NPTF fittings create a mechanical seal when a male and female fitting are mated. The female hose end crushes the thread of the male fitting creating a tight robust connection. NPTF fittings are known as "dry seal threads" because they don't require thread sealants which can dissolve and contaminate fluids or gases in high-temperature and high-pressure applications. NPTF fittings provide a more substantial leak-free seal but are more prone to damage from over-tightening and require careful handling during installation.

• National Pipe Tapered Fuel (NPTF) fittings are used in a variety of applications:• High-pressure systems: NPTF fittings are commonly used in high-pressure systems that carry fluids or gases such as natural gas and chemically aggressive liquids.• Fuel connections: NPTF fittings are used for fuel connections.