected sewer at most installation conditions should not result in excessive complication in the installation process, e.g. internal bracing of flexible pipe, but capable to offer the following structural properties:

Resist ring cracking or crushing, where rigid pipe is used; • •

•

• •

Resist excessive ring deflection, circumferential strain and ring buckling where flexible pipe is used; Resist shearing and longitudinal bending where sufficient or uniform underlying support cannot be provided to the pipeline or excessive ground movement is expected; For rising mains, resist cyclic pressure loading; and The shape of the pipe should not deform easily.

3.2.4 Quality Assurance Assurance is required that the material, pipe and fittings are manufactured and supplied so that they will consistently meet nominated standards/specifications. Such assurance is achieved by requiring the manufacturer to have a quality management system certified to comply with the International standard ISO 9001 or 9002 and an approved inspection and test plan to ensure conformance with the nominated material, pipe and fittings standards/specifications.

3.3 Selection Process Compliance to the selection criteria may vary among the pipeline systems under various installation conditions. The following steps shown in Figure 3.1 below can be adopted for preliminary selection of suitable pipeline systems using this guideline:

Figure 3.1: Steps of Preliminary Selection of Sewer Pipeline

Check the suitability of the selecpipeline to the design condition f

Table 3.2 and 3.3

A Guide to Sewer Selection and Installa13th November 2006

Identify the type of systems

p

ma

Identify the exclusion of use in certain pipeline system under

specific condition from Table 3.4

ted rom

tio

Identify the approved nufacturers/suppliers from Appendix D, Table D1

0
Getting the product information of the selected pipeline from Section 4.0, 5.0 and 6.
n

Identify the type of ipeline from Table 3.1

7


Table 3.1: Type of Pipelines for Various Sewerage Systems

System Type of Pipelines Available Size (Diameter) VC Pipe 100 mm to 600 mm (locally made)

400 mm to 600 mm (imported) RC Pipe 150 mm to 3600 mm GRP Pipe 50 mm to 3000 mm DI Pipe 80 mm to 1200 mm

Gravity Sewer

Profile Wall HDPE Pipe 100 mm to 3000 mm DI Pipe 80 mm to 1200 mm Steel Pipe 100 mm to 2200 mm GFRP Pipe 50 mm to 3000 mm ABS Pipe 10 mm to 630 mm

Force Main

Solid Wall HDPE Pipe 20 mm to 900 mm Solid Wall HDPE Pipe 20 mm to 900 mm Vacuum Sewer ABS Pipe 10 mm to 630 mm

Table 3.2: Application of Various Types of Pipes in Sewerage Systems

Type of Pipe Application

VC • All sizes are applicable. • Short pipe lengths can be specially used in mine subsidence areas. • Applicable as trenchless technology of pipe. • Longer pipe length is not recommended because the pipe is likely to suffer

beam failure due to the loss of flexibility since less flexible joints will be required for longer pipe.

RC • Where VC pipes is not available. Under local context, only RC pipes with DN375 mm and above is allowed.

• Applicable as trenchless technology of pipe. • As an alternative to large diameter flexible pipes where:

a. Native ground modulus inadequate to provide structural support. b. Inadequate geotechnical data available. c. Inadequate control over embedment placement and compaction. d. Likely third party interference to the pipe surrounding.

GRP • Only for nominated projects or as permitted by the relevant authority. • Under local context, only size DN 600mm or above are allowed. • Allowed for above ground use where pipeline is protected from vandalism. • Applicable as trenchless technology of pipe. • Use under railways only with encasing pipe. • Ends of cut pipe shall be sealed with resin. • Pipes and couplings used above ground to have power and water approved

UV protection. • Only on sewers that would not require provision of junction for future

pipeline extension. DI • Suitable for above ground use, i.e where bridging support is provided such

as water course, culvert, drain and exposed bridge crossings. • Only for area where superimposed loading are excessive for other types of

pipe.



Table 3.2: Application of Various Types of Pipes in Sewerage Systems (continued)

Type of Pipe Application

DI (continued)

• Pipe lining of high alumina cement or sulphate resisting cement or PPFA cement such as Mascrete is required to minimise corrosion possibility by septic sewage. All linings shall be hydraulically proven of conveying the sewage inside the pipe.

• Where there is potential for excessive differential settlement such as in fill ground (specify DI pipes with locking flexible joints to prevent joint pull out).

• Where minimum pipe covers are not possible. • Where superimposed loadings are excessive for other pipe types. • Only use in corrosive soil conditions, tidal zones, anaerobic ground

conditions and aggressive groundwater when it has an external polyethylene sleeving.

• When used in unstable ground, locking gasket must be provided. • Use restraining elastomeric seals where buried service congestion prevents

the use of thrust blocks or is subject to extreme ground movement. • Fittings for the pipe shall be made of mild steel. • Only use under or near DC traction systems with appropriate stray current

insulation. • Suitable for use as conduit pipe for high loading applications.

Steel • Only allow for pressure sewer larger than DN 600mm and with relevant authority approval.

• Not to be used near electricity transmission lines. • Suitable for above-ground use and inverted siphon application. • Welding of joints to be performed by qualified welders • Welded joints to have reinstatement of protection systems on site • Polyethylene coating should not be used where there is extended exposure

to direct sunlight. ABS • Only for specified depths of cover

• Applicable for above ground use (within conduits) where DI or steel are not suitable.

• Applicable in aggressive groundwater and tidal zone. • Applicable as inverted siphon under watercourse crossings.

Profile Wall PE

• Where VC or RC are not suitable • Only on sewers that would not require provision of junction for future

pipeline extension.

Solid Wall PE

• Applicable in aggressive groundwater and tidal zone. • Suitable in soils with differential movement. • Applicable as trenchless technology of pipe. • Applicable as syphon under watercourse crossings. • Not suitable for crossing under railways or major roadways unless within

an encasing pipe.


Sect

A 13

ion 3 Sewer Pipeline - Selection Guide

Guide to Sewer Selection and Installation 10 th November 2006

Table 3.3: Limit on Use for Various Types of Pipes for Sewerage Systems

Type of Pipe Limit on Use

VC • Not in unstable ground, i.e refilled ground, tidal zone. • Not suitable for above ground installation. • Not in the vicinity of trees with aggressive root systems. • Not use for crossing under water courses.

RC • Not suitable for high H2S levels unless good lining such as HDPE lining is provided.

• Not in aggressive soils/groundwater or tidal zone unless sulphate resistant cement is used.

GRP • Not in area where future works may affect the pipe side support. • Not in ground contaminated or possibly contaminated by certain chemicals

in concentrations deleterious to GRP resin. • Do not use pipes/couplings with chips, cracks, crazing, layer delamination or

exposed fibres. • Ends of cut pipe shall be sealed with resin. • Do not use pipe and couplings, stored unprotected from sunlight for more

than 9 months. • Do not use in ground conditions having low stiffness, e.g. tidal zone. • Not in location subjected to vehicular load and has insufficient cover. • Not in areas subjected to third party interference, e.g. excavations within

2m of pipeline by other parties. • Not in ground subject to differential settlement or extreme movement • Not in ground offering low side support strength to the pipe. • Do not use when control of construction practices is not adequate to ensure

quality of embedment for flexible pipes. • Not suitable for uncertainties in geotechnical analysis to determine if

flexible pipe structurally suitable. DI • Not to be used near electricity transmission lines.

• Corrosion may occur when installed above ground because of the tendency of temperature rise at the pipe and sewage, which thus promotes septicity and corrosive conditions.

• Externally coated bitumen pipes not suitable for use in extreme marine environment

Profile Wall PE and Solid Wall PE

• Not in location subjected to vehicular load and has insufficient cover. • Not in areas subjected to third party interference, e.g. excavations within

2m of pipeline by other parties. • Not in ground offering low side support strength to the pipe • Not in ground which allows migration of pipe embedment material into it • Not in ground contaminated with chemicals deleterious to HDPE • Not suitable for above ground installation • Not suitable as reticulations systems except for special applications.

ABS • Not suitable for crossing under railways or major roadways unless within an encasing pipe.

• Not in areas subjected to third party interference, e.g. excavations within 2m of pipeline by other parties.

• Not in ground offering a low side support strength to the pipe • Not in ground which allows migration of pipe embedment material into it.

Steel • Not to be used near electricity transmission lines.

3 Sewer Pipeline - Selection Guide

Guide to Sewer Selection and Installation 11 th November 2006

Section

A13

Table 3.4: Exclusion of Use

Exclusion of Use Condition

Pipeline System Reason • VC Subject to low impact damage. • GRP Subject to impact damage.

Above ground installation

• HDPE Excessive change in length with change in temperature. Conditions conducive to septic sewage (e.g. low flows, shallow grades, sewers receiving old sewage or turbulence is expected etc.)

• RC • DI • Steel

Potential for cement mortar corrosion subsequent metallic corrosion.

Environment corrosive to metals • DI • Steel Potential for metallic corrosion.

• VC • GRP Subject to low impact damage Minimum coverage not provided.

• HDPE Side support might be interfered with due to the impact.

• VC (unencased) • GRP (unencased) Subject to low impact damage (shallow cover).

Crossing under railway

• HDPE (unencased) Difficult to guarantee that side support will not be interfered with. • VC • GRP

Vulnerable to beam and shear failure due to low beam and shear strength.

Extreme Ground Movement

• RC, Steel, DI with elastomeric joint Susceptible to elastomeric joints pullout.

Very low pipe gradient • RC Vulnerable to have septic sewage which generate high hydrogen sulphide and cause corrosion at the cement mortar.

Ground contaminated with chemicals deleterious to plastic

• HDPE • ABS

The plastic will degrade if the chemical present is deleterious to the plastic.

Crossing under water courses • Any pipes with elastomeric joint

The ground is susceptible to settlement, which may lead to potential pullout of the joint and caused infiltration.


3.3.1 Exclusions of Use Explanations 1. Above ground installation

Pipelines above ground are in many instances exposed to vandalism, so the pipeline material and any corrosion protection coatings must have high resistance to impact and abrasion damage. Direct exposure to sunlight is another concern as this may cause degradation to some plastic materials. 2. Conditions conducive to septic sewage

Under these conditions, the sewage may become septic and produce hydrogen sulphide which may convert to sulphuric acid when released to the atmosphere. Sulphuric acid will corrode concrete pipes and cement mortar used to line ductile iron and steel pipelines and cause subsequent corrosion at the reinforcement bars or other metal parts. 3. Environment corrosive to metals

Environments corrosive to metals include marine environments and may also include some types of atmospheric industrial discharges. A marine environment is an environment in proximity to sea spray or wash. 4. Cover less than minimum

Installation with less than minimum cover may be considered where a downstream sewer level needs to be tied into, where it is not possible to go under existing pipelines, where crossing a watercourse or where installing with minimum cover will result in considerable increase in construction depth elsewhere. Prior approval must be obtained from the relevant authority. 5. Crossing under railway

The following factors limit the suitable pipeline systems and method of support of the pipeline under railways in general: • Catastrophic consequence from train derailment - pipelines and support conditions having a

low risk of deformation or collapse are required • Railways are generally active - pipelines suitable for installation by boring or

tunnelling/jacking are required • Trains generally pass frequently - cased boring or pipe jacked in closely behind the bore or

tunnel excavation is required to prevent ground collapse (not required for excavations 100 mm diameter or less where the size of any collapse generally would not be expected to cause significant overburden subsidence)

The following factors limit the pipeline systems and method of support in special circumstances: • Trains apply high impact loading - pipelines with good impact resistance is required • Disturbance during maintenance of rails and ballast - for shallow cover, pipelines that require

negligible side support required. • Catastrophic consequence from train derailment - blow out of a sewage rising main from joint,

corrosion or material fatigue failure leading to erosion of rail support For pressure pipelines, such as sewerage rising mains, it is required to encase the carrier pipeline with either another pipeline or reinforced concrete. For non-pressure pipelines, such as gravity sewers, encasement will lower the risk of failure and is thus recommended. High stiffness pipelines with high corrosion resistance (using appropriate coatings and linings and other means as required) offer the most foolproof solution.



Plastic pipelines should be encased either with concrete or cementitious grout (whilst ensuring the pipeline does not substantially deform during the grouting process) or with a very stiff pipeline of reinforced concrete, ductile iron or steel. Low ductility pipelines, such as GRP and VC at shallow cover should be similarly encased. 6. Extreme ground movement

All pipelines will be subject to some downward (and unusually upward) movement due to underlying material movement. The degree of movement will vary with the magnitude of loading and the movement modulus of the underlying material. Along a pipeline the degree of movement will be different due to variations in dead loads (depth of covered soil density) and live loads and variation in the movement modulus due to variations in bedding thickness/compaction and foundation composition. Upward movement may occur due to swelling clay types (depending on the season) or by tree root growth. The ability of a pipeline to accommodate differential movement of the support depends on the maximum angular deflection at the joints, pipe length bendability and pipe length beam strength and shear strength. All pipeline systems have either joint angular deflection capability and for pipe length bendability and/or sufficient beam strength/shear strength to accommodate some degree of differential movement. Each pipeline system will have different limits and this needs to be determined for the particular loading and underlying modulus movement conditions on the pipeline. Where there is large differential movement over short distances, the beam strength and shear strength of individual pipe lengths and the ability to resist joint failure will determine the pipeline system to use. VC and GRP pipes are the most vulnerable to beam and shear failure within a length. RC, steel and DI pipes will withstand greater beam and shear load but will be susceptible to elastomeric joint pullout (ductile iron pipelines are available with a lock-in elastomeric joint to counter pull out). uPVC will flex to a degree but its low beam strength will eventually cause failure. Solid wall polyethylene pipe is much more flexible than the other plastic sewerage pipeline systems so will accommodate much greater differential movement over short distances. In additional solid wall PE pipeline systems having welded joints will not be subject to joint pullout like elastomeric sealing joints. It may be difficult to determine the possible level of movement of a ground. Therefore it is advisable, where ground known to have potential for large movement such as fill sites, soft sands, and silts, saturated sands and silts and clays renowned for substantial swelling; to select a welded PE pipelines if structural design is favourable. Otherwise where design shows that the soft soils do not provide sufficient side support to PE, below certain depths of cover, a steel pipeline with welded joints should be used or pipes supported on piles. 7. Pipeline grading affected critically

Loss of gradient may be so severe that it may lead to surcharge and spillage of sewage upstream. Also with the loss of gradient, sewage may stagnate and become septic. Septic sewage which can produce hydrogen sulphide and subsequently sulphuric acid is not a concern with plastic pipelines recommended in such conditions but consideration needs to be given to downstream assets such as large diameter concrete pipelines.



8. Ground contaminated with chemicals deleterious to plastics

The chemicals which can be deleterious to plastics in general are principally organic solvents and for some plastics, strong acids and alkalis. The likelihood of damage depends on the contact time, chemical concentration, and temperature and for some plastics the strain in the plastics. However it is difficult to analyse the ground conditions to determine the degree of hazard at sites that may be a concern. Plastics like HDPE and ABS are therefore excluded outright from use near petrol stations, oil storage sites, land fill sites with known or suspected chemical dumping and chemical manufacturing sites. For other sites suspected of being contaminated or may be contaminated in the future with specific chemicals deleterious to plastics, the designer must obtain further advise and chemical resistance charts from pipe suppliers and undertake some site sampling to roughly gauge the likely hazard. 9. Crossing under water courses

Infiltration into a sewer under a watercourse is a major concern. Rehabilitation of such sewer is also relatively difficult and costly. Therefore pipeline system which offers the least chance of infiltration and failure needs to be selected. Welded joints pipeline system is also preferred because as the elastomeric joints are likely to fail of under such condition the ground conditions are generally more prone to differential settlement (permitting joint pullout), and greater external water pressure (particularly in extreme wet weather conditions). Pipeline systems with welded joints therefore offer the safest solution. (Note: Where pipeline are installed under watercourses using directional drilling techniques, a welded pipeline must be used anyway).


Section 4 Sewer Pipeline - Material Selection

4.0 SEWER PIPELINE – MATERIAL SELECTION

4.1 GRAVITY SEWERAGE SYSTEM

4.1.1 General This section provides the product data and information on manufacturers of the approved products for gravity pipeline system. The data is a summary of the information provided by the manufacturers during submission for approval and may not represent the latest products available. Minimum design requirements of gravity sewerage system in Malaysia as stated in MSIG Volume 3 are summarised as follows: • Domestic connection sewer - DN 150 minimum • Public sewer - DN 200 and above Table 4.1 showed the pipe materials and application conditions as approved by DGSS:

Table 4.1: Gravity Sewer Pipeline Materials and Application

Pipe Material Application VC DN100 and above RC DN375 and above GRP DN600 and above with prior approval from DGSS DI High load application Profile Wall PE For special circumstances with prior approval from DGSS

4.1.2 Definition A pipeline system is considered as gravity system when: a. It can operate at atmospheric pressure; b. There is no differential pressure; or c. There is no any additional internal pressure inside the system; and d. There is no additional force inside the system to assist the flow of the sewage. The gravity pipelines shall be able to withstand a buoyancy effect.

4.1.3 Precautions and Principal Applications of Sewerage Gravity Pipeline System

The precautions and basic principal applications of the pipe for sewerage gravity systems are shown in Table 4.2 below:

Table 4.2: Precautions and Principal Applications of Gravity Sewer Pipeline System GENERAL PRECAUTION

• All pipelines may be damaged, rendered structurally unsound or have inadequate joint performance due to incorrect installation practices.

• All pipes and fittings may be damaged prior to installation by inappropriate transportation, storage and handling practices.

• All pipelines shall be constructed by trained and certified pipelayers with a system of documentation for quality control of installation in place.


15

Section 4 Sewer Pipeline - Material Selection

Table 4.2: Principal Application of Gravity Sewer Pipeline System (continued) GENERAL PRECAUTION

•

•

•

•

All pipelines can be adversely affected in both the short and long term by third party damage to the pipe or corrosion protection system. All pipelines shall be installed with proper methods of pipeline embedment and haunches. All pipes require verification of the internal diameter for hydraulic design – the nominal size does not necessarily represent accurately the internal diameter. Larger diameter flexible pipelines require knowledge of the soil properties along the route of the pipeline and at the intended depth of the pipeline for accurate structural design.

GENERAL LIMITATIONS

•

•

•

All pipelines require detailed site investigation and special designs for installations in contaminated land and sites where the ground is subject to significant movement or subsidence. All pipes and fittings may be damaged by inappropriate cleaning practices and maintenance equipment. All pipeline systems have components that can be damaged by illegal discharges of trade waste.

GENERAL ADVANTAGES

•

•

•

•

•

•

•

Plastic pipes are resistant to H2S gas attack, impervious to groundwater and resistant to corrosion by almost all chemicals found in sewage except some specific organic compounds. Thermoplastic pipes allow handling of much longer lengths and larger sizes than VC and GRP pipes, and are easier to cut. Rubber ring jointed pipes are easily jointed and tolerate some joint deflection. All pipes can be used as slip liners inside microtunnelled/jacked encasing pipe. GRP, RC, VC and DI pipes can be supplied in designs for pipe jacking in microtunnelling installations. Rigid pipes have one or more pipe classes that have sufficient ring strength to not rely on side support for achieving structural adequacy. Metallic pipe are easy to trace and, when fully welded, are impermeable to organic contaminants and gases.

GENERAL DISADVANTAGES

•

•

•

• •

•

•

Flexible pipes may be susceptible to deflection after placement and compaction of embedment and fill. Plastic pipes may be susceptible to permeation and degradation by certain organic contaminants in soils. Plastic pipes and plastic coating or sleeving on metal pipes may be susceptible to degradation by certain organic contaminants in soils. Plastic pipelines are sensitive to point loading. Rubber rings may be susceptible to degradation by certain organic contaminants in soils and exposure to the sunlight and UV. Flexible pipes rely on support for embedment and adjacent native soil to achieve structural adequacy in buried installations (except for some shallow installations without live loadings) Non-black plastic pipes and fittings and plastic pipe coatings suffer UV degradation on prolonged exposure to direct sunlight (generally 12 to 24 months depending on the local condition)


16

Section 4 Sewer Pipeline – Material Selection (Gravity Sewerage System)

4.2 Vitrified Clay (VC) Pipe The design data and specifications of VC pipes for gravity sewerage system are summarised in Table 4.3 below:

Table 4.3: Summary of VC Pipes Design and Specifications for Gravity Sewerage System

Summary Material Vitrified clay Nominal Size (DN), mm DN100 to DN1200 mm Nominal Length, m 1.5, 1.75, 2.0, 2.5, 3.0 m Classes • Crushing Strength (FN)

• •

Conform to MS 1061:1999 and BS EN 295: 1991 Refer to Table 4.5

Jointing Methods • •

Spigot and socket with rubber ‘O’ ring Spigot and socket with skid type (prefabricated) seals

Protective Coating • •

External Internal

With or without glazing (depends on the product) With or without glazing (depends on the product)

Standards Manufacture Design Installation

MS 1061:1999 BS EN 295-1:1991 BS EN 295-2:1996 BS 65:1991 BS EN 752:1997 BS EN 752:1997 ASTM C12-91

Malaysian Sewerage Industry Guidelines (MSIG) • •

• •

Intercepting sewer Public gravity sewer

150 mm minimum diameter 200 mm minimum diameter

Approved Manufacturers/Suppliers Refer to Table D1 and DGSS latest approval list


17


4.2.1 Manufacture

Material compositions of VC pipes as in accordance with MS 1061:1999 comprise blends of suitable clays source from different locations and/or strata in a form of grog and fired to vitrification. The clays may contain shale, sand, prefired material of such a quality and homogeneity. Calcine clays shall be included to minimize pipe wall permeability. Recycle materials are not allowed in producing the VC pipes. The VC pipes can be manufactured into two different types of pipe as shown in Figure 4.1 below:

Figure 4.1: Types of VC Pipes

Spigot-socket pipe

Double spigot pipe


18


Typical manufacturing process of VC pipes is shown in Figure 4.2 below:

Figure 4.2: Typical Manufacturing Process for VC Pipes

1

G

Cut and joints

Extrusion

Mixing /Blend

Selection of raw material

Pipes, bends and fittings are trimmed and dried with hot air

Pipes are cut and jointed to form junctions and fittings

Blend clay is extruded to form the pipes or bends

The selected fine particles of dry clay is blended with water

Dry clay is crushed, grounded and screened to achieve desired fine particles

C

A Guide to Sewe13th November 20

Trim and dry

e

Final Inspection

Cooling 650ºC to 450ºC

Firing 050ºC to 1250ºC

lazing (optional) Pipes, bends and fittings are coated with a solution of salts to form ceramic glaze to reduce permeability

heck on soundness, straightness and sizes

r Selection and Installation 06

Stor

19


4.2.2 Protective Coatings/Linings

External and internal glazing is a mean of improving impermeability of VC pipes. The process involves coating the dried pipes prior to firing stage with a solution of salts to form ceramic glaze on pipe wall. Glazing is not compulsory so long the products perform to requirements. When glazed they need not be glazed on the jointing surfaces of the spigot and socket.

4.2.3 Sizes/Classes Nominal size (DN) is a numerical designation of the minimum internal diameter of VC pipes. It is a convenient round number approximately equal or equal to a manufacturing dimension and the bore of the pipe shall not deviate from the nominal size beyond the set limits in MS 1061: 1999. Nominal length of VC pipes for DN 200 and greater either shall be as in Table 4.4 or they shall be whole multiples of 250mm. There are no preferred nominal lengths for DN 100 and DN 150 pipes. The pipes length other than the offered standard length can be obtained by cutting the pipes with pipe cutting chain.

Table 4.4: Preferred Nominal Lengths of VC Pipes

Nominal Size (DN), mm Length, m 200 1.5, 2.0 225 1.5, 1.75, 2.0 250 1.5, 2.0 300 1.5, 2.0, 2.5 ≥ 350 1.5, 2.0, 2.5, 3.0

(Ref: MS 1061: Part 1: 1999, page 4) Classes of VC pipes is defined by the ring crushing strength (FN), which can be directly used in structural design calculations. The crushing strengths (kN/m) for various sizes of VC pipes as recommended in MS 1061: 1999 are shown in Table 4.5 below:

Table 4.5: Crushing Strength (FN) in kN/m for Various Sizes of VC Pipes

Class Number Nominal Sizes (DN) L# 95 120 160 200

≤ 150* N.A N.A 22 28 34 200 N.A N.A 24 32 40 225 N.A N.A 28 36 45 250 N.A N.A 30 40 50 300 N.A N.A 36 48 60 350 N.A N.A 42 56 70 400 N.A 38 48 64 N.A 450 N.A 43 54 72 N.A 500 N.A 48 60 80 N.A 600 48 57 72 N.A N.A 700 60 67 84 N.A N.A 800 60 76 N.A N.A N.A

1000 60 95 N.A N.A N.A 1200 60 N.A N.A N.A N.A

# Lower strength pipe * Class numbers do not apply for DN ≤ 150 pipe. Higher crushing strengths may be declared,

provided that the increase is in steps of 6 kN/m. (Ref: MS 1061: Part 1: 1999, page 5)


20


Crushing strength (FN) of the VC pipes shall be batch tested using either three-edge bearing test or segmented bearer test as described in MS 1061: 1999. Rigid bearer test may only be used for pipes of nominal length lower than 1.10m. The crushing strength of VC pipes may vary slightly but not significantly between batches. Only pipes of the same class and jointing system are compatible.

