Underground gas piping shall not be installed beneath that portion of a manufactured home site reserved for the location of a manufactured home or manufactured home accessory building or structure unless installed in the open-ended gastight conduit of Section E402.2.1. [NFPA 501A:220.127.116.11]
The open-ended gastight conduit shall conform to the requirements in the following:
- The conduit shall be not less than Schedule 40 pipe that is approved for underground installation beneath buildings.
- The interior diameter of the conduit shall be not less than 1/2 of an inch (15 mm) larger than the outside diameter of the gas piping.
- The conduit shall extend to a point not less than 4 inches (102 mm) beyond the outside wall of the manufactured home or accessory building or structure, and the outer ends shall not be sealed.
- Where the conduit terminates within a manufactured home or accessory building or structure, it shall be accessible, and the space between the conduit and the gas piping shall be sealed to prevent leakage of gas into the building. [NFPA 501A:18.104.22.168 - 22.214.171.124.4]