Low-melting-point materials (such as aluminum, copper or brass), materials that soften on fire exposure (such as nonmetallic materials) and nonductile material (such as cast iron) shall be acceptable for use underground in accordance with the applicable standard listed in Table 5703.6.2. Where such materials are used outdoors in aboveground piping systems or within buildings, they shall be in accordance with the applicable standard listed in Table 5703.6.2 and one of the following:
- Suitably protected against fire exposure.
- Located where leakage from failure would not unduly expose people or structures.
- Located where leakage can be readily controlled by operation of accessible remotely located valves.
In all cases, nonmetallic piping shall be used in accordance with Section 27.4.6 of NFPA 30.