58.99.08.1606_i_specification for piping flexibilty analysis

QUSAHWIRA FULL FIELD DEVELOPMENT PROJECT ADCO PROJECT No. P-14364

ADCO CONTRACT NO.: 7278.01/EC 10737 NPCC PROJECT No.: 9063

SPECIFICATION FOR PIPING FLEXIBILITY ANALYSIS

ADCO DOCUMENT No.: 58.99.08.1606

THIS DOCUMENT IS DEVELOPED FROM FEED DOC. NO. 30.78.12.0669 REV C PROJECT NO. P14364

I 23-NOV-2010 BS VS AS Issued For IDC REV. DATE ORIGINATOR REVIEWED APPROVED DESCRIPTION

THIS DOCUMENT IS INTENDED FOR USE BY ADCO AND ITS NOMINATED CONSULTANTS, CONTRACTORS, MANUFACTURERS AND SUPPLIERS.

EPC CONTRACTOR: NATIONAL PETROLEUM CONSTRUCTION COMPANY P.O. BOX 2058, ABU DHABI, UNITED ARAB EMIRATES

____________________________________________________________________

ENGINEER: ENGINEERS INDIA LIMITED , NEW DELHI, INDIA

ADCO DOC. No. 58.99.08.1606 CONTRACTOR DOC No.: A049-000-16-43-SP-0010 PAGE: 1 OF 30

DOCUMENT TITLE: SPECIFICATION FOR PIPING FLEXIBILITY ANALYSIS

PROJECT No. :P 14364 ADCO DOC.No.: 58.99.08.1606

REV I DATE: 23-NOV-2010 CONTRACTOR DOC. No. A049-000-16-43-SP-0010 PAGE: 2 OF 30

TABLE OF CONTENTS

1.0 INTRODUCTION .5 1.1 Project introduction ...5 1.2 Project scope .6

2.0 PURPOSE & SCOPE7 3.0 REFEREENCES7 3.1 Document Precedence ...8

4.0 APPLICABLE CODES AND STANDARDS.....8 4.1 Codes, Standards and Regulations ..8 4.2 Definitions ..9 4.3 Abbreviations9

5.0 PIPE STRESS ANALYSIS PHILOSOPHY...10 5.1 Analysis Software ..11 5.2 Process Design Data......11 5.3 Stress Analysis Code Requirements.11

6.0 DESIGN CONDITIONS11 6.1 Design Life...11 6.2 Temperatures.11 6.3 Stress Range Calculations..11 6.4 Calculating Equipment/Pipe Support Loads 11 6.5 Friction.12 6.6 Wind..12 6.7 Earthquak12

7.0 NOZZLE LOAD ALLOWABLES ...12

8.0 EQUIPMENT DESIGN CONSIDERATIONS FOR STRESS ANALYSIS.13 8.1 Pumps.13 8.1.1 Centrifugal Pumps ..13 8.1.2 Vertical in Line Pumps....13 8.1.3 Metering Pumps14

8.2 Centrifugal Compressors..14 8.2.1 Design Conditions...14 8.2.2 Temperature..14 8.2.3 Pressure..14 8.2.4 Wind ...14 8.2.5 Allowable loads.14 8.2.6 Friction Effect.14 8.2.7 Stress Requirements...14 8.2.8 Piping Alignment..15 8.2.9 Recommended Modeling ..15




8.3 Reciprocating Compressors.15 8.4 Air Coolers ..16 8.5 Storage Tanks..17 8.6 Packaged Equipment.....17 8.7 Pressure Vessels & Shell and Tube Heat Exchangers..17

9.0 GENERAL STRESS CONSIDERATIONS17 9.1 Glass Reinforced Epoxy Pipe...17 9.2 Flange Leakage.....18 9.3 Pipe Sag..18 9.4 Relief Valve Discharge Loads...18 9.5 Slug Flow18 9.6 Hydro test...18 9.7 Heat Tracing Elements ..18 9.8 Vessel Skirt Temperature..18 9.9 Vibration Analysis19 9.9.1 Reciprocating Pumps and Compressors.18

9.9.2 Acoustic Induced Vibration19 9.9.3 Dynamic Analysis.19 9.9.4 Surge Analysis ..19

9.10 45 Connections ..19 9.11 Insulation Density.....19 9.12 Sway.....19 9.13 Equipment settlement...19 9.14 Standard Pipe Supports...19 9.15 Special Pipe Supports ...19 9.16 Spring Supports.20 9.17 Temporary Pipe Supports20 9.18 Pipe Spans20 9.19 Indentation20 9.20 Welded Attachments.20 9.20.1 Trunnions & Dummy Legs..20 9.20.2 Line Stops, Lugs and Pipe Shoes20 9.20.3 Line Stop Displacements20

10.0 FLEXIBILTY APPLICATIONS (PIPE STRESS ANALYSIS SPECIFIC FUNCTIONS)..20 10.1 General.20 10.2 Computer Modeling of Equipment...20 10.2.1 Static Equipment ..20 10.2.2 Rotating Equipment.20 10.2.3 Air Cooled Heat Exchangers.21

10.3 Modeling Friction ..21




10.4 Load Case Combinations (Advisory) ....21 10.4.1 CAESAR II Hot Sustained Load Cases are shown below....21 10.4.2 Slug loads ....21 10.4.3 Seismic vs. Wind loads..22 10.4.4 Load Cases..22

11.0 STRESS GROUP WORKING PRACTICES..23 11.1 Critical Line List..23 11.2 Filing...23 11.2.1 General..23 11.2.2 Project data...23 11.2.3 Stress Sketches/Isometrics.24 11.2.4 Calculation Format and numbering...24 11.2.5 Nozzle Loads...25 11.2.6 Vessel Nozzle Load Approval.25 11.2.7 Vessel Clip Summary Sheets..25 11.2.8 Calculation Filing....25

11.3 Checking Procedure.25 11.3.1 Documentation..25 11.3.2 Stress Sketch/Calc Index...25 11.3.3 Stress Sketch Geometry.25 11.3.4 Calculation Input Data.....25 11.3.5 Calculation Output Data.27

12.0 STRESS PROGRESS MONITORING..27 12.1 Status Reporting .27 12.2 Status Descriptions and Values...............................................27

13.0 ADDITIONAL REQUIREMENTS 27 13.1 Supporting Arrangement...27 13.2 Flange Leakage....27 13.3 Stress Reporting..28 13.4 Checklists..28 13.4.1 Calculations..28 13.4.2 Isometrics ...28

13.5 Allowable Pipe Spans ...28




1.0 INTRODUCTION 1.1 PROJECT INTRODUCTION

ADCO has been chartered by their shareholders to expand sustainable crude oil productionFrom its current level of 1.4 million barrels oil per day (MMBOPD) to 1.8 MMBOPD.Accordingly, ADCO has undertaken projects for development of its marginal fields to help achieve this target, which involves increasing production at existing Bab & North-East Bab oil fields and beginning productions from two new oil fields, namely, Bida Al Qemzan & Qusahwira.

