NACE RP 0375 Wax Coating Systems For

STD-NACE RP0375-ENGL L777 b1152781 0502247 712 m

LhNACE" NACE Standard RP0375-99 Item No. 21013

THE C O R R O S I O N S O C I E T Y

Standard Recommended Practice

Wax Coating Systems for Underground Piping Systems

This NACE Intemational standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone, whether he has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE International standard is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnifying or protecting anyone against liability for infringement of Letters Patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use of better procedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this standard in specific instances. NACE Intemational assumes no responsibility for the interpretation or use of this standard by other parties and accepts responsibility for only those official NACE International interpretations issued by NACE International in accordance with its governing procedures and policies which preclude the issuance of interpretations by individual volunteers.

Users of this NACE International standard are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE Intemational standard may not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE International standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard.

CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn at any time without prior notice. NACE International requires that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of initial publication. The user is cautioned to obtain the latest edition. Purchasers of NACE International standards may receive current information on all standards and other NACE International publications by contacting the NACE International Membership Services Department, P.O. Box 218340, Houston, Texas 7721 8-8340 (telephone +1 [281]228-6200).

Reaffirmed 1999-04-28 Approved March 1975 Revised October 1994

NACE International P.O. Box 21 8340

Houston, TX 7721 8-8340 +1 281/228-6200

ISBN 1-57590-089-0 O 1999, NACE International

Copyright NACE International Provided by IHS under license with NACE

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Foreword

Wax coating systems are designed to provide underground pipes with protection against corrosive environments. This standard recommended practice covers surface preparation, material requirements, application, and handling of hot- and cold-applied wax and component wrappers and wax-tape coating systems for the protection of underground pipe, fittings, and valves.

This standard was originally prepared in 1975 by Task Group T-10D-16, a component of NACE International Unit Committee T-IOD on Protective Coating Systems. It supersedes NACE Publication 2L161.' The scope of the original NACE Standard RP0375 included only the application of hot- and cold-applied wax coatings. When this standard was revised by the authoring task group in 1994, the section on wax-tape coatings was added. In 1999 this standard was reviewed by Task Group T-10D-17n-6A-63, reaffirmed with editorial changes, and issued by NACE International under the auspices of Group Committee T-10 on Underground Corrosion Control.

In NACE standards, the terms shall, must, should, and may are used in accordance with the definitions of these terms in the NACE Publications Style Manual, 3" ed., Paragraph 8.4.1.8. Shall and must are used to state mandatory requirements. Should is used to state that which is considered good and is recommended but is not absolutely mandatory. May is used to state that which is considered optional.

NACE International i



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RP0375-99

NACE International Standard

Recommended Practice

Wax Coating Systems for Underground Piping Systems

Contents

1. General ..................................................................................................................... 1 2. Hot-Applied Wax Systems ......................................................................................... 1 3. Cold-Applied Wax Systems ....................................................................................... 3 4. Wax-Tape Coating Systems ...................................................................................... 4 5. Handling of Wax-Coated Piping ................................................................................. 5 6. Cathodic Protection of Wax-Coated Pipelines, Valves, and Fittings ........................... 5 References ..................................................................................................................... 5

i i NACE International



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RP0375-99

Section 1 : General

1.1 This standard covers hot- and cold-applied wax and component wrappers and wax-tape coating systems for the protection of underground pipe, fittings, and valves. It out- lines material requirements for hot-applied waxes, cold- applied waxes, component wrappers, and wax tapes as well as proper methods of surface preparation, coating application, and handling of the coated pipe.

1.2 Tables 1 through 4 provide material requirements and give references to ASTM(’) standard test methods for the various coating materials discussed.

1.3 Any reference made to wax tape and wax primer in this

standard also applies to petrolatum tape and petrolatum primer.

1.4 Hot-applied wax coatings may be applied by machine as a line-travel operation in the field or by hand. Cold- applied wax and wax-tape coatings are applied only by hand. These coatings may be used on new piping or for coating rehabilitation.

1.5 The sutface preparation required for hot-applied wax coatings differs from the surface preparation required for cold-applied wax and wax-tape coatings.

