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What diffrent between PT, NPT and FPT thread

What diffrent between PT, NPT and FPT thread

Hello! I have some problem with the different between pipe thread of PT, NPT, FPT. I used to supply aome air valve with port size from 1/4"NPTF to 1/2" NPTF. Because a customer if require NPTF thread then he /she will states NPTF. But sometimes a US customer only say nedd Pipe taper thread or PT port etc, I will have question on PT, NPT or FPT. Are PT, NPT, FPT same thread?

RE: What diffrent between PT, NPT and FPT thread

PT, NPT, FPT acronyms have the same meaning for American National Standard Pipe Threads. Female NPT threads can be designated as FPT and male NPT threads can be designated as MPT.

NPT:  National Pipe Taper Thread   A sealant or Teflon tape must be used for a leak-free seal.

FPT:  female(internal) National Pipe Taper Threads

MPT:  male(external) National Pipe Taper Threads

NPTF:  Dry-seal American National Standard Taper Pipe Thread (pressure-tight)  No sealant is needed for a seal.

The NPT and NPTF threads are interchangeable with sealants such as teflon tape.  None of the other thread standards are interchangeable.

NPS/NPSM:  American Standard Straight Pipe Thread   Used for mechanical joining -- holding a fitting in place.  An O-ring or a metal seal is required.

Two common pipe thread sizes exist, the tapered National Pipe Thread (NPT) and the straight National Standard Free-Fitting Straight Mechanical Pipe Thread (NPSM).  The tapered threads are for joining and sealing, the straight threads are only for joining. The Dry-seal thread (NPTF) allows for joining without sealants.

The other thread acronyms that exist are:
NPSI:  American National straight intermediate pipe thread
NPSF:  Dry-seal American National Standard Straight Pipe Thread
GHT:   Garden Hose Thread
NST:   Fire Hose Coupling
BSPT:  British Standard Pipe Taper threads
BSPP:  British Standard Pipe Parallel (straight) threads

Hope this helps.

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