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Specification for 3‐Coat Polypropylene External Coating for Offshore Pipelines

Specification for 3‐Coat Polypropylene External Coating for Offshore Pipelines 1 of 31

TABLE OF CONTENTS

1.0 GENERAL 2 2.0 APPLICATOR'S OBLIGATIONS 3 3.0 COMPOSITION OF COATING AND CHARACTERISTICS OF THE EPOXY UNDERCOAT, THE BINDER, THE POLYPROPYLENE, AND

THE REPAIR PRODUCTS 4 4.0 APPLICATION OF THE COATING MATERIAL AND REPAIR PRODUCT 5 5.0 CHARACTERISTICS OF COATING 4 6.0 INSPECTION 3 7.0 HANDLING, TRANSPORT, AND STORAGE RULES 8 8.0 PRECAUTIONS FOR WELDING BENDING 9 9.0 COATING OF THE FIELD JOINTS ‐ COATING REPAIR ON JOB SITE 9


1.0 GENERAL

1.1 Scope

1.1.1 This Specification covers the external anticorrosion coating of pipe joints used for offshore oil service.

1.1.2 The coating shall be plant applied 3‐coat polypropylene suitable for service temperature from ‐20ºC to +110C (‐4ºF to +230ºF).

1.1.3 Its purpose is to define the following:

a. Applicator's obligations. b. Composition of coating and

characteristics of the epoxy undercoat, the binder, and the polypropylene.

c. Application of the epoxy undercoat, the binder, and the extruded polypropylene and repairing.

d. Characteristics of the coating. e. Inspection. f. Handling, transport, and storage

rules. g. Field joint coating.

1.2 Definitions of Main Parties Involved

1.2.1 Company

Chevron Overseas Petroleum Inc. (COPI) or its subsidiary or agent acting on its behalf shall be referred to herein as the "Company."

1.2.2 Contractor

The Company, or their agents, designated in the Contract as being the selected main Contractor shall be referred to herein as the "Contractor."

1.2.3 Manufacturer

Means the company which produces and sells epoxy powder and repair product.

1.2.4 Applicator

Means the company in charge of epoxy powder application and pipe coating.

1.2.5 Inspector

The Company Representatives or members from Company‐elected inspection agencies for the time being or from time to time duly appointed in writing by the Company to act as its Representatives for the purpose of the contract shall be referred to herein as the "Inspector."

1.3 Reference Standards and Documents

1.3.1 American Society for Testing and Materials (ASTM)

ASTM B 117 Salt spray (fog) testing.

ASTM D 149 Test methods for dielectric breakdown voltage and dielectric strength of solid electrical insulating materials at commercial power frequencies.

ASTM D 257 Test methods for D.C. resistance or conductance or insulating.

ASTM D 543 Test method for resistance of plastics to chemical reagents.

ASTM D 570 Test method for water absorption of plastics.

ASTM D 638 Test method for tensile properties of plastics.

ASTM D 746 Test method for brittleness temperature of plastics and elastomers by impact.


ASTM D 785 Test method for Rockwell hardness of plastic and electrical insulating materials.

ASTM D 792 Test methods for specific gravity and density of plastics by displacement.

ASTM D 1002 Test method for strength properties of adhesives in shear by tension loading.

ASTM D 1076 Standard specification for rubber, concentrated, ammonia preserved, creamed, and centrifuged natural latex.

ASTM D 1238 Test method for flow rates of thermoplastics by extrusion plastomer.

ASTM D 1505 Test method for density of plastics by the density‐gradient technique.

ASTM D 1525 Test method for VICAT softening temperature of plastics.

ASTM D 2117 Test method for melting point of semicrystalline polymers.

ASTM D 2240 Test method for rubber property. Durometer hardness.

ASTM D 2370 Test for tensile properties or organic.

ASTM E 28 Test method for softening point by ring and ball apparatus.

ASTM E 96 Test method for water vapor transmission of materials.

ASTM G 8 Test method for cathodic disbonding of pipeline coating.

ASTM G 14 Test method for impact resistance of pipeline coatings (falling weight test).

ASTM G 17 Test method for penetration resistance of pipeline coatings (blunt rod).

Karl Fisher Method Moisture content.

1.3.2 Deutaches Institut Fur Normung (DIN)

DIN 30670 Polyethylene coating of steel pipes and components.

DIN 53 151 Testing of paints, varnishes, and similar coating materials; cross‐cut test on paint coatings and similar coatings.

DIN 53 153 Testing of paints, varnishes, and similar coating materials; Buchholz indentation test on paint coatings and similar coating.

1.3.3 L'Association Francaise De Normalisation

NF‐A‐49‐704 Steel Pipes: Polyethylene external.

Coating: Application by extrusion.

1.3.4 British Standards (BS)

BS 3900 ‐ E1 (70) Bend test (Cylindrical Mandrel).

BS 3900 ‐ E10 (79) Pull‐off test for adhesion.

1.3.5 Swedish Standard

SIS 0559 00 ‐ 1967 Pictorial surface preparation standards for painting steel surfaces.


1.3.6 Steel Structures Painting Council (SSPC)

SSPC‐SP1 Solvent cleaning.

