IPS-G-TP-335

MATERIAL AND CONSTRUCTION STANDARD

FOR

THREE LAYER POLYETHYLENE COATING SYSTEM

ORIGINAL EDITION

DEC. 1997

This standard specification is reviewed and

updated by the relevant technical committee on
Aug. 2002. The approved modifications are
included in the present issue of IPS.

This Standard is the property of Iranian Ministry of Petroleum. All rights are reserved to the owner.
Neither whole nor any part of this document may be disclosed to any third party, reproduced, stored in
any retrieval system or transmitted in any form or by any means without the prior written consent of the
Iranian Ministry of Petroleum.
 Dec. 1997 IPS-G-TP-335

GENERAL REQUIREMENTS

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 Dec. 1997 IPS-G-TP-335

CONTENTS : PAGE No.

GENERAL REQUIREMENTS

1. SCOPE ...........................................................................................................................................IV
2. REFERENCES ...............................................................................................................................IV
3. DEFINITIONS AND TERMINOLOGY ............................................................................................VI
4. UNITS .............................................................................................................................................VI

PART 1 REQUIREMENTS FOR FACTORY APPLIED COATING

MATERIALS AND METHODS OF TEST

1. SCOPE ............................................................................................................................................ 9
2. REFERENCES ................................................................................................................................ 9
3. DEFINITIONS AND TERMINOLOGY ............................................................................................. 9
4. UNITS .............................................................................................................................................. 9
5. COATING MATERIALS .................................................................................................................. 9
6. EPOXY POWDER ......................................................................................................................... 10
7. BASIC PROPERTIES AND TESTS FOR BONDING AGENT (ADHESIVE) ............................... 12
8. BASIC PROPERTIES AND TESTS FOR POLYETHYLENE....................................................... 12
9. QUALITY CONTROL REQUIREMENTS...................................................................................... 13
10. QUALITY SYSTEMS................................................................................................................... 13

PART 2 FACTORY APPLIED COATINGS

1. SCOPE .......................................................................................................................................... 18
2. REFERENCES .............................................................................................................................. 18
3. UNITS ............................................................................................................................................ 18
4. MATERIALS.................................................................................................................................. 18
5. PIPES IDENTIFICATION .............................................................................................................. 18
6. PROTECTION OF PIPE END PREPARATION............................................................................ 19
7. SURFACE PREPARATION .......................................................................................................... 19
8. COATING PROCEDURE TESTS ................................................................................................. 19
9. INSPECTION AND TESTING (QUALITY CONTROL) ................................................................. 19
10. QUALITY SYSTEMS................................................................................................................... 20
11. COATING PROCEDURE QUALIFICATION............................................................................... 21
12. PRODUCTION COATING REQUIREMENTS............................................................................. 24
13. INSPECTION OF FINISHED COATING ..................................................................................... 24
14. COATING REQUIREMENTS AND TEST METHODS................................................................ 24
15. DEFECT RATE ........................................................................................................................... 25
16. HANDLING AND STORAGE REQUIREMENTS........................................................................ 25
17. TRANSPORTATION LOADING ................................................................................................. 25
18. REPAIRS..................................................................................................................................... 25
19. STRIPPING OF COATING.......................................................................................................... 25

APPENDICES:

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 Dec. 1997 IPS-G-TP-335

APPENDIX A HOLIDAY DETECTION OF COATINGS ............................................................... 26

APPENDIX B COATING OF BUTT JOINTS - MATERIAL APPLICATION CHARTS................. 27
APPENDIX C APPROVAL OF FIELD JOINT AND FITTING COATING
EQUIPMENT AND APPLICATORS ...................................................................... 28

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 Dec. 1997 IPS-G-TP-335

1. SCOPE
This Standard deals with factory and field applied polyethylene coatings for external surfaces of
buried or submerged steel pipes. The standard is comprised of three parts as follows:

Part 1: Requirements for Factory Applied Coating Materials and Methods of Test.
Part 2: Factory Applied Coatings.
The coating may be 2 or 3 layers as will be specified by the Company.
Two layers polyethylene coating consists of adhesive primer and polyethylene and is suitable for
operating temperature up to 50°C.
Three layers polyethylene coating consists of epoxy primer, adhesive primer and polyethylene and
is intended for operating temperature up to 80°C.

Note:
This standard specification is reviewed and updated by the relevant technical committee on
Aug. 2002. The approved modifications by T.C. were sent to IPS users as amendment No. 1
by circular No. 192 on Aug. 2002. These modifications are included in the present issue of
IPS.

2. REFERENCES

Throughout this Standard the following dated and undated standards/codes are referred to. These
referenced documents shall, to the extent specified herein, form a part of this standard. For dated
references, the edition cited applies. The applicability of changes in dated references that occur
after the cited date shall be mutually agreed upon by the Company and the Vendor. For undated
references, the latest edition of the referenced documents (including any supplements and
amendments) applies.