4.2.4 Joints Joints method of VC pipes is basically of the type of flexible joints. The types of jointing available from the approved manufacturers are generally of the following types: 1. Rubber ‘O’ ring joint - Spigot-socket with rubber ‘O’ ring type is available from all

approved manufacturers and is the recommended type to be used in most applications. Figure 4.3 shows an example of spigot socket with rubber ‘O’ ring joint.

Figure 4.3: Spigot Socket with Rubber ‘O’ Ring Joint for VC Pipes

2. Skid type sealing joint - This is another type of push-in flexible mechanical joint which is

already prefabricated into the spigot/socket. There are two main types of skid type sealing joint: a. L-Joint by Sunway Keramo Sdn. Bhd. and GBH Clay Pipes Sdn. Bhd. and b. K-Joint by Sunway Keramo Sdn. Bhd. and JPC-Intan Sdn. Bhd. The samples of skid type sealing joint are shown in Figure 4.4 below:

Figure 4.4: Skid Type Sealing Joints for VC Pipes

L-Joint K-joint Sealing material used for the joints is varies depending on the type of joints used and shall be in accordance with BS EN 681-1: 1996. It shall be made of elastomeric compounds comprising suitable polymers that need to ensure long term sealing of the joint.


21


There are two common types and materials used as a joint seals for VC pipes that are approved by DGSS in Malaysia, which are:

1. Rubber ring seals – The rubber ring seals shall be made of EPDM or styrene butadiene rubber (SBR). When placed at the correct position over the end of the spigot, it will roll 360° (one full turn) into place when the joint is pushed in. It is critical that the ring is not twisted and the joint shall be cleaned before jointing to avoid loose joint.

The limitation of the rubber ‘O’ ring is that it cannot fill the gap between the spigot and socket completely because of its circular profile. It allows higher point compression and deteriorates with time. Therefore proper control of the spigot-socket diameters is crucial to prevent very high rubber compression (cause difficulty in jointing or additional cracking force on the socket) and very low compression (not effective jointing).

2. Rubber or polyurethane seals - These sealing elements is used in skid type sealing. The prefabricated lip ring (L-Joint) has a rubber lip ring fixed in the pipe socket with an epoxy sealant bonded to the pipe socket. No joint in the spigot is required. Light lubrication of the seal is needed before the spigot skids in. The conical joint (K-Joint) consists of a hard polyurethane compound cast inside the socket and a soft polyurethane element on the spigot end, providing a tight and flexible connection. Lubrication on the seals is required before jointing. Control of spigot and socket diameters during manufacture is less critical as the polyurethane seal can be cast to tighter tolerances.

Angular deflections of the joints in the field achieving two thirds of that specified in MS 1061: 1999 are acceptable. Table 4.6 lists the acceptable angular deflections for various sizes of VC pipes.

Table 4.6: Allowable Angular Deflection of VC Pipes

Nominal Size (DN) Angular Deflection DN 100 to DN 200 4.6° or 80mm per metre length DN 225 to DN 500 1.7° or 30mm per metre length DN 600 to DN 800 1.1° or 20mm per metre length

> DN 800 0.6° or 10mm per metre length (Ref: MS 1061: Part 1: 1999, page 10)

4.2.5 Fittings Fittings for VC pipes to BS EN 295-1: 1991 has a minimum internal diameter closely approximating the nominal size. The deviation of the minimum internal diameter from the nominal size increases as pipe diameter increases. Fittings are prone to unusual loading, which can cause differential loads and settlement. Therefore it is necessary to encase the fittings in concrete to prevent bending and shear failures which VC fittings are vulnerable to. Figure 4.5 shows the typical range of fittings available for VC pipes.

Figure 4.5: Typical Range of Fittings for VC Pipes

Socket-spigot reducer taper Socket-spigot increaser taper


22


Figure 4.5: Typical Range of Fittings for VC Pipes (continued)

Spigot-spigot taper Stopper

Spigot-socket bend Spigot-spigot bend

Single T joint Single Y joint

Double T joint Double Y joint

Backdrop Tumbling bay

Riley slope junction Slope junction

Spigot oblique saddle* Spigot square saddle*

*Note: Saddles are only used for tapping into the waterline.


23


Figure 4.5: Typical Range of Fittings for VC Pipes (continued)

Coupling with elastomeric seal 4.2.6 Pipeline Hydraulic Design Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 4.7 shall be referred to when determining discharge capacity of the VC pipes for gravity sewer application.

Table 4.7: Colebrook-White Roughness Coefficient, ks for VC Pipes

Pipe Condition Roughness, ks (mm) New Old

0.06 1.5

Whilst, the selection of the VC pipes diameter and gradient for gravity sewer application to cope with the peak flow, can be also based on the one of the following equations as shown in Table 4.8 below.

Table 4.8: Various Pipeline Hydraulic Design Equations of VC Pipes for Gravity Sewerage System

Design Equations Name of Coefficient Pipeline Condition Typical Value of Coefficient

Good 0.010 Manning Equation Manning Coefficient, n Bad 0.017 Hazen-Williams Equation

Hazen-Williams Coefficient, C N/A* 110

*N/A – not applicable Frictional head losses at the joints between VC pipes could be higher than other types of pipe due to its relatively short length but it could be minimised by proper jointing. Head losses due to pounding along the barrel should be minima provided that the VC pipes barrel is manufactured within straightness tolerances given in the manufacturing specification.


24


4.2.7 Application of Pipes The application of VC pipes for the gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. The advantages and disadvantages of the VC pipes for this application are listed in Table 4.9 below.

Table 4.9: Advantages and Disadvantages of VC Pipes

Advantages Disadvantages

• Installation requirements are less stringent than flexible pipes. Less imported granular material needed.

• Resistant to H2S attack, unlike RC. • More resistant to abrasion than RC. • Most resistant material to chemical

corrosion found in sewage. • Not degraded by UV radiation, unlike

plastics without carbon black. • No significant variation in dimensions or

shape with temperature variation, unlike plastics.

• Proven long term performance, unlike plastics.

• Jointing procedure relatively simple. A rolling rubber ring requires no lubricant, unlike skid joints.

• Some rotational movement of the joint is possible, unlike the uPVC solvent cement joint.

• Disturbance of pipe side support does not substantially impair structural performance unlike flexible pipe.

• VC pipe is not buoyant like plastic pipe, therefore is not likely to move off line and grade due to water in the trench.

• VC pipe will not bend along its length, unlike plastic pipe, which can bend along its length from loading or from temperature variations during storage. Such bending lends to pounding of flows.

• VC pipes do not need special procedures to retain a round profile unlike low stiffness large diameter plastic pipe.

• High ring strength.

• Heavier than plastic pipes. Mechanical lifting equipment is required in sizes DN 225 and above.

• Shorter pipe lengths than plastic pipes, thus more joints.

• Rougher bore than plastics, requiring steeper grades or larger diameter pipes. Slime adheres to VC more readily than plastics and is less easily washed off.

• Care is required in handling as pipes are susceptible to lower the impact damage.

• Pipes may fracture under differential settlement within a pipe length.

• Where poor bedding results in support only at the socket, pipes may fracture, depending on the load magnitude.

• Low shear strength. • Beam strength may be insufficient if pipe

barrel is not offered continuous support (load dependent).

• High protrusion of socket requires more careful preparation of bedding to prevent a pipe length just being supported at the socket.

• No longitudinal pipe barrel flexibility to accommodate any loss of pipe bedding continuity.

• Even minor cracks can lead to penetration and chokes by aggressive root systems.

• Fittings in riser structures more prone to failure than thermoplastic fittings.


25


4.3 Reinforced Concrete (RC) Pipe The design data and specifications of RC pipes for gravity sewerage system are summarised in Table 4.10 below:

Table 4.10: Summary of RC Pipes Design and Specifications for Gravity Sewerage System

Summary

Material • • • •

Cement Aggregates Water Reinforced steel with hard drawn wire

Nominal Size (DN), mm DN 150 to DN 3000 Effective Length, m •

• ≤ DN 600 : 3.0m maximum > DN 600 : 0.45m to 5.0m

Classes •

• • •

Crushing Strength (FN) Conform to MS 881:1991 Class L, M, H, 1.5H, 2H and 2.5H Higher strengths available upon request

Jointing Methods • • • • •

Spigot and socket joint with rubber ‘O’ ring Spigot and socket joint with cement mortar filling Rebated/ogee joint with rubber ‘O’ ring Rebated/ogee joint with cement mortar filling Double spigot joint with collar/ butt joint with collar


• • • •

External Internal

Bare DN < 1000 : High alumina cement mortar lining DN ≥ 1000 : HDPE/PVC lining is preferred Sacrificial concrete lining is an alternatives


MS 881:1991 BS 5911-1:2002 BS 5911: Part 100: 1998 BS 5911: Part 120: 1998 AS 3725-1989 AS 3725-1989

Malaysian Water Sewerage Industry Guidelines (MSIG) • •

• •

Other gravity sewer Pipe strength

DN375 mm and above Class L as a minimum strength class

Approved Manufacturers/Suppliers Refer to Table D1 and DGSS latest approval list.


26


4.3.1 Manufacture Material compositions for RC pipes comprise blends of cement, aggregates and water and reinforced with hard drawn wire. Ordinary Portland cement compliance to MS 522 shall be used, unless other types of cement are specified by the suppliers/manufacturers. The fully compacted concrete shall contain not less than 360kg cement/m3 and shall have a maximum water/cement ratio of 0.45. The coarse aggregates shall have the flakiness index of not more than 35 and 10% fines value of not less than 100kN. The maximum nominal size of aggregate shall not exceed 20mm. The RC pipes can be manufactured into two different types of pipe as shown in Figure 4.6 below:

Figure 4.6: Types of RC Pipes

Spigot socket pipe Rebated pipe The manufacturing processes that have been adopted by local manufacturers to produce RC pipes are as follows: 1. Centrifugal spinning process

In this process, the concrete and steel reinforcement is placed inside a mandrel, which is then spun. The compaction of concrete is achieved by combining centrifugal force and vibration to spin pipe horizontally.

2. Vertical cast process

The basic principle of this process is to feed the dry concrete into a vertically placed mould, which is vibrated at high frequency to compact the concrete. This process can be classified broadly into two sub-categories, which are:

a. Dry vertical cast process

The process uses the principle of core vibration to vibrate concrete and hydraulic compaction to form close tolerance joint profiles. The pipes are produced vertically at various machine stations using low slump concrete.

b. Wet vertical cast process

This process is mainly to produce large diameter of pipes. The process is using the principle of outer form vibration to compact the concrete. The pipes are being produced vertically with individual mould sets using high slump concrete.

3. Roller suspension process

This is an alternative process, which is currently on used in Malaysia. In this process, a horizontal roller is placed inside the pipe steel-reinforcing cage. While rolling the cage, concrete is added to form the pipe.

For the RC pipes that are manufactured with elliptically reinforcement, the load line shall be clearly marked to identify the laying orientation of the pipes.


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4.3.2 Protective Coatings/Linings External coating is not required for RC pipe. However, where corrosion is likely to occur from external aggressive soil, the pipes shall be manufactured using sulphate-resisting Portland cement complying with MS 1037. The other types of cements that can be used with the approval from the DGSS are: a. Portland pulverised fuel ash cement complying with MS 1227; or b. Portland blast furnace cement complying with MS 1389; or c. Supersulphated cement complying with BS 4248. The types of internal protective linings that shall be applied to RC pipes for sewerage application are as following: 1. High alumina cement mortar lining (HAL)

This type of lining is recommended in the MSIG 3 to be used with the RC pipes with nominal size less than DN 1000 mm. The layer of HAL with minimum thickness of 12 mm (to comply with MS 881: Part 1) shall comprise one part of high alumina cement and 3 parts of fine sand as a secondary process.

High alumina cement is coated on the pipe while the concrete is still wet to ensure firm adhesion of the lining to the pipe. However, deterioration of high alumina cement concrete is directly influenced by increased in heat and humidity, which accelerates conversion of the unstable calcium aluminate decahydrate. For this reason, pipe lined with high alumina cement concrete should not be steam cured.

2. PVC/HDPE lining This type of lining is preferred to be used with the RC pipes with the nominal size more than or equal to DN 1000 mm. The layer of the lining shall have a minimum thickness of 5 mm. It is suitable for sewers experiencing serious corrosion problem. The lining is projected by keying a PVC/HDPE sheet from one face around the inner of pipe before the concrete is cured. Continuity of the lining is provided by heat welding or fusing each individual sheet to the next.

Continuous longitudinal stud of lining is not allowed. The stud shall be of spirally arrangement to prevent water sipping into the area between the pipes and the lining. The lapping of PVC/HDPE at jointing shall be provided with stainless steel or other non-coated corrosion resistant metal ring.

PVC/HDPE lining may only be required on the wall above the lowest sewage level where sulphuric acid will react with the wall.

3. Sacrificial concrete lining This type of lining is an alternative protection lining to the pipe offered by all the manufacturers. Pipe with this lining is designed to sacrifice part of their walls up to 38 mm without affecting their designed strengths.

If pulverised fuel ash cement is used to produce the RC pipes, no protective lining is required.

4.3.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the size of RC pipes. It is a convenient round number approximately equal to a manufacturing dimension and the bore of the pipe shall not deviate from the nominal size beyond the set limits in MS 881: 1991. The use of RC


28


pipe for 300mm and less is handicapped by the lack of fittings for junction requirements, further the use of RC pipe smaller than DN 375mm is not recommended by DGSS. Effective length of pipes shall be between 0.45m and 5m inclusive with a maximum of 3m for pipes DN 600 or less. Pipe cannot be cut on site. Classes of RC pipe are defined in terms of the crushing strength in kN/m of the pipe cross section as tested according to MS 881: 1991. RC pipes are categorised into three main crushing strength classes, which are Low (L), Medium (M) and High (H). The crushing strength of RC pipe is varied by the strength of the concrete, the thickness of the wall and the amount and placing of reinforcement. The crushing test load of RC pipes for gravity sewerage system in kN/m is shown in Table 4.11 below.

Table 4.11: Crushing Test Loads of RC Pipes for Gravity Sewerage System

Nominal Size of Pipe, mm Class L Class M Class H

DN Works proof load

Maximum load

Works proof load

Maximum load

Works proof load

Maximum load

300 20 25 23 29 NA NA 375 20 25 31 39 36 45 450 20 25 35 44 41 52 525 20 25 38 48 46 58 600 20 25 46 58 54 68 675 20 25 50 63 60 75 750 38 48 53 67 65 81 825 41 52 58 72 69 86 900 46 58 67 84 85 106 975 48 60 72 90 91 114 1050 51 64 76 95 96 120 1125 53 67 82 103 106 133 1200 58 72 87 109 110 138 1350 63 79 96 120 122 153 1500 69 87 104 130 132 165 1650 75 94 116 145 146 183 1800 82 103 124 155 158 198

(Ref: MS 881: Part 3: 1991, page 15) Pipes with crushing strength higher than Class H is also available and defined by the figure in front of the alphabet. As an example Class 2.5H, indicates that the pipe crushing strength is 2.5 times stronger than Class H pipe.

4.3.4 Joints The joint methods for RC pipes in accordance with BS 5911 are generally of the following types: 1. Flexible joint of spigot-socket with rubber ‘O’ ring type is the recommended type to be

used in most applications. Manufacturing tolerances with the spigot and socket of RC pipe are not as wide as with VC pipe since RC pipe shrinkage during manufacturing is relatively smaller. Typical flexible joint of spigot-socket with rubber ‘O’ ring is shown in Figure 4.7.


29


Figure 4.7: Typical Flexible Joint of Spigot Socket RC Pipes

Spigot socket joint with rolling rubber ring Spigot socket joint with confined rubber ring (Ref: BS 5911: Part 100: 1998, page 9) 2. Rigid joint of spigot socket with cement mortar filling is commonly used where flexibility

is not an issue. It can be applied both for normal gravity and jacking pipe installation. 3. Flexible rebated/ogee joint with rubber ‘O’ ring is used to joint the rebated pipes as shown

in the following Figure 4.8.

Figure 4.8: Typical Flexible Joint of Rebated/Ogee RC Pipes

Rebated joint with rolling rubber ring Rebated joint with confined rubber ring (Ref: BS 5911: Part 120: 1988, page 8) 4. Rigid rebated/ogee joint with cement mortar filling is more commonly used for rigid

pipeline installation, like jacking pipe where flexibility is not required. 5. Double spigot joint with collar/ butt joint with collar is usually used for pipe jacking

application. Figure 4.9 shows the typical double spigot joint with collar.

Figure 4.9: Typical Double Spigot Joint with Collar of RC Pipes

Double spigot joint with collar and rolling rubber ring

Double spigot joint with collar and confined rubber ring

(Ref: BS 5911: Part 120: 1988, page 8)

The collars shall be fabricated from stainless steel 316 plate or glass reinforced plastic (GRP) or other non-coated corrosion resistant metal and shall not be attached to reinforcement.

Sealing materials used for the joints are varies depending on the type of the joints used. The descriptions and requirements of each types of sealing material that have been approved by DGSS to be used with RC pipes are as following:


30

1. Rolling rubber O ring is used in spigot-socket joint and rebated joint to allow flexibility of the pipeline. Normally it has circular cross section. When placed at the correct position over the end of the spigot, it will roll 360° (one full turn) into place when the joint is pushed in. It is critical that the ring is not twisted and the joint is cleaned before jointing to avoid loose joint.


Instead of rubber O ring with circular cross section, a triangular shaped rubber ‘O’ ring is also available. When the gasket is placed around the spigot end, it rests firmly against the spigot shoulder and is placed at the centre in the bell. The top section of the gasket will roll over and rest in the annular space after the spigot is pushed in.

The limitation of the rubber ‘O’ ring is that it cannot fill the gap between the spigot and socket

completely because of its circular profile although it allows higher point compression. Therefore proper control of the spigot-socket diameters is crucial to prevent very high rubber compression (cause difficulty in jointing or additional cracking force on the socket) and very low compression (not effective jointing).

2. Cement mortar can be used to fill the gap in a rebated joint. However, this will induced

rigidity at the joint and thus only suitable for application where flexibility is not required. Angular deflections of the joint for RC pipes shall be in accordance with BS 5911: Part 100: 1998. The allowable angular deflections of RC pipes are shown in Table 4.11 below:

Table 4.12: Allowable Angular Deflection of RC Pipes

Nominal Size (DN), mm Angular Deflection DN 150 to DN 600 2° or 35 mm per metre length

DN 675 to DN 1200 1° or 17.5 mm per metre length DN 1350 to DN 1800 0.5° or 9 mm per metre length

Above DN 1800 to be stated by the manufacturer (Ref: BS 5911: Part 100: 1988, page 15)

4.3.5 Fittings Fittings are not a stock item with RC pipes manufacturers and any junctions or bends are made up as specials. Specifications of fittings like bends and junctions are provided in MS 881: 1991. The typical ranges of fitting for RC pipes are shown in Figure 4.10.

Figure 4.10: Typical Range of Fittings for RC Pipes

Bends

Right angle socket junction Right-angle tumbling bay junction


31


Figure 4.10: Typical Range of Fittings for RC Pipes (continued)

Oblique-angled socket junction Oblique-angled tumbling bay junction

4.3.6 Pipeline Hydraulic Design Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 4.12 shall be referred to when determining discharge capacity of the RC pipes for gravity sewer application.

Table 4.13: Colebrook-White Roughness Coefficient, ks for RC Pipes

Pipe Condition Roughness, ks (mm) New Old

0.15 3.0

Whilst, the selection of the RC pipes diameter and gradient for gravity sewer application to cope with the peak flow, can be also based on the one of the following equations as shown in Table 4.13 below. Table 4.14: Various Pipeline Hydraulic Design Equations of RC Pipes for Gravity Sewerage

System

Design Equations Name of Coefficient Pipeline Condition

Typical Value of Coefficient

Colebrook-White Equation Roughness Coefficient, ks N/A* 0.3 to 3.0 Good 0.012 Manning Equation Manning Coefficient, n Bad 0.016

Hazen-Williams Equation Hazen-Williams Coefficient, C N/A* 120

*N/A – not applicable


32


4.3.7 Application of Pipes The application of RC pipes for gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. The advantages and disadvantages of the RC pipes for this application are listed in Table 4.14 below.

Table 4.15: Advantages and Disadvantages of RC Pipe

Advantages Disadvantages • For the same loading and ground

conditions, installation requirements are not as stringent as for flexible pipes like HDPE and GRP.

• High beam and ring crushing strength permits RC to bridge lengths without support and tolerate a degree of subsidence and differential settlement.

• Not degraded by UV radiation, unlike plastics without carbon black.

• No significant variation in dimensions or shape with temperature variation, unlike plastics.

• Not degraded by some chemicals, such as solvents that degrade HDPE and GRP.

• Where installed with an embedment that is not designed to give side support, there is no concern of structural failure where there may be third party interference, unlike flexible pipes.

• Rolling rubber ring requires no lubricant, unlike skid joints used with GRP and HDPE pipe.

• Available as microtunnelling and jacking pipe.

• Subject to H2S related corrosion. • Field welding of PVC/HDPE liner at pipe

joints is required to ensure integrity of liner for resistance to H2S attack.

• Heavier than HDPE and GRP. Mechanical lifting is always required.

• Pipe lengths are shorter than lengths available with HDPE and GRP thus more joints are required.

• Rougher bore than HDPE and GRP, requiring a steeper sewer grade or larger pipe diameter. Slime adheres more readily to RC than plastics and is less easily washed off.

• Less abrasion resistant than plastic pipes and VC.

• Risk of structural failure is increased where design requires side support. It is possible this side support may be disturbed from third party interference.

• When using only haunch support for RC pipe, then disturbance of the ground adjacent to the pipeline is not likely to affect the pipeline performance, unlike flexible pipe.

• Fittings are not readily available. • Retrospective installation of fittings /

repair is complicated.


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4.4 Ductile Iron (DI) Pipe The design data and specifications of DI pipes for gravity sewerage system are summarised in Table 4.15 below:

Table 4.16: Summary of Ductile Iron Pipes Design and Specifications for Gravity Sewerage

System

Summary Material Scrap ductile iron, steel, ferrosilicon, coke, limestone and

magnesium Nominal Diameter (DN), mm DN 100 to DN 2000 mm Standard Length 5.0 to 8.15 m Classes • Wall thickness • Pressure Class

• Conform to BS EN 545 • Minimum Class K9 • Conform to BS EN 598 • For pipes with operating pressure up to 6 bar (0.6 MPa)

Jointing Methods • Push-in joints with rubber ring • Self-anchoring push-in joints • Slip-on couplings • Flange end joints with rubber gasket • Self-anchoring tie-bar joints

Protective Coating •

•

External Internal

• Metallic zinc coating with bitumen finished coat. • Extra HDPE sleeving for severe ground conditions • High alumina cement mortar lining is preferred

Standards Manufacture HDPE Sleeving Design Installation

BS EN 598 BS EN 545 BS 8010 ISO 2531 AS 3680 AS/NZS 2566.1 BS EN 598 Annex C AS 2566.2 (basic) BS 8010 section 2.1 (detail)

Malaysian Sewerage Industry Guidelines (MSIG) • •

• • •

Public gravity sewer

For high load applications For above ground installation Pipe protection linings and coatings are required Polyethylene sleeving is required for all buried application.



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4.4.1 Manufacture Material used is basically ductile iron. Some may include certain percentages of recycled material produced during the casting process. Ductile iron is also known as spheroidal or nodular graphite (SG) cast iron. The casting material, i.e iron and carbon based, and the latter element is being present principally as graphite in spherical nodular form to improve the tensile, bending strength and fracture toughness of the material. It is also incorporated some of the miscellaneous components such as silicon, manganese, magnesium, phosphorus, sulphur. The raw materials are normally sourced from outside Malaysia. The DI pipes can be manufactured into two types of pipes as shown in Figure 4.11 below:

Figure 4.11: Types of DI Pipes

Spigot socket pipe

Flanged pipe Flanged pipes are used only where restrained DI joints are required and spigot-socket restrained DI joints are inappropriate. The common manufacturing process to manufacture DI pipes is centrifugal cast, while the DI fittings are cast using traditional gravity casting. The flanged DI spun pipes are manufactured by centrifugally casting the pipe barrel and then the DI flanges is welded or screwed loose on to specially prepared ends. Figure 4.12 shows the typical flow manufacturing process of centrifugal cast DI pipes.


