CSLB C-36 Plumbing ContractorRough-in PlumbingHard
A plumbing contractor is installing a new residential gas piping system. The exposed portion of the gas piping outside the building is made of black steel pipe. What is the required protective coating or treatment for this exposed piping?
- AGalvanized finish or approved corrosion-resistant coating
- BNo coating is required if it's Schedule 40 steel
- CA mastic coating and fabric wrap
- DA layer of epoxy paint
Show answer & explanationAnswer & explanation
Correct answer: A. Galvanized finish or approved corrosion-resistant coating
The California Plumbing Code (CPC) requires that exposed portions of gas piping that are subject to corrosion (such as black steel pipe outdoors) must be protected by a galvanized finish or an approved corrosion-resistant coating. This prevents oxidation and degradation of the pipe over time.
Why the other options are wrong
- B. Black steel pipe, even Schedule 40, will corrode when exposed to outdoor elements without proper protection.
- C. Mastic coating and fabric wrap are typically used for underground pipe protection, not exposed above-ground piping.
- D. While epoxy paint can provide some protection, a galvanized finish or specifically approved corrosion-resistant coating is the code requirement.
Exposed Gas Pipe Protection
The requirement to protect exposed outdoor gas piping from corrosion and physical damage to ensure its longevity and safety.
- Prevents rust and material degradation.
- Ensures structural integrity of the gas system.
- Mandated by plumbing codes for outdoor installations.
Memory trick: Gas pipe outside, don't let it rust, galvanized or coated, you must trust.