CSLB C-36 Plumbing ContractorRough-in PlumbingMedium
A plumbing contractor is installing a new gas piping system for a commercial building. The gas meter is located outside the building, and the gas piping enters the building through a concrete foundation wall. How must the gas pipe be protected where it passes through the foundation wall?
- AIt must be sleeved with an approved material and sealed at both ends.
- BIt must be installed in direct contact with the concrete, provided it is schedule 80 pipe.
- CIt must be coated with a bituminous paint and left exposed within the wall.
- DIt must be wrapped with electrical tape to prevent corrosion.
Show answer & explanationAnswer & explanation
Correct answer: A. It must be sleeved with an approved material and sealed at both ends.
Gas piping passing through concrete or masonry must be protected to prevent corrosion from direct contact with alkaline materials and to allow for movement. A sleeve with sealed ends prevents this contact and protects the pipe.
Why the other options are wrong
- B. Direct contact with concrete is prohibited due to the risk of corrosion, regardless of pipe schedule.
- C. Bituminous paint alone is not sufficient, and it must not be left exposed within the wall; proper sleeving is required.
- D. Electrical tape is insufficient protection against corrosion and physical damage in this application.
Gas Pipe Foundation Penetration
The method of protecting a gas pipe where it passes through a concrete or masonry foundation wall to prevent corrosion and allow for thermal expansion/contraction.
- Prevents direct contact with corrosive materials.
- Allows for pipe movement without stressing the pipe.
- Requires approved sleeving and sealing.
Memory trick: Gas Pipe through a wall needs a 'Sleeve for Safe Passage'.