Qusahwira is a new undeveloped field located about 80 Km Southeast of existing Asab oil field and approximately 200 km south-southeast of Abu Dhabi city. The location of the Qusahwira field is depicted in Figure 1-1 below:

Figure 1-1

The development drilling commenced at the end of year 2006 & full field development shall be completed in two phases. The development under Phase-1 is limited to the southern block of the field, which involves developing Thamama Zones A/B and F. The first phase of Qusahwira project will contribute 30 MBOPD to 1.8 MMBOPD scheme from




year 2013 for a period of about five years. After completion of second phase, its total production shall increase to 42.47 MBOPD. Additionally, 20 MBOPD from Mender and South East fields shall be implemented in future.

1.2 PROJECT SCOPE

The Phase-1 of Qusahwira Full Field Development Project shall have facilities at three locations and an interface with the existing Asab oil field. Broadly, the following facilities are part of Phase-1 project:

- Constructing a new Central Degassing Station (CDS) at Qusahwira. It shall include facilities as below: o Inlet manifolds for receiving production transfer line from a new

Remote Degassing Station (RDS-1) & two direct production flow lines o Multi phase flow meters (MPFMs) o Two trains of three phase production separators o Two trains of four stage gas compression o Gas injection directly to four gas injection wells o Two glycol contactors & one common glycol regeneration o Vapor recovery compressor package o Produced water treatment & disposal to five disposal wells o Main oil Line (MOL) booster pumps and MOL pumps for exporting

crude oil to Asab CDS o Various supporting utilities & chemical injections systems.

- Constructing a new Remote Degassing Station (RDS-1) at approximately 9.2 km southwest of the new Qusahwira CDS. The RDS -1 shall gather & test 22 production flow lines and deliver the raw crude to the Qusahwira CDS. This shall also serve as distribution points for injection gas from the Qusahwira CDS to 5 gas injection wells in Thamama A/B zone for pressure maintenance besides various supporting utilities and chemical injection facilities.

- Constructing two new Water Injection Clusters (WIC-1 and WIC2) southwest of the Qusahwira CDS for water injection to oil wells in Thamama F zone for




pressure maintenance including chemical injection facilities. Four wells shall be served from WIC-1 and one well from WIC-2.

- Constructing a 20 production fluid transfer line from RDS-1 to the CDS - Constructing a 6 gas injection trunk line from the CDS to RDS-1for

distribution to gas injection wells. - Constructing 22 flow lines from producing wells to RDS-1 and 2 flow lines

directly to the CDS and constructing 5 gas injection flow lines from RDS-1 and 4 gas injection lines directly from the CDS.

- Constructing a 14 Main Oil Line (MOL) to the CDS at Asab oil field. - Providing expandability for future facilities at CDS to support 62.47 MBOPD

crude oil production at Qusahwira by: Providing plot space for a third train of production separator, a third

train of gas compression, gas dehydration & glycol regeneration, additional water separation tanks and additional produced water disposal pumps.

Providing utility systems for both phase-1 and phase-2

2.0 PURPOSE & SCOPE This specification outlines the requirements for the stressing of piping systems for the ADCO-QUSAHWIRA Full Field Development Project. They are issued for the guidance of Stress Engineers performing stress analysis for the project. This Procedure provides design criteria and guidelines to ensure that the piping systems for the project are in accordance with the code requirements of ASME B31.3, Process Piping and DEPs. This Project Procedure covers:

The minimum technical requirements for the design, stress and flexibility analysis of piping systems for the project.

Methods and procedures to maintain consistency in the execution of work within the pipe stress group.

3.0 REFERENCES The following documents have been used to compile this procedure.

31.38.01.11-Gen Piping General Requirements (SHELL DEP) 31.38.01.29-Gen Pipe Supports (SHELL DEP)




30.99.12.0023 Plant Layout and Piping Basis of Design (ADCO STD) 58.99.12.1601 Piping Material Class Specification for (JOB SPEC) 58.99.16.2701 Pipe support standard. 31.22.20.31 Pressure Vessels ( Based on ASME section-VIII )

Tender bulletin related to stress analysis specification TB-37 PI-1 TB-37 PI-2 TB-39 PI-2 TB-25 SE-4

3.1 Document Precedence In case of conflict, the order of precedence of various specifications shall be:

The Laws, Standards and Regulations of United Arab Emirates. ADNOC Codes of Practice Project Equipment Data Sheets. This Project Specification. Approved Technical Deviations ADCO Procedures, Codes & Standards ADCO Specifications and Engineering Practices. ADCO Amendments and supplements to Shell DEPs. Shell DEPs (v26) International Oil & Gas industry Codes, Standards and Recommended practices (all

where specified in the above or, where none of the above is applicable, as proposed by Contractor and Approved by ADCO).

Internationally recognised Oil and Gas Industry sound practices

4.0 APPLICABLE CODES AND STANDARDS 4.1 Codes, Standards and Regulations

All piping systems shall meet the requirements of this Specification, other referenced Project Specifications and the following Codes, Standards and Statutory Regulations (where applicable).The vesrsions valid on the date of contract awarded of the standards/code shall be referred. API 610 Centrifugal Pumps for General Refinery Service API 617 Axial & Centrifugal Compressors API 618 Reciprocating Compressors API 619 Rotary Type Positive Displacement Compressors




API 650 Petroleum Storage Tanks API 661 Air-Cooled Heat Exchangers API 675 Positive Displacement Pumps Rotary ASME B31.3 Process Piping ASME B73.1 & B73.2 Horizontal and Vertical Pumps (General Purpose) ASME Sect. VIII Boiler and Pressure Vessel Code ASTM Material Testing / Certification IBC 2006 International Building Code, 2006 Edition NACE MR 0175 Sour Service Piping NFPA 20 Installation of Stationary Fire Pumps for Fire Protection WRC Bulletin 107 Local Stresses in Spherical and Cylindrical Shells due to External

Loadings WRC Bulletin 297 Local Stresses in Cylindrical Shells due to External Loadings on

Nozzles Supplement to WRC Bulletin 107 WRC Bulletin 449 Guidelines for the Design and Installation of Pumps

4.2 Definitions The following terms are defined as stated, unless otherwise indicated:

COMPANY: Abu Dhabi Company for Onshore Oil Operations - ADCO.

PROJECT: Qusahwira Full Field Development Project.

PROJECT MANAGEMENT CONSULTANT (PMC): Foster Wheeler International Corporation (FWIC)

SHALL: Indicates a mandatory requirement.

SHOULD: Indicates a strong recommendation to comply with the requirements of this document.

CONTRACTOR: National Petroleum Construction Company (NPCC).

