N.Y.C. Admin. Code § FGC 403: Section FGC 403: Piping Materials

403.1 General.

Materials used for piping systems shall be new and comply with the requirements of this chapter or shall be approved.

403.1.1 Pipe size and pressure limitations.

1. All requirements for installation of gas distribution piping shall be in accordance with Chapter 4. Gas distribution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with Appendix G.

2. Gas distribution piping operating at a pressure of over 1/2 psig (3.5 kPa gauge) shall be welded.

Exception: Manufactured and listed gas trains provided with the appliance may be threaded.

3. All welding of gas distribution piping shall be subject to radiography or special inspection as set forth in Section 406.

4. Threaded piping may be used up to 4 inches (101.6 mm) in diameter at pressure no greater than 1/2 psig (3.5 kPa gauge). All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.

5. All welded piping 2 1/2 inches (63.5 mm) or greater in diameter shall be butt-welded, and welded piping less than 2 1/2 inches (63.5 mm) in diameter may be socket-welded or butt-welded.

403.2 Used materials.

Used pipe, fittings, valves and other materials shall not be re-used.

403.3 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 subject to approval by the commissioner.

403.4 Metallic pipe.

Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.

403.4.1 Cast iron.

Cast-iron pipe shall not be used.

403.4.2 Steel.

Carbon steel and wrought-iron pipe shall be not less than standard weight and shall comply with one of the following standards:

1. ASME B36.10M

2. ASTM A 53/A53M.

3. ASTM A 106 / A 106M.

403.4.3 Copper and brass.

Copper and brass pipe shall not be used.

403.4.4 Aluminum.

Aluminum-alloy pipe shall not be used.

403.5 Metallic tubing.

Metallic tubing shall not be used except as provided in Section 404.2.

403.5.1 Standards.

Stainless steel flexible multiple leg hose assemblies shall be listed and labeled in accordance with UL 536 and designed in accordance with the requirements of this code and the manufacturer's recommendation.

403.5.2 Seismic requirements.

Stainless steel flexible multiple leg hose assemblies shall be designed to withstand seismic force and displacement in accordance with Section 1613 of the New York City Building Code.

403.5.3 Special inspection required.

The installation of stainless steel flexible multiple leg hose assemblies shall be subject to special inspection in accordance with Section 1705.12.3 of the New York City Building Code and Section 406 of this code.

403.6 Reserved.

403.7 Workmanship and defects.

Pipe 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 and fittings shall not be repaired. Defective pipe and fittings shall be replaced (see Section 406.1.2).

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

403.9 Metallic pipe threads.

Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME B1.20.1.

403.9.1 Damaged threads.

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

403.9.2 Number of threads.

Field threading of metallic pipe shall be in accordance with Table 403.9.2.

Table 403.9.2 Specifications for Threading Metallic Pipe

Iron Pipe Size (inches)

Approximate Length of Threaded Portion (inches)

Approximate Number of Threads to be Cut

1/2

3/4

10

3/4

3/4

10

1

7/8

10

1 1/4

1

11

1 1/2

1

11

2

1

11

2 1/2

1 1/2

12

3

1 1/2

12

4

1 5/8

13

For SI: 1 inch = 25.4 mm.

403.9.3 Thread joint compounds.

Thread joint compounds shall be in non-hardening paste or tape form and 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. Use of cotton thread (lamp wick) is prohibited. Threaded joint compound in tape form is prohibited for use at pressure regulator connections.

403.10 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 caused by the internal pressure and any additional forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.

403.10.1 Pipe joints.

Pipe joints shall be threaded, flanged, or welded.

403.10.1.1 Prohibited joints and fittings.

Unions and threaded close nipples shall be prohibited.

Exception: Unions shall be permitted to be installed downstream of the appliance valve in accordance with Section 411.1.6.

403.10.2 Tubing joints.

Tubing joints shall not be used.

403.10.3 Flared joints.

Flared joints shall not be used.

403.10.4 Metallic fittings.

Metallic fittings shall comply with the following:

1. Threaded fittings in sizes larger than 4 inches (101.6 mm) shall not be used.

2. Fittings used with steel or wrought-iron pipe shall be steel or malleable iron.

3. Bushings shall not be used.

403.11 Reserved.

403.12 Flanges.

Flanges and flange gaskets shall comply with Sections 403.12.1 through 403.12.7.

403.12.1 Cast-iron.

Cast-iron flanges shall not be used.

403.12.2 Steel.

Steel flanges shall be in accordance with ASME B16.5 or ASME B16.47.

403.12.3 Nonferrous.

Nonferrous flanges shall not be used.

403.12.4 Ductile iron.

Ductile-iron flanges shall be in accordance with ASME B16.42.

403.12.5 Raised face.

Raised face flanges shall not be joined to flat faced cast-iron, ductile-iron or nonferrous material flanges.

403.12.6 Flange facings.

Standard facings shall be permitted for use under this code. Where 150 pound (1034 kPa) pressure-rated steel flanges are bolted to Class 125 cast-iron flanges, the raised face on the steel flange shall be removed.

403.12.7 Lapped flanges.

Lapped flanges shall be used only above ground or in exposed locations accessible for inspection.

403.13 Flange gaskets.

Material for gaskets shall be capable of withstanding the design temperature and pressure of the piping system, 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. Acceptable materials include metal (plain or corrugated), non-asbestos fiber, and spiral wound metal gaskets. Where a flanged joint is opened, the gasket shall be replaced. Full-face flange gaskets shall be used with all non-steel flanges. Rubber-faced phenolic and elastomeric gaskets shall be prohibited.

403.13.1 Metallic gaskets.

Metallic flange gaskets shall be in accordance with ASME B16.20.

403.13.2 Nonmetallic gaskets.

Nonmetallic flange gaskets shall be in accordance with ASME B16.21.

403.14 Flange bolts.

Flange bolts and associated hardware shall be manufactured from corrosion-resistant materials.