35


Figure 4.12: Typical Manufacturing Process of Centrifugal Casting for DI Pipes

Melting

External coating

Internal lining

Finishing

Curing

Metallic zinc coating is applied on the external wall of the pipes

Raw materials are melted and chemically analysed

Centrifugally force moulding

Annealing

Chemical analysis

Nodularisation treatment


Cement mortar or bitumen is placed in slowly rotating pipes which is then spun rapidly

Bitumen paint is applied at the external wall to provide a bare protection to external corrosion

Pipes are formed by introducing the treated molten into a revolving, water cooled steel mould with centrifugal force

Inspection Storage

36


4.4.2 Protective Coatings/Linings The types of external protective coatings available for DI pipes are as follows: 1. Metallic zinc coatings and prime layer with bitumen paint as finished layer is commonly

used and recommended by DGSS. 2. Epoxy coating is to be used for all fittings and accessories as required by DGSS. 3. Bitumen paint can also be used as the protective coating for the pipes and fittings. However,

this is not commonly used and prior approval from DGSS is required. 4. Polyethylene sleeving can be used as a final layer to provide extra protection when installed

in corrosive ground. DGSS requires this sleeving to be used for all buried application. Polyethylene sleeve can be applied in the factory during pipe production or installed on site.

5. Cathodic protection is an alternative to the other protection system but is not normally preferred. Bonding across the joints is necessary to guarantee electrical continuity when this system is to be installed.

The types of internally protective lining available for DI pipes are as follows: 1. High alumina cement mortar lining is commonly used in sewage application and

recommended by DGSS. The smooth cement mortar surface protects the pipe against corrosion and allows a smoother flow pattern. Epoxy-based coating on the end surfaces is required if this lining is used. The HAC lining shall be in accordance with BS EN 598: 1994 as shown in Table 4.16 below:

Table 4.17: HAC Lining Thickness of Various Sizes of DI Pipes

Dimensions in milimetres Nominal Size, DN Nominal

Thickness Tolerance Maximum crack width and radial displacement

DN 100 to 300 3.5 -1.5 0.6 DN 350 to 600 5.0 -2.0 0.7 DN 700 to 1200 6.0 -2.5 0.8 DN 1400 to 2000 9.0 -3.0 0.8

(Ref: BS EN 598: 1994, page 10) 2. Other cement lining using Portland cement or sulphate resistant cements are also available.

However the usage of this cement lining is limited by the characteristic of the medium to be conveyed.

4.4.3 Sizes/Classes Nominal size (DN) for ductile iron pipes have dimensions based on imperial sizing. As a result, the metric nominal sizing relates only roughly to the internal diameter of the pipe after cement lining. The bore of the pipe is governed by the classes and pressure load to the pipe, which will then affect the iron wall thickness. The minimum iron wall thickness of the pipe shall not be less than the minimum values given in BS EN 598:1995.


37


Pipe Lengths are standardized according to BS EN 598:1995 and are within ±150 mm of the standard lengths as Table 4.17 below:

Table 4.18: Standard Pipe Lengths of Various Sizes of DI Pipes

Nominal Size (DN) Standard Length, m DN 100 to 600 5.0, 5.5 or 6.0 DN 700 to 800 5.5, 6.0 or 7.0

DN 900 to 1400 6.0, 7.0 or 8.15 DN 1500 to 2000 8.15

(Ref: BS EN 598: 1994, page 7) Classes of DI pipe have not been defined in the European Standard BS EN 598:1995 for sewerage applications. However, the standard has set specific requirements on pipe performance to ensure the pipes are capable to operate with pressures up to 6 bar (0.6 MPa). The approved DI pipes manufactured in Malaysia are classified according to BS EN 545:2002 – Ductile iron pipes, fittings, accessories and their joints for water pipeline. In this standard, the DI pipe is classified based on wall thickness and not pressure rating. Class K9 is the minimum class of ductile iron pipes. The wall thickness (e) of this class is determined from the formula e = K (0.5 + 0.001 DN) as given in BS EN 545:2000 for pressurized water pipelines and can withstand pressures up to 60 bar (6MPa) for DN 200 and below, decreasing to 30 bar (3MPa) for DN 600 and above for spigot-socket pipes. As a result the minimum wall thickness is almost doubled those set in BS EN 598:1995. Hence Class K9 is acceptable in sewerage application including gravity sewer system.

4.4.4 Joints The joints for DI pipe are generally of a type using elastomeric gaskets as a sealing medium. Joint methods used in DI pipe installation for gravity system are as follows: 1. Push-in joints are made on pipes having a chamfered plain spigot at one end and especially

formed socket at the other. The sockets shall be grooved to capture elastomeric seals. The seal is affected by means of a gasket placed within the socket before jointing. Figure 4.13 shows the typical push in joints for DI pipes.

Figure 4.13: Typical Push in Joints for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 18) 2. Self-anchoring push-in joints have a special gasket in respect of dimensions and shape but

stainless steel toothed inserts are moulded into the gasket. The locking mechanism is added to prevent pull out of the joint, which may result from internal pressure or movement of the pipeline due to external forces.


38


These joint types lend themselves for use in ground that may allow significant pipeline

settlement, for steep slopes, for watercourse crossings and for above ground. Tyton-Loc is an example of this type of joint. The typical self-anchoring push-in joint of DI pipes is shown in Figure 4.14 below.

Figure 4.14: Typical Self-anchoring Push-in Joint for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 18) 3. Flange joints are made on pipes by welding, screwing or integrally casting flanges onto the

end of the standard pipe with a seal of 3mm flat elastomeric full face gasket compressed between the flanges by means of bolts. Figure 4.15 shows the typical ranges of flange of DI pipes.

Figure 4.15: Typical Ranges of Flange for DI Pipes

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 22) Sealing materials are to be of elastomeric compounds comprising suitable polymers such as: 1. Ethylene propylene diene monomer (EPDM) with 40% minimum volume of compound for

IRHD of >=55<85; or 2. Styrene butadiene rubber (SBR) with 50% minimum volume of compound for IRHD of

>=55<85. The design of the seal’s profile and the compounding of the elastomer needs to ensure long term sealing of the joint. The elastomer seals shall be protected from unnecessary exposure to the effects of ultra-violet light and ozone.


39


Jointing lubricant of water based emulsion is required in the application of elastomeric seals to achieve the following:

Provide sufficient lubrication to prevent damage to joint seals or surfaces of jointing; • • •

Enable correctly configured jointing; To remain as an effective lubricant under wet conditions.

Allowable angular deflections of flexible joints for DI pipes include push-in joint and mechanical joint according to BS EN 598: 1995 is shown in Table 4.18 below:

Table 4.19: Allowable Angular Deflection of Jointing for DI Pipes

Nominal Size (DN) Deflection DN 100 to DN 300 3.5° DN 350 to DN 600 2.5°

DN 700 to DN 2000 1.5° (Ref: BS EN 598: 1998, page 12) Angular deflections of the self-anchoring push-in joints however could be slightly higher depending on manufacturing tolerance of particular manufacturers. 4.4.5 Fittings For gravity sewer applications, the exact fittings required for junctions and manhole drops are not available. The configurations of fittings also vary from those normally used in VC fittings. The fittings come with either Tyton joint, flange joint or other joints. Figure 4.16 shows the various ranges of fittings available for DI pipe.

Figure 4.16: Various Range of Fittings for DI Pipes

Flange-flange bend Spigot-spigot bend Socket-socket bend

Socket-socket-flange tee Spigot-spigot-flange tee Flange-flange-flange tee

Spigot-spigot-spigot tee Socket-socket-socket tee


40


Figure 4.16: Various Range of Fittings for DI Pipes (continued)

Flange-flange offset taper Flange-flange taper Spigot-flange taper

Spigot-spigot taper Socket-flange taper Socket-socket taper

Flange-spigot connector Flange-socket connector

Socket-socket connector

Socket-socket slip collar

Cap Plug

4.4.6 Pipeline Hydraulic Design The selection of the DI pipes diameter and gradient for gravity sewer application to cope with the peak flow, can be based on one of the following equations as shown in Table 4.19 below. Table 4.20: Various Pipeline Hydraulic Design Equations of DI Pipes for Gravity Sewerage

System

Design Equations Name of Coefficient Pipeline Condition Typical Value of Coefficient

Colebrook-White Equation

Roughness Coefficient, ks

N/A* 0.046

Good 0.012 Manning Equation Manning Coefficient, n Bad 0.015 Hazen-Williams Equation

Hazen-Williams Coefficient, C N/A* 130 to 140

*N/A – not applicable


41


4.4.7 Application of Pipes The application of DI pipes for gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. The advantages and disadvantages of the DI pipes for this application are listed in Table 4.20 below.

Table 4.21: Advantages and Disadvantages of Ductile Iron Pipes

Advantages Disadvantages • Higher beam, ring and shear strength than

VC and plastic pipes • Not affected by UV radiation. • Slight change in length with temperature

variations, unlike plastic pipes. • High ring stiffness permits use with very

shallow cover and up to unusually large superimposed loads unlike VC and plastic pipes.

• High beam and shear strength permits use in ground subject to substantial differential settlement. Also use of Tyton-Loc joint prevents joint pullout in such conditions.

• Not subject to damage from substantial impact loads making it suitable for rail, over dimensional highway and bridge crossings unlike unencased GRP and VC

• High resistance to shock or impact due to improper handling, water hammer or unstable condition.

• Able to deform when stressed beyond yield point.

• Superior tensile strength to withstand severe loads and high internal pressure.

• More expensive than plastics, RC and VC. • Heavier than plastics. Mechanical lifting

is required. • External polyethylene (PE) sleeving

required for buried application in corrosive soil conditions.

• Care is required to ensure sleeving completely wraps the pipe and is sealed. PE sleeving is easily damaged.

• Where sleeving is damaged in certain aggressive soils (pH ≤5 and ≥9), corrosion will occur.

• Internally less corrosion resistant than VC and plastics.

• Less abrasion resistant than plastic pipes and VC.

• Rougher bore than plastics thus require steeper grades or larger diameter pipes. Slime adheres more readily to DICL than plastics and is less easily washed off.

• Cement mortar lining is corroded by sulphuric acid produced from hydrogen sulphide generated in septic sewage.

• Ductile iron is corroded by hydrogen sulphide and sulphuric acid produced in septic sewage conditions.


42


4.5 Glass-fibre Reinforced Plastic (GRP) Pipe The GRP pipes are classified as a composite pipe where it is a heterogeneous combination of two or more materials (reinforce agent and matrix), differing in form or composition on a macro-scale. The design data and specifications of the GRP pipes for gravity sewerage system are summarised in Table 4.21 below:

Table 4.22: Summary of GRP Pipes Design and Specifications for Gravity Sewerage System

Summary Material •

•

• • • •

• • • • •

Filament Wound Pipe

Centrifugally Cast Pipe

Thermosetting resin or polyester resin Roving or woven fabrics of E-glass filaments Surface tissues Additional material such as additives and colourants

Thermosetting resin or polyester resin Chopped strand mat of E-glass filaments Surface tissues Aggregates and fillers Additional material such as additives and colourants

Nominal Diameter (DN), mm DN 100 to 4000 mm Effective Length, m 3.0 and 6.0 m Classes • •

• • •

Stiffness Classes (SN) Pressure Class

Conform to BS 5480: 1990 SN 1250, 2500, 5000, 10 000, 15 000, 20 000 G – can withstand internal hydrostatic pressures up to 0.5 bar

Jointing Methods • • • •

Integral socket and spigot joint with rubber ring Loose collar joint Butt joint Flange joint


• •

External Internal

Thermosetting resin Resin rich lining with superficial layers of C glass material

Standards Manufacture Structural Pipeline Design Installation

BS 5480: 1990 AS 3571: 1989 BS 8010: Section 2.5: 1989 ASTM D 3262 AS/NZS 2566.1: 1998 AS/NZS 2566.2: 2002

Malaysian Sewerage Industry Guidelines (MSIG)

•

•

Only pipe with DN600 mm and above is allowed at where VC and RC pipes are not suitable. Under special circumstances with prior approval from DGSS

Approved Suppliers/Manufacturers Refer to Table D1 and DGSS latest approval list


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4.5.1 Manufacture Material compositions of the GRP pipes consist mainly of thermosetting resin, normally isophthalic polyester, or vinyl ester resin for special chemical resistance requirements. It is incorporated with a fibrous reinforcement derived from continuously drawn filaments of E-glass and shall be used in the following forms alone or in any combination subject to compatibility with the resin used: a. Roving; b. Chopped strand mat; c. Woven fabric. A surface tissue shall be incorporated into the superficial layers of the internal surfaces of a GRP pipe or fittings to enhance chemical resistance. They shall be made of: a. Glass material of C-glass; or b. Woven textiles based on polyester or acrylic fibres; or c. Non-woven textiles based on polyester or acrylic fibres. An aggregates and fillers can also be incorporated into the GRP pipe as a part of the composite structure to enhance the stiffness of the pipe. The aggregates shall be of inert granular material with the size range between 0.05mm and 5mm and the inert fillers shall be of a fine material with a particle size below 0.05mm. The resin may incorporate the additives for modifying the properties of the resin, and pigments or dyes as a colourant. There are two types of manufacturing process for GRP pipes, which are: 1. Filament winding 2. Centrifugally casting The filament wound GRP pipe is constructed of two layers. The inner layer is the superior chemical resistance made by a resin rich hand laid liner and backed by the tremendous strength offered by a continuous filament helical wound on the outside (the outer layer). The inner liners provide very smooth surfaces. The outer layers that give the strength to the pipe are constructed by filament winding machine. The manufacturing process involves a band of continuous resin impregnated roving (fiberglass), which is wrapped around a rotating mandrel and then cured at room temperature to produce the final product. The technique offers high speed and precise method for placing the composite layers. The mechanical strength of the filament wound products/components parameters are winding angle, fiber tension, resin chemistry and curing cycle. The outer liner protects the resin rich chemical resistant liner from mechanical damage and preventing sagging between supports. The typical filament wound GRP pipe is shown in Figure 4.17 below.

Figure 4.17: Typical Filament Wound GRP Pipes


44


The centrifugally cast GRP pipe is a combination of two materials. An inner and outer liner of GRP is a combination of chopped strand of E-glass filament reinforcement and synthetic resin sandwiching a core of composite structure. Whilst the composite structure is a combination of aggregates of inert granular material such as graded silica sands and the inert fillers of a fine material as used in concrete mixed with synthetic resin. The typical form of centrifugally cast GRP pipe is shown in Figure 4.18 below:

Figure 4.18: Typical Centrifugally Cast GRP Pipes

4.5.2 Protective Coatings/Linings External protection of GRP pipe is by a layer of thermosetting resin. The layer provides scratch resistance and also acts as a barrier against ultraviolet. Internal protection of GRP pipe is by a smooth resin rich lining free of glass filament that has good corrosion resistance across a wide pH range. It also enhances a smooth flow in the pipe. The surface tissue shall be incorporated to the pipe to enhance chemical resistance.

4.5.3 Sizes/Classes Nominal size (DN) of GRP pipe is a numerical designation of size designated by outside diameters or by thread size. It is a convenient round number for reference purposes and is only loosely related to manufacturing dimensions. The GRP pipes shall be designated by a nominal size (DN) selected from the values given in Table 4.22 below:

Table 4.23: Nominal Sizes of GRP Pipes

Nominal size (DN) Increment ≥ 100mm to 500mm 50 >500mm to 2600mm 100

>2600mm to 4000mm 200 (Ref: BS 5480: 1990, page 7) Pipe Lengths should show the effective length of the pipes. The pipes shall comprise a straight length of either 3m or 6m with the permissible deviations of ± 25mm. The GRP pipes can be cut and chamfered to the desirable length by water-fed petrol driven abrasive disc cutter. Sealing of cut pipe ends is not required. Classes of GRP pipes for gravity system as in accordance with BS 5480: 1990 are defined by the pressure class and stiffness class of the pipe, as described below: 1. Pressure – GRP pipes is classified for use under gravity, indicated by G, imply that the

component is capable of withstanding internal hydrostatic pressure up to 0.5 bar.


45


2. Stiffness – GRP pipes is classified according to their minimum initial specific stiffness. This shall be referred to the preferred numbers (SN values) for nominal minimum initial stiffness in N/m2 of SN 1250, 2500, 5000, 10000, 15000 and 20000. The ring bending stiffness is increased as the wall thickness of the GRP pipe is increased. Figure 4.19 defines the stiffness of the GRP pipe.

Figure 4.19: Definition of Stiffness for GRP Pipes

External loading

Circumferential deflection

4.5.4 Joints Joints for GRP pipe are generally of a type of flexible joints using elastomeric sealing rings as a medium to allow a deflection for the pipe. The most commonly used types of joint for GRP pipe for gravity system are as following: 1. Integral socket and spigot joint is a push-in joint incorporating a specially formed socket

and spigot with the seal is effected by means of an elastomeric gasket. Spigots are to have witness marks to identify the insertion depth. Figure 4.20 shows the typical integral socket and spigot joint of GRP pipes.

Figure 4.20: Typical Integral Socket and Spigot Joint of GRP Pipes

(Ref: BS 8010: Section 2.5: 1998 Appendix A, page 15) 2. Loose collar joint is a simple push-in joint consisting of a full-width elastomeric profile,

usually of an EPDM rubber, overwrapped with GRP. The typical of this joint is shown in Figure 4.21 below.

(Ref: BS 8010: Section 2.5: 1998 Appendix A, page 15)

Figure 4.21: Typical Loose Collar Joint of GRP Pipes


46


Meanwhile, Figure 4.22 shows the methods of jointing for GRP pipes that can also be applied when the flexibility is not the major concern.

Figure 4.22: Typical Rigid Joints of GRP Pipe

Butt Joint Flange Joint (Ref: MI Pipe Catalogue, Appendix 1) Sealing materials are to be of elastomeric compounds comprising suitable polymers such as: 1. Ethylene propylene diene monomer (EPDM) with 40% minimum volume of compound for

IRHD of >=55<85; or 2. Styrene butadiene rubber (SBR) with 50% minimum volume of compound for IRHD of

>=55<85. The design of the seal’s profile and the compounding of the elastomer needs to ensure long term sealing of the joint. Jointing lubricant of water based emulsion is required in the application of elastomeric seals to achieve the following:

Provide sufficient lubrication to prevent damage to joint seals or surfaces of jointing; • • •

Enable correctly configured jointing; To remain as an effective lubricant under wet conditions.

Allowable angular deflections of flexible joint for the GRP pipes for gravity system such as rolling or restrained ring joints relative to the nominal size of the pipework according to BS 5480: 1990 are as Table 4.23 below:

Table 4.24: Angular Deflection Limits Relative to the Nominal Size of the GRP Pipework

Nominal Size (DN) Angular Deflection (°) < 500 3

≥ 500 to < 900 2 ≥ 900 to < 1800 1

≥ 1800 0.5

(Ref: BS 5480: 1990, page 10)

4.5.5 Fittings Fittings of the GRP pipe for gravity system are made of continuous glass rovings with either chopped strand mat or chopped rovings (E-glass) with coupling agent to bond to resin. The chopped rovings coupling shall be coated with pigmented resin or acrylic paint for above ground use. Figure 4.23 shows the various ranges of fittings for GRP pipe, to be used for gravity system.


47


Figure 4.23: Various Ranges of Fittings for GRP Pipe

Bends

Tees

Y Junction Tapers 4.5.6 Pipeline Hydraulic Design There are two methods of hydraulic design for the GFRP pipes as indicated in the Table 4.24 below:

Table 4.25: Methods of Hydraulic Design of GRP Pipe

Methods Coefficient Colebrooke-White Roughness, Ks = 0.003mm Hazen-Williams C = 150


48


4.5.7 Application of Pipes The application of GRP pipes for the gravity systems may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 4.25 below lists the advantages and disadvantages of the GRP pipe for this application.

Table 4.26: Advantages and Disadvantages of GRP Pipe

Advantages Disadvantages • Lighter than VC and RC. • Longer than VC and RC, thus less joints. • Immune to H2S attack unlike RC. • Smoother bore than VC and RC permits

flatter grades or smaller diameter pipes. Slime does not build up as readily as with VC and RC and is more easily washed off.

• Greater internal diameter than the equivalent size and class for other pipes permits greater flow.

• Resistant to more chemicals than RC. • Resin liner type can be altered to suit

chemical resistance required • Pipes can be cut to length on site and

joined with coupling (resin seal coat over cut surface is required).

• Thermoset GRP pipe does not distort with ambient temperature increase like thermoplastic HDPE pipe.

• Available as microtunnelling and jacking pipe.

• Heavier than HDPE. • Sides fill support is required to prevent

excessive pipe flexure. • Easily damaged by impact with hard

objects, particularly during backfill. • External impacts can result in star

cracking of the inner liner. This can go undetected in small diameter pipes where internal inspection is difficult.

• Degraded by high concentrations of certain chemicals after long contact.

• Badly damaged pipe is difficult to repair and must be replaced.

• Damaged sections require cutting out or repair using couplings or clamps; in-situ repair using epoxy patching not advisable as methods not proven.

• Branch connections to existing pipelines more difficult than other pipe types.

• Low beam shear strength makes it unsuitable in ground subject to large movements or subsidence.

• Short lengths of pipe are required immediately out of fixed structures, to prevent pipe shearing from differential settlement.


49

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System)

4.6 Profile Wall High Density Polyethylene (HDPE) Pipe The design data and specifications of profile wall HDPE pipes for gravity sewerage system are summarised in Table 4.26 below:

Table 4.27: Summary of Profile Wall HDPE Pipes Design and Specifications for Gravity

Sewerage System

Summary Material • High Density Polyethylene

• Carbon Black • Antioxidants

Nominal Diameter (ID), mm 100 to 3000 mm Effective Length, m 4.0, 6.0, 9.0 and 12.0 m Classes • Nominal Stiffness (SN) • Material Type

• • •

Conform to AS/NZS 2566.1:1998 and DIN 16961-1 SN 1250, SN 2500 PE 80, PE 100

Jointing Method • Spigot-socket with rubber ring seals • Thermofusion welding

a. Welded spigot-socket b. Welded plain ends using a fillet or butt weld c. Welded spigot socket using a butt weld d. Flange end joint


External Internal

• Not applicable • Not applicable


DIN 16961-1 CAN/CSA-B182.6-M92 ISO TC 138 SC1 CEN/TC 155/WG 13 SFS 3453 ASTM D 3350 ASTM D 3212 AS/NZS 2566.1:1998 AS/NZS 2566.1:2002

Malaysian Sewerage Industry Guidelines

Only for special circumstances with prior approval from DGSS



50

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System) 4.6.1 Manufacture Material composition of the profile wall HDPE pipes shall be a high density polyethylene (HDPE) plastic in the form of powders, granules or pellets with no more than 10% of recycled materials. The materials shall be as uniform in composition and size and as free of contamination. Some carbon black or titanium dioxide, about 2-3% may be added as ultraviolet stabiliser. Other additives added are lubricants, antioxidants and pigments. The profile wall HDPE pipes that are allowed for gravity system application shall be doubled wall or triple wall corrugated as shown in Figure 4.24 below.

Figure 4.24: Types of Profile Wall HDPE Pipe for Gravity System

Double Wall Corrugated HDPE Pipe Cross Sectional Area of the Pipe

Triple Wall Corrugated Pipe Cross Sectional Area of the Pipe The profile wall HDPE pipes can be manufactured into various forms of pipes depending on their jointing method as shown in Figure 4.25 below:

Figure 4.25: Various Forms of Profile Wall HDPE Pipe

Spigot socket pipe Threaded pipe

Double spigot pipe Flanged pipe


51

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System) Manufacturing processes of profile wall HDPE pipes can be by injection moulding or rotational moulding. The steps of manufacturing process of profile wall HDPE pipe is varied, depending on the patterns of the profile wall pipe, which is helical or annular.

Figure 4.26: Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes (Option 1)

Extrusion of hollow rib PE Strips

A molten PE is pass through a die to form a hollow rib PE strips

Helical Winding An extruded strip of PE is helically winded on a revolving heated mandrel

Overlapping Next winding overlapping on part of the previous winding

Thermofusion Bond The overlapping molten layers is fused together

Formation of Profile Wall Polypropylene tribes are inserted to hollow ribs to maintain the

round profile

Formation of Spigot Socket

The ends of the mandrel are of special shapes to form spigot and socket ends of solid wall contrition

Positions of Rubber Ring

Rubber seal with keys is placed around the mandrel end that forms the socket, so that it is mechanically bonded to the inside of the socket

Cooling

Storage Marking Inspection


52


Figure 4.27: Typical Manufacturing Process of Rotational Moulding Helical Profile Wall HDPE Pipes (Option 2)

Extrusion of A molten PE is pass through a die to form a hollow rib PE strips hollow rib

PE strips

An extruded strip is helically winded about a mandrel. However, Helical winding the cross section of the extruded strip can only have one hollow rib

Thermofusion The next winding fuses to the edge of the previous winding

Formation of A socket shape on the pipe end is mould at the end of the mandrel. spigot socket

Cooling

Figure 4.28: Helical Pattern of Profile Wall HDPE Pipe

Inspection Marking Storage

A rubber ring is not bonded to the socket


53


Figure 4.29: Typical Manufacturing Process of Annular Profile Wall HDPE Pipe

Extrusion of Solid A molten PE is extruded using continuos vacuum moulding PE Pipe through a circular die.

