BSP (British Standard Pipe) and NPT (National Pipe Thread) are two different standards for screw threads used in pipes and fittings. The main difference between BSP and NPT lies in their thread profiles and the way they seal.
Thread Profile
BSP: The thread profile for BSP is parallel. This means that the threads maintain a constant diameter along the length of the fitting or pipe. BSP threads are available in two forms: BSPP (British Standard Pipe Parallel) and BSPT (British Standard Pipe Tapered).
BSPP threads are parallel and require a sealing washer or an o-ring to create a seal.
BSPT threads are tapered, and the seal is achieved by the threads themselves.
NPT: The thread profile for NPT is tapered. The threads are angled, which means that as you tighten the connection, the threads compress against each other, creating a seal.
Taper
BSP: BSPT threads are tapered, and the taper is typically 1:16. BSPP threads are parallel.
NPT: NPT threads are tapered at a rate of 1:16.
Angle
BSP: The angle across the flanks of threads (if you sliced the fitting in half long-ways and measured the angle from root to crest to root) is 55 degrees
NPT: The angle across the flanks of threads is 60 degrees.
Sealing Mechanism
BSP: BSPT relies on the threads for sealing, while BSPP requires an additional sealing element like an o-ring or washer.
NPT: NPT relies on the taper of the threads to create a seal. The tightening of the threads compresses the fitting, providing a tight seal.
Usage
BSP: Commonly used in Europe, Asia, Australia, and some parts of Africa.
NPT: Predominantly used in the United States and Canada.
In terms of compatibility, mixing BSP and NPT fittings without proper adapters or conversions can lead to leaks or improper seals. If you need to connect BSP and NPT fittings, it’s advisable to use appropriate adapters to ensure a proper and leak-free connection. Adapters are available to convert from one thread type to another, allowing for compatibility between BSP and NPT systems. However, it’s essential to choose the right adapter for the specific application to ensure a secure and leak-free connection.
QC Hydraulics is a leading manufacturer and supplier of BSP NPT hydraulic fittings adapters, please contact us if you have any demands.