The Principal shall mean ADCO in the DEP

4.3 Abbreviations AIV Acoustic Induced Vibration ANSI American National Standards Institute ASCC Alkaline Stress Corrosion Cracking ASME American Society of Mechanical Engineers ASTM American Society for Testing And Materials BEDD Basic Engineering Design Data BOD Basis of Design DEP Design Engineering Practices (Shell) ESD Emergency Shut Down NPS Nominal Pipe Size




RPM Revolutions per Minute SIF Stress Intensification Factor SPS Special Pipe Support TOS Top of Steel

5.0 PIPE STRESS ANALYSIS PHILOSOPHY The Lead Piping Designer and the Lead Piping Engineer, or Lead Stress Engineer in the absence of this position, shall jointly be responsible for the production of an economic, flexible layout. It is the responsibility of the Stress Engineer to ensure that piping is routed and supported correctly so that no damage occurs to pipe and associated equipment due to the effects of thermal growth, weight, pressure, slug flow, wind, earthquake, vibration, shock, foundation settlement or any detrimental external loads. Every relevant mode of operation for stress critical piping systems shall be examined and every credible displacement stress range difference shall be considered. The Minimum criteria for defining the minimum acceptable flexibility are:

a. The maximum allowable stress range of the piping material. b. The maximum allowable forces and moments on the equipment to which the pipe is

connected. c. The maximum displacements are acceptable. d. Excessive stresses at supporting or restraining elements e. Unintentional disengagement of piping from its supports f. Interference between adjacent lines due to thermal expansion or contraction of the

piping system g. Resonance due to imposed vibration or fluid induced vibration. h. Excessive sag in piping systems, particularly those requiring slopes for drainage. i. Special supports requiring complex design details or impractical construction

tolerances. The minimum criteria for pipe support design shall be:

a. Maximum pipe deflection between pipe supports shall be limited to 10 mm b. Large diameter and thin wall piping shall be analyzed for crushing load at supports

and reinforced as necessary c. Pipe supports shall be allocated such as not blocking access or headroom

clearance. d. Pipes of 2 and larger laid on sleepers (if any) shall be provided with pipe shoes to

avoid external corrosion at support location. e. Excessive anchor loads, thermal loads, and friction loads for piping laid on pipe

racks should be provided for in structural design. f. Carrying/Supporting pipes from larger diameter headers is not allowed without

ADCO approval. g. Note about galvanic corrosion between piping and pipe supports of dissimilar

material shall be provided in the pipe support design reports.




5.1 Analysis Software The project approved program for the purpose of computer analysis is "CAESAR II" version 5.10. This program computes complete stress analysis to the requirements of the ASME B 31.1, ASME B 31.3 and several other relevant codes, and also provides a Code Compliance Report, when requested. All computer runs shall include temperature, pressure, weight and insulation if any as a minimum. Guides/stops shall normally be modeled with 3 mm gaps and friction in the horizontal and vertical planes shall be considered. Any specific gaps must be noted on the stress sketches and the isometrics. Friction shall be included in the analysis. In case the system is not converging during analysis than it is recommended that friction be removed from supports beginning with those farthest from anchors, guides, or stops.

5.2 Process Design Data All relevant process design data is included on the process line list including design, operating and upset temperatures pressures and density.

5.3 Stress Analysis Code Requirements All stress analysis shall comply with the requirements of ASME B31.3.

6.0 DESIGN CONDITIONS Detailed site specific design conditions are contained within project duty specification 30.99.91.0612. Relevant analysis parameters are included below.

6.1 Design Life For purposes of piping design the design life is 30 years unless stated otherwise.

6.2 Temperatures Installation temperature = 22C for restraint analysis and stress analysis of hot lines. Installation temperature = 35C for restraint loads and stress analysis of cold lines. Maximum Metal Temperature (MMT) due to Solar Gain = 85C

6.3 Stress Range Calculations For stress range calculation, whichever of the below listed equations producing the greatest temperature differential shall be used: Max design temp Minimum installation temp Maximum installation temp Minimum design temp Maximum design temp Minimum design temp Pipe design temperature shall be obtained from the Process Line List. Example cases for consideration within Caesar II models are shown in section 10.4.

6.4 Calculating Equipment/Pipe Support Loads To calculate equipment nozzle loads, forces and moments on flanges, pipe support and anchor loads the pipe temperature to be used for hot piping shall be at least the maximum operating temperature and for cold piping the minimum design temperature. Other temperature excursions due to start-up, shut down, steam out etc. shall also be considered. In order to reduce the number of stress cases to be analyzed, the design temperature instead of the maximum operating temperature may be used for nozzle loading. If this results in overloading the nozzles then the maximum operating temperature shall be used.




Maximum operating temperatures should be checked with process group where large differences occur (>30degC) between operating and design conditions within the line list. The appropriate installation temperature listed in clause 6.2 shall be used.

6.5 Friction The effects of friction on supports and strain sensitive equipment shall be considered. See friction table below. Friction coefficients:-

PTFE ON STAINLESS STEEL = 0.1 STEEL ON STEEL = 0.3 (as per TB-37, PI-2) STEEL ON CONCRETE = 0.45

6.6 Wind Wind effect calculations shall be in accordance with BS-6399 (as per TB-37, PI-2). wind velocity profile shall be developed based on the following site data for Design Wind Velocity:

30 m/s for 3 second gust. 30 m/s for fastest wind speed (at 10m above ground level). Wind speed at different elevations shall be in accordance with recommendations of BS-6399.A wind shape factor (Cf) of 0.7 shall be included in wind case analysis of piping. The effects of shielding by the structure and piping may also be taken into account at the discretion of the individual Stress Engineer. The wind load shall be considered for pipes 12 and above including insulation.

6.7 Earthquake The Earthquake zone for this facility is classified as Zone I. Therefore, for purposes of calculations on this project, the Importance Factor Ip = 1.0 to be used in calculations, as per ASCE-7-02. Procedures for seismic design shall be as required by IBC 2006.

7.0 NOZZLE LOAD ALLOWABLES Piping design codes generally contain recommendations or mandatory requirements but generally do not define limitations for terminal loads and moments. Allowable nozzle loads for rotating equipment shall be finalized during the early stages of the project. The Stress Engineer shall ensure that all equipment nozzle allowables supplied by the vendor(s) are sufficient to withstand reasonable piping loads whilst not adding significant cost to equipment. The Stress Engineer shall calculate nozzle loading based on the condition that result from using the minimum or maximum operating temperature (section 6.4) and any applicable permutation of those conditions. In case of multiple items of equipment connected to a common header, all possible operating permutations shall be considered. The Stress Engineer is responsible for compliance to the stated nozzle loads and, for those which exceed PO agreements, submitting loads to the Mechanical Group for vendor approval. Vendor acceptance correspondence shall be included in the final stress report.