A molten larger diameter pipe is molded with annular corrugation by travelling mould blocks and co-extended around the smaller diameter of solid wall PE pipe.

Figure 4.30: Annular Pattern of Profile Wall HDPE Pipe

Thermofusion

Cooling

Inspection Marking Storage

The two pipes is are fused together.

A socket of solid wall construction is formed on the pipe end on the outside pipe wall.

Formation of Socket

Co-extrusion of Large Diameter Pipe


54

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System) 4.6.2 Protective Coatings/Linings External and internal protection for profile wall HDPE pipe is not required.

4.6.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the internal diameter of HDPE profile wall pipes. It is a convenient round number approximately equal to a manufacturing dimension. In some cases, two internal diameters may be assigned to one nominal size. Pipe Lengths should show the effective length of the pipe. HDPE profile wall pipes can be cut on site using most types of saws. However, it is not desirable to cut helically wound profile pipe, as it is difficult to cut square and need to seal open end of profile. Classes of HDPE profile wall pipes for gravity sewer are classified according to: 1. AS/NZS 2566.1:1998 This standard defined the HDPE profile wall in terms of nominal stiffness of pipe, which is governed by the HDPE grade, wall thickness and cross-section geometry. The minimum pipe ring stiffness is determined using must not be less than SN 1250 and SN 2500 corresponding to a value between 1250 N/m2 and 2500 N/m2. The minimum value between these limits depends on the installation conditions. 2. MS 1058:1994 According to this standard, the HDPE profile wall pipes for gravity sewer are defined by the material type and the level of minimum required strength as shown in Table 4.27. The design stress of the pipe is obtained by applying a design coefficient of 1.25 to the minimum required strength value of the pipe.

Table 4.28: Classifications of Profile Wall HDPE Pipe

Type of Material Minimum Required Strength, MPa

Max. Allowable Design Stress, MPa

PE 80 8.0 6.3 PE 100 10.0 8.0

The wall thickness of profile wall HDPE pipe shall not be less than 2.3mm.

4.6.4 Joints The jointing methods for the profile wall HDPE pipes are of the following: a. Spigot-socket with rubber ring seals type as shown in Figure 4.31 below.

Figure 4.31: Spigot Socket with Rubber Ring Seals Joint for Profile Wall HDPE Pipes


55

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System) b. Thermofusion Welding is formerly known as fusion welding. This method uses heated tools

to weld the joint faces together and can be applied to specially make moulded socket fittings and also to those made for butt jointing. The thermofusion welding can be carried out to the following:

e. Welded spigot-socket

The socket fusion welding or known as extrusion welding is recommended for low pressure application only. The method can be employed when using moulded polyethylene fittings and spigot and socket joints.

Figure 4.32: Typical Socket Fusion Welding for Profile Wall HDPE Pipes

f. Welded plain ends using a fillet or butt weld

Butt fusion welding is suited to the jointing of HDPE for all sizes of pipe. The joint is produced by heating the faces of the components against a heated flat plate, which is usually coated with PTFE and then bringing them together under controlled pressure. An example of butt fusion welded is shown in Figure 4.33 below.

Figure 4.33: Butt Weld Joint of Profile Wall HDPE Pipe

• Welded spigot socket using a butt weld

One end of the pipe is opened up to act as the socket of a moulded fitting and thereafter the butt fusion welding is carried out. Figure 4.34 shows an example of this type of jointing.

Figure 4.34: Butt Welded Joint of Spigot Socket Profile Wall HDPE Pipe


56

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System) c. Flange end joint

Flange joints are most commonly used for larger diameter pipes. It consist either a full face or stub flanges welded to the pipe or alternately can be formed on the pipe.

Figure 4.35: Flange Ends Joint of Profile Wall HDPE Pipe

(Ref: Weholite Spiro Pipe System Catalogue) The jointing of the profile wall HDPE pipes can also be enhanced with the application of certain type of fittings such as: 1. Metal fittings

These fittings are based on the type of compression fittings commonly used with copper tube such as: a. Compression fittings - The dimensions of the pipe are generally unaltered, the joint being

effected by the use of an internal liner and a compression ring or sleeve which distorts and compresses the pipe wall onto the liner, thus gripping the wall of the pipe.

b. Screwed fittings used to joint the profile wall HDPE pipe is shown in Figure 4.36 below.

Figure 4.36: Screwed Fittings for Jointing of Profile Wall HDPE Pipe

2. Plastic Fittings – The types of plastic fittings for jointing of profile wall HDPE pipe is shown

in Figure 4.37 below.

Figure 4.37: Plastic Fittings for Jointing of Profile Wall HDPE Pipe

Compression fittings Flange fittings

(Ref: www.hdpefittings.com) Sealing material of rubber ring seal type shall be used for profile wall HDPE pipes. The rubber seal can be positioned and bonded in the socket prior to jointing or placed between the outer


57

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System) corrugations at the spigot end. All joints are of the skid type where application of lubricant is required at the jointing surfaces. The bonded rubber seals to the socket are to prevent displacement on jointing. However the seals have tendency to collect dirt. Rubber seal that retained between ribs can prevent sideways stress relaxation of the rubber and the rubber seal is less likely to be displaced from its correct sealing location. However, extra efforts are required to place the seal between the corrugations correctly as there is a tendency for it to twist. Maximum allowable vertical deflection for profile wall HDPE pipes shall not be more than 5% and 2° horizontal misalignment at 30 days from completion of placement and compaction of all trench and embankment fill material.

4.6.5 Fittings The fittings for profile wall HDPE can be moulded or fabricated. The fabricated fittings are less compact than the moulded fittings and are thus less convenient for handling and installation. They will also require a greater support area. For junctions, only the Y fitting need be of HDPE materials. An appropriately dimensioned spigot or socket end on the Y or the adaptor to the Y is permitted to be in another material. Figure 4.38 below shows the various ranges of fittings for profile wall HDPE pipe that can be used in gravity system.

Figure 4.38: Various Ranges of Fittings for Profile Wall HDPE Pipe for Gravity System

4.6.6 Pipeline Hydraulic Design

The profile wall HDPE pipe has limiting design criteria of deflection at joints and compressive strain that can be buckling. Colebrook-White roughness coefficients (ks) is recommended to be applied in hydraulic designs of profile wall HDPE pipes for gravity sewer pipelines are as Table 4.28 below:

Table 4.29: Colebrook-White Roughness Coefficients (ks) for Profile Wall HDPE Pipe

Pipe Condition Roughness Coefficient, ks

New Old

0.06 0.6


58

Section 4 Sewer Pipeline - Material Selection (Gravity Sewerage System) Old pipe can refer as a plastic pipeline with proper joints having sliming and light silting, as this would occur generally within 2 years of installation.

4.6.7 Application of Pipes The application of profile wall HDPE pipes for gravity system may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 4.29 lists the advantages and disadvantages of the profile wall HDPE pipe for this application.

Table 4.30: Advantages and Disadvantages of Profile Wall HDPE Pipe

Advantages Disadvantages • Lighter than VC, RC and GRP. • Longer than VC and RC thus less joints. • Immune to H2S attack. • Smoother bore than VC and RC, permits

flatter grades or smaller diameter pipes. • Resistant to more chemicals than RC and

uPVC. • Not degraded by UV radiation if carbon

black additive is added. • More abrasion resistant than RC. • Pipes can be manufactured to any length,

however this increases pipe cost per metre.

• Save on the amount of polyethylene used while still achieving the same pipe ring stiffness.

• Can easily be curved to eliminate need for bends.

• Suitable for directional drilling, e.g. water courses crossings for syphon.

• Available joint welding provides higher confidence in achieving long-term leak-free system.

• Resistant to failure from differential settlement or pipe longitudinal flexibility accommodates large differential ground settlement.

• Side fill support required to prevent excessive pipe flexure.

• PE degraded by high concentrations of certain chemicals, such as solvents over long contact times.

• Welding in the field to repair or add branch off-takes requires dry, clean conditions to be effective. Special equipment and trained equipment operators are required.

• Pipes susceptible to damage from heavy impact loads. Spigot ends are especially sensitive to damage.

• Pipes can be distorted in hot weather, that is, ovalisation and bending along the length.

• Pipe length changes significantly with temperature. Pipes laid in hot weather can decrease in length sometime after backfilling, causing some pull out at joints and fixed structures.

• Material can collect under the rubber seal, which can affect the seal if not removed. Cleaning under the seal can be overlooked or not done properly.

• Helical pipes cannot be cut to length. • Special puddle flanges are required to

achieve a watertight seal when connecting to concrete manholes. Proper sealing is depended on satisfactory vibration of concrete.

• Fusion repair is difficult to be successfully achieved due to high cleanliness/dryness requirements and heating controls.

• Requires much thicker wall than uPVC solid wall pipe to achieve equivalent stiffness.


59



60

Table 4.31: Technical Comparison of Various Types of Pipe for Gravity Sewerage System Description VCP RC DI GRP Profile Wall HDPE

Material Properties

Corrosion Resistance Resistant to acid Resistant to acid with proper

lining

Can corrode; requires protection in some acidic soils and septic waters

Resistant Resistant to acid

Chemical Resistance Moderate

Susceptible to acids (i.e: sulphuric acid); solvents may cause dissolution

Resistant to organic solvents; requires protection from acids

Good; not affected by salt and hydrogen sulphide attack

Very good

Impact Resistance Moderate Moderate High High; not subject to

brittle failure Moderate

Fire Resistance

Will not sustain combustion Will not sustain combustion Will not sustain

combustion Will sustain combustion Will sustain combustion

Abrasion Resistance High High; moderate under acidic

conditions Moderate; reduce High High

Soil Stress Resistance

Withstands high soil loads Withstands high soil loads Withstands high soil loads Withstands high soil

loads

Flexible; withstands stress with sidefill support

Hydrostatic Strength Low Low High High Moderate

Tensile Strength High

High; rigid sections; flexibility in system due to shorter lengths

High Higher than steel and plastic pipe

Has less strength to volume ratio

Pipe Stiffness Rigid Rigid Flexible; bends slightly Rigid on vertical, flexible on horizontal Flexible

Handling, weight Heavy Heavy Heavy

Light; better weight to strength ratio than concrete

Light

Joining Push on joint Push on joint; more joints Push on joints most common; mechanical joints possible

Push on joints most common; butt joint and flanged joints possible

Butt-fusion above ground mostly, bolted flange for equipment connections

(Ref: http://www.healthybuilding.net)


Table 4.31: Technical Comparison of Various Types of Pipe for Gravity Sewerage System (continued)

Description VCP RC DI GRP Profile Wall HDPE Installation Factors

Bedding Lower half support may be necessary

Lower half support may be necessary

More rigid at lower diameters; still requires careful bedding

Generally requires more sidefill support to control deflection

Generally requires more sidefill support to control deflection

Service

Durability High; long lifespan Moderate High (with corrosion control as required) High; long lifespan Decades

Joint Integrity

Long-term reliability with proper installation

Long-term reliability with proper installation Long term reliability Long-term reliability

with proper installation Butt-fusion results in tight seals

Water Flow Smooth wall; low friction

Slightly higher friction factor,

Slightly higher friction factor,

Smooth walls; low friction factor

Smooth walls; low friction factor

Temperature Range

Wide range application Wide range application Handles very high and low

temperatures

Low impact resistance with decreasing temperatures; lower tensile strength with increasing temperatures

Better low temperature resistance

(Ref: http://www.healthybuilding.net)


61


Table 4.32: Summary of Comparison for Various Types of Pipe for Gravity Sewerage System

No Type of Pipe Properties VCP Concrete DI/Steel HDPE GRP

1 Service Life * * * * * * * * * * * * * * * * * * * * 2 Corrosion Resistance * * * * * * * * * * * * * * * * * * * 3 Abrasion Resistance * * * * * * * * * * * * * * * * * 4 Chemical Resistance * * * * * * * * * * * * * * * * * * 5 Degradation by long contact with chemical * * * * * * * * * * * * * * * 6 Temperature Resistance * * * * * * * * * * * * * * * * * * 7 Impact Resistance * * * * * * * * * * * * * * * * * * * 8 Hydraulic Smoothness * * * * * * * * * * * * * * * * * * * * * 9 Structural Strength * * * * * * * * * * * * * * * * * * *

10 Impermeability * * * * * * * * * * * * * * * * * * * 11 Length * * * * * * * * * * * * * * * * * * * * * * * * * * * 12 Sizes (Diameter) * * * * * * * * * * * * * * * * * * * * * * * * 13 Degradation by UV radiation * * * * * * * * * * * * * * * 14 Weight * * * * * * * * * * * * * * * * * * * 15 Slime formation * * * * * * * * * * * * * * * * * * * 16 Level of wash off * * * * * * * * * * * * * * * * 17 Level of bore roughness * * * * * * * * * * * * * * * * * * * *


62

Section 5 Sewer Pipeline - Material Selection (Force Main)

5.0 FORCE MAIN

5.1 General Minimum design requirements of pressure sewerage pipeline system in Malaysia as stated in MSIG Volume 3 are as summarised below:

Minimum diameter - DN 100 minimum • • •

Maximum hydraulic retention time - 2 hours Minimum design pressure - 1.5 times working pressure

5.1.1 Definition Force main means a pipeline facility through which sewage moves in transportation, forcing by: a. Positive pressure created by pumping effect; or b. Differential pressure in the pipeline created by siphon effect.

5.1.2 Pipe Materials and Application Conditions Pipe materials and application conditions as approved by DGSS for pressure sewerage pipeline system is as Table 5.1 below:

Table 5.1: Pressure Sewer Pipe Materials and Application

Pipe Material Application Non-plastic DI Pipe Preferred material.

DN 100 and above Steel Pipe DN 600 and above Plastic GFRP Pipe DN 600 and above for special circumstances

with prior approval from DGSS ABS Pipe For special circumstances with prior approval

from DGSS, which require the benefits of such pipes

Solid Wall HDPE Pipe Prior approval from DGSS is required


63


5.2 Ductile Iron (DI) Pipe The design data and specifications of DI pipes for force main are summarised in Table 5.2 below:

Table 5.2: Summary of DI Pipes Design and Specifications for Force Main

Summary

Material Scrap ductile iron, steel, ferrosilicon, coke, limestone and magnesium

Nominal Diameter (DN), mm DN 100 to DN 2000 mm Standard Length, m 5.0 to 8.15 m Classes • Wall thickness •

•

• Pressure Class

Conform to BS EN 545

• Minimum Class K9 • Conform to BS EN 598

For pipes with operating pressure up to 6 bar (0.6 MPa) Jointing Methods • Push-in joints with rubber ring

• Self-anchoring push-in joints • Slip-on couplings • Flange end joints with rubber gasket • Self-anchoring tie-bar joints • Bolted mechanical joints • Flange adapters • Self-anchoring flange adapters • Self-anchoring bolted mechanical joints


•

External Internal

• Metallic zinc coating with bitumen finished coat. • Extra HDPE sleeving for severe ground conditions • High alumina cement mortar lining is preferred

Standards Manufacture HDPE Sleeving Design Installation

BS EN 598 BS EN 545 ISO 2531 AS 3680 AS/NZS 2566.1 BS EN 598 Annex C AS 2566.2 (basic) BS 8010 section 2.1 (detail)

Malaysian Sewerage Industry Guideline Vol.3

• • • •

For high load applications For above ground installation Pipe protection linings and coatings are required Polyethylene sleeving is required for buried application subjected to soil condition.



64


5.2.1 Manufacture Material compositions and manufacturing process of DI pipes for force main is identical with DI pipes applied for gravity sewerage system as described in Section 4.4.1.

5.2.2 Protective Coatings/Linings The protective coatings and linings of the DI pipe for force main has the same components with the DI pipe used for gravity system, as described in Section 4.4.2.

5.2.3 Sizes/Classes Nominal size (DN) and pipe lengths of DI pipe for force main shall be in accordance with BS EN 598:1995 as described in Section 4.4.3. Classes of DI pipe have not been defined in the European Standard BS EN 598:1995 for sewerage applications. However, the standard has set specific requirements on pipe performance to ensure the pipes are capable to operate with pressures up to 6 bar (0.6 MPa), the assumed maximum for pressure sewer applications. The approved DI pipes manufactured in Malaysia are classified according to BS EN 545:2002 – Ductile iron pipes, fittings, accessories and their joints for water pipeline. In this standard, the DI pipe is classified based on wall thickness and not pressure rating. Class K9, K10 and K12 are the classes of ductile iron pipes that can be used as a force main. The minimum class of DI pipe, i.e Class K9 can withstand pressures up to 60 bar (6.0 MPa) for DN 200 and below, decreasing to 30 bar (3MPa) for DN 600 and above for spigot-socket pipes. The minimum wall thickness of DI pipes is almost doubled those set in BS EN 598:1995, thus increasing the operating pressure of the pipes. 5.2.4 Joints Joint methods used for DI pipes installation for force main is basically same as the jointing methods recommended for gravity system as described in Section 4.4.4. The additional methods of jointing that can be used for force main are as following: 1. Bolted mechanical joints are made on pipes having a plain spigot at one end and a specially

formed socket at the other. The seal is affected by the compression of wedge-shaped gasket between a seating on the inside of the socket and the external surface of the spigot. The typical bolted mechanical joint for DI pipe is shown in Figure 5.1 below.

Figure 5.1: Typical Bolted Mechanical Joint of DI Pipes for Force Main

(Ref: BS 8010: Section 2.1: 1987 Appendix A, page 18) 2. Flange adapters are designed to connect flange pipe or any flanged fitting to plain-ended

pipe. They consist of a flange and sleeve piece, a wedge-shaped rubber gasket and a loose gland fastened to the main body by bolts. Figure 5.2 shows the typical flange adapters for DI pipe that can be used in force main.


65


Figure 5.2: Typical Flange Adapters of DI Pipe for Force Main


3. Self-anchoring flange adapters consist of a loose flange, bolts and one or more rubber seals carrying anchoring segments. The typical self-anchoring flange adapter is shown in Figure 5.3.

Figure 5.3: Typical Self-anchoring Flange Adapters of DI Pipe for Force Main


4. Self-anchoring bolted mechanical joints is incorporating a ductile iron circlip which is located in a chamber or groove cast in the socket and which registers with a groove specially machined in the spigot. Figure 5.4 shows the typical self-anchoring bolted mechanical joints of DI pipe that can be used for force main. Figure 5.4: Typical Self -anchoring Bolted Mechanical Joints of DI Pipe for Force Main


5. Slip-on couplings are designed for use with plain end pipes. The coupling consists of a

sleeve, at the ends of, which are wedge-shaped rubber gaskets and flanges held together by bolts. The typical slip-on coupling for DI pipes is shown in Figure 5.5 below:

Figure 5.5: Typical Slip-on Coupling for DI Pipes



66

Section 5 Sewer Pipeline - Material Selection (Force Main) 6. Self-anchoring tie-bar joints have a special loose anchor ring placed behind the socket and a

special anchor ring welded onto the outer surface of the spigot. Figure 5.6 shows the typical self-anchoring tie-bar joints used for DI pipes.

Figure 5.6: Typical Self-anchoring Tie-bar Joints for DI Pipes


Sealing materials and jointing lubricant requirements of DI pipes for force main shall follow to that recommended for gravity system as stated in Section 4.4.4. Allowable angular deflections of DI pipes for force main application shall meet the requirements recommended for DI pipes used for gravity system, as described in Section 4.4.4.

5.2.5 Fittings The range of fittings for DI pipes applied for force main is basically same as the fittings used for gravity system except for the tapers. Figure 5.5 shows the additional ranges of DI fittings that can be applied into the force main, other than those listed in Section 4.4.5.

Figure 5.7: Additional Ranges of DI Fittings for Force Main

Socket-socket flange scour tee Spigot-spigot flange scour tee

Socket-spigot-flange tee Spigot-spigot-flange tee

Non-thrust dismantling joint

(Ref: Power and Water – Water Supply and Sewerage Approved Products Manual/

www.powerwater.com.my)

Thrust dismantling joints (Ref: Power and Water – Water Supply and

Sewerage Approved Products Manual/ www.powerwater.com.my)


67

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.2.6 Pipeline Hydraulic Design Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 5.3 shall be referred to when determining discharge capacity of the DI pipes for force main.

Table 5.3: Colebrook-White Roughness Coefficient, ks for DI Pipes

Mean Velocity, V (m/s) Roughness, ks (mm) 0.8 ≤ V ≤ 1.5 0.6 1.5 ≤ V ≤ 2.0 0.3

V ≥ 2.0 0.15

5.2.7 Application of Pipe The application of DI pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.4 lists the advantages and disadvantages of the DI pipes for this application.

Table 5.4: Advantages and Disadvantages of DI Pipes for Force Main


• Higher beam, ring and shear strength than plastic pipes

• Not affected by UV radiation. • Slight change in length with temperature

variations, unlike plastic pipes. • High ring stiffness permits use with very

shallow cover and up to unusually large superimposed loads unlike plastic pipes.

• High beam and shear strength permits use in ground subject to substantial differential settlement

• Not subject to damage from substantial impact loads making it suitable for rail, over dimensional highway and bridge crossings unlike unencased GFRP.

• High resistance to shock or impact due to improper handling, water hammer or unstable condition.

• Able to deform when stressed beyond yield point.

• Superior tensile strength to withstand severe loads and high internal pressure.

• More expensive than plastics pipe. • Heavier than plastics. Mechanical lifting

is required. • External polyethylene (PE) sleeving

required for buried application in corrosive soil conditions.

• Care is required to ensure sleeving completely wraps the pipe and is sealed. PE sleeving is easily damaged.

• Where sleeving is damaged in certain aggressive soils (pH ≤5 and ≥9), corrosion will occur.

• Internally less corrosion resistant than VC and plastics.

• Less abrasion resistant than plastic pipes. • Rougher bore than plastics thus require

steeper grades or larger diameter pipes. Slime adheres more readily to DI than plastics and is less easily washed off.

• Ductile iron is corroded by hydrogen sulphide and sulphuric acid produced in septic sewage conditions.


68


5.3 Steel Pipes There are two types of steel pipe approved by DGSS that can be applied as force main pipeline system, which are mild steel and stainless steel. The design data and specifications of mild steel pipes for force main are summarised in Table 5.5 below:

Table 5.5: Summary of Mild Steel Pipes Design and Specifications for Force Main

Summary Material Carbon steel Nominal Diameter (DN), mm DN 100 to 2200mm Standard Length, m 6.0, 9.0 and 12.0 m. Longer lengths are available on special

request Classes •

• • Operating Pressure

Conform to BS 534:1990 Varies with pipe diameter, wall thickness and material grade


Butt-welded joint Sleeve joints for welding Slip-on type coupling Flange joint Threaded and coupled joint


•

•

•

External

Internal

Coal tar enamel, bitumen enamel, asphalt enamel and glass fibre. High alumina cement mortar, coal tar enamel, coal tar epoxy, sulphate resistant cement or bitumen.


BS 534:1990 BS 3600:1976 BS 3601:1987 AS/NZS 2566.1:1998 BS EN 10025:1993 ISO 559:1991 AS/NZS 2566.2:2002


• Approval for use from the DGSS is required • Pipe is allowed only for sizes 600mm and above • Pipe protection linings and coatings are required. • Permitted for inverted siphons (depressed sewers) and

internal pump station pipework. Approved Manufacturers/Suppliers Refer to DGSS latest approval list in Table D1


69

Section 5 Sewer Pipeline - Material Selection (Force Main) The design data and specifications of stainless steel pipes for force main are summarised in Table 5.6 below:

Table 5.6: Summary of Stainless Steel Pipes Design and Specifications for Force Main

Summary Material Stainless steel

Nominal Diameter (DN), mm DN 21.34 to 273.05m Standard Length, m Pipe length may be specified as long as transportable. Classes •

• • Operating Pressure

Conform to BS 3600: 1976 Varies with pipe diameter, wall thickness and material grade


Butt-welded joint Sleeve joints for welding Slip-on type coupling Flange joint Threaded and coupled joint


External Internal

None None

Standards Manufacture: Design: Installation:

BS 3600:1976 AS/NZS 2566.1:1998 AS/NZS 2566.2:2002

Malaysian Sewerage Industry Guidelines

• Approval for use from the Director General is required • Pipe is allowed only for sizes 600mm and above

Approved Manufacturers/Suppliers Refer to DGSS latest approval list in Table C1


70

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.3.1 Manufacture

5.3.1.1 Mild Steel Material compositions for mild steel pipes is carbon steel that shall consist of structural or analysis grade steel comply with BS EN 10025: 1993 and BS 3601: 1987.