SSPC‐SP10 Near‐white blast cleaning.

SSPC‐Vis1‐89 Visual standard for abrasive blast cleaned steel.

SSPC‐PA2 Measurement of dry paint thickness with magnetic gauges.

2.0 APPLICATOR'S OBLIGATIONS

2.1 The Contractor shall, in his tender, submit the data sheets of the epoxy undercoat material, the binder material, the polypropylene, and the repair products selected by him for approval.

2.1.1 Once approved, the epoxy undercoat material, the binder material, the polypropylene, and the repair products shall not be changed by the Applicator without prior written authorization of the Company.

2.1.2 The approval decision shall not in any case be considered as a guarantee from the Company with respect to the coating material and repair products but as most as an authorization for use.

2.2 The Contractor shall obtain through the Applicator from the Manufacturer and submit to Company:

a. The guarantee that the epoxy undercoat material, the binder material, the polypropylene, and the repair products delivered shall meet the required coating characteristics as set forth in Chapter 5 according to the specified methods.

b. Two production test certificates for the epoxy undercoat material, the

binder material, and the polypropylene.

c. In case epoxy powder is used as undercoat material, one test certificate shall be submitted per 5 tons batch approximately, including, respectively, the test results as defined in § 3.2 which shall be in conformity with the specified methods and acceptable values.

d. Standard infrared scan of epoxy powder for each production batch.

e. Major epoxy powder application data: • Substrate Temperature • Pickup Time

f. Conditions of application of the repair product.

g. Packaging and storage requirements of epoxy powder and repair product.

h. Delivery of powder packings including each epoxy resin originating from a single production batch or cast.

i. Legible marking on each packing of powder and repair product with mention of the following information: • Manufacturer's Name • Product Description • Lot Number • Location of Manufacture • Date of Manufacture

2.3 The Contractor shall notify the Company, at least five working days before coating application, of the dates of coating execution to permit mobilization of the Company‐designated Inspector.

2.3.1 The Inspector shall have free access to the workshops, storage yards, and laboratory of the Applicator who shall provide him with all the facilities necessary for the proper execution of


his mission; i.e., office, telephone and telex, personnel, handling equipment, measuring instruments, etc.

2.3.2 Upon arrival in the coating plants, the Inspector shall receive from the Contractor/Applicator the documents supplied by the Manufacturer as speci‐fied in § 2.2.

2.4 The Contractor/Applicator shall supply all personnel; coating material and repair products; and an operational coating facility that includes all necessary application, inspection, and handling equipment.

2.5 The Applicator shall unload, inspect, and store all inbound bare pipe. Damaged or otherwise unsuitable pipe shall be identified and segregated for review and disposition by the Company.

2.6 The Applicator shall store the coating material and repair products, perform coating application and inspection in conformity with the rules of practice.

2.7 The Applicator shall only use inspection equipment that is calibrated and controlled by a quality assurance equipment calibration program.

2.8 The Contractor and the Applicator shall cosign with the Inspector the coated pipes' acceptance certificate including the results of all tests and inspection as set forth in this specification.

2.8.1 The acceptance certificate of coated pipes shall certify that the tests and inspection have been performed by the Applicator under the responsibility of the Contractor on the Company‐ordered pipes and have been witnessed by the Inspector.

2.8.2 One copy shall be transmitted to the Company and one to the Inspector.

3.0 COMPOSITION OF COATING AND CHARACTERISTICS OF THE EPOXY UNDERCOAT, THE BINDER, THE POLYPROPYLENE, AND THE REPAIR PRODUCTS

3.1 Composition of Coating

3.1.1 The three‐layer polypropylene coating shall consist of:

• One Liquid or Powder Epoxy Undercoat

• One Extruded Binder Coat • One Extruded Polypropylene Coat

3.2 Characteristics of the Epoxy Undercoat

3.2.1 Liquid Epoxy Undercoat

3.2.1.1 It shall be a two‐part solvent‐free epoxy having excellent metal substrate wetting properties.

3.2.1.2 It shall cure within 1 minute at 210‐220ºC.

3.2.2 Powder Epoxy Undercoat

3.2.2.1 The epoxy powder shall be a solid matter divided into very small particles obtained by crushing of an artificial, stable mixture made up of ethoxyl resin(s), hardener(s), coloring agent(s), filler(s), and possibly other additives.

3.2.2.2 The selected epoxy powder for use at operating temperature up to 150oF shall meet the characteristics specified in Table 3.2.2 before or after conditioning at 30ºC for one month. For temperature greater than 150ºF and less than 230ºF 3M Scotchkote 226N or equivalent shall be specified.


Table 3.2.2

Characteristics Methods Units Acceptable

Sieve Analysis Below 120 Microns Below 32 Microns

Coulter Counter TA Particles Analyzer Orifice Tube: 280 mu O.D.

% Wt % Part

95 30

Gel Time at 200ºC Heating Plate Sec.

20‐45

Specific Gravity Standard Method /

1.20‐1.50

Moisture Content Karl Fisher Powder: 20 g Temperature: 105ºC Time: 30 mm

%

0.5 (Max.)

