Why are the fittings used to protect pipe threads during shipment not allowed in installations?

The fittings used to protect pipe threads during shipment are not permitted in installations primarily because they are made with running threads. Running threads do not form a proper seal, which is crucial in gas installations where preventing leaks is essential for safety and compliance with regulations. Unlike tapered threads that provide a tight seal when joined, running threads lack the necessary taper and, therefore, cannot achieve the leak-proof connection required in gas piping systems.

Using fittings with running threads in actual installations could lead to gas leaks, posing serious safety hazards. This understanding is crucial for anyone working with gas systems, as ensuring the integrity and safety of gas connections is a top priority in the industry.