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SECTION 403 (IFGS) PIPING MATERIALS

403.1 General.


403.1.1 Material Application.

Materials and components conforming to standards or specifications listed herein or acceptable to the authority having jurisdiction shall be permitted to be used for appropriate applications, as prescribed and limited by this Code.
403.1.2 Used Materials.

Pipe, fittings, valves, or other materials shall not be used again unless they are free of foreign materials and have been ascertained to be adequate for the service intended.
403.1.3 Other Materials.

Material not covered by the standards specifications listed herein shall be investigated and tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that service by the manufacturer and shall be acceptable to the authority having jurisdiction.
403.2 Metallic Pipe.

403.2.1

Cast-iron pipe shall not be used.
403.2.2

Steel and wrought-iron pipe shall be at least of standard weight (Schedule 40) and shall comply with one of the following standards:
1.    Standard for Welded and Seamless Wrought-Steel Pipe, ASME B36.10;
2.   Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated Welded and Seamless, ASTM A53; or
3.   Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service, ASTM A106.
403.2.3

Nodular (ductile) iron pipe shall comply with one of the following standards:
1.    Standard for Ductile-Iron Pipe, Centrifugally Cast, in Metal Molds or Sand-Lined Molds, for Gas, ANSI A21.52; or
2.    Specification for Ductile Iron Pressure Pipe, ASTM A377.

Such pipe shall be not less than 3-inch size (76 mm), shall not be welded, and shall be used only underground outside building foundation boundaries, or aboveground, provided that joints are properly restrained against movement and separation.
403.2.4

Copper and brass pipe shall not be used if the gas contains more than an average of 0.3 grains of hydrogen sulfide per 100 standard cubic feet of gas (0.7 milligrams per 100 liters). Threaded copper, brass, or aluminum alloy pipe in iron pipe sizes shall be permitted to be used with gases not corrosive to such material.
403.2.5

Aluminum alloy pipe shall comply with Specification for Aluminum-Alloy Seamless Pipe and Seamless Extruded Tube, ASTM B241 (except that the use of alloy 5456 is prohibited), and shall be marked at each end of each length indicating compliance. Aluminum alloy pipe shall be coated to protect against external corrosion where it is in contact with masonry, plaster, or insulation, or is subject to repeated wettings by such liquids as water, detergents, or sewage. Aluminum alloy pipe shall not be used in exterior locations or underground.
403.2.6 Metallic Tubing.

Seamless copper, aluminum alloy, or steel tubing shall be permitted to be used with gases not corrosive to such material.
403.2.6.1

Steel tubing shall comply with Standard Specification for Electric Resistance-Welded Coiled Steel Tubing for Gas and Fuel Oil Lines, ASTM A539, or Standard Specification for Copper Brazed Steel Tubing, ASTM A254.
403.2.6.2

Copper tubing shall comply with standard Type K or L, of Specification for Seamless Copper Water Tube, ASTM B88; or Specification for Seamless Copper Tube for Air Conditioning and Refrigeration Field Service, ASTM B280.

Copper and brass tubing and fittings (except tin-lined copper tubing) shall not be used if the gas contains more than an average of 0.3 grains of hydrogen sulfide per 100 standard cubic feet of gas (0.7 milligrams per 100 liters).
403.2.6.3

Aluminum alloy tubing shall comply with Specification for Aluminum-Alloy Drawn Seamless Tubes, ASTM B210, or Specification for Aluminum-Alloy Seamless Pipe and Seamless Extruded Tube, ASTM B241. Aluminum-alloy tubing shall be coated to protect against external corrosion where it is in contact with masonry, plaster, or insulation, or is subject to repeated wettings by such liquids as water, detergent, or sewage.

Aluminum-alloy tubing shall not be used in exterior locations or underground.
403.2.6.4

Corrugated stainless steel tubing shall be tested and listed in compliance with the construction, installation, and performance requirements of Interior Fuel Gas Piping Systems Using Corrugated Stainless Steel Tubing, ANSI/AGA LC 1.
403.3 Plastic Pipe, Tubing, and Fittings.