API (AMERICAN PETROLEUM INSTITUTE)

API PR5L5 "Recommended Practice for Marine Transportation of Line Pipe"

ASTM (AMERICAN SOCIETY FOR TESTING AND MATERIALS)

D 522 "Test Method for Elongation of Attached Organic Coating with
Conical Mandrel Apparatus"
D 570 "Test Method for Water Absorbtion of Plastic"
D 696 "Test Method for Coefficient of Linear Thermal Expansion of
Plastic"
D 746 "Test Method for Brittleness Temperature of Plastic and Elastomers
by Impact"
D 1002 "Test Method for Strength Properties of Adhesive In shear by
Tension Loading (Metal-to-Metal)"
D 1525 "Test Method for Vicat Softening Temperature of Plastics"
D 1603 "Test Method for Carbon Black in Olefin Plastic"
D 1673 "Test Method for Relative Permitivity and Displation Factor of
Expanded Cellular Plastics Used for Electrical Insulation"
D 1693 "Test method for Environment Stress-Cracking of Ethylene
Plastics"
D 2240 "Test Method for Rubber Property-Durometer Hardness"

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 Dec. 1997 IPS-G-TP-335

D 3176 "Method for Ultimate Analysis of Coal and Cock"

D 3180 "Method for Calculation Coal and Cock Analysis"
G8 "Test Method for Cathodic Disbanding of Pipeline Coating"
G 14 "Test Method for Impact Resistance of Pipeline Coating (Falling
Weight Test)"

BSI (BRITISH STANDARD INSTITUTION)

BS 3412 "Polyethylene Materials for Moulding and Extrusion"
BS 4232, "Specification for Surface Finish of Blast-Cleaned Steel for
Painting"
2nd Quality

DIN (DEUTCHES INSTITU FÜR NORMUNG)

DIN 30670 "Polyethylene Sheathing of steel Tubes and Steel Pipes and
Fittings"
DIN 50049 "Materials Testing Certificates"
(Parts 1, 2 & 3) 1986
DIN 53122 "Testing of Plastics Films; Elastomer Films; Paper, Board and
Other Sheet Materials; Determination of Water Vapor Transmission
Rate; Gravimetric Method"
DIN 53152 "Testing of Paints, Varnishes and Similar Coating Materials, Bend
Test on Paint Coating and Similar Coatings"
DIN 53155 "Testing of Paints, Varnishes and Similar Coating Materials, Chip-
Test of Coatings According to Peters"
DIN 53380 "Testing of Plastic Films; Determination of the Gas Transmission
Rate"
DIN 53455 "Testing of Plastic; Tensile Test"
DIN 53460 "Determination of the Vicat Softening Temperature of
Thermoplastic"
DIN 53479 "Testing of Plastics and Elastomers; Determination of Density"
DIN 53495 "Testing of Plastics; Determination of Water Absorbtion"
DIN 53505 "Testing of Rubber, Elastomers and Plastics; Shore Hardness
Testing A and D"
DIN 53735 "Testing of Plastics, Determination of the Melt Flow Index of
Thermoplastics"
DIN 55990 T2 "Testing of Paints, Varnishes and Similar Coating Materials-Powder
Coatings, Determination of Particle Size Distribution"
DIN 55990 T3 "Testing of Paints Varnishes and Similar Coating Materials-Powder
Coatings, Determination of Density"
DIN 55990 T8 "Testing of Paints-Varnishes and Similar Coating Materials, Powder
Coatings Assessment of the Chemical Storage Stability"
DIN 67530 "Reflectometer as a Means for Glass Assessment of Plane
Surfaces of Paint Coatings and Plastic"

IEC (INTERNATIONAL ELECTROTECHNICAL COMMISSION)

IEC 243 "Methods of Test for Electric Strength of Solid Insulating Materials"

ISO (INTERNATIONAL ORGANIZATION FOR STANDARDIZATION)

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 Dec. 1997 IPS-G-TP-335

ISO R527 "Testing of Plastic, Tensile Test"

ISO 868 "Testing of Rubber, Elastomer and Plastics Shore Hardness
Testing A and D"
ISO 1133D "Plastics-Determination of the Metal Mass-Flow Rate (MFR) and
the Metal Volume-Flow Rate (MVR) of Thermoplastic"
ISO 4599 "Test Method for Environment Stress Cacking of Ethylene Plastics"
ISO 9002 "Quality Systems-Model for Quality Assurance in Production,
Installation and Servicing"

IPS (IRANIAN PETROLEUM STANDARDS)

IPS-C-TP-101 "Surface Preparation"
IPS-C-TP-274 "Coating"
IPS-M-TP-313 "Hand Applied Laminated Tape Suitable for Cold Applied Coating
Systems"
IPS-M-TP-314 "Hand Applied Laminated Tape Suitable for Hot Applied Coating
Systems"
IPS-M-TP-317 "Petrolatum Impregnated Tape & Its Primer"
IPS-M-TP-318 "Wrap & Heat Shrinkable Sleeve"

SIS (STANDARDISERINGS-KOMMISSIONEN I SVERIGE)

SIS 05 5900 "Swedish Standards Institution Practice, Surface Preparation
Standard for Painting Steel Surface"

3. DEFINITIONS AND TERMINOLOGY

Batch
A batch shall consist of all materials which is processed at the same conditions and submitted for
inspection at one time.

Homopolymer
A polymer ( as polyethylene) consisting of identical monomer units.

Typical value
A value exhibiting the essential characteristic of a special type of material.

4. UNITS
This Standard is based on international System of Units (SI), except where otherwise specified.

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 Dec. 1997 IPS-G-TP-335

PART 1

REQUIREMENTS FOR FACTORY APPLIED COATING MATERIALS

AND

METHODS OF TEST

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 Dec. 1997 IPS-G-TP-335

1. SCOPE
1.1 This Part 1 of the Standard specifies materials for use in 3-layer polyethylene coating system. It
deals specifically with the properties, minimum requirements and related methods of tests to
establish suitability for use with Part 2 of this Standard which cover factory applied coatings and
field applied coatings respectively.
1.2 Materials specifications and method of tests for two layer polyethylene coating system shall be
in accordance with DIN 30670.