Glass Transition Temperature 1st Cure 2nd Cure

Differential Heat Analysis Powder: 10 mg Temperature Rise: 10∞C/mn From 25 to

250ºC ‐ Gas = Helium

ºC ºC

40‐60 90‐105

Residual Enthalpy cal/g

10‐13

Adhesion DIN 53 151 ‐ 1981 Crosshatch: 1 mm

GUITER SCHNIT Degree

Gto

Impact Strength ASTM G 14 Steel Plate: 7.6 x 7.6 x 3.2 mm Coating: 400 Microns

J

1.8 (Min.)


3.3 Characteristics of the Binder Material

Its main characteristics are given in Table 3.3 below:

Table 3.3

Characteristics Standards Units Acceptable Values

Melt Flow Rate ASTM D 1238 g/10 mn

5 to 12

Density ASTM D 1505 0.90 to 0.92

Breaking Strength Elongation at Break ASTM D 638 MPa %

≥³20 ≥200

Rockwell Hardness ASTM D 785 ≥60

Brittle Point ASTM D 746 ºC

‐30

VICAT Softening Point (9.8 N) ASTM D 1525 ºC

125

Melting Point ASTM D 2117 ºC

140


3.4 Characteristics of the Polypropylene

Its main characteristics are given in Table 3.4 below:

Table 3.4

Characteristics

Standards Units Acceptable Values

Melt Flow Rate ASTM D 1238 g/10 mn

0.7 to 1.0

Density ASTM D 1505 0.91 to 0.92

Carbon Black Content ASTM D 1603 %

0

Strength at Yield Point at 23ºC ASTM D 638 MPa

≥20

Breaking Strength ASTM D 638 MPa

≥20

Elongation at Break at 23ºC ASTM D 638 %

>200

Rockwell Hardness ASTM D 785 ≥60

Water Absorption ASTM D 570 % 24 H

£0.005

VICAT Softening Point (9.8 N) ASTM D 1525 ºC

>135

Melting Point ASTM D 2117 ºC

≥150

Brittle Point ASTM D 746 ºC

<‐30


3.5 Characteristics of the Repair Product

3.5.1 Polypropylene Repair Product

3.5.1.1. The repair products shall be:

• Convenient for the protection of the pipeline.

• Compatible with the three‐layer polypropylene coating applied.

4.0 APPLICATION OF THE COATING MATERIAL AND REPAIR PRODUCT

4.1 Application of the Coating

4.1.1 The coating shall be plant applied on each pipe except at pipe ends.

4.1.2 Surface Preparation

4.1.2.1 Before grit‐blasting, the pipe surface shall be inspected for dents, bevel damage, and other damage. Debris inside pipe shall be removed. All traces of oil, grease, and loose deposits shall be removed from the exterior of the pipe. All visible oil and grease traces shall be removed using an appropriate solvent. The solvent shall be nontoxic and leave no residue. Pipe ends shall be protected from damage and suitably sealed to prevent abrasive from entering the interior of the pipe.

4.1.2.2 If pipes have been left more than one month in a marine and/or polluted atmosphere, they shall be subject to chemical cleaning before grit‐blasting to remove mainly chlorides and/or sulfides.

4.1.2.3 All moisture on pipe surface shall be removed by heating to at least 40ºC but in no case above 180ºC before grit‐blasting. Pipe that is visibly dry and has a surface temperature less than 3ºC above the dew point temperature

should be preheated prior to abrasive blasting.

4.1.2.4 The pipe surface shall be shot‐blasted by means of an automatic blasting machine to minimum SSPC‐SP10 (SA 2‐1/2 surface finish as per Swedish Standard SIS 05 59 00), with a surface profile between 35 and 85 microns.

• SA 2‐1/2 finish is interpreted to mean all metal surfaces shall be dry sand or grit‐blasted to remove all dirt, mill scale, rust, corrosion products, oxides, paint, and other foreign matter. Very light shadows, very slight streaks, or slight discolorations shall be acceptable; however, at least 95% of the surface shall have the uniform gray appearance of a white metal‐blast cleaned surface. Oil and grease shall be removed with a non‐oily solvent prior to blasting.

4.1.2.5 Recycling of the grit is allowed provided the blasting material contains at any time a maximum of 50% of already used material.

4.1.2.6 The surface roughness shall be checked as indicated in paragraph 6.3.3 hereafter.

4.1.2.7 Immediately before coating application, all dust and grit‐blast traces shall be removed from the pipe surface by brushing and vacuum cleaning.

4.1.2.8 Cleaned pipes shall again be inspected for detection of surface defects as indicated in paragraph 4.1.1 here above. Any defect detected shall be removed as specified in paragraph a).

4.1.2.9 Cleaned pipes, free of dust, without surface defects shall be coated within 6


hours of being blasted and before any visible rust forms or the blasted surface is otherwise contaminated. Blasted pipe not coated within 6 hours or pipe that is contaminated should be reblasted prior to coating.

4.1.3. Coating

4.1.3.1 The pipe shall be coated on a continuous coating line performing without any risk of deterioration (external pipe wall, bevels, coating) to the various heating, power spraying, curing, and quenching operations.

