What is a common method of connecting gas piping?

A common method of connecting gas piping is threading. This technique involves cutting a helical groove into the end of the pipe, allowing for easy connection to other threaded pipes or fittings. Threaded connections are popular in gas piping due to their relative ease of installation, ability to create a secure seal, and the availability of various fittings that can be used to accommodate different piping configurations.

Welding is typically reserved for materials that require a stronger, more permanent bond, predominantly in applications beyond standard gas systems. Flanging involves the use of flanges which are generally used for larger pipe or equipment connections. Soldering is most often used in plumbing for copper pipes and is not a method suitable for gas lines due to the potential for weak joints under the pressure and characteristics of gas. Thus, threading stands out as the most appropriate and commonly used method for connecting gas piping in many applications.