IRON Pipe Thread (IPT) 1 : A standard system of thread dimensions used for various types of rigid piping; it is much finer and more difficult to connect in the field than National Standard (NS) fire hose thread
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}