Product Description
British parallel pipe (BSPP) is commonly deployed on many types of imported European and Japanese machinery, however, British pipe thread (BSPT) is not anywhere near as common.
Male BSPP fitings can seal in two ways:
Method 1: The male BSPP fittings have an internal chamfered seat which seals against the inverted cone found on female BSPP swivel fittings.
Method 2: The male BSPP fitting can be equipped with a bonded sealing washer and installed into a female port similar to how an oring boss (ORB) or metric (DIN) fitting works.
British pipe threads (BSPT) seal in the same way as North American (NPT) threads but have different dimensions.
The thread angle on NPT is 60°, but only 55° on BSPT.
Tapered pipe fittings will loosen and cause leakage if NPT is substituted for BSPT or vise versa.
Greenline International Fitting Catalog