Section 2: Hot-Applied Wax Systems

2.1 Hot-applied wax coating systems for underground pipes usually consist of a microcrystalline wax coating applied directly to the surface followed by an overwrap of component wrapper.

2.2 Hot-applied wax coating materials shall have the following characteristics:

2.2.1 Microcrystalline Wax

2.2.1.1 Microcrystalline wax shall be inert, flexible, waterproof, adhesive, and have good wetting

characteristics.

2.2.1.2 Microcrystalline wax shall be capable of being blended with suitable wetting agents and rust inhibitors.

2.2.1.3 Microcrystalline wax shall meet the r e quirements given in Table 1 when tested in accordance with the test methods listed therein.

2.2.1.4 Microcrystalline wax shall be heated in a clean kettle.

TABLE 1 Requirements for Hot-Applied Wax

Properties Physical Requirements Test Method

Specific Gravity at 25°C (77°F) 0.85 to 0.92 ASTM D 706 Needle Penetration at 25°C (77°F) 26 to 50 ASTM D 1 321 ’ Melting Point 71 to 79°C (160 to 175°F) ASTM D 1278 Flash Point 260°C (500°F) minimum ASTM D 92’ Dielectric Strength 4 V/pm (100 V/mil) minimum ASTM D 149’’

2.2.2 Component Wrappers ance with the test methods listed therein.

2.2.2.1 Component wrappers shall consist of plastic film (supported or unsupported) that is compatible with the microcrystalline wax coating.

2.2.2.2 Component wrappers shall be used over fittings and valves and have the ability to conform to the contours of the surface.

2.2.2.3 Component wrappers shall meet the requirements in Table 2 when tested in accord-

2.2.2.4 Component wrappers are normally applied using a spiral wrap.

2.2.3 Outerwrap may consist of suitable material such as kraft paper, plastic film, glass cloth, or synthetic fiber mat, and may be used to assist in the pre- vention of handling damage and to help with visual detection of physical damage to the coating system. Additional outerwrap (rockshielding) may be necessary.

American Society for Testing and Materials (ASTM), 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959.

NACE International 1



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RP0375-99

2.3 Suggested Application Systems

2.3.1 Traveling machine application

(1) One coat of hot-applied wax coating; (2) One wrap of component wrapper; and (3) One wrap of suitable outerwrap (if specified).

TABLE 2 Property Values of Component Wrappers


Supported Wrapper - Wax-Laminated Plastic Film on Spun Plastic Mat or Cotton Scrim

Plastic Film Thickness 13 to 25 pm (0.5 to 1 mil) ASTM D 1000” Wax Melt Point 71 to 99°C (160 to 210°F) ASTM D 127 Total Thickness 250 to 360 pm (10 to 14 mils) ASTM D 1000 Dielectric Strength 14 Wpm (350 V/mil) minimum ASTM D 149

Supported Wrapper - Extruded Polyethylene on Glass Mesh

Polyethylene Film Thickness 50 to 150 pm (2 to 6 mils) ASTM D 1000 Total Thickness 150 to 250 pm (6 to 1 O mils) ASTM D 1000 Dielectric Strength 28 Wpm (700 V/mil) minimum ASTM D 149

Unsupported Wrapper - Polyvinylidene Chloride

Thickness ($ply) 38 pm (1.5 mils) ASTM D 1000 Dielectric Strength 79 Wpm (2,000 V/mil) minimum ASTM D 149

2.4

2.5

2.3.2 Hand application

(1) One coat of hot-applied wax coating; (2) One wrap of component wrapper; and (3) An additional overcoat of hot-applied wax (if specified).

Surface Preparation

2.4.1 The surface shall be free from oil and grease and, if necessary, shall be solvent cleaned in accordance with SSPC“’-SP I.*

2.4.2 Unless otherwise specified, the surface shall be hand-tool cleaned in accordance with SSPGSP

2.4.3 The surface shall be dry prior to application of the coating.

2.4.4 The prepared surface shall be visually inspected to determine whether foreign material has been removed in accordance with the degree of cleanli- ness specified.