2. REFERENCES
See General Requirements.

3. DEFINITIONS AND TERMINOLOGY

See General Requirements.

4. UNITS
See General Requirements.

5. COATING MATERIALS

5.1 Selection of Coating Materials

5.1.1 Only coating systems, which comply with this Part one of the costruction standard shall be
used.
5.1.2 The coating materials supplied shall be certified by the manufacturer ensuring that all coating
materials and equipment comply with all of the provisions contained in this Part one of standard
originally and prior to application and the purchaser may make any investigations necessary, by
way of testing, batch sampling, manufacturing and factory inspection, to satisfy itself of compliance
by the contractor.
5.1.3 The contractor shall be responsible for ensuring that the range of values for any material
under consideration will be capable of providing a finished product in compliance with Part 2 of this
Standard when related to the specific mode of operation to be used.
5.1.4 It is intended that this specification be used to encourage and stimulate the development of
progressively better external pipeline coatings. Thus, where certain minimum performance values
are stated, should future coating material test submissions yield better than specification
requirements then, after economic evaluation, these new values may be adopted as the minimum
requirements and the specification would be upgraded accordingly.

5.2 Identification of Materials

All materials supplied for coating operations shall be suitably marked giving the following
information:
5.2.1 The manufacturer’s name and address.
5.2.2 The material and order number.
5.2.3 The batch number.
5.2.4 Date of manufacture and stable working shelf life (including storage condition limits).
5.2.5 Directions for mixing and/or thinning with solvents as required.
5.2.6 Directions for handling and storing of the coating materials.

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 Dec. 1997 IPS-G-TP-335

5.2.7 Information and warnings (if needed).

The contractor shall require the material manufacturer to supply certificates confirming that tests
detailed in this specification have been carried out on the batches supplied and that the materials
meet this Standard. These certificates shall be made available for examination by company on
request.

5.3 Production Data Sheets

The contractor shall be responsible for obtaining data sheets from the materials manufacturer which
shall include values for all the basic properties of the materials as specified in the "basic properties"
clause in the appropriate section of this Standard. These data sheets shall be made available for
examination by company on request.

6. EPOXY POWDER

6.1 Basic Properties and Tests for the Raw Powder

6.1.1 General
6.1.1.1 Epoxy powder is a thermosetting material for use as primer in a three layer polyethylene
coating system for steel pipe. It shall be specifically formulated and designed so as to be suitable
for electrostatic application and to improve adhesion of the coating system and also provide
maximum cathodic disbanding resistance.
6.1.1.2 The contractor shall obtain from the manufacturer specified and qualified ranges of values
for all properties listed in Table 1.1 and detailed in 6.1.2 to 6.1.3 inclusive that will ensure an
acceptable coating. The frequency of testing shall be in accordance with Clause 11 of Part 2.

6.1.2 Infrared scan

Using an approved method, an infrared spectrogram, preferably made by using a standard KBr
(potassium bromide) disc, shall be obtained from a first batch of the powder epoxy. This shall
subsequently be used for comparison with type spectrogram.

6.1.3 Thermal analysis

Thermal analysis data for each batch shall be made available showing, by use of a DSC
(Differential Scanning Calorimeter) the Glass Transition (GT) of the raw powder and also the
enthalpy of the curing powder. The Glass Transition Temperature (G.T.T) of the fully cured powder
shall also be quoted. The reference curve shall be provided as part of the production data sheet.
The limiting values of Δ H, TG1 and TG2 shall be identified by the manufacturer.

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 Dec. 1997 IPS-G-TP-335

TABLE 1.1 - TYPICAL VALUES OF RAW EPOXY POWDER PROPERTIES

PROPERTY UNIT TEST METHOD TYPICAL VALUE
Gloss at 60° angle % DIN 67530 65 ±5

Gel time sec DIN 55990-T8 43 ±10

Density g/cm³ DIN 55990-T3 1.5

Particle size % DIN 55990-T2 90 between 10 to 80 microns

Moisture content % weight Acceptable method to company 0.5 Max.

Shelf life at 30°C & %60 humidity Month --- 12 Min.

Theoretical coverage g/m² Acceptable method to company 90 g for 60 microns DFT

(Dry Film Thickness)

Note:
The test for raw epoxy power properties is under the responsibility of manufacturer.

6.2 Basic Properties and Tests for Cured Coating

6.2.1 General
6.2.1.1 The tests defined in 6.2.2 to 6.2.6 inclusive shall be carried out, on a laboratory coated steel
plate with a coating thickness of 60 microns.
Prior to coating, the steel surface shall be blast cleaned to a level of Sa 2½ to Swedish Standard
SIS 05 5900 and surface profile of approximately 50 microns peak to valley height.
6.2.1.2 The contractor shall ensure that the powder manufacturer shall carry out the tests specified
in 6.2.2 to 6.2.6 inclusive, on each batch.

6.2.2 Appearance
The coating shall exhibit uniform appearance.

6.2.3 Thermal analysis

Glass Transition Temperature (G.T.T) shall be measured on a prepared laboratory sample for
record and checking purposes.
The typical value of G.T.T is above 100°C.

6.2.4 Flexibility/bending
The flexibility/bending shall be measured in accordance with DIN 53152; - typical value < 5 mm.

6.2.5 Hardness
The hardness of the cured epoxy film shall be more than 85 bucholtz when tested in accordance
with DIN 53155.