4.1.3.2 Epoxy Undercoat

a. Liquid Epoxy Undercoat • The pipes are heated in an

induction oven to obtain a pipe temperature of 210‐220ºC.

• The liquid epoxy components, preheated at 80ºC, are mixed in the gun nozzle and sprayed on the heated pipe. The thickness of the coat shall be between 60 and 100 microns.

b. Powder Epoxy Undercoat • The pipes are heated in an

induction oven to obtain a pipe temperature of 180‐200°C.

• The epoxy powder is sprayed using electrostatic spray guns. The thickness of the coat shall be between 40 and 60 microns.

c. Extruded Binder Coat • The binder coat shall be applied

by lateral (side) extrusion between one and two minutes after the epoxy undercoat has been applied.

• The die temperature shall be between 185 and 210ºC.

• The binder coat thickness shall be 250 to 300 microns.

d. Extruded Polypropylene Coat

• The extruded polypropylene coat shall be applied by lateral (side) extrusion.

• The extrusion temperature, at the die, shall be between 240 and 260ºC.

• The number of wrap and the overlapping shall be such that the polypropylene coat thickness achieved shall meet § 5.2 requirements (2.5 mm to 3.5 mm according to pipe OD).

• The coating shall be smoothed by pressure roller(s).

e. Nonslip Surface for Concrete Weight Coating • Apply suitable polypropylene

powder with a sintering weir with adjustable feed control to create a rough (sandy) surface condition. It is important that the polypropylene powder "bites" into the extrusion layer to anchor it, but still leaving a rough, textured finish.

4.1.4 Cooling

When wrapping is completed, the joint shall be sprayed with water in order to cool it down to approximately 60ºC. During cooling, the pipe shall be handled so as to avoid damage to the coating.

4.2 Application of Repair Products

4.2.1 All defects detected by the holiday detector and damaged coating areas less than 100 cm2 resulting from destructive testing or mechanical accidents shall be repaired at the Applicator's expense according to the following procedure.

4.2.2 If the damaged area is greater than 100 cm2, the pipe will be recoated as per paragraph 6.6.


4.2.3 A maximum of three repairs per joint is allowed.

4.2.4 Surface Preparation

4.2.4.1 If part of the wrapping is not bonded satisfactorily in the faulty area, it shall be removed by means of a wire brush or a knife.

• The edges of the wrapping shall be beveled.

• The area shall be made free of dust and degreased with methyl isobutyl ketone.

4.2.4.2 If the bare metal is exposed, it shall be carefully cleaned by brushing and sandblasting as indicated in paragraph 4.1.

4.2.5 Repair

Either one of the three following methods can be used:

Method A (for small repairs below 10 cm2)

• If bare metal is exposed, sandblast the area as indicated above and apply on the metal only a coat of liquid epoxy primer. If no bare metal is exposed, start by next step.

• Heat the pipe surface to a temperature around 180ºC using a hot air blower or an electric induction heating system.

• Apply the binder coat by extrusion or using a sheet of binder. Have it melt using the hot air blower.

• With a trowel, smooth the surface and eliminate the excess of material.

Method B (for repairs above 10 cm2 but below 100 cm2)

• If bare metal is exposed, sandblast the area as indicated above and apply on the metal area a coat of liquid epoxy primer. If no bare metal is exposed, start straight by the next step.

• Heat the pipe surface to a minimum temperature of 220ºC using an electric induction heating system or a hot air blower.

• Apply the binder coat by extrusion or using a sheet of binder. Make sure the binder coat fills the defect area and extends over a few cm over the surrounding sound coating.

• Apply a coat of polypropylene on top of the binder coat.

• Wrap around a Teflon tape and a fabric tape to maintain tightly the polypropylene patch during the post heating.

• Heat the area to 220‐240ºC to weld the polypropylene patch.

Method C (for repairs of any size up to 100 cm2 and on barge)

• If bare metal is exposed, carefully clean and sandblast the area. Apply on the metal surface a coat of liquid epoxy primer. This coat is recommended but can be omitted.

• Wrap around and open heat shrinkable polypropylene sleeve with a 5.0 cm overlap, on both sides, on the sound coating.

• By external side, heat the sleeve to a surface temperature of 200‐240ºC with a hot air ring unit or a gas torch or preferably an electric induction heating unit. Heat progressively and regularly, starting from the middle of the


sleeve and going toward to ends to avoid forming air pockets.

5.3 Cutbacks

5.3.1 A 200 ± 10 mm cutback shall be provided at each pipe end. 4.2.6 Inspection

The repaired area shall be 100% checked with a holiday detector set to 25,000 volts according to the requirements or paragraph 6.4.4.

5.3.2 The wrapping shall be cut just after cooling and removed manually. The stripped steel ends shall be brushed clean but leaving the epoxy undercoat.

5.3.3 The epoxy undercoat shall be removed on 50 mm at each pipe end.

5.0 CHARACTERISTICS OF COATING

The coating shall meet the characteristics as set forth in this chapter according to the following methods and acceptable values.

5.3.4 The ends of the wrapping shall be beveled in order to ensure a satisfactory bonding of joints on site. The bevel length shall be 12 mm approximately.