Coating Application

2.5.1 Hot wax shall be flooded directly on the surface at the temperature recommended by the manu

facturer and approved by the engineer in charge or a representative of the owner. The application temperature range is based on ambient conditions and pipe temperature.

2.5.2 Coating application shall produce a contin- uous film of 500 pm (20 mils) minimum thickness and adhere well to the surface.

2.5.3 The wrappers shall be applied in a uniform, snug-fitting, and overlapping pattern following the application of the hot wax coating.

2.5.3.1 Wrapper tension shall be sufficient to ensure tight application over the coating.

2.5.3.2 Overlap at the edges of the wrapper shall be maintained as recommended by the manufacturer and approved by the engineer in charge or a representative of the owner. Usually a minimum of 2.5 cm (1 .O in.) of overlap and 8 cm (3 in.) of existing coating is required.

2.5.4 Application of the wax coating and wrapper shall be visually inspected to determine that the application conforms to contract specifications and is free from holidays or other coating irregularities. Granny ragging is necessary to ensure adequate coverage.

The Society for Protective Coatings (SSPC), 40 24’h Street, sih Floor, Pittsburgh, PA 15222-4656.

2 NACE International



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STD-NACE RP0375-ENGL

RP0375-99

2.5.5 An electrical inspection of the complete coat- the additional voltage recommended for the outer- ing and wrapping system should be made using a holi- wrap used. day detector to locate holidays.

2.5.6 Defects in the coating shall be repaired in ac- 2.5.5.1 Holiday detector voltage shall be set at 4 cordance with Paragraphs 2.4 and 2.5. Wpm (100 V/mil) of hot wax coating thickness plus

Section 3: Cold-Applied Wax Systems

3.1 Cold-applied wax coating systems for underground piping systems consist of a wax coating that is hand applied to the surface without primer and overwrapped with a component wrapper.

3.2 Materials for Cold-Applied Wax Coating Systems

3.2.1 Cold-Applied Wax Coating

3.2.1.1 Cold-applied wax coatings shall be composed of petroleum wax and plasticizers and may contain fillers, inhibitors, and additives.

3.2.1.2 Cold-applied wax coatings shall be of a consistency that allows a build-up of coating thickness.

3.2.1.3 Cold-applied wax coatings shall be inert, flexible, waterproof, adhesive, have good wetting characteristics, and have dielectric strength in accordance with values in Table 3.

3.2.1.4 Cold-applied wax coatings shall meet the requirements in Table 3 when tested in accordance with the test methods listed therein.

3.2.2 Component Wrapper

3.2.2.1 The component wrapper shall consist of a plastic film (supported or unsupported) that is compatible with the cold-applied wax.

3.2.2.2 The component wrapper shall have the ability to conform to the contours of the irregular surface if used over fittings and valves.

3.2.2.3 The component wrapper shall meet the requirements in Table 2 when tested in accordance with the test methods listed therein.

3.3 Surface Preparation

3.3.1 Loose rust, mill scale, old coating, and dirt shall be removed in accordance with SSPCSP 2. Wet surfaces shall be wiped until they are as dry as possible.

3.3.2 The prepared surface shall be visually inspected prior to application of the wax coating system.

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TABLE 3 Requirements for Cold-Applied Wax


Congeal Point 66°C (150°F) minimum ASTM D 938’* Specific Gravity at 25°C (77°F) 0.88 to 0.94 ASTM D 70 Cone Penetration at 25°C (77°F) 160 to 290 ASTM D 93713 Flash Point 93°C (200°F) minimum ASTM D 92 Dielectric Strength 4 Wpm (100 V/mil) ASTM D 149

3.4 Application

3.4.1 A thin film of cold-applied wax shall be applied by hand or brush. An additional buildup of coating shall be applied.

3.4.2 If moisture is present, the cold-applied coating shall be rubbed and pressed onto the surface until the coating adheres to the surface. The manufacturer shall be consulted for recommended procedures.

3.4.3 The cold-applied wax does not require drying

or curing time, and the component wrapper shall be applied immediately after coating in order to avoid con- tamination or abrasion of the coated surface.

3.4.4 A wrapper shall be applied using a spiral wrap, a cigarette wrap, or precut pieces formed over irregular surfaces, with a minimum 2.5 cm (1.0 in.) overlap.