6.2.6 Impact resistance

The impact resistance of the cured epoxy film shall be Min. 120 kg/cm at 20°C in accordance with
ASTM G14 test method. (Test panel thick 3 mm)

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 Dec. 1997 IPS-G-TP-335

7. BASIC PROPERTIES AND TESTS FOR BONDING AGENT (ADHESIVE)

7.1 This adhesive is used as second layer in a three-layer polyethylene coating system for steel
pipes. It shall be an ethylene base copolymer, specifically formulated and designed so as to be
suitable for extrusion application.
7.2 The contractor shall obtain from the manufacturer specified values for all properties listed in
Table 2.1 in accordance with 7.3.
7.3 The contractor shall ensure that the adhesive manufacturer shall carry out the tests Nos. 1, 2 in
Table 2.1 for each batch and the remaining tests shall be carried out as type tests twice per each
order as a minimum.
7.4 The adhesive shall be uncolored and made of raw material with the best quality to provide the
following properties:
- Excellent peeling resistance.
- Excellent mechanical strength.
- Excellent thermal stability.
- Strong adhesion to fusion bonded epoxy film as well as to steel surface.
- Homopolar bond with the polyethylene top coat (third layer).

TABLE 2.1 - PHYSICAL PROPERTIES OF ADHESIVE

PROPERTY UNIT TEST METHOD VALUE
1) Density g/cm³ DIN 53479 0.900 - 0.950

2) Melting index (2.16 kg/190°C) g/10 Min. DIN 53735 0.5-8 or as suitable for application
As PE (top coat)

3) Elongation % DIN 53455 95 (Min.)

4) Melting point °C DSC (Differential 9 (Typical)

Scanning Calorimeter)
5) Co monomer content %

Note:
The test for raw epoxy power properties is under the responsibility of manufacturer.

8. BASIC PROPERTIES AND TESTS FOR POLYETHYLENE

8.1 Polyethylene is a thermoplastic resin for use as topcoat in a three-layer polyethylene coating
system for steel pipe. It shall be specifically formulated and designed for extrusion application.
8.2 The contractor shall obtain from the manufacturer specified values for all properties listed in
Table 3.1 in accordance with 8.3.
8.3 The contractor shall ensure that the polyethylene manufacturer shall carry out the tests Nos. 1,
2, 7, 10 and 14 in Table 3.1 for each batch and the remaining tests shall be carried out as type tests
twice per each order as a minimum.
8.4 The polyethylene shall be made of raw material with the best quality to provide following
properties:
- Excellent peeling resistance.
- Excellent mechanical strength.
- Excellent thermal stability.
- Excellent Impact resistance.
- Excellent penetration resistance.
- Strong adhesion to adhesive layer.

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 Dec. 1997 IPS-G-TP-335

- Excellent stability against ultra violet rays.

8.5 The polyethylene shall be adequately weather-resistant and stable for fabrication and use, for
this purpose the nature and quantity of antioxidant shall be in accordance with BS 3412-76.

8.6 Color
The polyethylene shall be uniform in color and free from obvious foreign matters; the color shall be
black using carbon black; the carbon black characterization, dispersion and content shall be in
accordance with BS 3412-76.

TABLE 3.1 - PHYSICAL PROPERTIES OF BLACK POLYETHYLENE

PROPERTY UNIT TEST METHOD VALUE
1) Density (in black) g/cm³ DIN 53479 0.946 Min.

2) Melting index (2, 16 kg/190°C) g/10 Min. DIN 53735 ISO 1133D 0.3 (Typical)

3) Elongation % DIN 53455 600 - 700

4) Tensile strength at yield N/mm² DIN 53455 or ISO R 527 15 Min.

5) Tensile strength at break DIN 53455 or ISO R 527 25 Min.

6) Hardness Shore. D DIN 53505 or ISO 868 55 Min.

7) Vicat softening point °C DIN 53460 115 Min.

8) Melting point °C DSC 125

9) Low temperature brittleness °C ASTM D 746 -70 no fracture

10) Stress cracking resistance Hour ASTM D 1693 or ISO 4599 >1000
(methyl-ethylceton)

11) Carbon black content % ASTM D 1603 2 - 2.5 Min.

12) Dielectric strength kV/mm IEC 243 30 Min.

13) Fungus bacteria ASTM D 3173 and Pass no growth

ASTM D 3180
o o
14) 01T in 200C C /min EN 728 30 min

9. QUALITY CONTROL REQUIREMENTS

Before dispatch, the materials manufacturer shall carry out sampling and testing of the
manufactured materials covered by this specification in accordance with 7.3 and 8.3

10. QUALITY SYSTEMS

10.1 The contractor shall set up and maintain such quality assurance and inspection systems as are
necessary to ensure that the goods or services supplied comply in all respects with the
requirements of this Standard.
10.2 The company shall have the right to undertake inspection or testing of raw materials or
purchased components before application.

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 Dec. 1997 IPS-G-TP-335

PART 2

FACTORY APPLIED COATINGS

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 IPS-G-TP-335

1. SCOPE
This Part 2 of the standard specifies the operations and requirements for the factory application of
materials identified in Part 1, to buried steel pipes providing a finished product capable of pipe
laying and operating up to 80°C for 3-layer polyethylene coating.

2. REFERENCES
See General Requirements.

3. UNITS
See General Requirements.

4. MATERIALS

4.1 Acceptable Materials

4.1.1 Only polymer systems conforming to this Standard shall be considered for use as coatings
applied in accordance with this Part 2 of this Standard.
4.1.2 The contractor shall be responsible for the conformity with the requirements of this
construction standard. The contractor shall obtain and retain all certificates and manufacturer’s data
sheets. Certificates shall be made available on request to company.