5.1 Aspect (§ 6.4.1) 5.4 Electrical Porosity

The coating shall be of a uniform color free of any defect detrimental to its quality. It shall not show any blister or lamination or disbonding.

5.4.1 The finished and possibly repaired coating shall be free of porosities detectable by a holiday detector set to 25,000 volts.

5.2 Thickness (§ 6.4.2)

The coating thickness shall be that given in Table 5.2.

Table 5.2

Pipe Diameter D in mm Minimum Coating Thickness in mm

D < 114.3 114.3 < D < 273 273 < D < 508 508 < D < 762

762 < D

1.2 1.5 1.8 2.0 2.5


5.5 Other Characteristics

Characteristics Methods Units Acceptable Values

Impact Resistance at 0ºC

DIN 30670 NF‐A‐49‐704

Nm/mm >15

Rockwell Hardness ASTM D 785 R Scale ≥60

Resistance to Peeling at 23 ± 2ºC

DIN 30670 NF‐A‐49‐704

N/50 mm >750

Indentation DIN 30670 NF‐A‐49‐704

Maximum Depth at 25ºC 100ºC mm

0.10 0.30

Bendability Bending the coated pipe to a radius equivalent to 20 times the pipe OD. Tests after bending: ‐ Holiday Detection

No Holiday

‐ Resistance to Peeling: • On Compression Side • On Tension Side

N/50 mm N/50 mm

>750 >750

‐ Visual Inspection

No Crack No Wrinkle No Surface Defect

Cathodic Disbonding After 60 Days

ASTM G 8 mm £5

Coating Specific Resistivity

NF‐A‐49‐704 OHM x m2 >108

UV Aging NF‐A‐49‐704 Variation of elongation at break (ASTM D 638).

% <‐35

Water Absorption ASTM D 570 % 24 H £0.005


6.0 INSPECTION

The Inspector shall have free access to all departments of the plants where the powder is produced and where it is applied.

An office and all necessary means to the perfect completion of his work shall be made available for him as well by the Manufacturer as by the Applicator.

Coating inspection shall be carried out by the Applicator in the presence of the Inspector. It shall include the following five operations:

• Inspection of the epoxy powder or liquid epoxy, binder material and polypropylene deliveries.

• Inspection of the epoxy powder or liquid epoxy, binder material and polypropylene quality.

• Inspection of the various application parameters of the epoxy undercoat, the binder coat, and the polypropylene coat.

• Systematic inspection of pipe coating or test samples taken from pipe end.

• Systematic inspection of each coated pipe.

The Inspector may check by himself the conformity of any characteristic mentioned in Chapter 5.

The Inspector may take samples of the coating materials or repair product and test specimens of coated pipe(s) for testing in laboratories selected by the Company in order to check the quality of the tested products.

6.1 Inspection of Coating Materials and Repair Product Delivery

This inspection shall be performed upon delivery of the coating materials and repair product for packaging and marking checking.

Packaging shall be in accordance with the Manufacturer's instructions and marking shall be in conformity with this specification (§ 2.2).

Nonconformity with any of the specified requirements shall cause the immediate rejection of the delivery concerned.

In order to face any dispute arising at a later stage, three 50‐g samples of each of the raw coating materials shall be taken from the production batches. One shall be reserved for the Applicator, one shall be transmitted to the Company, and one shall be kept as check sample in the Applicator's laboratory for six months, away from humidity at a temperature below and close to 20ºC.

6.2 Inspection of Coating Materials and Repair Product Quality

Such inspection is carried out before coating application to ascertain the quality of the coating materials and repair products by checking that all the documents to be supplied by the Contractor have been requested from the Manufacturer and are available in the required form (§ 2.2).

Any missing document and/or nonconformity of the production test certificates with the specifications will cause the rejection of the concerned coating material and repair product.


For example, infrared scans shall in no case be supplied in reduced copy.

6.3 Inspection of the Various Application Parameters of the Coating Materials

This inspection shall be performed during coating application in order to check the following parameters:

• Finish of Prepared Surface • Dust Degree of Prepared Surface • Total Roughness of Prepared Surface • Pipe Temperature When Entering

Spraying Machine • Pipe Travel Speed

6.3.1 Finish of Prepared Surface

Material: As per SSPC‐SP10 (SIS 05 99 00).

Method: Comparison of prepared surface finish with the illustration corresponding to SSPC‐SP10 or SA 2‐1/2 surface finish according to the initial metal rust degree (A, B, C, or D) or pipe metal.

Inspection 100% of the prepared surface of each pipe.

Specification Requirements: The inspection of each pipe shall be considered as acceptable when the whole prepared surface shows the same aspect as the relevant illustration.

Failing this, the pipe shall be reblasted.

6.3.2 Dust Degree of Prepared Surface

Material: Adhesive tape.

Method: Application of the adhesive tape on prepared surface and removal for visual inspection.

Inspection: Four per shift on each of the first 25 pipes.

Specification Requirements: The inspection of the dust degree of each pipe shall be considered as acceptable when the proportion of adhesive surface‐‐magnified 40 times‐‐showing dust particles is less than 25%.

Failing this, the pipe shall be dedusted again.