The most common manufacturing process that can be applied to produce all sizes of mild steel pipes is by using helical winding method as shown in Figure 5.8 below.

Figure 5.8: Typical Manufacturing Process of Mild Steel Pipes for Force Main

Helical Winding

Welding

Formation of Socket

A steel strip is helically winded and continuously welded to the adjacent windings

Socket is formed on the pipe end

Hydrostatic Testing X-ray Inspection Blasting and Priming

Coating Lining Inspection Storage

The mild steel pipes can also be manufactured using other methods of manufacturing processes that is dependent on the sizes of the pipe, such as: 1. Steel pipes with diameter less than DN 500

Hot rolling billets, bars, or ingots into a seamless tube; and • • Involves cold rolling steel strip through rollers into the pipe shape and then welding.

2. Steel pipes with diameter DN 500 and up to DN 1050

The manufacturing process for these sizes of pipes involves a formation of steel plates into a circular shape using a ‘U’ press followed by an ‘O’ press. Then the joint is welded along the pipe barrel by submerged arc welding.

3. For sizes up to DN 3000 The production for these sizes of pipes involves a cold rolling of steel plates into a circular or half-circular shape. One circular shaped steel plate is then welded along the barrel. For larger diameter pipes two half-circular shapes will be welded together along the barrel.


71

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.3.1.2 Stainless Steel Material compositions of stainless steel pipes is consist of stainless steel mother coils, which their grades and compositions shall comply with BS 3600:1976 The manufacturing process of stainless steel pipes is shown in the flow chart of Figure 5.9 below.

Figure 5.9: Typical Manufacturing Process for Stainless Steel Pipes for Force Main

Packing

Acid Pickling

Straightening Sizing Water

Quenching

Annealing

Cutting

Welding

Forming

Uncoiling

Pipes are annealed to further upgrade the quality of the pipes

Pipes are cut into the required length

Pipes are formed to precise dimension using tri-cathode welding technology

Slit coils are cold formed into pipes

Mother coils are slitted into required width with slitter machine

A Guide to Sewer Sele13th November 2006

Pipes to undergo acid pickling process to obtain superior corrosion resistance and a silver grey finish

Marking Inspection

Hydrostatic Test

ction and Installation 72

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.3.2 Protective Coatings/Linings

5.3.2.1 Mild Steel External coating for mild steel pipes that commonly applied for the pipe’s protection is bitumen whereas a coal tar enamel, asphalt enamel and glass fibre still can also be used in accordance with BS 534:1990. The polyethylene coating is applied by rotating a preheated pipe in a bath of polyethylene powder. For exposed steel at the joints, the polyethylene can be wrapped manually, around the ends to finish under the later applied cement mortar lining. Internal lining is applied at the end of the manufacturing process. High alumina cement mortar, sulphate resistant cement mortar, coal tar enamel, coal tar epoxy or bitumen shall be used as the internal lining protection to the pipes. In accordance with BS 534:1990, the minimum cement content shall be 330kg/m3 and the maximum water:cement ratio shall not exceed 0.46:1. The steel pipe is subjected for priming before the internal coal tar or bitumen protection is applied. For cement mortar lining, the cement mortar is applied by feeding the mortar into a slowly rotating pipe. With the mortar in place the pipe is rotated rapidly in order to densely compress the mortar and form a uniformly thick lining with as smooth as possible flow characteristics. Thermosetting (epoxy paint or powder or epoxy tar resin) and thermoplastic (polyethylene, polyurethane) shall be applied to the internal and external surfaces of the pipe.

5.3.2.2 Stainless Steel Protective coatings and linings are not applicable for stainless steel pipe.

5.3.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the outer diameter of steel pipes. It is a convenient round number approximately equal to a manufacturing dimension. The bore of the pipe, which is affected by the wall thickness will govern the pressure load to the pipe. Pipe sizes are not restricted to these nominal sizes and can be made to any outside diameter upon request from the purchaser. Effective length of steel pipe is referred to the actual length that a pipe contributes when correctly assembled in a run of piping. This dimension excludes the additional length contributed by a slip-on type coupling when this is used. The pipes shall be supplied in either random lengths or cut lengths. Where cut length is specified, the maximum variation in length shall be +6, -0mm for lengths up to and including 6m. For every 3 m increase in length above 6 m, the plus tolerance shall increase by 1.5 mm to maximum of 12.5 mm. The pipe can also be cut on site by oxy-cutter. Classes of the steel pipe have not been defined in BS EN 534:1990. The classification of grades and qualities of steel pipe are derived in BS EN 10025:1990.


73

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.3.4 Joints

Jointing of steel pipes can be achieved with the following methods:

1. Butt-welded joints This is commonly used but is not suitable for lined steel pipes in sizes 610mm OD and smaller. Figure 5.10 shows the preparation of butt-welded joint for steel pipes.

Figure 5.10: Butt-welded Joint Preparation of Steel Pipes

(Ref: BS 534: 1990, page 9)

2. Sleeve joints for welding The steel pipes are supplied with the spigot end and the sleeve end. These joints are the preferred type of DGSS but it is exceptional for pump station pipe work and valve connections where flange joints shall be used. Types of sleeve joints for welding are shown in Figure 5.11 below.

Figure 5.11: Sleeve Welded Joints of Steel Pipes

Parallel sleeve Taper sleeve

Collar sleeve Surface sleeve (Ref: BS 534: 1990, page 11)

3. Slip-on type coupling This type of coupling is to be applied with plain end pipe as shown in Figure 5.12.

Figure 5.12: Slip-on Type Coupling of Steel Pipes

(Ref: BS 534: 1990, page 12)


74

Section 5 Sewer Pipeline - Material Selection (Force Main) 4. Flange joint

In accordance with MSIG, flange joint is compulsory to use for pump station pipe work and valve connections

5. Threaded and coupled joint Where bitumen lined pipes required with threaded and coupled joints, the thread shall have a taper thread on both the pipe and the coupling. The coupler shall be recessed in the centre to take the lining as shown in Figure 5.13.

Figure 5.13: Threaded and Coupled Joints Recessed for Bitumen Lining

(Ref: BS 534: 1990, page 12)

Mechanical joints are only permitted for cut pipe lengths, where internal cement mortar lining at joint is not possible and where movement of the pipeline is to be allowed for.

5.3.5 Fittings Fittings are fabricated by welding together sections of steel pipe and are tailor-made which have been hydraulically tested before coating. Hence, they are considered as steel pipe specials. The end fittings produced are prepared to match those of the pipes to which they are to be joined. Steel fittings are much more costly because fabrication is labour intensive with the need to manually weld and apply cement mortar lining. Figure 5.14 shows the various ranges of fittings for steel pipe.

Figure 5.14: Various Ranges of Fittings for Steel Pipes

Long radius bend Short radius bend Gusseted bend

Plain end tee Sleeve joint tee Tee with flange

Concentric reducer Eccentric reducer Stub flange


75

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.3.6 Pipeline Hydraulic Design Colebrook-White roughness coefficients (ks) recommended for hydraulic design of steel pipes for force main are as recommended in Table 5.7 below:

Table 5.7: Colebrook-White Roughness Coefficient (ks) for Steel Pipes

Mean velocity, V (m/s) Roughness Coefficient (ks,),

mm 0.8 ≤V≤ 1.5 0.6 1.5 ≤V≤ 2.0 0.3

V≥ 2.0 0.15

5.3.7 Application of Pipes The application of steel pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.8 lists the advantages and disadvantages of the steel pipes for this application.

Table 5.8: Advantages and Disadvantages of Steel Pipes

Advantages Disadvantages • More flexible than DI pipe. • Polyethylene external coating makes it

resistant to aggressive soils and is more reliable than PE sleeving used with DI pipe.

• Longer pipe lengths. • Polyethylene internal coating is inert to

chemical attack from hydrogen sulphide and is resistant to the maximum sulphuric acid concentrations that could be developed from septic sewage conditions.

• Less change in length with temperature variations compared with PE and uPVC.

• Hard, smooth surfaces resist scratches and impact damage.

• Better strength and safety. No corrosion, resulting in lasting durability.

• Thinner gauge material is used, resulting in lasting durability.

• Have a longer life-span, saving maintenance and replacement costs in the long term.

• If the PE internal coating is damaged to expose the steel, corrosion may result.

• Heavier than thermoplastic pipes. • A range of fittings as required for sewer

reticulation is not available. • Careful checking for pinholes in the

internal lining is required to ensure possible points of steel corrosion do not exist.


76


5.4 Glass-fibre Reinforced Plastics (GRP) Pipe The design data and specifications of GRP pipes for force main are summarised in Table 5.9 below:

Table 5.9: Summary of GRP Pipe Design and Specifications for Force Main

Summary

Material •

•

• • • •

• • • • •

Filament Wound Pipe

Centrifugally Cast Pipe

Thermosetting resin or polyester resin Roving or woven fabrics of E-glass filaments Surface tissues Additional material such as additives and colourants

Thermosetting resin or polyester resin Chopped strand mat of E-glass filaments Surface tissues Aggregates and fillers Additional material such as additives and colourants

Standard Nominal Diameter 100mm to 1000mm Standard Effective Length 3.0 and 6.0m Jointing Method • Integral socket and spigot joint

• Loose collar joint • Butt Joint • Flange Joint • DI coupling

a. Slip-on coupling b. Stepped slip-on coupling c. Band coupling d. Flange adapters e. Flange joints

Classes • •

Stiffness Classes (SN) Pressure Classes (PN)

• SN 1250, 2500, 5000, 10 000, 15 000, 20 000 • PN 12.5, 16, PN 20


External Internal

Thermosetting resin Resin rich lining with superficial layers of C glass material

Standards Manufacture Structural Pipeline Design Installation

BS 5480: 1990 AS 3571: 1989 ASTM D 3262 AS/NZS 2566.1: 1998 AS/NZS 2566.2: 2002

Malaysian Sewerage Industries Guidelines (MSIG)

Under special circumstances with prior approval from DGSS

Approved Suppliers/Manufacturers Refer to Table D1 and DGSS latest approval list


77

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.4.1 Manufacture The material compositions and manufacturing processes of GRP pipe for force main are identical with the GFRP pipe applied for gravity system as described in Section 4.5.1.

5.4.2 Protective Coatings/Linings The protective coatings and linings of GRP pipes for force main are generally same with those recommended for the GRP pipe applied for gravity system as described in Section 4.5.2.

5.4.3 Sizes/Classes Nominal size (DN) of GRP pipes for force main is same with the nominal sizes for GRP pipes applied for gravity system as described in Section 4.5.3. However, the application of the GRP pipes for force main is limited for diameter up to 1000mm due to the higher pressure rating that need to be catered inside the pipe. Pipe lengths of the GRP pipe for force main has the same value with those recommended for GRP pipe applied for gravity system as described in Section 4.5.3. Classes of the GRP pipes for force main are defined by both pressure class and stiffness class as following: 1. Pressure – GRP pipe that classified for use under pressure is capable of withstanding internal

hydrostatic pressure more than 0.5 bar. The pressure classes are referred as PN 12.5, PN 16 and PN 20 that corresponding to 12.5, 16 and 20 bar of working pressure. The pressure rating of the GRP pipe is not dependent on the wall thickness but the GRP composite through wall is the component that increases the pressure rating of the GRP pipe.

2. Stiffness – GRP pipe shall be classified according to their minimum initial specific stiffness.

This shall be referred to the preferred numbers (SN values) for nominal minimum initial stiffness in N/m2 of SN 1250, 2500, 5000, 10000, 15000 and 20000. The ring bending stiffness is increased as the wall thickness of the GRP pipe is increased.

5.4.4 Joints Jointing methods that are recommended for GRP pipes used in gravity system described in Section 4.5.4 are also can be applied for force main. The GRP pipes for force main is also compatible to be jointed with the application of DI couplings, as follows: 1. Slip-on coupling is designed for use with plain-ended pipes. It consists of a sleeve, at the

ends of, which are wedge-shaped elastomeric gaskets and flanges held together by bolts as shown in Figure 5.15 below.

(Ref: BS 8010: Section 2.5: 1989, page 15)

Figure 5.15: Typical slip-on


78

Section 5 Sewer Pipeline - Material Selection (Force Main) 2. Stepped slip-on coupling is a special slip on couplings used to connect pipes of different

diameters or materials as shown in Figure 5.16 below. (Ref: BS 8010: Section 2.5: 1989, page 15) 3. Band coupling is designed for used with plain-ended pipes. It consists of a metallic band

encasing a shaped elastomeric profile as shown in Figure 5.17 below. (Ref: BS 8010: Section 2.5: 1989, page 16)

Figure 5.16: Typical stepped slip-on coupling

Figure 5.17: Typical band coupling

4. Flange adapters as shown in Figure 5.18 is designed to connect flanged pipe or any flanged fitting to plain-ended pipe. It consists of a flange and sleeve piece, a wedge-shaped elastomeric gasket and a loose gland fastened to the main body by bolts.


Figure 5.18: Typical flange adapter

5. Flange joints are made by integral forming or attaching a preformed GRP flange or forming a stub flange with metallic backing flange. The assemblies of this joint is shown in Figure 5.19 below.


Figure 5.19: Typical flange joints


79

Section 5 Sewer Pipeline - Material Selection (Force Main) However, the jointing of GRP pipe for force main shall be carefully done to ensure that it can stand the pressure rating of the system. Sealing material and jointing lubricant for the GRP pipe applied for force main shall follow the requirements described in Section 4.5.4. Allowable angular deflections of flexible joint for the GRP pipe for force main such as rolling or restrained ring joints or clamped joints relative to the nominal size of the pipework according to BS 5480: 1990 are as Table 5.10 below:

Table 5.10: Angular Deflection Limits Relative to the Nominal Size of GRP Pipelines

Nominal Size (DN) Angular Deflection (°) < 500 3

≥ 500 to 1000 2

5.4.5 Fittings The GRP pipe for force main shall be used with the ductile iron fittings. The DI fittings shall have the allowable operating pressure of PN 16 and PN 35 with thermal bonded polymer of internal lining and external coating. The requirements to joint these fittings to the GRP pipe shall be as follows: 1. The sockets shall be grooves to capture elastomeric seals. 2. Spigot ends shall be chamfered over 10 to 20mm at approximately 20º to pipe barrel. 3. Flange shall be equipped with 1.5mm or 3mm flat elastomeric full face gasket depending on

the pressure rating of the pipe.

Figure 5.20 shows the various ranges of DI fittings that can be used with GRP pipe for the application of force main.

Figure 5.20: Various Ranges of DI Fittings for GRP Pipes

Flange-socket connector Socket-socket connector Socket-socket bend

Cap Socket-socket-flange scour tee

5.4.6 Pipeline Hydraulic Design Typical roughness coefficient, ks values of Colebrook-White equation as recommended in MSIG Volume 3 given in Table 5.11 shall be referred to when determining discharge capacity of the GRP pipes for force main.


80


Table 5.11: Colebrook-White Roughness Coefficient, ks for GRP Pipes

Mean Velocity, V (m/s) Roughness, ks (mm) 0.8 ≤ V ≤ 1.5 0.6 1.5 ≤ V ≤ 2.0 0.3

V ≥ 2.0 0.15

5.4.7 Application of Pipes The application of GRP pipes for the force main may subject to certain conditions and limitations as described in Table 3.2 and 3.3, Section 3. Table 5.12 lists the advantages and disadvantages of the GRP pipe for this application.

Table 5.12: Advantages and Disadvantages of GFRP Pipes for Force Main


• Lighter than DI. • Less joints. • Immune to H2S attack. • Smoother bore permits flatter grades or

smaller diameter pipes. Slime does not build up and is more easily washed off.

• Greater internal diameter than the equivalent size and class for other pipes permits greater flow.

• Resistant to more chemicals than HDPE. • Resin liner type can be altered to suit

chemical resistance required • Pipes can be cut to length on site and

joined with coupling (resin seal coat over cut surface is required).

• Compatible to use with ductile iron fittings.

• Thermoset GFRP pipe does not distort with ambient temperature increase like thermoplastic HDPE pipe.

• Heavier than HDPE. • Sides fill support required to prevent

excessive pipe flexure. • Easily damaged by impact with hard

objects, particularly during backfill. • External impacts can result in star

cracking of the inner liner. This can go undetected in small diameter pipes where internal inspection is difficult.

• Degraded by high concentrations of certain chemicals after long contact.

• Badly damaged pipe is difficult to repair and must be replaced.

• Damaged sections require cutting out or repair using couplings or clamps; in-situ repair using epoxy patching not advisable as methods not proven.

• Branch connections to existing pipelines more difficult than other pipe types.

• Low beam shear strength makes it unsuitable in ground subject to large movements or subsidence.

• Short lengths of pipe are required immediately out of fixed structures, to prevent pipe shearing from differential settlement.


81

Section 5 Sewer Pipeline – Material Selection (Force Main)

5.5 Acrylonitrile Butadiene Styrene (ABS) Pipe The design data and specifications of ABS pipes for force main are summarised in Table 5.13 below:

Table 5.13: Summary of ABS Pipes Design and Specifications for Force Main

Summary Material Acrylonitrile, Butadiene and Styrene Nominal Diameter, mm DN 10 to 200 mm Standard Effective Length, m 6.0 m Classes: • Pressure Class (PN)

Conform to MS 1419:Part 1: 1997 Class 4.5, 6, 9, 12, 15, T

Jointing Method • Spigot-socket with solvent cement welding joint • Spigot-socket with elastomeric seal joint • Stub flange joint

Protective Coating • External • Internal



MS 1419:Part 1 to 3: 1997 MS 1419: Part 4 : 1998 AS 3518: Part 1 & 2: 1988 AS 3690: 1989 AS 3691: 1989 BS 5391: Part 1 BS 5392: Part 1 AS 2566.1: 1998 AS 2566.2: 2002


For special circumstances with prior approval from DGSS, which require the benefits of such pipe

Approved Manufactures/Suppliers Refer to Table D1 and DGSS latest approval list


82


5.5.1 Manufacture Material compositions of ABS pipes are consist of a copolymer of the monomers acrylonitrile, butadiene and styrene. Each monomer brings to the copolymer different properties, such as: a. Acrylonitrile is to provide resistance to chemicals and ageing (ultraviolet light) and rigidity; b. Butadiene provides impact strength, toughness and abrasion resistance; and c. Styrene contributes to strength and ease of processing. Varying the quantities of each monomer will modify the performance properties of ABS pipes. For pipe applications as a pressure sewerage system, appropriate quantities of each monomer are selected to optimise the performance properties of tensile strength, chemical resistance, ductility and weatherability. Material suitable for pressure pipe applications shall be Type 12142 in conformance with MS ISO 2580-1. Manufacturing process of ABS pipes is much the same as used for other extruded thermoplastic pipe as shown in Figure 5.21 below:

Figure 5.21: Typical Manufacturing Process Flow of ABS Pipes

Sockets are formed on the pipes using a belling machine

Blending

Melting

Mixing

Extrusion of pipe

Sizing

Cooling

Cutting

Marking

Formation of socket Inspection

Pipes are sized and cooled using water

Pipes are marked and cut to size

Storage

Homogeneous molten ABS is then passed through a series of dies to be extruded to a certain diameter and wall thickness

Raw material (compounded ABS) is fed into a screw


83


The ABS pipes for pressure system can be manufactured into various forms of pipe depending on their jointing method as shown in Figure 5.22 below.

Figure 5.22: Types of ABS Pipes

Plain ended pipe

Spigot end pipe

Spigot socket pipe

5.5.2 Protective Coatings/Linings The protective coating and lining is not required for ABS pipe since the material itself can resist the corrosion attack from the sewage.

5.5.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the outside diameter of ABS pipe. ABS pipe is extruded with a fixed outside diameter while the inside diameter is varied to achieve the range of pipe classes. The ABS pipe without couplings shall conform to the dimensions recommended in MS 1419: Part 1-1997 as given in Table 5.14.

Table 5.14: Dimensions of ABS for Force Main

Mean Outside Diameter, Dm Nominal Size (DN) Min Max

10 17.0 17.3 15 21.2 21.5 20 26.6 26.9 25 33.4 33.7 32 42.1 42.4 40 48.1 48.4 50 60.2 60.5 80 88.7 89.1

100 114.1 114.5 150 168.0 168.5 200 218.8 219.4


84


Pipe lengths should show the standard overall length of the pipe, exclusive of coupling, of 6 + 0.05, - 0m. All measurements shall be adjusted to an equivalent length at 20ºC. The ABS pipe can be cut at site to the desirable length by handsaw or powersaw. However, care must be taken to ensure squareness of cut ends. Classes of ABS for force main are defined according to maximum static working pressure at a pipe material temperature of 20°C, as Table 5.15 below:

Table 5.15: Classifications of ABS Pipes for Force Main

Class of Pipe Maximum Static Working Pressure, MPa Class 4.5 0.45 Class 6 0.60 Class 9 0.90 Class 12 1.2 Class 15 1.5 Class T 1.2 after threading

(Ref: MS 1419: Part 1: 1997, page 3)

5.5.4 Joints The methods of jointing ABS pipes for force main are as following: 1. Spigot-socket with solvent cement welding joint

This jointing as shown in Figure 5.23 is commonly used for ABS pipe. The jointing process shall be properly performed to provide an ideal joint for the elimination of infiltration and root intrusion.

Figure 5.23: Typical Spigot-socket with Solvent Cement Joint of ABS Pipes

2. Spigot-socket with elastomeric seal joint

Spigot and socket pipe for elastomeric seal jointing shall carry a witness mark such that when the spigot is inserted into a matching pipe socket to the witness mark, the joints are confined to the socket and jointing seal as shown in Figure 5.24 below.

Figure 5.24: Typical Spigot-socket with Elastomeric Seal Joint of ABS Pipes


85


3. Stub flange joint The flange is required to be solvent cemented onto a spigot end. The stub flange requires the use of a backing plate and a rubber gasket between the flanges for specific joint application. Figure 5.25 shows the typical stub flange for ABS pipes.

Figure 5.25: Typical Stub Flange Joint for ABS Pipes

(Ref: Azeeta Pipe System Catalogue) The jointing of ABS pipe requires special trainings because of the care required to make a solvent cement joint, particularly in large diameters. Solvent cement shall consist of one or more solvents and a sufficient quantity of base ABS material dissolved in the solvents to give the cement the body and consistency required for proper application. Small amounts of inert fillers are added to control shrinkage during drying.

5.5.5 Fittings ABS fittings for making of junction connections are available and it can be injection moulded or fabricated. Figure 5.26 shows the various ranges of fittings for ABS pipe that can be applied into force main.

Figure 5.26: Various Ranges of Fittings for ABS Pipes

Socket Reducing socket 90° elbow

Equal tee Reducing tee Reducing bushes

Long radius plain bend Short radius plain bend Saddle

(Ref: Azeeta Pipe System Catalogue)


86


5.5.6 Pipeline Hydraulic Design Colebrook-White roughness coefficients (ks) recommended for hydraulic design of ABS pipes for force main are as Table 5.16 below:

Table 5.16: Colebrook-White Roughness Coefficients (ks) of ABS Pipes

Mean velocity, V (m/s) Roughness Coefficient Ks, mm

0.8 ≤V≤ 1.5 0.6 1.5 ≤V≤ 2.0 0.3

V≥ 2.0 0.15

5.5.7 Application of Pipes The application of ABS pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.17 lists the advantages and disadvantages of ABS pipes for this application.

Table 5.17: Advantages and Disadvantages of ABS Pipes

Advantages Disadvantages • Lighter than DI and steel pipes. • Resistant to corrosive soils and ground

water. • Pipes can be cut to length on site. Simpler

to cut than non-plastics. • Higher impact resistance than PE. • Excellent abrasion resistance. • Range of working temperature is wider

compare to PE. • Resistant to more chemicals than PE. • Better resistant to UV degradation than

other thermoplastics like HDPE. • Infiltration and root intrusion eliminated

with solvent cement joints. • Tolerant of ground subsidence. • Pipe lengths can be assembled out of the

trench. • Solvent cement welding permits

continuous pipe lengths for slip lining. • Narrower trench is permissible than DI

and steel pipes. • Mode of failure • Weather resistance • Homogeneous joint • Non-toxic/taint free • Smooth bore • Minimal maintenance

• Thermal expansion less than HDPE. • Side fill support required to prevent pipe

flexure. • Bedding requirements more stringent

than for rigid pipes. • Any later disturbance of pipe side support

may affect pipe performance. • Pipes can be distorted in hot weather, that

is, ovalisation and bending along length. • Pipe length can change significantly with

temperature change. Pipes laid in hot weather can decrease in length sometime after backfilling.