4.2 Identification of Coating Materials

The contractor shall ensure that all materials supplied for coating operations are clearly marked with
the following information:
- Manufacturer’s name, trademark and address.
- Name of material, order number and L/C number.
- Batch number.
- Date of manufacture, and expiry date for use.
- Safety data sheet.
- Technical data sheet.

4.3 Storage of Coating Materials

To ensure that the properties of all coating materials are maintained in compliance with the relevant
section of Part 1. All coating materials consigned to the coating plant shall be properly stored in
accordance with the manufacturer’s recommendations at all times to prevent damage and
deterioration prior to use. Materials shall be used in the order in which they are delivered.

5. PIPES IDENTIFICATION
5.1 All identification markings, whether internal or external to the pipes shall be carefully recorded
before surface preparations begin.
5.2 The date of coating finish and the coating factory markings including pipe identification shall be
legibly marked on coating surface of each pipe.

This Standard is the property of Iranian Ministry of Petroleum. All rights are reserved to the owner.
Neither whole nor any part of this document may be disclosed to any third party, reproduced, stored in
any retrieval system or transmitted in any form or by any means without the prior written consent of the
Iranian Ministry of Petroleum.
 Dec. 1997 IPS-G-TP-335

6. PROTECTION OF PIPE END PREPARATION

6.1 Pipe end preparations shall be protected from mechanical damage during handling, storage,
surface preparation and the coating processes. The methods used shall also ensure that no
damage occurs to the internal surface of the pipe.
6.2 Pipe end preparations shall be protected from coating during the process by a suitable method
approved by the Company.
6.3 For technical welding reasons the ends of the pipes shall be free of any coating layer (cut back)
over a length of 100 (-0, +20) mm up to pipe size DN 500 mm (20 in.) inclusive and over a length of
150 (-0, +20) mm for sizes over DN 500 mm, unless specified otherwise by the Company.
6.4 The uncoated ends of pipes shall be temporarily protected against atmospheric corrosion by a
temporary paint easily removable by brushing.

7. SURFACE PREPARATION
7.1 The method of surface cleaning and surface preparation shall be specified by the contractor as
part of the coating procedure qualification and shall take into account the requirements specified in
7.2 to 7.5 inclusive, in accordance with (IPS-C-TP-101).
7.2 Where oil, grease or other contaminants are present they shall be removed, without spreading
them over the surface, with a suitable solvent. For pipes, which have been subjected to
contamination, the contaminant shall be removed by washing either with potable water or an
approved chemical cleaner. If a chemical cleaner is used, subsequent washing with potable water
will be necessary. The pipe shall be dried before blast cleaning. All processes shall be in
accordance with IPS-C-TP-101.
7.3 Pipes shall be blast cleaned to a minimum of Sa 2½ finish to SIS 05 5900. The blast profile shall
be between 40 µm and 75 µm height, measured by an agreed method. The blast cleaning medium
used shall be according to IPS-C-TP-101.
7.4 The metal surface (RZ) shall be inspected immediately after blast cleaning and all slivers,
scabs, etc., made visible by blast cleaning and detrimental to the coating process shall be removed
using a method approved by company. After the removal of defects, the remaining wall thickness
shall comply with the relevant pipe specification. Any rectified areas shall be blast cleaned to meet
the requirements of 7.3.
7.5 Any pipe found to have defects which exceed the levels permitted in the relevant pipe
specification shall be set aside for examination by an authorized company representative and no
subsequent action taken without the agreement of the Company.
7.6 Directly before coating, any dust, grit or other contaminants shall be removed from the pipe
surface by a method established as acceptable by the relevant coating procedure test and recorded
in the relevant coating procedure.
7.7 Where rust blooming or further surface contamination has occurred, the pipe shall be cleaned
again in accordance with 7.2 and again blast cleaned in accordance with 7.3 Coating shall take
place before any further contamination or rust blooming appears.

8. COATING PROCEDURE TESTS

The coating process shall comply with the procedure established in the coating procedure
qualification (see 11). Any changes in coating materials, pipe dimensions, pipe manufacturing
process or the coating process may, at the discretion of Company, necessitate a new coating
procedure approval tests.
Additionally, approved procedure tests shall be confirmed as proving tests, at intervals of not more
than 1 year for each type of powder, adhesive and polyethylene used by the contractor and for each
size of pipe and pipe manufacturing process as requested by the Company.

9. INSPECTION AND TESTING (QUALITY CONTROL)

9.1 The quality control system shall include as a minimum the requirements listed in Table 1.2.

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9.2 All inspections and testings listed in Table 3.2 shall be made by the contractor and witnessed
and certified by the inspector.
9.3 After examination or test, should the inspector find out that any pipe has not been cleaned or
coated in accordance with this Standard, the contractor shall be required to remove the coating
which is considered defective or inadequate, and to reblast and recoat the pipe to the requirements
for approval of the inspector.
9.4 The inspector shall have access at any time to the construction site and to those parts of all
plants that are concerned with the performance of work under this standard.
9.5 The contractor shall provide the necessary inspection tools and instruments for the inspector as
well as normal facilities necessary for inspection.