6.3.3 Total Roughness of Prepared Surface

Material: Tape made up of thermoplastic measuring patches such as "Press‐o‐Film" of TESTEX.

Method: Take the impression of the prepared surface by pressing a patch on the prepared surface. The total roughness value is then measured using an appropriate comparator and taking into account the thickness of the support.

Inspection: Four per shift on each of the first 25 pipes.

Specification Requirements: The inspection of each pipe shall be considered as acceptable when the four total roughness values are within the range of 50‐75 microns. In the case of value(s) out of range, four additional measurements shall be made around the critical point.

If the total roughness obtained from one of the four new measurements is:

• Below 50 microns, the pipe shall be reblasted.

• Above 80 microns, the pipe shall be examined by the Inspector. If the Inspector deems that more than 10% of the surface shows a total roughness value exceeding 80 microns, the pipe shall be rejected and reblasted.


6.3.4 Pipe Temperature When Entering Spraying Machine

Material: Optical pyrometer, temperature recorder manometer, or monitor.

Method: Specific to the instrument used which shall be calibrated at least twice per shift by means of heat indicating sticks.

Inspection: Continuous over total pipe length.

Specification Requirements: The inspection of pipe temperature when entering spraying machine shall be considered as acceptable when the temperature recorded does not deviate more than ±10C from the Manufacturer‐specified temperature.

Failing this, the pipe shall be reblasted.

• Any pipe heated above 280ºC shall be rejected and Company will decide for further action to be taken on such pipe.

6.3.5 Pipe Travel Speed

Material: At the Applicator's option.

Method: Specific to the equipment used which shall be calibrated at least twice per shift using a tachometer.

Inspection: Continuous during pipe travel along the coating line.

Specification Requirements: The inspection of pipe travel speed shall be considered as acceptable when the measured speed does not deviate by more than ±0.5 m/mn from the calculated speed Vc.

Vc = Distance (From Last Spray Gun to First Roller Support) Pickup Time (Specified by Manufacturer)

Failing this, the manufacturing process shall be adjusted until conformity with specified requirements is obtained. The pipes already coated with unaccepted travel speed shall be put apart and recoated as per § 6.6.

6.4 Systematic Inspection of Each Coated Pipe

This inspection shall be performed after coating application on each dry‐coated pipe cooled down at ambient temperature which shall be less than 35ºC and more than 10ºC in order to check the following:

• Aspect • Thickness • Cutbacks • Electrical Porosity

6.4.1 Aspect

Method: Visual.

Inspection: 100% of the pipe coated surface.

Specification Requirements: The inspection of each pipe shall be considered as acceptable when the aspect is in conformity with the requirements of § 5.1.

Failing this, the Inspector shall be alone entitled to decide of any further action.

6.4.2 Thickness

Material: Magnetic or electromagnetic type overlap measuring instruments.

Method: Specific to the instrument used which shall be suitably calibrated.

Inspection: Four thickness readings made on each pipe at equal intervals along any pipe axis taken at random.


Specification Requirements: The inspection of each pipe shall be considered as acceptable if the thickness readings are within the range: specified thickness (§ 5.2) minus 10% or plus 20%.

If more than 2% of the pipes are found with any coating thickness reading out of the above‐mentioned range, the manufacturing process shall be modified until conformity with the specified requirements is obtained. Only 2% of pipes will be accepted per shift with coating thickness between specified thickness and specified thickness minus 10%. All pipes with thickness below specified thickness minus 10% shall be rejected and recoated as per Paragraph 6.6.

6.4.3 Cutback

Material: Rule or template.

Method: Specific to the material used.

Inspection: At both ends of each coated pipe.

Specification Requirements: The inspection of each pipe shall be considered as acceptable when the cutback length is in conformity with the requirement of § 5.3.

Failing this, the Inspector shall be alone entitled to decide of any further action.

6.4.4 Electrical Porosity

Material: Adjustable DC holiday detector with voltage indicator‐‐maximum voltage 40,000 volts‐‐and electrode consisting of:

• One circular metal searching coil. • One elastomer element for

possible defect location.

Method: Setting of supply voltage to 25,000 volts. Total contact of electrode with coating. Pipe travel speed below or equal to 0.2 meter per second. The holiday detector shall be calibrated once per shift.

Inspection: Continuous over the entire coated surfaces.

Specification Requirements: The inspection of each pipe shall be considered as acceptable when the number of holidays such as bubbles, scratches, and other minor defects does not exceed three per tube. Defects shall be repaired as per § 4.2.

If two successive pipes show, respectively, a number of defects equal or superior to three (3), the Applicator shall stop the coating line immediately to find the cause and remedy it.

Any pipe showing a number of pinholes and/or defects exceeding three (3) shall be rejected and recoated as per Paragraph 6.6.

6.5 Systematic Inspection of Pipe Coating or Test Samples Taken at Pipe Ends

The inspection shall be performed upon completion of coating application on dry‐coated pipes cooled down at ambient temperature which shall be less than 35ºC and more than 10ºC in order to check the following characteristics:

• Impact Resistance • Rockwell Hardness, R Scale • Resistance to Peeling • Indentation • Bendability • Coating Specific Resistivity


6.5.1 Impact Resistance

Material: As per DIN 30670.