3.4.5 The cold-applied wax may be used to fill the voids in irregular surfaces of fittings and valves. The




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RP0375-99

wrapper shall be applied so that it does not bridge over with a holiday detector equipped with a wand-type irregular surface configurations. electrode to detect holidays.

3.5 Inspection and Repair 3.5.2.1 Holiday detector voltage shall be set at 4 V/pm (100 V/mil) of cold-applied wax coating

3.5.1 The completed application of the cold-applied thickness plus the additional voltage recom- coating shall be visually inspected to determine mended for the outerwrap used. whether it complies with contract specifications and is free from holidays or other coating irregularities. 3.5.3 Defects in the coating shall be repaired in

3.5.2 The coating should be electrically inspected accordance with Paragraphs 3.3, 3.4, and 3.5.

Section 4: Wax-Tape Coating Systems

4.1 Wax-tape coating systems consist of a petroleum wax primer applied to the surface and then overwrapped with a petroleum wax tape. If extraordinary construction or backfill conditions that could result in mechanical damage exist, a double thickness of wax tape or an additional outerwrap may be used.

4.2 Materials for Wax-Tape Coating Systems

4.2.1 Primer

4.2.1.1 The primer shall be composed of petroleum waxes and plasticizers.

4.2.1.2 The primer may contain fillers, inhibitors, and additives that are compatible with the wax- tape system.

4.2.1.3 The primer may be used as a surface conditioner to wet the surface, displace moisture, arrest active corrosion, and ensure adhesion of the wax tape.

4.2.1.4 The primer shall meet the requirements in Table 4 when tested in accordance with the test methods listed therein.

4.2.2 Wax-Tape Coating

4.2.2.1 The wax-tape coating shall be composed of a synthetic fiber fabric saturated with a petroleum wax blend.

4.2.2.2 The wax saturant shall be composed of petroleum wax and plasticizers and may contain fillers, inhibitors, and additives.

4.2.2.3 The plasticizers may be of a solvent or nonsolvent type, and the tape may either become firm or remain pliable over a period of time.

4.2.2.4 The coating shall meet the requirements in Table 4 when tested in accordance with the test methods listed therein.

TABLE 4 Requirements for Wax Tape and Primer


Primer

Congeal Point 57" to 68°C (135tO 155°F) Flash Point 66°C (150°F) minimum Specific Gravity at 25°C (77°F) 0.88 to 1.25 Cone Penetration at 25°C (77°F) 74 to 224 Dielectric Strength 4 Wpm (100 V/mil) minimum

Tape

ASTM D 938 ASTM D 92 ASTM D 70 ASTM D 937 ASTM D 149

Congeal Point of Saturant 63 to 71°C (145 to 160°F) ASTM D 938 Flash Point of Saturant 60°C (140°F) minimum ASTM D 92 Thickness 1,000 pm (40 mils) minimum ASTM D 1000 Dielectric Strength 6.7 Wpm (170 L'/mil) minimum ASTM D 149




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STD-NACE RP0375-ENGL

4.2.3 An outerwrap that consists of suitable material such as plastic film, glass mesh, or synthetic fiber mat may be used for additional mechanical protection.

4.3 Surface Preparation

4.3.1 Loose rust, mill scale, old coating, and dirt shall be removed by hand-tool cleaning in accordance with SSPC-SP 2. Wet surfaces shall be wiped until they are as dry as possible.

4.3.2 Surface preparation shall be visually inspected prior to application of the wax-tape coating system.

4.4 Application

4.4.1 A thin film of primer shall be applied by hand or brush to the surface.

4.4.2 If moisture is present, the primer shall be rubbed and pressed onto the surface until it adheres to the surface. The manufacturer shall be consulted for recommended procedures.

4.4.3 Because the primer does not require drying or curing time, the wax tape may be applied immediately after priming.

RP0375-99

4.4.4 The wax tape may be applied using a spiral wrap, a cigarette wrap, or precut pieces formed over irregular surfaces with a minimum 2.5 cm (1.0 in.) overlap.

