What type of joints may only be used with nonferrous pipe and tubing in a gas system?

• A. Flared
• B. Threaded
• C. Welded
• D. Compression

Answer: (A)

In gas piping, the type of joint chosen depends on the pipe material. Flared joints are designed specifically for nonferrous tubing (like copper). The end of the copper tube is flared, and a nut and flare cone seal the connection, providing a reliable gas-tight joint without threads or welding. This method relies on the ductility of nonferrous metal and isn’t used with ferrous (steel) piping, which typically employs threaded or welded joints. Compression fittings, while common on copper tubing, aren’t exclusive to nonferrous and aren’t restricted to just that material, so they aren’t the type described as limited to nonferrous in this context. Therefore, the joint type that may only be used with nonferrous pipe and tubing is the flared joint.