Inspection: Per shift, one test every 50 pipes starting from the first pipe.

Specification Requirements: Work shall be more than 15 Nm per mm of coating thickness.

Method: To determine resistance to shock a pile hammer shall be used. The coated pipe is placed on a steel block with a V‐notch (120º angle). The pile hammer surface is a section of a sphere with a size diameter of 25 mm. Test temperature shall be 0ºC.

Pile hammer drop height shall be 1 m, work generated by impact shall be measured within an accuracy of 1%. Spacing between two points of impact shall be at least 30 mm.

During the testing, check that the impact force is constant.

The coating shall be examined with a holiday detector, over the points of impact, at a voltage of 25 kV.

For 100 impact points, the detector should not detect more than two defects.

6.5.2 Rockwell Hardness, R Scale

Material: As per ASTM D 785.

Inspection: One test per shift.

Specification Requirements: Equal or more than 60.

Method: Test shall be carried out at 23 ± 2ºC. A Type D indentation shall be used with a weight of 5 kg.

6.5.3 Resistance to Peeling

Material: As per DIN 30670 or NF‐A‐49‐704.

Inspection: One test per shift starting from the first pipe but not less than five tests. If one test does not satisfy the requirements given hereafter, measurements shall be taken from 10 new specimens, none of them shall be defective.

Specification Requirements: More than 750 N/50 mm.

Method: Test shall be carried out at 20ºC (+3ºC ‐ 0ºC). The polypropylene coat shall be cut down to the steel surface using a double saw with blades spaced 50 mm apart. This band shall be cut along a generatix. The band shall be stripped off on 20 mm approximately.

The free end of the band shall be held in the jaws of a traction machine. The traction shall be made at a constant speed of 10 mm per minute.

Record the peeling force over the entire circum‐ference. Discard the last 20 mm.

The average peeling force shall be determined and reported.

6.5.4 Indentation

Material: As per DIN 30670 or NF‐A‐49‐704.

Inspection: One test per shift, but five tests minimum. If one fails, ten new samples shall be tested; none of the ten shall be defective.

Specification Requirements: Penetration shall be less than:

• 0.10 mm at 25ºC • 0.30 mm at 100ºC


Method: Test shall be carried out at a stable temperature comprised between 15 and 25ºC but controlled within 2ºC.

The testing device consists of a metal rod mounted at the end with a metal punch with a frontal plane surface area of 2.5 mm2 (\|O(/,O) 1.8 mm). The total weight of the rod and punch shall be 2.5 kg. The pressure exerted on the coating shall be 10 N/mm2.

The assembly shall be relayed to a penetrometer, whose dial allows a reading to within an accuracy of 1/100 of a millimeter. The depth of penetration shall be read to within an accuracy of 1/100 of a millimeter.

6.5.5 Bendability

Material: Adapted bending machine.

Inspection: Two tests among the coated pipes. If one test does not satisfy the requirements, two other tests shall be made; none of them shall be defective.

Specification Requirements: No holiday, no crack, no wrinkle, no surface defect. Resistance to peeling: >750 N/50 mm.

Method: Bending shall be carried out at 15‐25ºC. Bending radius shall be 20 times the pipe OD; i.e., 10.16 m.

6.5.6 Cathodic Disbonding

Material: As per ASTM G 8.

Inspection: Three tests for the coating system performed in an independent laboratory. Tests may have been performed previously.

Specification Requirements: Less than 5 mm after 60 days.

Method: The test shall be performed at room temperature. A 7‐mm hole shall be drilled through the coating sample. The hole and the surrounding coating shall be immersed in a 3% NaCl solution and polarized at ‐1.5 volt by impressed current or with a magnesium anode.

After 60 days, the disbonded length shall be measured.

6.5.7 Coating Specific Resistivity

Material: As per NF‐A‐49‐704.

Inspection: Five tests for the coating system performed in an independent laboratory. These tests may have been performed previously. The results shall be given to the Inspector.

Specification Requirements: More than 108 ohm x m2.

Method: The test shall be performed in 0.1 M NaCl solution.

Materials needed:

• A back electrode, e.g., copper cloth.

• Direct current power source supplying a voltage U adjustable from 0 to 50 volts minimum.

• A voltmeter and an amperometer.

One end of the pipe shall be made waterproof so that none of the uncoated metallic surface is in contact with the electrolyte. The other end out of the electrolyte shall be fitted with an electrical connection. Before insertion


into the electrolyte, absence of pores shall be verified with the holiday detector and the insulation quality at the submersible end checked.

To measure resistivity, the coated sample shall be connected to the "+" pole and the back electrode to the "‐" pole of the direct current source.

Coating resistivity RS is computed from the values of U, S, and I according to the formula:

where:

U = Voltage in volts from the direct current source.

S = Surface area in m2 of the sample in contact surface with electrolyte. It must be equal to 0.3 m2 minimum.

I = Current in A, flowing through coating. If the insulation on the submerged end is correct, the I read is the current passing through the coating.

Electric voltage shall only be applied during reading.

The test shall be continued for 100 days with daily readings.

6.5.8 UV Aging

Material: As per NF‐A‐49‐704 and ASTM D 638.

