What is the smallest size pipe allowed to be concealed in a wall?

What is the smallest size pipe allowed to be concealed in a wall?

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

Answer: (B)

The idea being tested is the minimum size allowed for hiding gas pipe inside a wall. In typical fuel-gas installations, you can conceal piping inside walls only if it is at least half an inch nominal. This size provides enough cross-sectional area to carry usual residential gas loads with manageable pressure drop, while still letting the system be tested and inspected after installation. Pipes smaller than that are generally restricted to exposed or easily accessible locations because they would be hard to test for leaks once hidden and could complicate maintenance or future servicing. So, half an inch is the practical minimum for concealed runs.

The idea being tested is the minimum size allowed for hiding gas pipe inside a wall. In typical fuel-gas installations, you can conceal piping inside walls only if it is at least half an inch nominal. This size provides enough cross-sectional area to carry usual residential gas loads with manageable pressure drop, while still letting the system be tested and inspected after installation. Pipes smaller than that are generally restricted to exposed or easily accessible locations because they would be hard to test for leaks once hidden and could complicate maintenance or future servicing. So, half an inch is the practical minimum for concealed runs.