8.0 EQUIPMENT DESIGN CONSIDERATIONS FOR STRESS ANALYSIS 8.1 Pumps

8.1.1 Centrifugal Pumps Pumps are often arranged with one pump operating and another at stand-by. If this occurs, three different cases shall be considered: -

1) Both pumps operating. 2) Pump A operating, Pump B stand-by. 3) Pump B operating, Pump A stand-by.

Pumps can be arranged with two pumps operating and another at stand-by. If this occurs, three different cases shall be considered: -

1) Pumps A & B operating, Pump C stand-by. 2) Pumps A & C operating, Pump B stand-by. 3) Pumps B & C operating, Pump A stand-by.

The pipe to/from the stand-by pump can be taken as the average of the maximum operating temperature and the installation temperature (or as determined by heat transfer calculations) if the check valve is fitted with a by-pass to facilitate a warm up. If a by-pass is not provided, the temperature of the dead leg for the stand-by pump from the tee to the block valve, for both suction and discharge lines, shall be considered to be as the average of the maximum operating temperature and the installation temperature. The temperature of the piping from the block valve to the pump shall also be taken as ambient. Where springs are positioned local to pump nozzles a separate nozzle loading check is required to cover the short term condition where the springs are active, but the line is empty. The final mandatory check that the Stress Engineer must perform is a case with the nozzles disconnected. Deflections at the free flanges must be less than 2mm in any direction. This will ensure a relatively easy alignment of rotating equipment, as very low loads will be imposed on the pump due to the weight case. Where possible the first support local to the pump shall be located on the pump foundation. The first rigid support local to the pump shall be adjustable. The allowable loads at centrifugal Pump nozzles shall be determined as a factor times the allowable loads specified in API 610 Table 4 as per below criteria. The factored allowable loads shall be provided for inclusion in mechanical requisitions. Nozzle Rating Allowable Loads 150# 2 X Table 4 API 610 300# 2 X Table 4 API 610 600# 3 X Table 4 API 610 900# 4 X Table 4 API 610 1500# 4 X Table 4 API 610

8.1.2 Vertical in Line Pumps Small vertical in-line pumps (15 kW or less) shall be supported immediately adjacent to suction and discharge flanges using conventional pipe supports. Piping forces shall be




determined with the pump considered as a rigid, but as an unanchored segment of the piping system. Larger vertical pumps furnished with casing foot-mounts shall be supported on suitable foundations. Loads shall be in accordance with API 610 criteria as minimum.

8.1.3 Metering Pumps Metering pumps shall be designed to API 675. Allowable nozzle loads shall be agreed with the vendor.

8.2 Centrifugal Compressors

8.2.1 Design Conditions In order to develop the most severe loadings on the equipment, all possible operating and upset scenarios shall be considered.

8.2.2 Temperature Maximum Operating temperatures for each operating condition under consideration shall be used in analyses. The support and anchor displacements resulting from the expansion or contraction of the compressors and attached equipment due to temperature changes shall be included in the analysis. Displacements of the equipment nozzles shall be based on Vendor supplied data.

8.2.3 Pressure Maximum operating pressures for each operating condition under consideration shall be used in analyses. For large diameter piping pressure effects (e.g. pressure stiffening, Bourdon effects, etc.) can be considerable and shall be considered in the analyses. Sustained stress shall be calculated using design pressure.

8.2.4 Wind The project specific static wind pressure profile shall be used in the analyses. Wind direction shall be considered in determining the most severe equipment loadings. Where shielding factors are used, changes to the factors with wind direction shall be included in the analyses. Where wind loads are excessive, it may be necessary to consider the natural shielding of the piping from the surroundings (piping, steelwork, equipment, etc.) in order to reduce loads on the compressors.

8.2.5 Allowable loads Equipment nozzle loads shall be evaluated using the NEMA SM23 calculation methods. Allowable nozzle loads shall be twice the values mentioned in the above standard. These loads shall also be sent to the equipment engineer for his records and approval.

8.2.6 Friction Effect A friction and non-friction analysis shall be considered for all large compressors.

8.2.7 Stress Requirements Stresses shall be calculated and evaluated according to the formulae and procedures outlined in ASME B31.3 code.




8.2.8 Piping Alignment The final mandatory check that the Stress Engineer must perform is a case with the nozzles disconnected i.e. nozzle released case. Deflections at the free flanges must be less than 2mm in any direction. This will ensure a relatively easy alignment of piping, as very low loads will be imposed on the equipment due to the weight case.

8.2.9 Recommended Modeling It is important when modelling equipment that the inlet, extract and exhaust are modelled in three separate Caesar models. Care must be taken to ensure that in all three models the global axis remain the same. In the case of the inlet and extract, (or inlet and other connection in the case of the compressor), a connecting node must be placed followed by a rigid element to the position of the exhaust. This means that loads at the exhaust point can be read straight from the Caesar output and entered into the NEMA SM23 spreadsheet without the need for more complex translation equation. The piping system shall be designed for minimum loads. The dead weight of the piping shall be entirely supported by pipe hangers or supports. The initial stress calculations shall be weight only calculations, for spring support selection purposes. Spring supports shall be located directly above, below or adjacent to nozzles to achieve minimum load to the nozzle. Certified vendor weights for valves and actuators shall be obtained for use in calculations. Weights for insulation and cladding, pipe support attachments, flanges (including the piping flange connected to the equipment) and bolts for flanges shall be included. If variable support springs are used, the variability shall be kept as low as possible to avoid cold loading the nozzle. Pedestal springs shall be avoided where possible, and shall not be used if horizontal movement exceeds 5mm due to frictional loads and the spring binding. When spring selection has been made and all other restraint types and locations have been determined a nozzle released calculation shall be run. This is to ensure that the nozzle alignment falls within the agreed tolerances (see 7.2.8). The main restraints local to the compressor, protecting the nozzle, shall be designed to enable site adjustment. Adjustable struts, which are frictionless, are the preferred method of restraint.

8.3 Reciprocating Compressors The compression stroke of the piston within the reciprocating compressor causes pressure pulses that induce vibration in the suction and discharge pipes. This vibration will exist from the compressor to a receiver (pulsation damper) that should have at least 10 times the area of the pipe, or to a point that can be considered to be at an infinite length (approx. 60 metres) in order for the pulsation to decay. Air coolers and shell and tube heat exchangers cannot be considered as receivers. In order to prevent the vibrations from the pressure pulsation becoming a problem, piping systems shall be supported, ensuring that their frequency is higher than the critical frequency. The critical frequency shall be agreed with the compressor vendor, but it will not normally be higher than the 4th natural frequency of the compressor. Pipe supports shall be located to avoid the natural frequency of piping spans and a frequency (modal) static frequency analysis should be run to check this. However, spacing between the supports shall be varied so as to to prevent adjacent spans having identical frequencies.




