A fitting that provides a liquid and vapor-tight seal around both the piping or conduit and the wall of a containment sump.

A requirement for environmental protection. Without this component functioning as it should, the entire secondary containment system is to be considered compromised. To function as intended a penetration fitting must feature long-term compatibility with continuous exposure all common and alternative fuels including their vapors and various additives.

These are commonly considered to prevent water from entering containment sumps in areas where high water tables are present or prevalent. More importantly, they ensure that any fuel or contaminants that may mix with water or accumulate within the sump cannot escape into the ground.

Typically manufactured of a type of flexible material, fiberglass, metal or other blend of proprietary materials.

See also PEI/RP900.