Iron Pipe Thread, an older designation for the standardized straight and tapered threads used on metal pipes. It originated when most threaded plumbing was iron or steel. The term is still stamped on fittings and tools, though it is technically synonymous with the National Pipe Thread (NPT) standard. It specifies the thread angle, pitch, and taper required to make a pressure-tight mechanical seal.
Heard on the job
This brass fitting has a half-inch male IPT connection so you'll need a matching female adapter.
Insider tip
You will usually see this broken down into FIP (Female Iron Pipe) and MIP (Male Iron Pipe) on hardware bins.
Also heard as
- Iron Pipe Thread
- FIP
- MIP
Do not mix it up with
- BSP: IPT/NPT uses a 60-degree thread angle, while BSP uses a 55-degree angle, making them incompatible.