Pipe support frequency shall also be kept above the critical frequency. To achieve this piping shall be routed at low level. The above work shall be completed before the Compressor vendor carries out an acoustic simulation and mechanical response study, in accordance with API618 para 3.9. The force generated by the pressure pulse (F) is calculated by: F = Design Pressure x Inside Area of Pipe x max. % Pressure Surge. This force will only occur at the change of direction and can be used as a basis for structural design.

8.4 Air Coolers The header boxes for multiple bundled Air Coolers shall be supported on PTFE slide plates. In general the inlet piping to multiple bundled Air Coolers shall be as rigid as possible local to the header boxes, therefore the piping will move the header boxes. The header box movement of a multiple bundled Air Cooler can be controlled in two ways: -

One of the centre header boxes is fixed to the support frame. The inlet header pipe is anchored. In either case, a suitable clearance shall be provided between the header boxes and the supporting framework. It should be noted that the minimum clearance required by API 661 is often insufficient and piping stress engineer shall always check. This should be checked at the first issue of vendor drawings. The resulting loads, due to the rigid piping, will be mainly shear forces and not bending moments, these loads will normally be acceptable. At even-pass units the outlet piping shall have sufficient flexibility to cater for the lateral expansion of the air cooler bundles. At odd-pass units the outlet piping shall allow for failure of a single fan. Temperature of the outlet piping shall be assumed to be the same as the inlet piping. If this causes problems a more accurate outlet temperature is to be obtained from the Mechanical Department. If isolation valves are located at each Air Cooler bundle a case of one bundle at stand-by and the others operating shall be considered. Process shall advise on the different operating possibilities. The allowable loads at Air-cooled heat exchangers nozzles shall be determined as a factor times the allowable loads specified in API 661 Table 4 as per below criteria. The factored allowable loads shall be provided for inclusion in mechanical requisitions. Nozzle Rating Allowable Loads 150# 2 X Table 4 Figure-6 (API-661) 300# 2 X Table 4 Figure-6 (API-661) 600# 2 X Table 4 Figure-6 (API-661) 900# 3 X Table 4 Figure-6 (API-661) 1500# 3 X Table 4 Figure-6 (API-661) 2500# 3 X Table 4 Figure-6 (API-661) The statement regarding the allowable nozzle loads shall be included in the mechanical requisition and also that equipment shall be able to slide while maintaining the nozzle loads within the allowable limit with the force exerted on inlet nozzles.




8.5 Storage Tanks Differential settlement at tanks is particularly important and data shall be obtained prior to the design of piping and this shall provide the:

Amount of settlement (and recovery) that will occur following construction and hydro test.

Amount of settlement after hydro test and period of time over which it will occur. When large storage tanks are filled the walls bulge and nozzles located in the lower courses are rotated downwards. Any restraint on this rotation by the stiffness of the connected piping will cause a stress in the tank shell that shall be limited to values defined by the Lead Mechanical Engineer. For API 650 tanks, use the method provided in Appendix P of API 650. Piping to and from tanks shall be rotated through 90o as close to the tank wall as practical. This reduces the amount of vertical displacement of the pipe due to tank bulge, and also reduces the longitudinal moment acting on the tank. This will, however, increase the torsional moment, but this is of minor consequence according to API 650, which states that there is no maximum allowable torsional moment. The combined effects of settlement and tank bulge may suggest supporting the piping on springs. The use of springs shall be limited due to the possibility of the line becoming drained and an excessive upward load being applied to the tank nozzle. To enable design to proceed, it is imperative that the values of tank bulge, nozzle rotation and the method of calculation are agreed early in the project. Tanks to other codes require appropriate review and consultation with the tank engineer / vendor.

8.6 Packaged Equipment Unless agreed otherwise, the piping to Packaged equipment shall be anchored on the vendors piping as close to the vendor interface as practical.

8.7 Pressure Vessels & Shell and Tube Heat Exchangers Stress Analysed piping to pressure vessels and shell and tube exchangers shall be analysed for all possible cases including start-up, steam-out and normal operating conditions. The allowable loads at pressure vessels nozzles shall be as per tabulated in ANEX VIII of DEP 31.22.20.31-Gen.( pressure vessels based on ASME section- VIII). Nozzle flexibility between the nozzle and the vessel shell can be used to reduce nozzle loads but should be stated in nozzle loads submitted to Mechanical Group for review along with the specific method employed. On shell and tube exchangers any force created by piping loads that is greater than 12% of the attached equipment weight, shall be issued to Civil / Structural. The fixed end of horizontal shell and tube heat exchangers and drums shall be determined by Piping Stress.

9.0 GENERAL STRESS CONSIDERATIONS 9.1 Glass Reinforced Epoxy Pipe

The vendor shall carry out stress analysis of all GRE piping. The vendor will design and manufacture the piping to ISO14692 or equivalent as agreed by the principal. Surge and stress analysis of GRE piping, whether it be buried or above ground, should be performed




by specialists as GRE behaves differently in tension to elastic, homogeneous materials such as steel.

9.2 Flange Leakage Flange leakage shall be checked for conditions listed as below. Pipe size 26 & above except air & water lines (up to 600# rating) Pipe size 8 & above, other lines (900# rating & above)

9.3 Pipe Sag Pipe sag or pipe deflections due to weight of piping and contents shall be kept to 10 mm recommended maximum deflection for the normal operating weight case. For all piping analysis, mid-point nodes shall be considered in order to monitor deflections and stresses. Temporary supports shall be considered only as a last resort.

9.4 Relief Valve Discharge Loads Relief valve discharge forces shall be calculated in accordance with API RP 520 Part II. Suitable restraints will be required to absorb these forces and prevent overloading and over stressing of the piping or valve in line with good engineering practices.

9.5 Slug Flow Where slug flow is expected in a piping system, slug loads shall be calculated and considered at all changes of direction. Particular attention shall be given to the pipe support design for these systems. Pipe supports shall be capable of restraining the piping system without concurrently overstressing the pipe in the thermal expansion cases. A dynamic factor of 2 shall be applied. In long length piping runs subject to slug flow, consideration shall be given to the time lag between slug impact at changes in direction such that lines of force do not balance out in calculations.

9.6 Hydro test The hydro test pressure shall be calculated in accordance with ASME B31.3 345.4.2.

Hydrostatic test pressure for all on plot piping shall not be less than 1.5 times the maximum piping class pressure limits that corresponding to the test medium temperature as per piping material specification. Test pressure calculated to 1.5 times the actual service design pressure is not acceptable(as per TB-39 PI-02 & TB-31 PI-3).

A hydro test load case with the piping full of water is required for all gas and vapor lines where the test medium is water (check against line list).

9.7 Heat Tracing Elements Where piping is heat traced and subject to a process flow off/heat tracing on, the process piping metal temperature shall be considered 100% of the trace element design temperature.

9.8 Vessel Skirt Temperature Vessel skirt temperature and movements shall be modeled in stress analysis and recorded on the stress sketch.




