What type of fitting is commonly used to create a gas-tight seal on threaded connections?

A commonly used method for achieving a gas-tight seal on threaded connections involves the use of Teflon tape or pipe dope. These materials are specifically designed for sealing threaded joints to prevent gas leaks. Teflon tape, a type of non-adhesive tape made from polytetrafluoroethylene (PTFE), is wrapped around the threads of the pipe before they are screwed together. This creates a lubricated surface that not only helps to ensure a tighter fit but also provides a flexible seal that conforms to any minor irregularities on the threads.

Pipe dope, or pipe joint compound, is a paste applied to the threads that acts as a sealant, filling in gaps and ensuring a more secure connection. Both of these sealing methods are widely accepted in the industry and formulated to withstand the various temperatures and pressures encountered in fuel gas systems.

The alternatives, such as compression fittings, welded fittings, and flared fittings, serve different purposes in piping systems. Compression fittings rely on a mechanical compression force to create a seal, typically used for non-threaded pipes. Welded fittings involve joining two pieces of metal through a welding process to create a robust and permanent bond but are not applicable for threaded joints. Flared fittings involve creating a