1" NPT (National Pipe Taper) (1-11.5 NPT)
Where 1-11.5 NPT is used, its real dimensions, and how to connect it to other standards.
1-11.5 NPTThread standard
Designation1-11.5 NPT
Major diameter33.4 mm
Threads per inch / pitch11.5
Thread formtapered, 60 degree
Seals onon the thread flanks with PTFE tape
Used on: 1 inch US pump ports, irrigation manifolds and tank fittings.
1 inch NPT drops to 11.5 TPI on a 1.315 inch outside diameter. It is close in size to G1 and 1 inch NPSH but mates with neither without an adapter.
Quick-connect click fittings from Hozelock, Gardena and Karcher are proprietary and do not interchange. They all sit on top of a standard thread underneath, so the reliable way to move between brands is to adapt at the threaded tap or hose-end fitting, then use each brand's own connector above it.
Connect this thread
Connect 2-1/2" NH fire hose thread (NST) to 1" NPT (National Pipe Taper)needs an adapter1/8" NPT (National Pipe Taper)related standard (1/8-27 NPT)1/4" NPT (National Pipe Taper)related standard (1/4-18 NPT)3/8" NPT (National Pipe Taper)related standard (3/8-18 NPT)1/2" NPT (National Pipe Taper)related standard (1/2-14 NPT)3/4" NPT (National Pipe Taper)related standard (3/4-14 NPT)1" BSP parallel (G1 / BSPP)often confused with 1-11.5 NPT1" NPSH straight hose threadoften confused with 1-11.5 NPT
Sources: ANSI/ASME B1.20.1 (NPT pipe threads) · NPT thread dimensions chart (ASME B1.20.1), Machining Doctor