Penetration of gas pipe through floors, patio or slab must have at least how many inches of unthreaded pipe?

Penetration of gas pipe through floors, patio or slab must have at least how many inches of unthreaded pipe?

• A. 1 inch
• B. 2 inches
• C. 3 inches
• D. 4 inches

Answer: (B)

The requirement is to leave a short length of pipe that has no threads where it passes through floors, patios, or slabs—specifically, at least two inches of unthreaded pipe. This keeps the threaded portion of the pipe away from the finished surface, protecting threads from damage during floor finishing and future maintenance. It also provides a straight, accessible section that makes disassembly or service easier without stressing the joints. Less than two inches wouldn’t provide enough clearance or protection, while two inches meets the standard.

The requirement is to leave a short length of pipe that has no threads where it passes through floors, patios, or slabs—specifically, at least two inches of unthreaded pipe. This keeps the threaded portion of the pipe away from the finished surface, protecting threads from damage during floor finishing and future maintenance. It also provides a straight, accessible section that makes disassembly or service easier without stressing the joints. Less than two inches wouldn’t provide enough clearance or protection, while two inches meets the standard.