• No rotational movement of solvent cement pipe joints to accommodate any ground movement.

• Fumes from solvent cementing, depending on contact time and ventilation may have a toxic effect. Solvent cement may also cause skin and eye irritation.


87

Section 5 Sewer Pipeline - Material Selection (Force Main) 5.6 Solid Wall HDPE Pipe The design data and specifications of solid wall HDPE pipe for force main are summarised in Table 5.18 below:

Table 5.18: Summary of Solid Wall HDPE Pipe Design and Specifications for Force Main

Summary

Material • High Density Polyethylene • Carbon Black • Antioxidants

Nominal Diameter (ID), mm DN 16 to DN 900 mm Standard Length, m 6.0 and 12.0 m Classes • Material Type • Pressure Class (PN)

PE 80, PE 100 PN 2.5 to a maximum of PN 16

Jointing Method •

• • •

Thermofusion welding a. Butt fusion welding b. Butt fusion welding of spigot socket joints Electrofusion Flange joints Mechanical metal couplings


Not applicable Not applicable


CP 312: Part 1 & 3: 1973 SFS 3453 WIS 04-32-15 WIS 04-24-01 WIS 04-32-14 AS/NZS 2566.1: 1998 AS/NZS 2566.2: 2002


• •

•

Prior approval from DGSS is required Shall not be used in ground contaminated with high concentration of chemicals that can degrade the pipes Shall not accept any industrial or other aggressive discharges that may affect the pipe integrity.

Approved Manufactures/Suppliers Refer to Table D1 and DGSS latest approval list


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Section 5 Sewer Pipeline - Material Selection (Force Main) 5.6.1 Manufacture Material compositions of the solid wall HDPE pipes pipe is polyethylene (PE) resins with density range of 950-965 kg/m3 containing no more than 10% of recycled materials. The PE plastic can be in the form of powders, granules or pellets. Some carbon black or titanium dioxide, about 2-3% shall be added as ultraviolet stabiliser. Other additives added are lubricants, antioxidants and pigments. Manufacturing process of HDPE solid wall pipes is shown in typical flow chart of Figure 5.27.

Figure 5.27: Typical Manufacturing Process of Solid Wall PE Pipe

5.6.2 Protective Coatings/Linings External protection and internal protection is not required for solid wall HDPE pipes.

Storage

Preheating

Melting, compressing and degassing

Formation of pipe

Sizing

1st stage cooling

2nd stage cooling

Cutting

Inspection

Pipes are cut into the required length

Pipes are passed through water bathing of even lower temperatures till it reaches ambient temperatures

Pipes are cooled by external vacuum or internal pressure while passing through the forming sleeves

Molten PE is passed through a die at the end of the extruder to form the pipes

Raw materials are fed to an extruder where a helical screw mechanism moves the granules along the extruder through zone

Pelletised raw materials is preheated to remove volatile and moisture


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Section 5 Sewer Pipeline - Material Selection (Force Main) 5.6.3 Sizes/Classes Nominal Outside Diameter, dn of solid wall HDPE pipes is a numerical designation of size to HDPE piping system other than flanges and components designated by thread size. It is a convenient round number for reference purposes. This diameter is fixed while the internal diameter varies depend on the classes. The increment is not constant and the sizing follows the adopted international standards for thermoplastic pipe for pressure applications. Standard length of pipe indicated the overall effective length of the pipe. HDPE solid wall pipes can be cut on site using most types of saws. Classes of solid wall uPVC pipes is designated by the material types, PE 100 and PE 80, which correspond to the level of minimum design strength at 20°C for up to 50 years. PE 80 and PE 100 show the capabilities of the pipes to withstand 80 bar (8 MPa) and 100 bar (100 MPa) of strength respectively. The maximum design stress is obtained by applying a design coefficient of 1.25 to the strength. PE is available in various compounds of different density and this alters the allowable stress that a pipe can withstand. The higher the allowable design stress, the thinner the wall for the same working pressure. Ring stiffness of 8 kN/m2 (8000 MPa) is generally taken as the minimum stiffness for smaller diameter pipe. Hence PE 80 with typical resins density of 950 to 955 kg/m3 is recommended for use in pressure sewerage. Working pressure is increased by increasing the wall thickness (to ensure pipe bores align at joints requires that each pipe have the same pressure class).

5.6.4 Joints The jointing methods for solid wall HDPE pipe shall be as follows: 1. Thermofusion welding is formerly known as fusion welding. This method uses heated tools

to weld the joint faces together and can be applied to specially made moulded socket fittings and also to those made for butt jointing

a. Butt fusion welding is suited for the jointing of HDPE for all sizes of pipe. The joint is

produced by heating the faces of the components against a heated flat plate, which is usually coated with PTFE and then bringing them together under controlled pressure. Butt welding also leaves a raised bead about the joint inside the pipe which will interfere with the flow. Tools are available to remove this internal bead but because this is not easily inspected for, installers may avoid this operation. Figure 5.28 shows the typical butt fusion welding for solid wall HDPE pipes.

Figure 5.28: Typical Butt Fusion Welding for Solid Wall HDPE Pipes

b. Spigot socket joints – For this joint one end of the pipe is opened up to act as the socket

of a moulded fitting and thereafter the butt fusion welding is carried out as shown in Figure 5.29.

Figure 5.29: Butt Fusion Welding of Spigot Socket Joints for Solid Wall HDPE Pipes


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2. Electrofusion is simpler than butt fusion but only applicable for small diameter of pipe up to

315 mm only. The heating and timing operations are all automatically undertaken by a control unit of the following procedures: - Electrofusion coupling slipped over the ends of the pipe to join - Resistance wires in the coupler are heated by a controlled electrical current - The coupler and pipe are melted and then fused to each other. The main deterrent to the use of electrofusion joints is their greater cost compare to the method of thermofusion welding.

3. Flange joints can be used when require jointing to fittings or pipes of other material and most

commonly used for larger diameter pipes. It consist either a full face or stub flanges welded to the pipe or alternately can be formed on the pipe. The rotational flexibility that this joint type provides is however compensated for by the longitudinal flexibility of polyethylene pipe. Figure 5.30 shows the typical flange joints of solid wall HDPE pipes.

Figure 5.30: Typical Flange Joints of Solid Wall HDPE Pipes

Flange joint for HDPE-HDPE pipes Flange joint for HDPE-steel pipes 4. Mechanical metal couplings do not provide the strength or long term performance as

compare to a properly made fusion joint and are only considered for some repair operations. There are wide ranges of plastic (acetal and GRP used) fittings for small diameters that use mechanical (compressed rubber seal) joints and development continue on larger sizes.

5.6.5 Fittings The fabricated fittings for solid wall HDPE pipes are available in sizes 225 and larger. It comprise of pipe sections that are fillet welded together to form the fitting configuration. Like the pipes,


91

Section 5 Sewer Pipeline - Material Selection (Force Main) fittings are also jointed by butt fusion. The various ranges of fabricated fittings for solid wall HDPE pipes are shown in Figure 5.31 below.

Figure 5.31: Fabricated Fittings for Butt Fusion of Solid Wall HDPE Pipes

The stub end and MS flange fittings are also available to jointing the HDPE pipes as shown in Figure 5.32.

Figure 5.32: Stub End and MS Flange Fittings for Solid Wall HDPE Pipes

Stub end MS flange There are several types of plastic fittings available, some of, which require the pipe to be specially form such as compression fittings and flange fittings. The compression fittings are effected by the use of components of plastics or rubber material. Schematics of typical plastic compression fittings are shown in Figure 5.33.

Figure 5.33: Plastics Compression Fittings for Solid Wall HDPE Pipes

Straight coupler Elbow coupler Tee coupler Saddle

5.6.6 Pipeline Hydraulic Design Colebrook-White roughness coefficients (ks) recommended for hydraulic design of profile wall HDPE pipes as force main are as Table 5.19 below:

Table 5.19: Colebrook-White Roughness Coefficient (ks) for Solid Wall HDPE Pipes

Mean velocity (V ), m/s Roughness (Ks,), mm

0.8 ≤V≤ 1.5 0.6 1.5 ≤V≤ 2.0 0.3

V≥ 2.0 0.15

5.6.7 Application of Pipes


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Section 5 Sewer Pipeline - Material Selection (Force Main) The application of solid wall HDPE pipes for force main may subject to certain conditions and limitations as described in Section 3, Table 3.2 and Table 3.3. Table 5.20 below lists the advantages and disadvantages of solid wall HDPE pipes for this application.

Table 5.20: Advantages and Disadvantages of Solid Wall HDPE Pipe


• Lighter than DI and steel pipes. • Longer pipe lengths than DI pipe is

available. • Immune to H2S attack. • Pipes can be cut to length on site.

Simpler to cut than non-plastics. • Infiltration and root intrusion eliminated

with electrofusion and butt welded joints properly made.

• Pipeline will bend to conform to subsidence under pipe.

• Resistant to UV degradation (due to carbon black light stabiliser).

• Pipe lengths can be assembled out of the trench, where welded.

• Welding permits continuous pipe lengths to be made for slip lining.

• Narrower trench than with DI and steel pipes is permissible.

• Side fill support required to prevent excessive pipe flexure and Any disturbance of pipe side support may affect performance.

• Bedding requirements more stringent than for rigid pipes.

• PE degraded by high concentrations of certain chemicals, such as solvents after long contact.

• For PE welding to be effective, the welding area must be clean and dry.

• Where butt or fillet welding is required, special welding equipment is used. Trained equipment operators are required to ensure a satisfactory weld.

• Pipes are susceptible to damage from heavy impact loads.

• Pipes can be distorted in hot weather, that is, ovalisation and bending along length.

• Pipe length changes more with temperature change than other plastics. Pipes laid in hot weather can shorten after backfilling causing possible damage.

• Butt welding leaves an internal bead to cause sewer snagging and fouling. Remote controlled devises are available overseas to remove beads but not readily obtainable in Malaysia.

• Welding between different grades of polyethylene is not possible.


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Section 6 Sewer Pipeline – Material Selection (Vacuum Sewerage System)

6.0 VACUUM SEWERAGE SYSTEMS

6.1 General Vacuum sewerage system shall only be considered where the life-cycle costs of a conventional gravity sewerage system are clearly shown to be higher. The application of this system is considered when all sewage transportation modes have been identified, their respective feasibilities evaluated against technical, environmental, financial, economic and other relevant criteria over the design life of the asset and that the vacuum sewerage system has been confirmed as the best option. The net present value (NPV) calculations shall be submitted to DGSS for all options prior to approving construction of a vacuum sewerage system. Vacuum sewerage system is suitable for application in the following conditions: • Unstable soil likely to settle • Restricted construction access Typical sizes of the pipelines of the system are as follows: • Branch lines - dn 90 mm to dn 150 mm • Main lines - dn 150 mm to dn 250 mm Pipeline types approved for vacuum sewers are mainly from the plastic pipes which are: • ABS pipe (for internal use) • Solid wall HDPE pipe (for external use)


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6.2 Acrylonitrile Butadiene Styrene (ABS) Pipe The design data and specifications of ABS pipes for vacuum sewerage system are summarised in Table 6.1 below:

Table 6.1: Summary of ABS Pipes Design and Specifications for Vacuum Sewerage System

Summary Material Acrylonitrile, Butadiene and Styrene Nominal Diameter, mm DN 10 to 200 mm Standard Effective Length, m 6.0 m Classes: Pressure Class (PN)

Conform to MS 1419:Part 1: 1997 Class 4.5, 6, 9, 12, 15, T

Jointing Method • Spigot-socket with solvent cement welding joint • Stub flange joint




MS 1419:Part 1 to 3: 1997 MS 1419: Part 4 : 1998 AS 3518: Part 1 & 2: 1988 AS 3690: 1989 AS 3691: 1989 BS 5391: Part 1 BS 5392: Part 1 AS 2566.1: 1998 AS 2566.2: 2002


For special circumstances with prior approval from DGSS, which require the benefits of such pipe

Approved Manufactures/Suppliers Refer to Table C1 and DGSS latest approval list


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6.2.1 Manufacture Material compositions and manufacturing process of ABS pipes for vacuum sewerage system are same as the compositions and method to produce ABS pipe for force main as described in Section 5.5.1. The various forms of ABS pipes is produced depending on their jointing method and application as shown in Figure 5.22, Section 5.5.1.

6.2.2 Protective Coatings/Linings The protective coating and lining is not required for ABS pipe since the material itself can resist the corrosion attack from the sewage.

6.2.3 Sizes/Classes Nominal size (DN) is commonly used as a numerical designation of the outside diameter of ABS pipe. The ABS pipe without couplings shall conform to the dimensions recommended in MS 1419: Part 1-1997 as given in Table 6.2 below.

Table 6.2: Dimensions of ABS for Vacuum Sewerage System

Mean Outside Diameter, Dm Nominal Size (DN) Min Max

10 17.0 17.3 15 21.2 21.5 20 26.6 26.9 25 33.4 33.7 32 42.1 42.4 40 48.1 48.4 50 60.2 60.5 80 88.7 89.1

100 114.1 114.5 150 168.0 168.5 200 218.8 219.4

Pipe lengths show the standard overall length of the pipe, exclusive of coupling, of 6 + 0.05, - 0m. All measurements shall be adjusted to an equivalent length at 20ºC. The ABS pipe can be cut at site to the desirable length. However, care must be taken to ensure squareness of cut ends. Classes of ABS for force main are defined according to maximum static working pressure at a pipe material temperature of 20°C, as Table 6.3 below:

Table 6.3: Classifications of ABS Pipes for Vacuum Sewerage System

Class of Pipe Maximum Static Working Pressure, MPa Class 4.5 0.45 Class 6 0.60 Class 9 0.90 Class 12 1.2 Class 15 1.5 Class T 1.2 after threading

(Ref: MS 1419: Part 1: 1997, page 3)


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6.2.4 Joints The methods of jointing ABS pipes for vacuum sewerage system are as following: 1. Spigot-socket with solvent cement welding joint

This jointing as shown in Figure 6.1 is commonly used for ABS pipe. The jointing process shall be properly performed to provide an ideal joint for the elimination of infiltration and root intrusion.

Figure 6.1: Typical Spigot-socket with Solvent Cement Joint of ABS Pipes

2. Stub flange joint

The flange is required to be solvent cemented onto a spigot end. The stub flange requires the use of a backing plate and a rubber gasket between the flanges for specific joint application. Figure 6.2 shows the typical stub flange for ABS pipes.

Figure 6.2: Typical Stub Flange Joint for ABS Pipes

(Ref: Azeeta Pipe System Catalogue)

The jointing of ABS pipe requires special trainings because of the care required to make a solvent cement joint, particularly in large diameters. Solvent cement shall consist of one or more solvents and a sufficient quantity of base ABS material dissolved in the solvents to give the cement the body and consistency required for proper application. Small amounts of inert fillers are added to control shrinkage during drying.

6.2.5 Fittings ABS fittings for making of junction connections are available and it can be injection moulded or fabricated. The various range of fittings for ABS pipe for vacuum sewerage application are same as shown in Figure 5.26, Section 5.5.5.

6.2.6 Pipeline Hydraulic Design Colebrook-White roughness coefficients (ks) recommended for hydraulic design of ABS pipes for vacuum sewerage system shall be in accordance with those recommended for force main application described in Section 5.5.6.


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6.3 Solid Wall HDPE Pipe The design data and specifications of solid wall HDPE pipe for vacuum sewerage system are summarised in Table 6.4 below:

Table 6.4: Summary of Solid Wall HDPE Pipe Design and Specifications for Vacuum

Sewerage System

Summary

Material • High Density Polyethylene • Carbon Black • Antioxidants

Nominal Diameter (ID), mm DN 16 to DN 900 mm Standard Length, m 6.0 and 12.0 m Classes • Material Type • Pressure Class (PN)

PE 80, PE 100 PN 2.5 to a maximum of PN 16

Jointing Method •

•

Thermofusion welding a. Butt fusion welding b. Butt fusion welding of spigot socket joints Electrofusion


Not applicable Not applicable


CP 312: Part 1 & 3: 1973 SFS 3453 WIS 04-32-15 WIS 04-24-01 WIS 04-32-14 AS/NZS 2566.1: 1998 AS/NZS 2566.2: 2002


• •

•

Prior approval from DGSS is required Shall not be used in ground contaminated with high concentration of chemicals that can degrade the pipes Shall not accept any industrial or other aggressive discharges that may affect the pipe integrity.

Approved Manufactures/Suppliers Refer to Table C1 and DGSS latest approval list


98


6.3.1 Manufacture Material compositions and manufacturing process of the solid wall HDPE pipes are same with those specified for solid wall HDPE pipes applied for force main described in Section 5.6.1.

6.3.2 Protective Coatings/Linings External protection and internal protection is not required for solid wall HDPE pipes.

6.3.3 Sizes/Classes Nominal Outside Diameter, dn of solid wall HDPE pipes is a numerical designation of size to HDPE piping system other than flanges and components designated by thread size. It is a convenient round number for reference purposes. This diameter is fixed while the internal diameter varies depend on the classes. The increment is not constant and the sizing follows the adopted international standards for thermoplastic pipe for pressure applications. Standard length of pipe indicated the overall effective length of the pipe. HDPE solid wall pipes can be cut on site using most types of saws. Classes of solid wall uPVC pipes is designated by the material types, PE 100 and PE 80, which correspond to the level of minimum design strength at 20°C for up to 50 years. PE 80 and PE 100 show the capabilities of the pipes to withstand 80 bar (8 MPa) and 100 bar (100 MPa) of strength respectively. The maximum design stress is obtained by applying a design coefficient of 1.25 to the strength. PE is available in various compounds of different density and this alters the allowable stress that a pipe can withstand. The higher the allowable design stress, the thinner the wall for the same working pressure. Ring stiffness of 8 kN/m2 (8000 MPa) is generally taken as the minimum stiffness for smaller diameter pipe. Hence PE 80 with typical resins density of 950 to 955 kg/m3 is recommended for use in pressure sewerage. Working pressure is increased by increasing the wall thickness (to ensure pipe bores align at joints requires that each pipe have the same pressure class).

6.3.4 Joints The solid wall HDPE pipes and fittings less than DN 160 shall be jointed using electrofusion fittings. Pipes and fittings DN 160 and larger shall be jointed with electrofusion fittings or butt fusion welding.

6.3.5 Fittings The fabricated fittings for solid wall HDPE pipes are available in sizes 225 and larger. It comprise of pipe sections that are fillet welded together to form the fitting configuration. The various ranges of fabricated fittings for solid wall HDPE pipes are shown in Figure 5.31 to Figure 5.33, Section 5.6.5.

6.3.6 Pipeline Hydraulic Design Colebrook-White roughness coefficients (ks) recommended for hydraulic design of solid wall HDPE pipes for vacuum sewerage system shall be in accordance with those recommended for force main application described in Section 5.6.6.


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Section 7 Sewer Pipeline – Material Selection (Pipe Jacking)

7.0 Pipe Jacking

7.1 General

Jacking method of pipe laying shall be employed only when the conditions or the requirements of the responsible authorities require such a method. The pipes used for jacking shall be able to withstand the laterally induced jacking stresses of 2000 psi without damage.

The setting out of the guide rails for the pipe and the actual jacking operation shall maintain a high accuracy level of line and grade. The direction and grade for jacked sewer shall not deviate from the designed alignment for more than 100 mm for every 100 meters of sewer.

All the joints used for connecting the jacked pipes shall be watertight and durable.

The types of the pipe that approved by DGSS to use as the pipe jacking are of the following: • Vitrified Clay (VC) Pipe • Reinforced Concrete (RC) Pipe


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7.2 Vitrified Clay (VC) Pipe The design data and specifications of VC pipes for pipe jacking are summarised in Table 4.3 below:

Table 7.1: Summary of VC Pipes Design and Specifications for Pipe Jacking

Summary Material Vitrified clay Nominal Size (DN), mm DN300 to DN600 mm Nominal Length, m Not specified in BS EN 295-7: 1995 Classes Conform to BS EN 295-7: 1995 Jointing Method Double spigot flexible joints with sleeve/collar Protective Coating • •

External Internal

With or without glazing (depends on the product) With or without glazing (depends on the product)

Standards • BS EN 295-1:1991 • BS EN 295-2:1996 • BS EN 295-2:1991 • BS EN 295-7:1995



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7.2.1 Manufacture

Material compositions and manufacturing process of VC pipes for pipe jacking is same as applied for gravity sewerage system as described in Section 4.2.1. Only double spigot type of VC pipe can be used for the pipe jacking application as shown in Figure 7.1 below.

Figure 7.1: Type of VC Pipe for Pipe Jacking

Double spigot pipe

7.2.2 Protective Coatings/Linings

The protective coatings and linings of the VC pipes for pipe jacking has the same components with the VC pipes used for gravity sewerage system, as described in Section 4.2.2.

7.2.3 Sizes/Classes Nominal size (DN) is a numerical designation of the internal diameter of VC pipes. The internal and external diameter of the barrel of a pipe shall not deviate from the manufacturer’s stated value by an amount greater than that shown in Table 7.2 below:

Table 7.2: Tolerance on Internal and External Diameter of VC Pipes for Pipe Jacking

Tolerance on Stated Diameter Nominal Size (DN), mm

Internal External ≤ 300 ± 5 - 10 400 ± 6 - 12 500 ± 7.5 - 15 600 ± 9 - 18 800 ± 12 - 24

> 800 ± 15 - 30 Length of VC pipes for pipe jacking shall have the tolerance of ± 2 mm on the manufacturer’s stated nominal length. The length shall be measured at 90º intervals around the circumference. The tolerance applies to the mean of these measurements. Classes of VC pipes for pipe jacking is defined by the various types of strength specified herein, which used in structural design calculations. a. Crushing strengths (FN) of VC pipes or pipe sections shall be not less than 28 kN/m for

pipes of nominal size DN 100 and DN 150. The crushing strength for VC pipes with nominal sizes greater than DN 150 shall be same as specified for gravity sewerage system as tabulated in Table 4.5, Section 4.2.3.

b. Compressive strength of VC pipes for pipe jacking shall not be less than 75 N/mm2.


102


c. Jacking strength shall be determined in accordance with BS EN 295-7:1995 by applying the load without shock and increase it at a convenient rate not exceeding 35.0 N/mm2.min up to half the maximum anticipated load. The test shall be done of at least 10 specimens cut from the same pipe.

d. Design jacking load shall be declared by the manufacturer. This will depend on jacking strength and on the specific design of the joint and packing ring.

e. Maximum working jacking load shall be determined by using factors of safety of either 1.6 for automatically steered jacking machines or 2.0 for manually steered systems.

7.2.4 Joints Jointing materials of VC pipes for pipe jacking are of the following types: 1. Rubber sealing elements

Rubber sealing elements shall be in accordance with BS EN 295-1: 1991 as described in gravity sewerage system, Section 4.2.4.

2. Polyurethane sealing elements Polyurethane sealing elements shall be in accordance with BS EN 295-1: 1991 as described in gravity sewerage system, Section 4.2.4.

3. Stainless steel sleeves The corrosion resistance of stainless steel shall be equal or greater than the resistance of austenitic stainless steel with minimum chrome content of 17% and minimum nickel content of 8%. The sleeves shall be edge dressed and free from sharp edges. The internal surface of the sleeve shall be finished to provide a sealing surface.

4. Polypropylene sleeve couplings Polypropylene sleeve couplings shall meet the requirements of BS EN 295-1: 1991 as following:

Melt flow index - ≤ 1.5 times nominal value • • •

Tensile strength - ≥ 20 N/mm2 Elongation at break - ≥ 200%

5. Materials of other components Components of other materials shall comply with the relevant European Standards or the manufacturer’ declared specifications, which shall also include requirements for long term behaviour.

Angular deflections of the joints assembly shall be deflected by the method described in BS EN 295-3:1991 by the values in Table 7.3 and when so deflected shall withstand constant pressure of not less than both 5 kPa (0.05 bar) and 50 kPa (0.5 bar) for 5 min without visible leakage.

Table 7.3: Allowable Angular Deflection of VC Pipes for Pipe Jacking

Nominal Size (DN), mm Minimum deflection per meter of deflected pipe length, mm

≤ 800 20 > 800 10

(Ref: BS 295-7: 1995, page 6)

7.2.5 Pipeline Hydraulic Design The pipeline hydraulic design of VC pipes for pipe jacking shall have a low hydraulic roughness and shall be in accordance with BS EN 295-7:1995 as described in Section 4.2.6.