TABLE 1.2 - MINIMUM QUALITY CONTROL REQUIREMENTS

REQUIREMENTS CLAUSE
REFERENCE
1. Check cleanliness of pipes immediately prior to blast cleaning. 7.2

2. Monitor size, shape and cleanliness of the blast cleaning material and process. 7.3

3. Check visually in good light, the surface of the pipes for metal defects, dust and entrapped grit. 7.4

4. Check pipe surface blast profile. 7.3

5. Check for residual contamination of pipe surface. 7.4

6. Pipe temperature control of the pipe surface (pipe temperature shall not exceed 250°C). ---

7. Check recycled coating material for contamination and moisture. ---

8. Check the coating thickness (first, second layers and total) 14.2

9. Check the temperature control of quenching system. ---

10. Check the coating adhesion. 14.4

11. Holiday detection of 100% of the surface area of all coated pipes. 14.3

12. Supervision to ensure the adequate and proper repair of all defects. 18

13. Check on coating color and appearance, e.g. uniformity and flow. 13.2

14. Check for damage to pipe end preparations. 6

10. QUALITY SYSTEMS

10.1 The contractor shall set up and maintain such quality and inspection systems as are necessary
to ensure that the goods and services supplied comply in all respects with the requirements of this
Standard.
10.2 The Company shall assess such systems against the recommendations of the applicable parts
of ISO 9002 and shall have the right to undertake such surveys as are necessary to ensure that the
quality assurance and inspection systems are satisfactory.
10.3 The Company shall have the right to undertake inspection and testing of the goods and
services during any stage of manufacturing at which the quality of the finished goods may be
affected and to undertake inspection or testing of raw materials and/or purchased pipes.

10.4 Compliance Certificates

For each contract, the contractor shall issue the required certificates in accordance with EN 10204
and presented to the Company.

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 Dec. 1997 IPS-G-TP-335

10.5 Test Certificates

10.5.1 The contractor shall issue the required certificates in accordance with EN 10204 for all
coating production tests identified in 14.1 to 14.3 inclusive and presented to the Company.
10.5.2 For all tests witnessed by the inspector a certificate shall be prepared and issued by the
contractor and certified by the inspector in accordance with EN 10204.

11. COATING PROCEDURE QUALIFICATION

11.1 General
11.1.1 Before bulk coating of pipes commences the requirements of 11.2 and 11.3 shall be met and
a detailed sequence of operations to be followed on the coating of pipe shall be presented to the
Company for checking the compliance with this Standard and formal approval.
11.1.2 The Company shall also specify which coated pipes are to be subjected to the test specified
in 10.3.2 and 10.3.3 for formal approval of coating procedure. No coated pipes shall be dispatched
to the Company or no coating process shall be done until the coating procedure has been approved
and approval confirmed in writing by the Company.

11.2 Coating Procedure Specification

The coating procedure specification shall incorporate full details of the followings, but not limited to
them:
a) The polyethylene coating system to be used together with appropriate data sheets as
defined in Clause 4.
b) pipe cleaning,
c) blast cleaning medium and technique,
d) blast cleaning finish, surface profile and surface cleaning,
e) dust removal,
f) preheat time and temperature,
g) powder epoxy, adhesive and polyethylene including use of recycled material,
h) curing and quenching time and temperature,
i) repair technique,
j) coating stripping technique.

11.3 Coating Procedure Approval Tests

11.3.1 General
11.3.1.1 A batch of 10 to 20 pipes of any specific pipe mill shall be selected by the inspector and
coated by the contractor in accordance with the approved coating procedure specification (see
11.2), the coating operations being witnessed by the inspector. Three pipes from the coated pipes
shall be selected by the inspector and subjected to the complete set of tests specified in 11.3.2 and
11.3.3. Testing shall be witnessed by the inspector and a full set of records shall be presented to
the Company for consideration.

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TABLE 2.2 - MINIMUM COATING THICKNESS IN mm

PIPE DIAMETER POWDER EPOXY ADHESIVE POLYETHYLENE
Mm (in) RESIN
(1ST LAYER) (2ND LAYER) (3RD LAYER)
Up to DN 250 ( 10′′ ) 0.060 0.30 2.5
0.060 0.30 3.0
DN 250 ( 10′′ ) up to DN 500 ( 20′′ ) 0.080 0.35 3 (Normal) or
>DN 500 ( 20′′ )
3.5 (reinforced)
when specified

11.3.1.2 Bulk coating of pipes shall not commence until all short and long term tests (see 11.3.2 and
11.3.3) results have been approved officially by company, unless the contractor takes responsibility
of failure for any long term test.
11.3.1.3 All test methods shall be in accordance with Table 3.2.

11.3.2 Short-term approval tests

11.3.2.1 Thickness
For this purpose, at least two measurements shall be made in accordance with Table 3.2 at
locations uniformly distributed over the length and periphery of each pipe selected for the test and
checked for compliance with Table 2.2.
50% of these measurements shall be made along and over the longitudinal weld seam, if any.

11.3.2.2 Porosity
Each pipe selected for the test shall be holiday detected over 100% of its coated surface and
checked for compliance with Table 3.2.

11.3.2.3 Adhesion
This test shall be carried out on each pipe at 5 locations uniformly distributed over the length and
periphery of the pipe, in this respect the mean force necessary to pull off the coating shall comply
with Table 3.2. None of these tests must fail.

11.3.3 Long-term approval tests

The tests identified in 11.3.3.1 to 11.3.3. Inclusive shall be performed on test sections taken from all
three coated pipes selected for the coating procedure approval tests.

11.3.3.1 Adhesion
This test shall be carried out at 5 different locations on 5 test sections in accordance with 11.3.2.3,
but after 30 days keeping in the hot air of 80°C. No change in the mean force necessary to pull of
the coating must occur.

11.3.3.2 cathodic disbanding

The test sections shall be tested and checked for compliance with Table 3.2.