9.9 Vibration Analysis

9.9.1 Reciprocating Pumps and Compressors Piping connected to reciprocating compressors and pumps is prone to vibration. Care shall be taken to avoid this. A comprehensive dynamic analysis will therefore be undertaken. Specialists in the field shall carry out this analysis. Problem lines connected to reciprocating pumps etc. must therefore be brought to the attention of the lead piping engineer and the principal so that a consultant can be engaged early (Reference section 8.3).

9.9.2 Acoustic Induced Vibration Any lines subject to acoustic fatigue will be identified on the line list. The measures to be used to safeguard against acoustic fatigue will be identified by consultants. Consideration should however, be given to recommendations contained within Marine Technology Directorate (MTD) Guidelines for the Avoidance of Vibration Induced Fatigue in Process Pipe work for general guidance.

9.9.3 Dynamic Analysis Dynamic analysis shall only be used where vibration exists in newly installed pipework local to reciprocating machinery where the reason for resonance is not immediately apparent.

9.9.4 Surge Analysis Surge effects should be considered on firewater lines and where specified by the Process Group.

9.10 45 Connections The effect of 45-degree connections shall be reflected in any stress analysis with respect to their effect on stress raisers. Stress Intensification Factor (SIF) Indices should be considered carefully in each case and stated in all calculations and included on the stress sketch.

9.11 Insulation Density Equivalent densities shall be calculated taking into account the cladding weight.

9.12 Sway The effect of sway of equipment and of structures shall be considered in analysis.

9.13 Equipment settlement The effect of differential settlement shall be considered. This information shall be obtained from Civil / Structural Engineering groups.

9.14 Standard Pipe Supports Standard pipe supports, as detailed in DEP 31.29.01.11-Gen & 58.99.16.2701, shall be used except in special cases. Pipe supports shall be chosen to withstand loads given on the stress Sketches.

9.15 Special Pipe Supports Special Pipe Support drawings are used to identify unusual or complicated pipe support requirements. All Special Pipe Support Drawings shall be allocated a reference number, indexed and stored in the relevant file.




9.16 Spring Supports The use of spring supports shall be minimized by careful consideration of support location and alternative pipe routing

9.17 Temporary Pipe Supports The use of temporary pipe supports for hydrotest and for transportation shall be minimized. If required they shall be clearly identified on the Stress Sketch for inclusion in the final design isometrics / detail design drawings. Final design should consider easy identification for removal prior to commissioning.

9.18 Pipe Spans Pipe support spans, maximum, are as shown in 13.5. Piping Spans are limited to a maximum mid span deflection of 10 mm due to self weight or a stress limit of 25N/mm2. Deviation from these pipe spans is permitted subject to approval from the stress group. It should be noted that pipe spans are to be limited to 7m (max) within process units in accordance with 31.38.01.11-Gen.

9.19 Indentation Large diameter, thin wall pipes can deform locally when sitting on narrow supports e.g. un-insulated lines sitting on steelwork with rubbing bars. These local stresses shall be considered.

9.20 Welded Attachments Local stresses at attachments welded to piping shall be reviewed to check whether reinforcing pads are required.

9.20.1 Trunnions & Dummy Legs Local stresses at trunnion type supports shall be checked if required.

9.20.2 Line Stops, Lugs and Pipe Shoes Local stresses in the pipe work/welds/supports at all line stops shall be checked if required.

9.20.3 Line Stop Displacements Structural displacements at all line stops next to equipment shall be specifically checked and excessive displacement should be avoided..

10.0 FLEXIBILITY APPLICATIONS (PIPE STRESS ANALYSIS SPECIFIC FUNCTIONS) 10.1 General

Wherever possible all load cases for code stresses, nozzle loads, restraint loads, slug and relief loads shall be contained within the one stress model.

10.2 Computer Modeling of Equipment

10.2.1 Static Equipment Flexibility of nozzles in vessels and exchangers may be included in the analysis if required. Displacements of nozzles due to vessel/column thermal growth shall be evaluated with thermal gradients taken into account.

10.2.2 Rotating Equipment Nozzles on rigid equipment such as pumps shall be modeled as a rigid anchor.




10.2.3 Air Cooled Heat Exchangers Special attention shall be paid to the correct modeling of header boxes of air cooled heat exchangers. Therefore care must be taken to ensure that the mathematical model used in the piping flexibility model reflects as close as is reasonable the actual mechanical mechanism of the air fin.

10.3 Modeling Friction Friction at sliding supports shall be modeled in all calculations. Only when analyzing Compressor piping are non-friction cases to be considered. Values to be used in calculations are stated in section 6.5.

10.4 Load Case Combinations (Advisory) Components used in Flexibility analysis are defined below: T1: Thermal case #1 Operating temp T2: Thermal case #2 Maximum operating temp or Design temp (as per section 6.4) T3: Thermal case #3 Minimum Design temp P1: Design Pressure case #1 HP: Hydrotest pressure D1: Displacement case #1, where required F1: Concentrated force case #1 (eg. relief valve or slug load ), where required U1, U2: Uniform (g) load cases #1&2 for seismic WIN1, 2, 3 & 4 Wind load cases #1, 2, 3 & 4 in situ W: Weight WW: Water Filled Weight H: Application of spring support. L#: Load case # (eg. 1, 2, 3 etc.)

10.4.1 CAESAR II Hot Sustained Load Cases are shown below. Hot sustained load cases can be analyzed where non-linear (i.e. one direction) restraints are used, including piping that lifts off its supports when operating, reference ASME B31.3 Interpretation 16-04. The following load cases should be run for the hot sustained case: Case #1. Operating analysis W+D1+T1+P1+H

2. Sustained stresses W+P1+H(cold sustained) 3. Expansion D1+T1 4. Expansion L1-L2 5. Sustained Stress L1-L3 (hot sustained)

10.4.2 Slug loads Typical load cases for two (2) slug impact loads are shown below: Line Load Case Type Purpose 1 W+D1+T1+P1 OPE - Loads/deflections for operating temp. 2 W+D1+T1+P1+F1 OPE - Normal operating + slug load 1




3 W+D1+T1+P1+F2 OPE - Normal operating + slug load 2 4 W+P1 SUS - Maximum sustained stress 5 L2-L1 OCC - Slug occ stress increment (F1) 6 L3-L1 OCC - Slug occ stress increment (F2) 7 L5+L4 OCC - Total slug occasional stress (F1) 8 L6+L4 OCC - Total slug occasional stress (F2)

10.4.3 Seismic vs. Wind loads Wind loading only to be considered, unless wind shielding has been used in the analysis. If wind shielding has been considered then seismic analysis shall be carried out.