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7.3 Reinforced Concrete (RC) Pipe The design data and specifications of RC pipes for pipe jacking are summarised in Table 7.4 below:

Table 7.4: Summary of RC Pipes Design and Specifications for Pipe Jacking

Summary

Material • • • •

Cement Aggregates Water Reinforced steel with hard drawn wire

Nominal Size (DN), mm DN 300 to DN 3000 Effective Length, m •

• ≤ DN 600 : 3.0m maximum > DN 600 : 0.45m to 5.0m

Classes • Conform to BS 5911-1:2002 and AS 4058:1992 Jointing Methods •

• •

Rebated/ogee joint with rubber ‘O’ ring Rebated/ogee joint with cement mortar filling Double spigot joint with collar/ butt joint with collar


• • • •

External Internal

Bare DN < 1000 : High alumina cement mortar lining DN ≥ 1000 : HDPE/PVC lining is preferred Sacrificial concrete lining is an alternatives

Standards Manufacture BS 5911-1:2002 Approved Manufacturers/Suppliers Refer to Table D1 and DGSS latest approval list.


104


7.3.1 Manufacture Material compositions and manufacturing processes of RC pipes for pipe jacking is same as applied for gravity sewerage system as described in Section 4.3.1. The RC pipes for pipe jacking shall be compacted so that when hardened they shall be free from honeycombing and from any individual large void greater than 6mm. Surface of the pipes shall be free from voids of less than 12mm deep. The RC pipes for the pipe jacking can be manufactured into two different types of pipe as shown in Figure 6.3 below:

Figure 7.2: Types of RC Pipes for Pipe Jacking

Pipe with rebated joint Pipe with butt-end joint and collar

7.3.2 Protective Coatings/Linings External coating and internal linings of RC pipes for pipe jacking shall be in accordance with those specified for gravity sewerage system as described in Section 4.3.2.

7.3.3 Sizes/Classes Nominal size (DN) and effective length of RC pipes for pipe jacking is similar to the RC pipes used for gravity sewerage system as described in Section 4.3.3. Crushing strength of RC pipes shall be tested in compliance to BS 5911-1: 2002. The maximum, work proof and ‘no-crack’ crushing load of RC pipes for pipe jacking shall be as Table 7.5 below:

Table 7.5: Crushing Loads of RC Pipes for Jacking Pipe

‘No-crack’ Load Works Proof Load Maximum Load Nominal Size (DN),

mm Kilonewtons per metre of effective length 900 55 88 110

1050 60 96 120 1200 70 112 140 1350 80 128 160 1500 85 136 170 1650 95 152 190 1800 100 160 200 1950 100 176 220 2100 100 184 230 2250 105 200 250 2400 105 216 270 2550 105 224 280 2700 110 240 300 2850 110 256 320 3000 110 264 330

(Ref: BS 5911: Part 120: 1989, page 10)


105


7.3.4 Joints The joint methods for RC pipes are generally of the following types: 1. Flexible rebated/ogee joint with rubber ‘O’ ring is used to joint the rebated pipes as shown

in the following Figure 7.3.

Figure 7.3: Typical Flexible Joint of Rebated/Ogee RC Pipes

Rebated joint with rolling rubber ring Rebated joint with confined rubber ring (Ref: BS 5911: Part 120: 1988, page 8) 2. Rigid rebated/ogee joint with cement mortar filling is more commonly used for rigid

pipeline installation, like jacking pipe where flexibility is not required. 3. Double spigot joint with collar/ butt joint with collar is usually used for pipe jacking

application. Figure 7.4 shows the typical double spigot joint with collar.

Figure 7.4: Typical Double Spigot Joint with Collar of RC Pipes

Double spigot joint with collar and rolling rubber ring

Double spigot joint with collar and confined rubber ring

(Ref: BS 5911: Part 120: 1988, page 8)

The collars shall be fabricated from stainless steel 316 plate or glass reinforced plastic (GRP) or other non-coated corrosion resistant metal and shall not be attached to reinforcement.

Angular deflections of the RC pipes for pipe jacking shall be tested in accordance with BS 5911-1:2002 which is not less than that given in Table 7.6 below.

Table 7.6: Minimum Angular Deflection and Straight Draw Joints of RC Pipes for Pipe Jacking

Nominal Size (DN), mm Minimum Angular Deflection Minimum Straight Draw, mm

DN 900 to DN 1200 1° 20 DN 1350 to DN 1800 1/2° 20 DN 1900 to DN 3000 to be stated by the manufacturer

(Ref: BS 5911: Part 120: 1988, page 11)

7.3.5 Pipeline Hydraulic Design The pipeline hydraulic design of RC pipes for pipe jacking shall have a low hydraulic roughness and shall be in accordance with BS 5911-1:2002 as described in Section 4.3.6.


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Section 8 Sewer Pipeline - Design Guide

A Guide to Sewer Selection and Installation13th November 2006

107

8.0 SEWER PIPELINE - DESIGN GUIDE

8.1 GeneralThis section provides general guides on good practice and general concept on sewer pipelinestructural design and pipeline embedment. Detail requirements and procedures shall be referred tothe MSIG Volume 3 and DGSS Design Manual series as well as other relevant standards.

General concept and requirements on the pipeline structural design and pipeline embedment ofeach type of pipe material are provided in this section. The purpose of this section is to serve as aquick guide to the designer for the selection of sewer pipeline system.

8.2 Rigid Pipe

8.2.1 Vitrified Clay (VC) Pipe

8.2.1.1 Pipeline Structural DesignThe basis of structural design for VC pipeline is to determine whether the crushing strength of thepipe, enhanced by a field supporting strength can support the working loads under actual fieldconditions. The field supporting strength of VC pipe is materially affected by the method ofinstallation. It is dependent upon two factors:1. The inherent strength of the pipe;2. The bedding of the pipe.

The factor of safety of greater than 1.0 and less than or equal to 1.5 shall be applied to the fieldsupporting strength to determine a safe supporting strength for the installed VC pipe.

The allowable working load to the crushing strength of the VC pipe under the actual fieldcondition is determined by the bedding factor. The magnitude of the bedding factor is depended onthe type of bedding. The higher the bedding factor, the higher the height of support from materialplaced at the side of the pipe. Thus, the permissible loading on VC pipe increases as the beddingfactor increases.

The types of working loads considered on installed VC pipe are due to:a. Materials covering the pipes;b. Superimposed dead load; andc. Superimposed live loads.

The working loads, due to the dead load of trench fill or in-situ material is proportionately to thetrench width. It is increases as the trench width, measured at the top of the pipe, increases. So, thetrench width shall be kept as narrow as possible.

The live loads may be produced by wheel loading, construction equipment or by compactioneffort. The impact factor of 2.0 shall be applied for wheel or tracks loads including constructionand other equipment.

The working load on pipes due to the mass of water carried by the pipe may be disregarded.

The compaction method shall be properly selected so that the combined dead load and live loaddoes not exceed the field supporting strength of the pipe, or cause a change in its properties orgrade.



108

Structural design of VC pipe is to be performed in accordance to:a. MSIG Volume 3;b. BS EN 752:1997 – Drain and sewer systems outside buildings;c. AS 4060:1992 – Loads on buried vitrified clay pipes; andd. ASTM C 12 – 9: Standard practice for installing vitrified clay pipelines.

8.2.1.2 Pipeline EmbedmentThe pipeline embedment method as described in the ASTM C 12 – 91 recommended four classesof bedding (Class ‘A’, Class ‘B’, Class ‘C’ and Class ‘D’) and two encasement (concreteencasement and crushed stone encasement) for VC pipe installation in trenches to achieveimprovements in allowable loading.

However, there are only two bedding and one encasement for pipeline embedment defined inASTM C 12 – 9 have been used for the installation of VC sewer pipeline, in line with thoserecommended in MSIG 3, which are:1. Class ‘A’ bedding;1. Class ‘B’ bedding; and2. Concrete Encasement

The constructions of this pipeline embedment method for VC pipe installation are describedbelow.

1. Class ‘A’ beddingThis class of bedding can be achieved by either of two construction methods as shown inFigure 8.1 below:

Figure 8.1: Construction Method of Class ‘A’ Bedding

Concrete Cradle

Concrete ArchNote: p is the ratio of the area of steel to the area of concrete.

(Ref: ASTM C 12 – 91, page 8)

ODCompacted Selected

Backfill Material300mm(min)

0.25 OD0.25 ID or100mm (min)

Bedding Factor: 3.4, p:

Grade 20 ConcreteTransverse Steel

OD

ID

CompactedSelected Backfill

Material

Grade 20Concrete

Bedding Factor: 3.4, p: 0.4%

Granular WellCompacted Material

0.25 ID or100 mm (min)

OD

0.5 OD

0.25 OD or100 mm (min)

ID

Transverse Steel



2. Class ‘B’ beddingThe typical drawing of this class of bedding is shown in Figure 8.2 below:

Figure 8.2: Construction Method of Class ‘B’ Bedding

(Ref: ASTM C 12 – 91, page 9)

3. Concrete EncasementThe typical drawing of this concrete encasement is shown in Figure 8.3 below:

Figure 8.3: Construction Method of Concrete Encasement

In the installation of VC sewer pipeline under the• Crossing a drain; or• Crossing a road; or• Installation depth ≥ 900mm and < 1200mmonly the Class ‘A’ bedding and concrete encasem

Otherwise, Class ‘B’ bedding is permissible to be

The concrete support and encasement shall hrecommended that wire mesh reinforcement or unbar be used in the concrete support design.

A compacted selected backfill material shall bematerial and large stones.

OD

Bedding Factor: 1.9

Compacted SelectedBackfill Material

Granular WellCompacted

Material

30mm(min)

0.5 OD

0.125 ID or100 mm (min)

ID

OD

Bedding F

VC Pipe

Grade 20Concrete

IDID

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circumstances of:

ent is permitted for the installation of VC pipe.

applied for the installation of the VC pipe.

ave strength grade not less than Grade 20. It isiformly distributed small diameter reinforcement

of finely divided material free of debris, organic

actor: 3.0

0.25 OD or100mm (min)



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A granular well-compacted material for pipe support shall mean material that has been spadedor shovel-sliced so that the material fills and supports the haunch area and encases the pipe to thelimits. It shall be using of well-grade not more than 20 mm particles size of crushed stone or othernon-consolidating bedding material not subject to migration. This particle size is effective becauseit can readily achieve a density close to its optimum with little compacting effort. The granularsupport may require cement stabilisation for certain in situ conditions such as on steep slopes.

The degree of compaction for the granular bedding and haunch support, measured by the densityindex (ID), shall not be less than 60 percent to prevent any damage to the pipe.

8.2.2 Reinforced Concrete (RC) Pipe

8.2.2.1 Pipeline Structural DesignThe basis of the structural design of RC pipeline is to determine whether the cracking load of RCpipe, enhanced by pipe support and bedding can withstand of the following types of the verticalload:1. Working load due to the fill material;2. Working load due to superimposed dead load;3. Working load due to superimposed live load.

The assessment of working loads on the RC pipe is dependent on the factors of:1. Height of the fill material above the top of the pipe;2. Assessed unit weight of the fill material;3. Magnitude and nature of any superimposed loads;4. Type of bedding, support and foundation materials;5. Pipe installation conditions;6. Width of trench;7. External diameter of pipe.

A bedding factor shall be applied to working loads, for the purpose of test load of the RC pipeline.The bedding factor of 1.5 is taken for all live loads irrespective of the type of pipe supportprovided.

The bedding factor for working dead load is dependent on the type of pipe support provided. Thehigher the bedding factor, the higher the height of support from material placed at the side of thepipe. Thus, the permissible loading on the RC pipe increases as the bedding factor increases.

The working dead loads due to fill or in-situ materials are dependent on the trench width measuredat the top of the pipe. The narrower the trench width, the lesser the working dead loads on thepipeline.

An impact effects shall be taken into account for all live loads imposed by wheel loads, vehicleloads, railway loading, construction equipment loads and other equipment loads. An appropriateimpact factor shall be applied to the live loads for the installation of the RC pipe.

The vertical working load on pipes due to the mass of water carried by the pipe may bedisregarded for pipe less than 1800 mm diameter but should be considered for larger diameterpipe.

Structural design of RC pipe is to be performed in accordance to MSIG Volume 3 and AS 3725 –1998 – Loads on Buried Concrete Pipe.



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Haunch Zone, yBed Zone, x

Type 1 CompactedSelect Fill Material

Haunch Zone, yBed Zone, x

Grade 20Concrete

8.2.2.2 Pipeline EmbedmentThe pipeline embedment method of RC pipe as described in AS 3725:1989, recommended threemajor types of pipe supports of RC pipe, which are:1. Type U support;2. Type H support comprises of type H1, H2, H3; and3. Type HS support comprises of type HS1, HS2, HS3.

However, only type H and HS support defined in AS 3725:1989 have been normally used for theembedment of RC sewer pipeline, in line with those recommended in MSIG 3, which are:

1. Type H SupportThe typical drawing of type H1 and type H2 support is shown in Figure 8.4 below:

Figure 8.4: Construction Method of Type H1 and Type H2 Support

(Ref: AS 3725-1989, page 16)

The typical drawing of type H3 support is shown in Figure 8.5 below:

Figure 8.5: Construction Method of Type H3 Support

(Ref: AS 3725-1989, page 17)



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2. Type HS SupportThe typical drawing of type HS support is shown in Figure 8.6 below:

Figure 8.6: Construction Method of Type HS Support

(Ref: AS 3725-1989, page 17)

The compositions of fill material for RC pipeline embedment are shown in Table 8.1 below:

Table 8.1: Compositions of Fill Material for RC Pipeline Embedment

Type of Fill Particle/AggregateSize (mm) Composition

Type 1 Type 2Select Fill≤ 75 ≤ 20

Conforms with the following soil classes:1. SC – clayey sands with fines of low plasticity;2. SP – poorly graded sand;3. SW – well graded sand;4. GC – clayey gravels with fines of low plasticity5. GW – well graded sand and gravel mixtures with

little or no plastic fines;6. GP – poorly graded sand and gravel mixtures with

little or no plastic finesOrdinary Fill 75 to 150 Mass of stone is not more than 20%

The bedding factors for dead loads for various types of pipe support shall be not greater than thevalues in Table 8.2 as recommended in AS 3725-1989.

Table 8.2: Bedding Factors for Working Dead Loads for Various Types of Support

Minimum Depth, mm

Bed Zone Haunch ZoneSupport TypeX Y

MaximumBedding Factor

(f)

H H1 0.1D 1.5H2

O.D ≤ 1500 : 100O.D > 1500 : 150 0.3D 2.0

H3 0.25O.D but not less than 100 0.3D 2.5HS HS1 0.1D 2.0

HS2 0.3D 2.5HS3

O.D ≤ 1500 : 100O.D > 1500 : 150 0.3D 4.0

(Ref: AS 3725-1989, page 18)

Type 2

Type 1



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The compressibility of the side support will affect the loading. The lower the compressibility ofthat side support, the higher the possible loading, i.e. the more densely the embedment iscompacted, the higher the load. Embedment materials need to be placed in layers not exceeding250 mm in depth to ensure that any compaction will achieve a uniform increase in densitythroughout the depth of the layer.

Concrete cradle could also be used to achieve a high enhancement of pipe strength. The use ofconcrete support is not desirable due to difficulties achieving the close fitting of the concrete to thepipe. Concrete undergoes shrinkage, and if the concrete is too wet, it can result only in pointsupport of the concrete for the pipe.

With the high strengths to which reinforced concrete pipes can be made today it is normally notnecessary to use concrete support for the type of trench installation loadings encountered bysewerage pipes.

8.3 Flexible PipeThe pipeline structural design and pipeline embedment method of flexible pipeline recommendedin this part of the section is applicable for all types of flexible pipes conveying sewage for bothpressure and non-pressure applications that are manufactured from the materials listed in Table8.3, and that are:1. Homogeneous or composite;2. Creep affected (plastics) or unaffected (metallic); or3. Plain or structural wall

Table 8.3: Typical Flexible Pipe Materials

Plastics MetallicAcrylonitrile butadiene styrene (ABS) Ductile Iron (DI)

Glass filament reinforced plastics (GFRP) SteelPolyethylene (PE)

Additional requirements on the pipeline design and pipeline embedment for the specific type ofpipe material are described in the following clause of this section.

8.3.1 Flexible Pipeline Structural DesignThe basis of flexible pipeline structural design is to select appropriate embedment materialdensities and pipe stiffness for the particular loading and native soil stiffness so that values forvertical ring deflection, circumferential pipe wall strain and ring buckling resistance do not exceedallowable longer long term values.

The structural design of flexible pipelines relies primarily upon side support to resist vertical loadswithout excessive deformation by adopting an elliptical shape.

The basis design of the pipeline for flexible pipe is to determine whether:1. The loads acting on the pipe due to fill and superimposed load can causes vertical diametral

deflection in the pipe resulting in bending stresses; and2. The effect of internal pressure in a pipe can introduce a uniform stress in the wall of the pipe.

The installation of pipeline shall be designed to give no more than 5% vertical diametral deflectionin the empty pipe condition.



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For carrying out a pipeline design of flexible pipe, it is dependent on the factors of:1. The height of the fill material above the top of the pipe;2. The maximum density of the fill material;3. The magnitude of any loads superimposed on the fill material and the nature of the loads, e.g

whether the loads are distributed or concentrated, static or dynamic.4. Pipe installation condition;5. The width of the trench;6. The mean outside diameter of the pipe;7. The type of bedding as defined by the bedding factor value.

The effect of impact causes by the dynamic superimposed loads, road vehicle loading and railwayloading shall also be taken into the consideration for designing the sewer pipeline for flexible pipe.

Floatation of the pipeline shall be prevented before any further pipe laying by either, placementand compaction of sufficient height of fill material over the installed pipeline, or by filling thepipeline with water to prevent floatation.

Compaction equipment or methods that produce horizontal or vertical earth pressures on thepipeline, which can cause damage or excessive distortion to the pipeline, shall not be used.

Structural design of flexible pipe is to be performed in accordance to MSIG Volume 3 and AS2566.1- 1992 – Structural Design for Buried Flexible Pipelines.

8.3.2 Flexible Pipeline Embedment

The typical drawing of the embedment method for flexible pipe as described in AustralianStandard AS/NZS 2566.2:2002 – Installation for Buried Flexible Pipelines is shown in Figure 8.7.

The embedment material for the flexible pipe shall be in accordance with AS/NZS 2566.2:2002which:1. Comply with the maximum particles size of Table 8.4 and be of particle size and grading that

will allow the specified relative compaction to be achieved with the intended compactionmethods;

Table 8.4: Maximum Particle Size of Embedment Material for Flexible Pipeline

Nominal pipe diameter,DN

Maximum particle size,mm

< 100 10> 100 ≤ 150 14

> 150 20

2. Contain no organic material that will affect embedment material performance;3. Be free of materials that would be physically and chemically harmful to any pipeline

component, including any protective coating; and4. For unprotected metallic pipes, be a granular fill with a resistivity greater than 50 ohm.m.

The higher the granular content of the embedment material, particularly higher gravel content, themore supportive it becomes to the pipe, where an equivalent compactive method is used.

Sharp granular embedment material should not be used with some pressure pipe materials as it caneither score the external surface of the pipe, or damage the protective coatings and sleeving.



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The materials for flexible pipeline embedment shall be of the following:

1. Native soils, especially cohesionless soils containing of sand or coarse-grained soil with lessthan 12% fines and particles size less than 20mm. Sand prone to ‘bulk’ when moist shall beavoided. Whatever materials are used, ensure that the required density is to be met.

2. Imported cohesionless material containing of processed aggregates with nominal size ofgraded aggregate not more than 20mm. Graded aggregates are considered more susceptible tosegregation in transport and handling. Particular care shall be taken to remix or wash thismaterial to minimize the effect of segregation.

3. Other materials containing the gravel gradings of:a. Well graded crushed rock with particles size not more than 20mm;b. Crushed rock dust with particles size not more than 10mm; andc. Sand with particles size not more than 5 mm.

The application of this type of material embedment is to facilitate the achievement of the soilmoduli.

Where there is a possibility of migration of fines between the native soil and the embedment zone,a geotextile filter fabric, such as non-woven fabric made from filaments of synthetic fibres shall beprovided to ensure that the integrity of the side support to the pipe is not compromised.

The compacted bedding material surface shall be continuous, smooth and free of stones largerthan those 20mm, so as to provide a uniform support to the pipe. Following grading, and whererequired compaction, pockets for sockets, couplings, flanges or other projections shall beexcavated in the bedding material, so as to ensure the pipeline is fully supported along the pipebarrels. The bedding shall be provided with joint holes to ensure that the pipe rests on the barreland not the joint.

The side support and overlay material shall be placed in layers of appropriate thickness for themethod of compaction, to achieve the relative compaction or soil modulus specified. The sidesupport material shall be brought up evenly on each side of the pipe.

Ordinary fill shall be a material obtained from the excavation or imported and containing notmore than 20% by mass of rock with size between 75mm and 150mm and none larger than150mm.

Control of the relative compaction of soils in the side support zone during pipe installation is theusual means for ensuring the soil moduli will be at least equal to those assumed at design stage.

Each layer of the embedment material shall be compacted as recommended in Table 8.5 below inaccordance with AS/NZS 2566.2:2002.

Table 8.5: Minimum Relative Compaction of Embedment Material for Flexible Pipeline

Trafficable Areas Non-Trafficable AreasSoil Type Test Method Embedment

Material %Trench FillMaterial %

EmbedmentMaterial %

Trench FillMaterial %

Cohesionless Density Index(ID) 70 70 60

CohesiveStandard drydensity ratio(RD)

95 95 90

Compactionwill depend

on siterequirements



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Embedment material is to be compacted in layers not exceeding 250 mm or 0.4 of the pipe externaldiameter, whichever is less. Bedding is to be compacted with a vibrating plate.

Replacement of embedment material by alternative structural support may be required in thefollowing circumstances:a. Pipes are laid on steep grades;b. Forces, due to hydrostatic or hydrodynamic pressure, may not be contained by the embedment

material;c. The foundation for the pipeline is inadequate;d. The embedment material or native soil support may be washed away.

The concrete encasement shall be considered as an alternative embedment material where:a. Gradients are 30% or greater;b. Additional embedment material stiffness is required;c. The trench foundation is inadequate;d. Buoyancy considerations could result in excessive uplift forces; ande. The risk of erosion is high (such as through water course)

The requirements of the pipeline embedment for flexible pipe shall be in accordance with theAustralian Standard AS/NZS 2566.2:2002 - Installation for Buried Flexible Pipelines.

8.3.3 DI Pipe

8.3.3.1 Pipeline Structural DesignThe structural design sewer pipeline used with ductile iron pipe is referred to as flexible pipe withhigh ring stiffness design. The design combines elements of rigid pipe design and flexible pipedesign.

The basis of structural pipeline design for DI pipe is to provide a high degree of security for thepipeline during its operating life. It is dependent on the factors of:1. Pipe ovalization – is proportionately to diameter of pipe. It is limited to 4% for DN ≥ 800 with

safety factor of 1.5 at minimum elastic limit in bending of 500MPa and maximum stress in thepipe wall of 330 MPa.

2. Pressure from earth loading;3. Pressure from traffic loading;4. Bedding factor – depends upon the soil pressure distribution at the top of the pipe;5. Factor of lateral pressure;6. Modulus of soil reaction – depends upon the nature of soil used in the pipe zone and upon the

laying condition; and7. Heights of cover.

The failure mode of ductile iron pipe is from fracture through ring bending. The ductile iron crosssection can deform considerably before fracture, but not as great a deformation as that with plasticpipe. Sufficient load provided over the pipe can help to provide some resistance to the pipedeformation. For the loading situations normally encountered for sewerage pipelines, the sidesupport plays a negligible role in resisting the overburden loadings.

The cement lining of ductile iron pipe can suffer cracking with small deformations of the pipecross section. Hence, the limit placed on the vertical deflection due to cement lining governs thedesign and overrides any stress limit in the ductile iron due to bending.



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This deflection limit, however, although low compared to thermoplastic pipe, is not expected to beexceeded under the worst loading conditions for sewerage. It is therefore only necessary toundertake a structural design analysis for unusual loadings such as when a high load issuperimposed over a pipeline with shallow cover.

Structural design of DI pipe is to be performed in accordance with the British Standards BS 8010-2.1:1987 – Code of Practice for Ductile Iron Pipelines, BS EN 598:1995 (Annex C) – Ductile IronPipes, Fittings, Accessories and their Joints for Sewerage Applications.

Other than what has been required here, the structural design of DI Pipe shall be in accordancewith AS 2566.1-1992 as described in Clause 8.3.1.

8.3.3.2 Pipeline EmbedmentThe main functions of the embedment with ductile iron pipe are to ensure that the pipeline retainsany specified gradient and that the external corrosion protection system is not exposed to abrasionwith sufficient coating or tear by providing a sleeving.

