Iron Pipe Thread (IPT) 

  • A tapered thread standard that is used for connecting various sizes of rigid pipe. This standard may be referred to as tapered iron pipe thread (TIPT), National pipe thread (NPT), iron pipe thread (IPT), or iron pipe standard thread (IPS). With tapered thread, the threads and pipe sealant perform the seal at the connection. This is opposed to straight thread connectors which use a gasket to form the seal.