10.4.4 Load Cases As a minimum, the following load cases, which include hanger sizing shall be used: Line Load Case Type Purpose 1 W HGR Hanger sizing - sustained 2 W+D1+T1+P1 HGR Hanger sizing operating 3 WW+HP+H HYD Maximum hydrotest sustained stress 4 W+D1+T1+P1+H OPE Loads/deflections for operating temp. 5 W+D2+T2+P1+H OPE Loads/deflections for design temp. 6 W+D3+T3+P1+H OPE Loads/deflections for min design temp. 7 W+D1+T1+P1+H+WIN1 OPE Normal operating plus wind (+X) 8 W+D1+T1+P1+H+WIN2 OPE Normal operating plus wind (-X) 9 W+D1+T1+P1+H+WIN3 OPE Normal operating plus wind (+Z) 10 W+D1+T1+P1+H+WIN4 OPE Normal operating plus wind (-Z) 11 W+P1+H SUS Maximum sustained stress 12 W+D1+T1+P1+H+U1 OPE Normal operating plus seismic (X) 13 W+D1+T1+P1+H+U2 OPE Normal operating plus seismic (Z) 14 L7-L4 OCC Wind occ stress increment (+X) 15 L8-L4 OCC Wind occ stress increment (-X ) 16 L9-L4 OCC Wind occ stress increment (+Z) 17 L10-L4 OCC Wind occ stress increment (-Z) 18 L12-L4 OCC seismic (X) occ stress increment 19 L13-L4 OCC seismic (Z) occ stress increment 20 L11+L14 OCC Total wind occasional stress (+X) 21 L11+L15 OCC Total wind occasional stress (+Z) 22 L11+L16 OCC Total wind occasional stress (-X) 23 L11+L17 OCC Total wind occasional stress (-Z) 24 L11+L18 OCC Total seismic occasional stress (X) 25 L11+L19 OCC Total seismic occasional stress (Z)




26 L4-L11 EXP Exp stress range(installed to operating) 27 L5-L11 EXP Exp stress range(installed to design) 28 L5-L11 EXP Exp stress range(installed to min temp) 29 L5-L6 EXP Exp stress range(Max. to min. temp)

The following shall be noted: The displacement stress range shall be taken as the difference between the minimum and maximum design temperatures. The displacement stress range from ambient to maximum design temp and from ambient to minimum

design temp shall also be considered for all critical lines. The effect of hot and cold bypasses shall be investigated and the stress analysis

shall investigate the full stress range that these conditions cause in the pipe. Other external loads to be considered include impact (relief, slug), settlement and

structural displacement. As shown, non-linear effects shall be taken into account when setting up load cases

for analysis. If necessary, hydrotest case shall be carried out for piping system to determine worst-case support loads and to check whether temporary supports are required during the hydrostatic pressure test. Refer to the Process Line List for testing fluid type.

11.0 STRESS GROUP WORKING PRACTICES 11.1 Critical Line List

The critical line list identifies lines from the piping line list which meet the criticality criteria outlined in section 7 of 58.99.23.1602.

11.2 Filing

11.2.1 General All calculations, records, load sheets etc are to be stored electronically.

11.2.2 Project data Project data shall be maintained by the Lead Stress Engineer and shall contain the following as a minimum:

a) Critical line list (Deliverable) b) Project data file c) Calculation files (Deliverable) d) Stress Isometric files (Deliverable) e) Spring support schedule f) Special support schedule

Some of the above documents are non-deliverables and are Piping Group use only. The stress isometrics should be provided for all lines analyzed with details about the support type, location. Node numbers should be indicated for support, change in direction, junction and at maximum stress points.




Calculations file shall also include basic design conditions and summary for stress and forces at different load cases.

11.2.3 Stress Sketches/Isometrics Stress Sketches/Isometrics are single line drawings of piping systems that are issued to the Stress Group for review. They originate from the PDS Piping Group who shall allocate a system number to all lines marked as Criticality 1, 2 & 3 in the Critical Line List. PDS Piping Design should extract stress sketches/ isometrics for piping stress on completion of modeling into PDS. Stress sketches should be logged for date of issue and by revision and on return from Piping Stress Group on completion of stress review.

The Piping Stress Engineer should ensure that the Stress Sketches includes the following before issue back to PDS Piping Design: -

The Calculation number, revision, date of issue and stress engineers name. Required piping reroutes Significant pipe support loads Pipe displacements larger than 50mm Location and types of pipe supports Spring supports shall be identified with an item code number, an operating load and

displacement. Note - the stress engineer shall complete the spring data sheet. Support types and locations shall be clearly marked on the stress sketches with the reference calculation node numbers. Restraint loads from flexibility outputs shall then be identified on the stress sketch isometrics. Node numbers and Equipment nozzle loads shall also be shown. The original shall be filed in the stress isometric file under its system number, unmarked, and a copy reviewed and handed back to the PDS Piping Group on completion.

11.2.4 Calculation Format and numbering For flexibility calculations the following calculation number sequence is to be used as the computer filename and shall be recorded on the Critical Line List. AA-XXYYZZZZ Where: AA = Plant Area e.g. 01,11 etc. XX = Pipe size (in inche) of the the largest dia. Pipe in calculation. YY = Service requirement. ZZZZ = Pipe serial no. of the largets dia. Pipe in calculation (Whose size has been mentioned above). Example: 01-03VG0317, 01= Plant area, XX = 3 Dia.( largest dia. of Pipe in calualtion) , VG = Vent gas service, 0317 = Line serial no. Hard copies of Flexibility calculations shall be stored in the relevant file and should typically contain the following:

Calculation cover sheet. Copy of Stress Sketch and Stress Data Sheet.




Input Echo (Elements, Set Up File, Control, Title) Reference information (as required).

11.2.5 Nozzle Loads All Nozzle Load Sheets shall be allocated a reference number from the Nozzle Loads Register indexed and stored in the relevant file.

11.2.6 Vessel Nozzle Load Approval In those instances where one or more components of a nozzle loading exceeds the standard allowable value, the Nozzle Load Sheet is to be submitted to the Mechanical Group for approval.

11.2.7 Vessel Clip Summary Sheets All requirements for welded attachments to vessels shall be identified on The Vessel Orientation Drawing and returned to the Design department.

11.2.8 Calculation Filing These hard files shall contain all stress analysis calculations that are compiled during the project. The number given to each calculation shall correspond to the calculation number. The final report shall be produced once the model and inputs have been checked. Until that time only a copy of the stress sketch, Flexibility inputs/outputs, vendor and other data shall be included under each section.

11.3 Checking Procedure Checking is an essential activity to maintain quality and consistency of work on a project. A Stress Engineer other than the originator shall check all calculations. The Lead Stress Engineer shall prepare a checklist, which he will keep current with any job specific checks originating from other team members.

11.3.1 Documentation All checked calculations and checking prints should be filed complete with checkers signature and date together with copies of source information (piping data sheet, pipe spec, vessel drawing etc).