The DI pipe is a flexible pipe that has a very high stiffness of most diameters, with maximumallowable vertical deflection of 1.5%. This high ring stiffness means that the pipe does not have aneed for the embedment to function as side support unlike other more flexible pipe such as plasticpipe. However, the bedding is still required to give uniform continuous support to the pipeline.

Crushed rock, even though it fulfils the side support requirements, is unsuitable as sharp rockedges can damage the external coating. Cohesive materials (e.g. clays, sandy clays, and silty clays)will not damage the coating but are difficult to place and compact to achieve sufficient sidesupport. The preferred embedment medium is sand.

The requirements of the pipeline embedment for DI Pipe other than what is required here shall bein accordance with the Australian Standard AS/NZS 2566.2:2002 as described in Section 8.3.2.

8.3.4 GRP Pipe

8.3.4.1 Pipeline Structural DesignThe structural design of GRP pipeline is to ensure that the assumptions made during design areachieved in the field. For non-pressure pipelines, the installed pipeline should be capable of takingthe maximum external water pressure. The pressure pipelines should be capable of withstandingthe combined effects of the maximum external water pressure and a complete internal vacuum.

For external loading, when correctly installed, GRP pipes shall have sufficient strength for allnormal conditions when operating at pressures up to their rated pressure.

It is necessary to consider the combined effect of internal and external loads to determine thebehaviour of the pipes. The factors taken into account should include the following:1. Type of installation2. Depth of burial;3. Type of traffic loading;4. Any additional surcharges;5. Native soil type;6. Height of water table;7. Maximum and minimum working pressure;8. Magnitude and frequency of any surge;9. Minimum and maximum operating temperatures.



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Because GRP pipes are flexible conduits which in the buried condition normally rely on the pipe-soil structure interaction for their load bearing capacity, it is important that the pipes are beddedand surrounded in a material which is capable of transmitting lateral thrusts from the pipe to thenative soil forming the trench wall and that the native soil does not become over-stressed.The backfill and compaction procedures are dependent on these factors:a. The classification and the density of the native soil;b. Groundwater levels along the length of the pipeline;c. Classes of pipe

Heavy mechanical compactors shall not be used within 300mm of the pipe crown.

Structural design of GRP pipe is to be performed in accordance with the British Standard BS 8010:Section 2.5: 1989 – Pipelines on land: design, construction and installation (Glass reinforcedthermosetting plastics).

Other than what has been required here, the structural design of GRP Pipe shall be in accordancewith AS 2566.1-1992 as described in Clause 8.3.1.

8.3.4.2 Pipeline EmbedmentThe GRP pipeline embedment method shall be in accordance with the AS/NZS 2566.2:2002 asdescribed in Clause 8.3.2.

8.3.5 Profile Wall HDPE Pipe

8.3.5.1 Pipeline Structural DesignThe basis of the profiled wall HDPE pipeline structural design is to determine whether the pipesatisfies the deflection at joints, compressive strain and buckling pressure resistance limits. For theparticular installation conditions, this requires the selection of the suitable combination of pipe classand embedment support.

Structural design of the profiled wall HDPE pipeline is to be performed in accordance withAS/NZS 2566.1:1998 as described in Clause 8.3.1 and British Standard BS 8010 - Pipelines onland: design, construction and installation.

8.3.5.2 Pipeline EmbedmentThe GRP pipeline embedment method and requirements shall be in accordance with AS/NZS2566.2:2002 as described in Clause 8.3.2.

8.3.6 ABS Pipe

8.3.6.1 Pipeline Structural DesignStructural design of ABS pipeline is to be performed in accordance with AS/NZS 2566.1:1998 asdescribed in Clause 8.3.1.

8.3.6.2 Pipeline EmbedmentAs with other flexible pipe, ABS pipe cannot support the soil overburden loading without theassistance of the material that surrounds the pipe. The embedment requirements as would apply toother thermoplastic pipe such PE are necessary.



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For underlay preparation, a minimum thickness of 75mm shall be provided in the bottom of thetrench. The overlay material should be levelled and compacted in layers to a minimum height of150mm above the top of the pipe trench.

The ABS pipeline embedment method and requirements pipeline is to be performed in accordancewith MS 1419: Part 4: 1998.

Other than what has been required here, the structural design of ABS Pipe shall be in accordancewith AS 2566.2-2002 as described in Clause 8.3.2.

8.3.7 Steel Pipe

8.3.7.1 Pipeline Structural DesignSteel pipe in the wall thickness normally offered come within the flexible pipe designation. Thering stiffness (the measure of flexibility) decreases as the pipe size increases. When compare toequivalent sizes of plastic pipelines, steel pipe are much stiffer than plastic pipe.

Steel pipes will not fail from circumferential tension like ductile iron pipe and unlined steel piperequire a limitation on deflection to prevent reverse curvature (buckling). The maximum verticaldeflection limit to prevent reverse curvature of steel pipe is 4.0%.

However, the cement lining of the steel pipe is prone to fracture and a deflection limitation of2.5% is required for buckling. The deflection limits for steel pipe with elastomeric joint thereforebecomes equivalent to that for cement lined ductile iron pipe, which is 1.5%.

For small diameter flexible pipe of medium stiffness as the steel pipe, experience has shown thatexcept for unstable ground conditions, the use of good quality embedment materials at the relativecompactions will ensure acceptable deflection with no structural design of pipeline is necessary.

It is therefore only necessary to undertake a structural design analysis for unusual loadings such aswhen a high load is superimposed over a pipeline with shallow cover.

Structural design of steel pipe is to be performed in accordance with AS 2566.1-1992 as describedin Clause 8.3.1.

8.3.7.2 Pipeline EmbedmentThe embedment medium for steel pipe is governed by the need to protect the external coating ofthe pipeline while providing pipe side support without great care in placement of the embedmentmedium.

Sand of equivalent density to crushed rock is less supportive than the crushed rock but the higherstiffness of steel pipe compared to plastic pipe, generally means that steel pipe will perform at leastas well as plastic pipe in terms of ovalisation.

The ABS pipeline embedment method and requirements pipeline is to be performed in accordancewith AS/NZS 2566.2:2002 as described in Clause 8.3.2.



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8.3.8 Solids Wall HDPE Pipe

8.3.8.1 Pipeline Structural DesignFor a buried flexible pipe to have long term structural adequacy, it is required that the combinedstiffness of the pipe ring and surrounding soil prevent pipe ring deformation and ringtension/compression/crushing stress limits being exceeded when external pressures (and possiblyinternal vacuum) are applied. Further, it is required that the flexible pipe have a minimum ringstiffness to prevent localised deformation when placing backfill around the pipe.

Structural design of solid wall HDPE pipe is to be performed in accordance with AS 2566.1-1992as described in Clause 8.3.1.

8.3.8.2 Pipeline EmbedmentThe use of polyethylene solid wall pipe is generally limited to special applications for pressuresewers. As with other flexible pipe, PE pipe cannot support the soil overburden loading withoutthe assistance of the material that surrounds the pipe. Where the PE pipe chosen is of equivalentstiffness to other plastic pipe then the same embedment conditions would be appropriate.

The solid wall HDPE pipeline embedment method shall be in accordance with AS/NZS2566.2:2002 as described in Clause 8.3.2.



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Figure 8.7: Terminology and Typical Construction of Pipe Support for Flexible Pipeline

l l

D D

l

D

l

B



122

Table 8.6: Notations Applicable in the Guidelines

Symbol Definition Unit ofmeasurement

BWidth of trench or embedment zone measured at thespringline of the pipe

mm

De Diameter of the most extreme external surface along the pipebarrel, averaged in two directions

mm

Di (Minimum) mean internal diameter, which is the average ofthe maximum and minimum internal diameters

mm

H Cover, vertical distance between the top of the pipe and thefinished surface

mm

ID Density index %

lb Depth of bedding below the bottom of the pipe mm

lc Horizontal distance between the spring line and the trenchwall or permanent trench support (not distance to temporarytrench supports)

mm

lo Depth of overlay mm

Ref.: Modified from AS/NZS 2566.2:2002, pg. 10

Table 8.7: Minimum Cover (H) for Flexible Pipeline

Loading condition Minimum cover Hm

Not subject to vehicle loading 0.30Land zoned for agricultural use 0.60Subject to vehicular loading –

(a) no carriageway;(b) sealed carriageways; and(c) unsealed carriageways

0.450.600.75

Pipelines in embankments or subject toconstruction equipment loads

0.75

Ref.: AS/NZS 2566.2:2002, pg. 16

Table 8.8: Minimum Embedment Zone Dimensions

Minimum dimension (mm)De lb lc lo B = De + 2lc

≥75, ≤150 100 100 100 275 – 350>150, ≤300 100 150 150 450 – 600>300, ≤450 100 200 150 700 – 850>450, ≤900 150 300 150 1050 – 1500>900, ≤1500 150 350 200 1600 – 2200

>1500, ≤4000 150 0.25De 300 2250 – 6000Ref.: AS/NZS 2566.2:2002, pg. 17

Section 9 Sewer Pipeline – Testing Guide, Site Handling and Installation


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9.0 SEWER PIPELINE – TESTING GUIDE, SITEHANDLING AND INSTALLATION

9.1 GeneralThis section specifies methods of test and their application to field testing of pipelines for thepurpose of determining pipeline acceptability. Field testing includes leak or hydrostatic pressuretesting and deflection testing, as appropriate, for pressure and non-pressure pipelines.

It is very often that the pipelines are not handling properly at site during loading, unloading andinstallation, thus resulted in necessary pipe cracking, improper joints etc. This section does notprovide details in handling and installation procedures and requirements as the information can beobtained from relevant standards and guidelines, but it emphasises on the good practices thatshould be adopted while handling various types of pipeline.

The common errors and recommended practices for site handling and installation of pipelines arepresented as an illustrated guide attached at the end of this section.

9.2 Field TestingThe types of field testing require for various sewer pipelines are summarised in Tables 9.1. Detailsof the testing requirements and constraints shall be referred to MSIG Volume 3.

Table 9.1: Summary of Field Testing for Sewer Pipelines

Pipeline System Type of TestTest for straightness and grade:- Laser beam with sighting targets;- Sight rails and boning rod;- Lamp and mirror;- Insertion of a smooth ball.Exfiltration test:- Hydrostatic test- Low pressure air testInfiltration testDeflection test

Gravity Sewer

CCTV InspectionTest for straightness, obstruction and grade:- Same as recommended for gravity sewer.Exfiltration test:- Same as recommended for gravity sewer.High pressure water testHigh pressure leakage test

Pressure Sewer

CCTV InspectionCheck the SDR of the pipe before installation (SDR is thethickness to diameter ratio of the pipe).

Vacuum Sewer

Vacuum test.



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9.2.1 General Pipeline Testing GuideThe following guides are generally applicable to all water, air and vacuum tests.

• The testing should be conducted before and after the backfilling of the trench.• The pipeline must be cleaned and cleared of obstruction before the test is conducted.• All plugs must be installed securely.• Concrete thrust blocks must be completed and cured before the test.• If solvent welding is used, the joint must be cured for at least 24 hours before testing.• Air test is easier to apply but results can be affected by small changes in temperature.• Water test is less stringent than air test but it suffers from the disadvantage of providing and

disposing of large quantities of water.• If the pressure drop is above that allowable limit on air testing, it is recommended to conduct

water test to confirm the result.• All air and vacuum testing of pipes shall be carried under the shade away from direct sunlight

to avoid temperature effects on the pipe.• Do not over-pressurise the pipelines to prevent sudden expulsion of a poorly installed plug.

Brief description on the procedures and requirements of the testing are given below. Detailedinformation of the testing can be obtained from MSIG Volume 3 and relevant standards.

9.2.2 Test for Straightness, Obstruction and GradeFor gravity sewers and pressure sewers, the grade and straightness are important to achieve thedesign velocity. The laser beam with sighting targets and sight rails and boning rod methods willprovide more exact assurance for both the grade and straightness, which shall be used wheneverpossible.

The lamp and mirror and insertion of smooth ball methods will provide a rough idea on whetherthe sewers are laid graded or straight, which should be used only for a quick check.

9.2.3 Low Pressure Air TestThe procedure of low pressure air test shall be as follows:

a. Pump in air slowly until a pressure of 25 +5,-0 kPa is reached. Where the pipeline is below thewater table this pressure shall be increased to achieve a differential pressure of 25 kPa. In nocircumstances should the actual pressure exceed 50 kPa.

b. Maintain the pressure for at least 3.0 min.c. Where no leaks are detected, shut off the air supplyd. Where the pipeline fails the test, repressurised to 25 +5,-0 kPa and check for leaks by pouring

a concentrated solution of soft soap and water over accessible joints and fittings.

The test length shall be acceptable, where the pressure drops by 7kPa, or less, over the requiredtest period.

9.2.4 Hydrostatic TestThe procedure of hydrostatic test shall be as follows:

a. The test pressure shall be not less than 20 kPa, or 20kPa above the ground water pressure atthe pipe soffit at its highest point, whichever is the greater, and not exceed 60 kPa at the lowestpoint of the section.



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b. Steeply graded pipelines shall be tested in stages where the maximum pressure, as statedabove, will be exceeded if the whole section is tested in one length.

c. The pressure shall be maintained for at least 2 hrs by adding measured volumes of water wherenecessary.

d. Any visible leaks detected shall be repaired and the pipeline shall be retested.

The test length shall be acceptable, where the addition of make-up water shall be 0.5 L/hour permetre length per metre diameter.

9.2.5 High Pressure Water TestThe procedure of high pressure water test shall be as follows:

a. Close all valves apart from the test pump input and pressurized the test length to the specifiedtest pressure or 1.5 times the design operating pressure;

b. Apply and then maintain the test pressure by the addition of measured and recorded quantitiesof make-up water at regular intervals over a period, within the range of 1 hr to 12 hr;

c. Where pressure measurements are not made at the lowest part of the test length, make anallowance for the static head, between the lowest point of the pipeline and the point ofmeasurement, to ensure that the test pressure is not exceeded at the lowest point.

There must be a drop in test pressure during the pressurised filling and in the next 10 minutes afterthe required pressure is achieved.

9.2.6 High Pressure Leakage TestThe test is normally conducted immediately after the high-pressure water test, i.e. before the wateris drained out. The test pressure mentioned in high water pressure test must be maintained for 24hours. The measure the amount of additional fill water requires to maintain the test pressure. Themeasured amount must not exceed 0.1 litre per millimetre of pipe diameter per kilometre of pipeper day for each 3 bars of pressure applied. Also check for visible leakage. The typical fieldpressure test equipment in AS/NZS 2566.2:2002 shown in Figure 9.1 below is recommended foradoption:

Figure 9.1: Typical Field Pressure Test Equipment Layout



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9.2.7 Vacuum TestThe procedures of vacuum test shall be as follows:

a. Apply a vacuum until a negative pressure of 25kPa to 30kPa is achieved.b. Maintain the vacuum for at least 3.0 min.c. Where no leaks are detected, isolate the test section from the vacuum pump.d. Where the pipeline fails the test, reapply the vacuum and check for leaks. Pouring water over

joints and fittings will improve the possibility of leaks detectable by auditory methods.

The test length shall be acceptable, where the vacuum drops by 7kPa, or less, over the test period.

9.2.8 Infiltration TestThe pipeline shall be observed for infiltration over a 24 hr period, or as appropriate. In all caseswhere infiltration is observed, the source shall be investigated, and any leak detected shall berepaired.

This method is applicable where a freestanding water table exists at a level of at least 1.5m abovethe test section and 150mm above any sideline connections.

9.2.9 CCTV InspectionInspection by CCTV shall in accordance to the procedures:-

1. Coverage

a. Initial CCTV testing & inspection shall be conducted for a minimum 10% random selection ofsewer pipeline in accordance with standard procedure.

b. If the mandatory requirement of clause 9.2.9-2 is less then 5% of the entire development area,the minimum CCTV testing & inspection is 10% as in 9.2.9-1a. If the mandatory requirementof clause 9.2.9-2 is more than 5%, the minimum CCTV testing & inspection shall have anadditional of 10%.

c. All new sewer pipeline shall undergo the CCTV inspection except:

i) Development with sewer length < 500m long with no interval.ii) Vacuum sewer.iii) Existing network to be taken over by SSD under the concessionaire agreement.

d. Prior to taking over existing network that has been approved from any owner or afterrehabilitation works have been completed.

2. Characteristics of 100% CCTV Inspection

A 100% CCTV inspection shall be conducted for sewer pipelines lay on ground with greater riskof failure and have the following characteristics.

b. Deeper than average of 6m or more.c. Pipe diameter above 600mm.d. Areas that are restricted vehicular access for repair when encounter failure (e.g. central

business district)e. Under buildings, lakes, rivers, roads and railway line.f. Ground slopes greater 30° inclination.g. All sewers installed using pipe jacking method.h. All diversion or re-alignment of existing sewer networks.



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3. Stage of Inspection

a. Stage 1 - All projects are to start with stage 1 inspection where 10% (by length) of sewernetwork and property connections involved, shall be randomly selected and CCTV inspected.

b. Stage 2 - Should any Grade 3,4 and 5 conditions as defined in the Manual for Sewer ConditionClassification approved by SSD, found in stage 1 inspection, the CCTV inspection shallproceed to stage 2 inspection. Stage 2 inspections shall include another 40% of the sewernetwork to be randomly selected for CCTV inspection.

c. Stage 3 - Should any Grade 3,4 and 5 conditions as defined in the Manual for Sewer ConditionClassification approved by SSD, found in stage 2 inspection, the CCTV inspection shallproceed to stage 3 where all the remaining network shall be CCTV inspected.

After the CCTV inspection and recording have been completed for a project, a report on the CCTVinspection together with the recording and recommendations shall be prepared by the CCTVcontractor and submitted to the relevant SSD branch office, 7 days after the date of inspection. Thecopy of the tape (or other recording media used to store the record) containing the CCTVinspection records shall be submitted together with the certificate duly signed by the qualifiedperson responsible for the CCTV inspection. The qualified person shall declare the authenticity ofthe recording submitted and that the CCTV inspection has been done in accordance with theprocedure.

9.3 Factory TestingThe types of factory testing require for various types of pipe for sewerage system are summarisedin Tables 9.2 below.

Table 9.2: Summary of Factory Testing for Various Types of Sewer Pipe

Types of PipeType of FactoryTestingVC RC DI GFRP Steel ABS HDPE

Visual inspection √Crushing test √ √Dimensions test √ √ √ √ √ √ √Deflection test √ √ √ √ √ √ √Shear resistance √ √Water absorption test √ √Straightness of pipe √ √ √ √ √ √Impermeability test √Tensile test √ √ √ √ √Brinell hardness test √ √Strain corrosion resistance test √Ovality test √Specific stiffness test √ √ √

Note: The test methods shall be referred to their respective standards.



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9.4 Site Handling and Installation Guide9.4.1 Dos and Don’ts

DOs DON’TsPipe Delivery

Site Handling

Site Unloading

Pipe Storage



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DOs DON’TsLoading to Trench

Excavation



DOs DON’TsPipe Bedding

Pipe Fitting

RUBBER RING JOINTS

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131

DOs DON’TsPlacement

Pipe Embedment



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Pipe Embedment

DOs DON’TsProtection



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9.5 Handling and Installation Practice

9.5.1 Storage

9.5.2 Excavation



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9.5.3 Pipe Cutting

9.5.4 Pipe Jointing



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9.5.5 Pipe Inspection

APPENDIX A

Checklist B

APPENDIX B

Product Details: Sewer Pipes andFittings Form

APPENDIX C

Evaluation Criteria Form

APPENDIX C

Summary of ApprovedSuppliers/Manufacturers

REFERENCES

1. Valve, Piping andPipeline Handbook

( 3rd Edition ), T.C.

2. Developer GuidelineVolume III

Sewer Networks and Pump Station ( 2nd Edition ) May 2002

3. Power and Water Water Supply and Sewerage Approved Products Manual

Malaysian Standards (MS)

1. MS 1058: 2002 Specification for polyethylene (PE) Piping systems for water supplyPart 1:General (Third revision)Part 2: Pipes (Third revision).

2. MS 1061: 1999 Vitrified clay pipes and fittings and pipe joints for drains and sewers3. MS 881: 1991 Specification for pre-cast concrete pipes and fittings for drainage

and sewerage4. MS 1419 Part 1: 1997: Pipes

Part 2: 1998: Guides for Installation of ABS Pipe System

British Standards (BS)

1. BS 5480:1990 Specification for glass reinforced plastics (GRP) pipes, joints andfittings for use for water supply or sewerage

2. BS 5911-1:2002 Concrete pipes and ancillary concrete products. Specification forunreinforced and reinforced concrete pipes (including jackingpipes) and fittings with flexible joints(complementary to BSEN1916:2002)

3. BS 6076:1996 Specification for polymeric film for use as a protective sleeving forburied iron pipes and fittings (for site and factory application)

4. BS 65:1991 Specification for vitrified clay pipes, fittings and ducts, also flexiblemechanical joints for use solely with surface water pipes and fittings

5. BS 8010-2.1:1987 Code of practice for pipelines. Pipelines on land: design,construction and installation. Ductile iron

6. BS EN 295-1:1991 Vitrified clay pipes and fittings and pipe joints for drains andsewers. Requirements

7. BS EN 295-7:1996 Vitrified clay pipes and fittings and pipe joints for drains andsewers. Requirements for vitrified clay pipes and joints for pipejacking

8. BS EN 545:2002 Ductile iron pipes, fittings, accessories and their joints for waterpipelines. Requirements and test methods

9. BS EN 598:1995 Ductile iron pipes, fittings, accessories and their joints for sewerageapplications. Requirements and test methods

10. BS 8010 British Standard Cord for practice for Pipeline:Part 1: 1987: Pipeline on Land: GeneralPart 2: 1989: Pipeline on Land: Design, construction andinstallation. Section 2.1: 1987 Ductile Iron Section 2.5: 1989 Glass reinforced thermosetting plastics

11. BS 5911 Precast Concrete Pipes, fittings and ancillary products: Part 100: Specification for unreinforced and reinforced pipes

and fitting with flexible joints Part 200: Specification for reinforced jacking pipes with

flexible joints12. BS EN 752: 1997 Drain and sewer systems outside buildings.

International Organization for Standardisation (ISO)

1. ISO 2531: 1998 Ductile iron pipes, fittings, accessories and their joints for water or gasapplications

2. ISO TC 138 SC1 Plastics pipes and fittings for soil, waste and drainage (including landdrainage)

3. ISO TR 10465-1: 1993 Underground installation of flexible glass-reinforced thermosetting resin(GRP) pipes - Part 1: Installation procedures

4. ISO TR 10465-3: 1999 Underground installation of flexible glass-reinforced thermosetting resin(GRP) pipes - Part 3: Installation parameters and application limits

Australian Standard (AS/NZS)

1. AS 3680-1989 Polyethelene sleeving for ductile iron pipelines2. AS 3725-1989 Loads on buried concrete pipe3. AS 4060-1992 Loads on buried vitrified clay pipe4. AS/NZS 2280: 2004 Ductile iron pipe and fittings5. AS/NZS 2566.1: 1998 Buried flexible pipelines-Structural design6. AS/NZS 2566.2: 2002 Buried flexible pipelines-Installation

American Society for Testing and Materials (ASTM)

1. ASTM D 3212 Standard Specification for Joints for Drain and Sewer Plastic Pipes UsingFlexible Elastomeric Seals

2. ASTM D 3262 Specification for “Fiberglass” Glass-Fiber-Reinforced Thermosetting-Resin Sewer Pipe

3. ASTM D 3350 Standard Specification for Polyethylene Plastics Pipe and FittingMaterials

4. ASTM D-2321 Practice for Underground Installation of Flexible Thermo Plastic SewerPipe.

5. ASTM F 894 Specification for Polyethylene (PE) Large Diameter Profile Wall Sewer.and Drain Pipe.

German Institute for Standardization (DIN)

1. DIN 16961-1 (2000-03) Thermoplastic pipes and fittings with profiled outer and smooth innersurfaces-Dimensions

Canadian Standards Association (CSA)

1. CAN/CSA-B182.6-M92 Profile Polyethylene Sewer Pipe and Fittings

Code of Practice

1. CP 312 Code of practice for plastics pipe work ( thermoplastics material ) Part 1: 1973: General principles and choice of materials Part 3: 1973: Polyethylene pipes for the conveyance of liquids

under pressure

Water Industry Specifications (U.K) (WIS)

1. WIS 04-24-01 Specification for mechanical fittings and joints for polyethylene pipesfor nominal sizes 90 to 1000

2. WIS 04-32-14 Specification for PE 80 and PE 100 electrofusion fittings for nominalsizes up to and including 630

Website

1. http://www.plasticpipes.com

2. http://www.pslc.ws

3. http://www.healthy building.net

4. http://www.powerwater.com.my

(msia) guide to sewer selection and installation (dec2006)_vc pipe pg17～

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