Plastic pipe, tubing, and fittings shall be used outside underground only and shall conform with Standard Specification for Thermoplastic Gas Pressure Pipe, Tubing, and Fittings, ASTM D2513. Pipe to be used shall be marked “gas” and “ASTM D2513.”

Anodeless risers shall comply with the following:

1.   Factory-assembled anodeless risers shall be recommended by the manufacturer for the gas used and shall be leak tested by the manufacturer in accordance with written procedures.
2.   Service head adapters and field-assembled anodeless risers incorporating service head adapters shall be recommended by the manufacturer for the gas used by the manufacturer and shall be designed certified to meet the requirements of Category I of ASTM D 2513, and U.S. Department of Transportation, Code of Federal Regulations, Title 49, Part 192.281(e). The manufacturer shall provide the user qualified installation instructions as prescribed by the U.S. Department of Transportation, Code of Federal Regulations, Title 49, Part 192.283(b)

The use of plastic pipe, tubing and fittings in undiluted liquefied petroleum gas piping systems shall be in accordance with Standard for the Storage and Handling of Liquefied Petroleum Gases, NFPA 58.
403.4 Workmanship and Defects.

Gas pipe or tubing and fittings shall be clear and free from cutting burrs and defects in structure or threading, and shall be thoroughly brushed, and chip and scale blown.

Defects in pipe or tubing or fittings shall not be repaired. When defective pipe, tubing, or fittings are located in a system, the defective material shall be replaced. [See 404.15.1.3.]

403.5 Protective Coating.


Where in contact with material or atmosphere exerting a corrosive action, metallic piping and fittings coated with a corrosion-resistant material shall be used.

External or internal coatings or linings used on piping or components shall not be considered as adding strength.

403.6 Metallic Pipe Threads.


403.6.1 Specifications for Pipe Threads.

Metallic pipe and fitting threads shall be taper pipe threads and shall comply with Standard for Pipe Threads, General Purpose (Inch), ASME B1.20.1.
403.6.2 Damaged Threads.

Pipe with threads that are stripped, chipped, corroded, or otherwise damaged shall not be used. If a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.6.3 Number of Threads.

Field threading of metallic pipe shall be in accordance with Table 403.6.3.


Table 403.6.3
Specifications for Threading Metallic Pipe


Iron Pipe Size
(inches)

Approximate Length of Threaded Portion
Approximate No. of Threads to be Cut
½
¾
10
¾
¾
10
1
7/8
10

1
11

1
11
2
1
11


12
3

12
4
15/8
13

For SI units: 1 inch = 2.54 cm
403.6.4 Thread Compounds.

Thread (joint) compounds (pipe dope) shall be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be conducted through the piping.
403.7 Metallic Piping Joints and Fittings.

The type of piping joint used shall be suitable for the pressure-temperature conditions and shall be selected giving consideration to joint tightness and mechanical strength under the service conditions. The joint shall be able to sustain the maximum end force due to the internal pressure and any additional forces due to temperature expansion or contraction, vibration, fatigue, or to the weight of the pipe and its contents.

403.7.1 Pipe Joints.

Pipe joints shall be threaded, flanged, or welded, and nonferrous pipe shall be permitted to also be brazed with materials having a melting point in excess of 1,000%F (538%C). Brazing alloys shall not contain more than 0.05 percent phosphorus.
403.7.2 Tubing Joints.

Tubing joints shall either be made with approved gas tubing fittings or be brazed with a material having a melting point in excess of 1,000°F (538°C). Brazing alloys shall not contain more than 0.05 percent phosphorus.
403.7.3 Flared Joints.