11.3.3.3 Environmental stress cracking resistance

The test sections shall be tested and checked for compliance with Table 3.2.

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11.3.3.4 Thermal cycle resistance

The test sections shall be notched with a length of 30 mm and a depth of 0.3 mm and then tested
and checked for compliance with Table 3.2.

11.3.3.5 Impact resistance

The test sections shall be tested and checked for compliance with Table 3.2.

11.3.3.6 Thermal aging

The test sections shall be tested and checked for compliance with Table 3.2.

11.3.3.7 Elongation
The samples taken from the three pipes shall be tested and checked for compliance with Table 3.2.

11.3.3.8 Specific electrical resistance

The samples taken from the three pipes shall be tested and checked for compliance with Table 3.2.

11.3.3.9 Indentation resistance

The samples taken from the three pipes shall be tested and checked for compliance with Table 3.2.

TABLE 3.2 - COATING REQUIREMENTS AND TEST METHODS FOR COATING

PROCEDURE APPROVAL TESTS
TESTS/INSPECTION TEST METHODS AND REQUIREMENTS
1. Surface preparation 1. Visual inspection
2. Acceptable limit: as specified in 7.3
2. Coating thickness - Electro-magnetic thickness gage is used.
- The gage shall be calibrated daily with the standard calibrated plates.
- Min. requirements: As specified in Table 2.2.
3. Porosity DIN 30670
No defect at 25 Kv
4. Adhesion DIN 30670, Method I
o
Acceptable limit: min 23 C 8Kg/cm
o
min 80 C 2Kg/cm
5. Impact resistance DIN 30670
Acceptable limit: 5 Jul/mm
6. Elongation DIN 30670
Acceptable limit: Min. 200% for extruded coating.
7. Indentation (hardness) DIN 30670
Acceptable limit: 0.3 mm
8. Thermal cycle resistance -30°C 1 Hr
- 1 cycle:
+60°C 1 Hr
- Number of cycles: 100
Acceptable limit: No crack.
9. Environmental stress ASTM D 1693
cracking resistance Acceptable limit: No crack after 300 Hr.
10. Thermal aging DIN 30670
Acceptable limit: ±35% change in melting index value.
11. Specific electrical DIN 30670
Acceptable limit: 10 Ω m Min.
8 2

12. Cathodic disbonding ASTM G8

Acceptable limit: 5 mm

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 Dec. 1997 IPS-G-TP-335

12. PRODUCTION COATING REQUIREMENTS

12.1 Surface Preparation

The surface of the pipe to be coated shall be prepared in accordance with Clause 7.

12.2 Coating Process

12.2.1 The production coating process shall be carried out using a procedure approved in
accordance with Clauses 4, 8 and 11.
12.2.2 The thickness of each layer and the total thickness shall comply with the values in the Table
2.2 when tested in accordance with DIN 30670.

12.3 Protection of Pipe end Preparations

Protection of weld end preparations shall be in accordance with Clause 6.

13. INSPECTION OF FINISHED COATING

13.1 General
The inspection of finished coating shall be in accordance with Clause 14. The quality and values to
be achieved shall be the same as those identified in 13.2 and Clause 14.

13.2 Check on coating Color and Appearance

Coating color and appearance shall be uniform and free from runs, sags, blistering, roughness,
foaming and general film defects.

14. COATING REQUIREMENTS AND TEST METHODS

14.1 General
14.1.1 After formal approval of all short and long term tests by Company, the contractor will be
authorized to commence the bulk production.
14.1.2 The contractor shall perform the routine inspection and tests in accordance with 14.2 to 14.4
inclusive during coating production.
14.1.3 All the inspection and tests witnessed by the inspector shall be certified.
14.1.4 The pipe coating shall comply with all requirements identified in 14.2 to 14.4 inclusive.

14.2 Thickness
This test shall be carried out 3 times during each 8 hour production shift and each time on 4
consecutive pipe lengths in accordance with DIN 30670 (Sections 5.2.1 and 6.3) every pipe which
does not comply with the minimum requirements of Table 3.2 shall be rejected for subsequent
stripping and recoating. Should two consecutive pipes fail to satisfy the requirement, the cause shall
immediately be investigated. If the cause is not resolved after four consecutive pipes, the coating
process shall be stopped for full investigation; this shall involve checking all pipes back to the
preceding acceptable pipe.

14.3 Porosity
Each individual line pipe shall be holiday detected over 100% of its coated surface in accordance
with DIN 30670. Up to 2 holidays per pipe length will be allowed for repair on a max. of 5% of

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coated pipe lengths during each 8 hour production shift.

Any individual pipe with more than 2 holidays shall be rejected for subsequent stripping and
recoating. If more than 2 holidays per pipe length are detected on two consecutive pipes, the cause
of the high holiday rate shall immediately be investigated. If the cause is not resolved after four
consecutive pipes, the coating process shall be stopped for full investigation. All holidays detected
on non-rejected pipes shall be repaired in accordance with Clause 15 and satisfactorily retested.

14.4 Adhesion
This test shall be carried out 3 times during each 8 hour production shift, each time on one
individual line pipe. The test shall be carried out at room temperature and at 2 ends of the pipe
coating surface and checked for compliance with Table 3.2. If the coating adhesion at any location
is below the requirement of Table 3.2 the pipe shall be rejected for subsequent stripping and
recoating; in this case the second consecutive pipe shall be checked. Should two consecutive pipes
fail to satisfy the requirement, the cause shall immediately be investigated; if the cause is not
resolved after four consecutive pipes, the coating process shall be stopped for full investigation, this
shall involve checking all pipes back to the preceding acceptable pipe.

