How to Work with Gas Pipes
Ask This Old House plumbing and heating expert Richard Trethewey explains how gas piping is installed in a home
- In general, residential houses start with 1” gas pipes at the gas meter and then branch out to smaller diameter pipes using T fittings as they reach their appliance destinations.
- To connect gas appliances to the main branch, there are gas pipes that come in a variety of lengths that you can piece together to reach each appliance. They are secured with pipe dope and gas fittings. Because of the way the threads work, piping always has to start at the source and work its way outward toward each appliance.
- It’s also possible to thread your own gas pipes at the exact length you need if you have a pipe-threading tool.
- Before turning the gas back on, any professional will test for leaks by connecting a manometer to the pipes, locking in the air pressure, and waiting overnight to see if the pressure drops.
- If the new gas work passes the manometer, a soap test should also be done as the gas is turned back on. If the soap solution bubbles over any of the new work, that means there is a leak.
Richard emphasizes that only a licensed professional should work with gas. The materials they use for gas pipe fittings, including the pipes, nipples, and pipe dope, can be found at home centers and plumbing supply houses.