Flared joints shall be used only in systems constructed from nonferrous pipe and tubing where experience or tests have demonstrated that the joint is suitable for the conditions and where provisions are made in the design to prevent separation of the joints.
403.7.4 Metallic Fittings

(Including Valves, Strainers, Filters).
1.   Threaded fittings in sizes larger than 4 inches (100 mm) shall not be used unless acceptable to the authority having jurisdiction.
2.   Fittings used with steel or wrought-iron pipe shall be steel, brass, bronze, malleable iron, ductile iron, or cast iron.
3.   Fittings used with copper or brass pipe shall be copper, brass, or bronze.
4.   Fittings used with aluminum alloy pipe shall be of aluminum alloy.
5.   Cast-Iron Fittings:
i.   Flanges shall be permitted to be used.
ii.   Bushings shall not be used.
iii.   Fittings shall not be used in systems containing flammable gas-air mixtures.
iv.   Fittings in sizes 4 inches (100 mm) and larger shall not be used indoors unless approved by the authority having jurisdiction.
v.   Fittings in sizes 6 inches (15 cm) and larger shall not be used unless approved by the authority having jurisdiction.
6.    Brass, Bronze, or Copper Fittings. Fittings, if exposed to soil, shall have a minimum 80 percent copper content.
7.    Aluminum Alloy Fittings. Threads shall not form the joint seal.
8.    Zinc-Aluminum Alloy Fittings. Fittings shall not be used in systems containing flammable gas-air mixtures.
9.    Special Fittings. Fittings such as couplings, proprietary type joints, saddle tees, gland-type compression fittings, flared, flareless, or compression type tubing fittings may be used provided they are (1) used within the fitting manufacturers’ pressure-temperature recommendations; (2) used within the service conditions anticipated with respect to vibration, fatigue, thermal expansion, or contraction; (3) installed or braced to prevent separation of the joint by gas pressure or external physical damage; and (4) acceptable to the authority having jurisdiction.
403.8 Plastic Piping, Joints, and Fittings.

Plastic pipe, tubing, and fittings shall be joined in accordance with the manufacturers’ instructions. The following shall be observed when making such joints:

1.   The joint shall be designed and installed so that the longitudinal pull-out resistance of the joint will be at least equal to the tensile strength of the plastic piping material.
2.    Heat-fusion joints shall be made in accordance with qualified procedures that have been established and proven by test to produce gas tight joints at least as strong as the pipe or tubing being joined. Joints shall be made with the joining method recommended by the pipe manufacturer. Heat fusion fittings shall be marked “ASTM D2513.”
3.   Where compression type mechanical joints are used, the gasket material in the fitting shall be compatible with the plastic piping and with the gas distributed by the system. An internal tubular rigid stiffener shall be used in conjunction with the fitting. The stiffener shall be flush with the end of the pipe or tubing and shall extend at least to the outside end of the pipe or tubing and shall extend at least to the outside end of the compression fitting when installed. The stiffener shall be free of rough or sharp edges and shall not be a force fit in the plastic. Split tubular stiffeners shall not be used.
4.   Plastic piping joints and fittings for use in liquefied petroleum gas piping systems shall be in accordance with Standard for the Storage and Handling of Liquefied Petroleum Gases, NFPA 58.
403.9 Flanges.

All flanges shall comply with Standard for Cast Iron Pipe Flanges and Flanged Fittings, ASME B16.1; Standard for Ring-Joint Gaskets and Grooves for Steel Pipe Flanges, ASME B16.20; Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings, AWWA C111/A21.11; or Standard Finishes for Contact Faces of Pipe Flanges and Connecting-End Flanges of Valves and Fittings, MSS SP-6. The pressure-temperature ratings shall equal or exceed that required by the application.

403.9.1 Flange Facings.

Standard facings shall be permitted for use under this Code. Where 150-pound steel flanges are bolted to Class 125 cast-iron flanges, the raised face on the steel flange shall be removed.
403.9.2 Lapped Flanges.

Lapped flanges shall be permitted to be used only aboveground or in exposed locations accessible for inspection.
403.10 Flange Gaskets.

Material for gaskets shall be capable of withstanding the design temperature and pressure of the piping systems, and the chemical constituents of the gas being conducted, without change to its chemical and physical properties. The effects of fire exposure to the joint shall be considered in choosing material:

1.   Acceptable materials include:
metal or metal-jacketed, asbestos (plain or corrugated), asbestos, and aluminum “O” rings and spiral wound metal gaskets.
2.   When a flanged joint is opened, the gasket shall be replaced.
3.   Full-face gaskets shall be used with all bronze and cast-iron flanges.