15. DEFECT RATE

Should tests specified in 14.2 to 14.4 inclusive in any production shift show a rejection rate of more
than 10% for 50-457 mm ( 2′′ - 18′′ ) and 5% for 508-1420 mm ( 20′′ - 56′′ ) of coated pipes for any
one test, then every pipe in that shift shall be individually subjected that test.
In such cases the contractor shall simultaneously conduct an investigation to establish the cause of
the defect.
The cost of retrieval and/or any additional expenses incurred as a result of additional examination
shall be borne by the contractor.

16. HANDLING AND STORAGE REQUIREMENTS

16.1 All coated pipes shall be handled and stored in such a manner as to prevent damage to the
pipe walls, the weld end preparations and the coating.
16.2 Nylon slings or protected hooks, which do not damage pipe ends, shall be used for loading,
unloading and stacking.
16.3 The coated pipes shall be stored at all times free from the ground. Storage may be effected by
the use of battens suitably covered with soft material such as rubber sheet.
16.4 The coated pipes may only be stacked to a height such that no flattening of the coating occurs,
in this respect the formula given in API RP 5L5 shall be used for the calculation of static load stress.
16.5 The pipes shall be separated from each other with sufficient and proper dun age.
16.6 During long storage the polyethylene coating shall be protected from contact with petrol, oil or
grease, as some of these substances can cause swelling in the polyethylene layer.

17. TRANSPORTATION LOADING

17.1 The loading operations shall be witnessed and certified by the inspector.
17.2 The coated pipes shall be loaded on trucks with provisions of 16.2.
17.3 The Contractor shall provide all necessary means, such as saddles, battens, etc., for safe
transporting of the coated pipes.

18. REPAIRS
The procedure for repairs of holidays and damaged areas due to destructive test should be prepare
by manufacturer and approved by A.R.

19. STRIPPING OF COATING

Rejected coating shall be removed only by the procedures specified by the Company. The process
shall cause no mechanical damage to the pipe and the steel temperature shall not exceed 250°C.

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 Dec. 1997 IPS-G-TP-335

APPENDICES

APPENDIX A
HOLIDAY DETECTION OF COATINGS

A.1 Holiday detection shall be carried out using equipment approved by Company on surfaces,
which are at ambient temperature and free from moisture.
A.2 For all coatings (except adhesive tape) the operating voltage shall be 125 V per 25 µm of
coating thickness (e.g. 2 kV for 400 µm).
The rate of travel of the probe over the surface shall be a maximum of 300 mm/s. All holidays shall
be repaired.
A.3 For fusion bonded epoxy coating systems carbon impregnated neoprene or rolling spring types
of electrodes shall be used. For other coatings the splayed brush electrode may also be used, if
authorized by the Company.
A.4 The brush and carbon impregnated neoprene types of electrode shall be of the curved type,
conforming to the contour of the pipe.
A.5 All holidays, imperfections and damaged areas shall be identified with a waterproof marker.
All markings shall be sufficiently distant from the holiday, imperfection or damaged area to allow
surface preparation and patching to take place without detriment to the adhesion of the coating.
A.6 All holiday detectors shall be calibrated at the start of every workday and additionally when
requested by the Company.

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 Dec. 1997 IPS-G-TP-335

APPENDIX B
COATING OF BUTT JOINTS - MATERIAL APPLICATION CHARTS

EXISTING COATING BUTT JOINT EXISTING COATING TABLE 1.3

REFERENCE
FBE FBE FBE A
MCL MCL MCL B
FBE MCL MCL C
CTE MCL + TAPE or H-TAPE FBE D
CTE MCL + TAPE or H-TAPE MCL E
CTE TAPE or H-TAPE CTE F
PE TAPE or H-TAPE FBE G
CTE TAPE or H-TAPE PE H
PE TAPE or H-TAPE MCL I
PE TAPE or H-TAPE PE J

Key to abbreviations and markings:

FBE Fusion Bonded Epoxy Coating
MCL Multi Component Liquid Coating
TAPE Hand Applied Laminate Tape Epoxy
H-TAPE Heat Shrinkable Tape
Tape Wrapped Zone
CTE Coal Tar Enamel
PE Polyethylene

Notes:
Bare or painted pipe or fittings shall be coated with tape (see Note 1 g Table 1.3) before the
relevant butt joint coating is applied (see 4.2 and 4.3).

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 Dec. 1997 IPS-G-TP-335

APPENDIX C
APPROVAL OF FIELD JOINT AND FITTING COATING EQUIPMENT
AND APPLICATORS

C.1 Process Approval

All processes/equipment for applying field joint coating shall be approved by the Company prior to
applicator qualification trials.

C.2 Field Joint Coating Applicators

C.2.1 General requirements

Written procedures and drawings must be submitted prior to undertaking qualification trials,
providing all details of the method of working and parameters to be used. These procedures must
have the acceptance of the Company representative before trials commence.

C.2.2 Test procedure

Ten welded joints shall be coated under the supervision of Company representative under
simulated or actual field conditions. All ten joints produced shall meet the requirements of Appendix
A.

C.3 Operator Qualification

C.3.1 All operators who carry out successfully the coating including heating when required
applications shall be deemed to be qualified to carry out production work on any contract, using the
same process and equipment within 12 months of completing the trial.
C.3.2 Additional and subsequent operators shall demonstrate their ability to coat joint within the
specification requirements on production work, which shall be supervised or carried out by
previously qualified operators in the ratio of four skilled/two unskilled.

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