11.3.2 Stress Sketch/Calc Index The Stress Sketch Calc Index shall be including all critical lines as defined in the critical line list, together with their criticality category. Any reference to hand calculations should also be included.

11.3.3 Stress Sketch Geometry The Stress Sketch geometry shall be checked against the construction issue isometrics if available or the latest fabrication isometric available.

11.3.4 Calculation Input Data Flexibility Analysis A print-out of the input echo containing the basic element geometry, material properties, bend elements, rigid information, piping restraints, (displacements and forces where




applicable) shall be signed and dated to indicate that ALL of the piping input data has been checked. The checker shall ensure that the following input data is accurate, current and correctly specified within the computer model: Note this is a minimum check and a more through check shall be carried out if required. Element geometry

a) Coordinates b) Pipe diameter and Wall Thickness c) Material d) Corrosion allowance e) Mill Tolerance f) Insulation thickness and density g) Fluid Density h) Bends and bend stiffening factors i) Tees and branch SIFs j) Rigid elements, valve types/weights etc k) Branch Reinforcement, l) Type, pad width etc see section 9.11 m) Restraints n) Location o) Function p) Springs (check load case for spring selection is normal operating case)

Analysis Condition a) Design/Op Pressure b) Design/Op Temperature c) Ambient Temperature d) Assumptions

Vessel/Equipment a) Material b) Temperature c) Nozzle movements

Load cases

a) Ambient temperature b) Sustained (weight, pressure) c) Thermal load case combinations d) (Ensure that there is a load case for max. displacement stress range) e) Wind (if applicable) f) Settlement (if applicable) g) R.V. Reaction forces (if applicable)




h) Slug or surge forces Ensure correct Piping Code has been applied

11.3.5 Calculation Output Data The following information shall be detailed on the final signed stress sketch.

a) Maximum Stresses b) Sustained c) Occasional (if applicable) d) Displacement e) Restraint loads (check for hold downs) f) Maximum deflections g) Springs h) Check spring selection for loads, travel and are locked in.

12.0 STRESS PROGRESS MONITORING 12.1 Status Reporting

Two columns are included in the Stress Critical Line List and these are used for tracking progress through the stress analysis activity. Below are listed the 5 values these should be entered into the STATUS column. The STATUS REMARKS column shall be used to describe current issues with the calculation, such as HELD FOR VENDOR DATA.

12.2 Status Descriptions and Values. The table below shows the 5 status categories. Next to them are listed the required components of analysis which must all be complete before this level of status can be reported. STATUS CODE PROGRESS DESCRIPTION 1 40% Modelling & analysis by analyst 2 70% Checking & comments by checker 3 80% Checking comments incorporation 4 90% Back checking by checker 5 100% Finalisation of calculation

13.0 ADDITIONAL REQUIREMENTS 13.1 Supporting Arrangement:

The checker should review the supporting arrangement with and consider providing additional restraints to control the piping movements for thermal, slug or wind etc. Do not introduce additional restraints unless there is a real benefit from doing so.

13.2 Flange Leakage: Flange Leakage checks shall be carried out if required .




13.3 Stress Reporting Each critical line identified on the critical line list shall be designated either a level 1, 2, 3 or 4 criticality rating by the Lead Stress Engineer. Appropriate stress reports for the levels of criticality shall be produced.

13.4 Checklists

13.4.1 Calculations Comprehensive checklists shall be produced for all levels of stress report signed and stored with final checked calculations.

13.4.2 Isometrics A comprehensive isometric checklist will be produced for pipe stress checking of isometrics.

13.5 Allowable Pipe Spans For allowable piping spans see below span tables, extracted from DEP 31.38.01.11-Gen CARBON STEEL AND HEAVY WALL STAINLESS STEEL The data below are applicable to:

Carbon steel pipes, STD wall and heavier, with a maximum temperature of 350 C. Austenitic stainless steel pipes, schedule 40S and heavier, < 16, with a maximum

temperature of 350 C

Duplex stainless steel pipes, schedule 10S and heavier, with a maximum temperature of 280 C.




Maximum Span (mm) (NOTES 1 and 2) Vapour service Liquid service

Size Bare Insulated

(NOTE 3)

Bare Insulated (NOTE 3)

1 3 850 2 300 3 450 2 250 1 4 750 3 000 4 100 2 800 2 5 350 3 600 4 550 3 300 3 6 550 4 600 5 450 4 200 4 7 500 5 550 6 100 4 900 6 9 150 6 800 7 100 5 800 8 10 500 8 050 7 950 6 700

10 11 800 9 050 8 700 7 400 12 12 900 9 800 9 150 7 800 14 15 150

(NOTE 4)

11 850 10 850 9 300

16 16 250 (NOTE 4)

12 850 11 200 9 750

18 17 250 (NOTE 4)

13 750 11 500 10 150

20 18 200 (NOTE 4)

14 450 11 750 10 400

24 18 950 (NOTE 4)

16 050 12 150 10 950

NOTES: 1. Spans are based on straight pipe, other configurations shall be multiplied by a

shape factor (see sketch below). 2. Free draining pipes with a slope less than 1.5 mm/m require an additional check

of the span. 3. The weight of insulation and sheeting is based on insulation thickness varying

from 70 mm for 1 NB pipe to 200 mm for 24 NB pipe and a density of 190 kg/m3.

4. Spans limited by deflection. All other spans are limited by longitudinal bending stress.




STAINLESS STEEL, SCHEDULE 10S The data below are applicable to austenitic stainless steel pipes, schedule 10S with a maximum temperature of 350 C.

Size

Maximum Span (mm) (NOTES 1, 2 and 3) Vapour service Liquid service



1 3 900 2 200 3 450 2 100 1 4 850 2 800 4 000 2 600 2 5 450 3 300 4 300 3 000 3 6 700 4 050 4 950 3 500 4 7 650 4 800 5 300 4 000 6 9 400 5 750 5 950 4 600 8 10 750 6 800 6 450 5 200

10 12 000 7 600 6 950 5 650 12 13 000 8 250 7 350 6 050 14 13 750 8 700 7 600 6 300 16 14 700 9 450 7 750 6 550 18 15 650 10 150 7 850 6 750 20 16 450 11 000 8 400 7 300 24 18 050 12 700 9 050 8 050

Notes: 1. Spans are based on straight pipe, other configurations shall be multiplied by a

shape factor (see sketch above). 2. Free draining pipes with a slope less than 1.5 mm/m require an additional check

of the span. 3. Spans are limited by longitudinal bending stress. 4. The weight of insulation and sheeting is based on insulation thickness varying

from 70 mm for 1 NB pipe to 200 mm for 24 NB pipe and a density of 190 kg/m3.

5. Pad requirements need to be checked based on the support type, thickness of pipe and spans.

58.99.08.1606_i_specification for piping flexibilty analysis

Documents

dynamic analysis

analysis software

project introduction

surge analysis

pipe spans20

pipe shoes20

india adco

project scope