17.03 Is secondary containment required for piping in building?

Aboveground piping is often required to be double contained by State and local regulations – however, requirements vary widely. NFPA 30 requirements for piping allow for single wall piping, however, piping within walls or otherwise inaccessible needs to have welded pipe joints.

In practice, most technical building have double wall piping within buildings for all piping that can contain fuel. Vent piping is typically single wall.

An alternative for piping inside buildings is single wall piping within floor trences designed for fluid containment. This piping arrangement is often used in generator rooms to simplify pipe routing, and to allow for gravity return flow from day tanks.