NPTF Threaded FittingsNational Pipe Tapered Fuel (NPTF) thread is one of the most common taper pipe threads in the United States. When a male fitting and female fitting mate, a seal is created by the female hose end crushing the thread, creating a mechanical lock. However, it is recommended that teflon tape or pipe sealant is used with NPFT fittings to prevent leaks.
NPTF fittings are used in a wide array of applications, including electrical conduits, fuel connections, hand railings, and high pressure pipes that carry gas or fluids. While NPTF hose ends are still widely used in hydraulic applications, the National Fluid Power Association (NFPA) states that using NPTF fittings for hydraulic applications is not recommended.