In gas piping, what does "FPT" stand for?

In the context of gas piping, "FPT" stands for Female Pipe Thread. This term is significant because it denotes a type of threading found on pipe fittings that allows for connection with male pipe threads. Female threads have recessed, inward-facing grooves, which help to ensure a secure and leak-resistant connection when joined with male threaded pipes or fittings. Understanding the distinction between female and male threads is crucial in plumbing and gas system installations to ensure proper fittings and functionality, as a mismatched connection could lead to leaks or other issues.

The other options do not correctly define "FPT" within the context of gas piping. Flat Pipe Thread and Flexible Pipe Thread do not represent standardized terms used in the industry. Fuel Piping Type, while potentially relevant in discussing types of piping used for gas applications, does not relate directly to the threading format specified by "FPT."