Inspection: Five tests on the same exposed sample of the polypropylene. These tests may have been performed previously in an independent labora‐tory. The results shall be given to the Inspector.

Specification Requirements: The elongation at break according to ASTM D 638 shall be larger than 390%.

Method: A piece of polypropylene wrap shall be stripped off. The binder coat shall be removed from it. The sample is exposed to the light of a 400 W xenon bulb for 800 hours.

R\|S\|do4(S) = \|F(U\|,S,I) ohms x m\|S\|up4(2)

The elongation at break shall be measured before and after exposure.

6.5.9 Interpretation of Results

6.5.9.1 The inspection shall be considered as acceptable when conforming to the specified conditions. The inspected coating shall then be repaired and checked (electrical porosity/thickness) according to the prescriptions applicable to the repair material.

6.5.9.2 If the results of one or several tests do not conform to the specified conditions, additional tests shall be run at the rate of two per defective test, respectively, on the pipe coated immediately prior and after the pipe found to be defective.

6.5.9.3 If all additional tests are acceptable, the coating of the pipes shall be considered in conformity with the specified requirements (except for the pipe where the test failed which shall be


treated as per § 6.6) and the pipes inspected shall be repaired and then checked.

6.5.9.4 In case of unsatisfactory result of one of these additional tests, the Applicator shall perform the test concerned on each pipe and submit the results obtained with mention of the values corresponding to a correct test. The objectionable pipes shall be rejected and recoated as per § 6.6.

6.6 Objectionable Pipes

6.6.1 The objectionable pipes shall be stored apart before repair. These pipes shall be heated to a temperature not exceeding 280ºC and shall have their coating removed by scratching in the presence of the Inspector who shall decide if they have to be rejected or reblasted and recoated.

6.6.2 The pipes rejected by the Inspector will be treated further as per Company requirements.

6.7 Repairs

See Paragraph 4.2.

7.0 HANDLING, TRANSPORT, AND STORAGE RULES

The Applicator shall be responsible for any damage occurring to the pipes from unloading to reloading on the relevant transportation means.

The Applicator shall consequently:

a. Inspect the bare pipes upon delivery to check that they have suffered no previous damage.

b. Take all necessary precautionary measures to prevent any deterioration during the following operations:

• Handling • Transfer to Storage Yard • Storage • Loading of Pipes for Shipment

All repairs and inspections shall be at the Applicator's expense.

7.1 Handling

7.1.1 The pipes shall be handled without causing damage to the pipe bevels and coating.

7.1.2 Direct contact with steel or hemp slings or with any material whose shape or nature may deteriorate the pipe coating shall be strictly prohibited. Canvas slings or hooks fitted with thermoplastic protection may be used.

7.1.3 Use of electromagnetic device is recommended.

7.2 Transfer to Storage Yard

During transport of pipes to the storage yard of the Applicator, the latter shall take all the required measures to avoid pipe and coating damage.

7.3 Storage Yard of the Applicator

Stockpiling of coated pipes shall be made so as to avoid any deterioration of coating. Coated pipes, when nonconcrete weight coated, shall be protected against ultraviolet rays action in particular.

7.4 Pipe Loading for Shipment

When loading the coated pipes for shipment, the Applicator shall take all necessary measures to avoid the deterioration of pipes and coating during handling and transport.


7.5 End Caps

If the bare pipes have been delivered to the Applicator with end caps, these end caps (or new ones) should be fitted again on the pipe ends after coating if required in the CONTRACT.

8.0 PRECAUTIONS FOR WELDING BENDING

8.1 During the welding process, in order to avoid that hot weld spatters burn the coating, a shield shall be used to protect the coating. For that purpose, a 50‐cm wide edge weighted shield of asbestos cloth will be draped over the top quadrant of the pipe on each side of the weld.

The welding ground lead contact shall not be made on a coated part of the pipe.

8.2 Bending must be done in properly padded machines equipped with rubber rollers.

9.0 COATING OF THE FIELD JOINTS ‐ COATING REPAIR ON JOB SITE

9.1 Field Joints

The following procedure shall be adhered to:

a. Before welding, position an adhesive polypropylene shrinkable sleeve just beside the weld or use an open type polypropylene shrinkable sleeve.

b. After welding, clean the area with a powered wire brush until a degree of cleanliness SSPC‐SP10 (St 2.5) is achieved, the edges of the wrapping shall be beveled with a fine file.

c. Preheat the area to be coated to 70ºC.

d. Position the sleeve with a 5.0‐cm overlap, on both sides on the sound coating.

e. By external side heat sleeve to a surface temperature of 220‐240ºC with a hot air ring unit or a gas torch or preferably an electric induction heating unit. Heat progressively and regularly, starting from the middle of the sleeve and going towards the ends to avoid forming air pockets.

f. Check covering quality with a holiday detector. Test voltage 25 kV.

9.2 Coating Repairs on Job Site

9.2.1 The eventual repairs to be done on job site shall be implemented as specified in paragraph 4.2 if the damaged area is less than 100 cm2.

9.2.2 If the damaged area is more than 100 cm2, heat shrinkable sleeves should be used as specified in paragraph 9.1.

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