Supply Fitting Connections

Trying to make sense of NPS, IPS, MIP, BSP, NPT and a half-dozen other fitting acronyms? We'll get you connected.

Supply Connections

Most of our faucets, showers, sprayers, etc. have NPS fittings, which is the standard connection for faucets sold in North America. However, there are many acronyms used for this common fitting. Many manufacturers (faucet, hose, supply line and/or adapters manufacturers) specify NPT, IPS, FIP/MIP and/or FPT/MPT fittings, but almost all are interchangeable; one primary exception – the fittings must NOT have tapered threads. Often, the "T" in NPT or FPT/MPT is used to represent "Tapered" instead of "Thread".

Due to the many acronyms for the same fittings and multiple definitions of specific acronyms, in North America, many faucet connections are often referred to simply as – 1/2" Faucet

STRAIGHT VS. TAPERED THREADS

NPS = National Pipe Straight
NPT = National Pipe Tapered
( -M = Male -F = Female )

Plumbing fitting are commonly referred to as “NPT”, however, in reality, nearly all faucets are actually “NPS”. NPS is the North American “STANDARD” for faucets, regardless of brand, style, application, etc. Outside North America, BSP is the most commonly used standard.

Both NPS and NPT have the same thread angle, shape, and pitch (threads per inch). However, NPS threads are straight (parallel) and NPT threads are tapered (reduced).

Straight Pipe thread is commonly found on faucets, showerheads, hose connections and fittings. Tapered Pipe thread is commonly found on pipe ends, nipples and fittings (i.e. couplings, elbows, tees, etc.). Straight Pipe threads need a gasket or o-ring to create a seal. Both styles require sealant or plumber’s tape for optimal seal. While NPS and NPT threads will engage, they do not seal properly with each other.

COMMON FITTINGS IN THE PLUMBING MARKET
Acronym	Definition	Compatible with most Supply Connections
NPS	National Pipe Straight National Pipe Standard
NPT	National Pipe Thread National Pipe Tapered National Pipe Thread (Tapered)
IPS	International Pipe Size International Pipe Standard Iron* Pipe Size Iron* Pipe Standard
FIP	Female Iron* Pipe Female International Pipe
MIP	Male Iron* Pipe Male International Pipe
FPT	Female Pipe Thread Female Pipe Tapered Female Pipe Thread (Tapered)
MPT	Male Pipe Thread Male Pipe Tapered Male Pipe Thread (Tapered)
GHT	Garden Hose Thread
BSP	British Standard Pipe BSP is the standard fitting, adopted worldwide, EXCEPT in North America.

* Although it refers to “Iron”, actual material may differ. Today, iron is rarely used in plumbing, as it has been replaced with safer materials such as brass, stainless steel, PEX, PVC and other composites.

Still have a question? Send us an e-mail or give us a call!