Gas Piping Installations

The scope of Chapter 4 piping systems extends from the point of delivery to the connections with appliances. It covers design, materials, components, fabrication, assembly, installation, testing, inspection, operation, and maintenance of piping systems.

• Piping systems within buildings must comply with the International Building Code (IBC) for utility services.
• LP-gas storage systems must be designed and installed per the International Fire Code and NFPA 58.

Piping systems must be sized to supply gas sufficient to meet maximum demand and deliver gas to each appliance inlet at not less than the minimum pressure required by the appliance.

• Pipe sizing between a regulator and an appliance is based on the sum of the maximum input rates of all appliances served.
• Pipe sizing may be based on loads other than total connected hourly load when diversity of load exists in the distribution system.

All materials used in piping systems must be adequate for the service intended and free of foreign materials.

• Metallic tubing shall not be used with gases corrosive to the tubing material (§403).
• Reused pipe, fittings, valves, and components shall not be reused unless free of foreign materials and adequate for the intended service (§403).
• Materials must be installed per the standards under which they are accepted and approved; when no such standards exist, follow manufacturer's instructions (§404).
• Steel pipe or tubing exposed to corrosive action requires corrosion protection (§404).

• Regulator capacity must be adequate to supply the appliances served, based on the manufacturer's published ratings.
• An indoor MP (medium-pressure) regulator must be vented to the outdoors or equipped with a leak-limiting device.
• A tee fitting between an MP regulator and its upstream shutoff valve serves two purposes: connecting a pressure-measuring instrument and acting as a sediment trap.

• Appliances may be connected using connectors made of materials allowed for piping systems, or by piping that passes through walls, floors, or ceilings when correctly installed.
• Suspended low-intensity infrared tube heaters require a connector listed for the application and complying with ANSI Z21.24/CGA 6.10.
• Semirigid metallic tubing and listed connectors in the same room as an appliance have a maximum length of 6 feet (1829 mm).

• A manual shutoff valve and an excess flow-control check valve must be located in the liquid line between the pump and the dispenser inlet for remote LP-gas dispensing devices.
• The minimum distance between a combustible overhang and a building with a 1-hour fire-resistance-rated wall is not less than 10 feet (3048 mm).