4.4.5 The wax tape shall be applied by pressing and molding the tape into conformity with the surface so that it does not bridge over irregular surface configurations.

4.5 Inspection and Repair

4.5.1 The completed application of the wax-tape coating shall be visually inspected to determine whether it complies with contract specifications and is free from holidays or other coating irregularities.

4.5.2 The coating should be electrically inspected with a holiday detector equipped with a wand-type electrode to detect holidays.

4.5.2.1 Holiday detector voltage shall be set at 6.7 V/pm (170 V/mil) of wax-tape coating thickness plus the additional voltage recommended if an outerwrap is used.

4.5.3 Defects in the coating shall be repaired in accordance with Paragraphs 4.3,4.4, and 4.5.

Section 5: Handling of Wax-Coated Piping

5.1 The coated and wrapped pipe shall be handled in such a manner as to minimize damage to the coating.

5.2 All supported areas of the coated pipe shall be inspected, and damaged areas shall be repaired before installation.

5.3 The pipeline ditch shall be graded and free of rocks, foreign matter, and projections that could cause damage to the coating system.

5.5 All equipment used for the handling of coated pipe shall be designed to minimize damage to the protective coating system and shall be approved by the engineer in charge or a representative of the owner.

5.6 If weights, supports, or anchoring devices are used on the coated pipe, they should be attached or applied without damaging the coating system. Such damage can be min- imized by protecting the coating system with protective padding such as rockshields.

5.4 A rockshield, additional layers of coating and wrapping 5.7 When excavations are made for repairs, tie-ins, lateral material, padding of the ditch bottom, or selected backfill connections, or any other purpose, all damaged or deter- materials may be used to prevent coating damage. iorated coating shall be repaired.

Section 6: Cathodic Protection of Wax-Coated Pipelines, Valves, and Fittings

6.1 If required, cathodic protection shall be installed in ac-cordance with NACE Standard RP0169.5

(3)NACE Publication 10D1 944 contains additional information on the subject.




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RP0375-99

References

1.

2.

3.

4.

5.

6.

7.

NACE Publication 2L161 (withdrawn), ‘Tentative Recommended Minimum Requirements for Hot- Applied Wax-Type Protective Coatings and Wrappers for Underground Pipelines” (Houston, TX: NACE). Available from NACE as a historical document only.

SSPC-SP 1 (latest revision), “Solvent Cleaning” (Pittsburgh, PA: SSPC).

SSPC-SP 2 (latest revision), “Hand Tool Cleaning” (Pittsburgh, PA: SSPC).

NACE Publication 1 OD1 94 (latest revision), “State-of- the-Art Report on Rockshielding” (Houston, TX: NACE).

NACE Standard RP0169 (latest revision), “Control of External Corrosion on Underground or Submerged Metallic Piping Systems” (Houston, TX: NACE).

ASTM D 70 (latest revision), “Standard Test Method for Density of Semi-Solid Bituminous Materials” (West Conshohocken, PA: ASTM).

ASTM D 1321 (latest revision), “Standard Test Method for Needle Penetration of Petroleum Waxes” (West Conshohocken, PA: ASTM).

8. ASTM D 127 (latest revision), “Standard Test Method for Drop Melting Point of Petroleum Wax Including Petrolatum” (West Conshohocken, PA: ASTM).

9. ASTM D 92 (latest revision), “Standard Test Method for Flash and Fire Points by Cleveland Open Cup” (West Conshohocken, PA: ASTM).

IO. ASTM D 149 (latest revision), “Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies” (West Conshohocken, PA: ASTM).

11. ASTM D 1000 (latest revision), “Standard Test Method for Pressure-Sensitive Adhesive-Coated Tapes Used for Electrical and Electronic Applications” (West Conshohocken, PA: ASTM).

12. ASTM D 938 (latest revision), “Standard Test Method for Congealing Point of Petroleum Waxes, Including Petrolatum” (West Conshohocken, PA: ASTM).

13. ASTM D 937 (latest revision), “Standard Test Method for Cone Penetration of Petrolatum” (West Conshohocken, PA: ASTM).




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RP0375-99

ISBN 1-57590-089-0 NACE International



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NACE RP 0375 Wax Coating Systems For

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