The difference between BSPT, NPT and BSPP threads
Sealing pipes and fittings can be a tricky business, so it’s important to understand the differences between the types of sealings available to you. Here’s all you need to know about the three most common stainless steel thread types – BSPT, NPT and BSPP.
BSPT (British Standard Pipe Thread)
BSPT is a tapered thread, which means that the thread gets narrower in diameter towards its end – as the thread is tightened, the fitting becomes wider. This allows the male and female components of the thread to fit tightly together, since the adapter stretches the component it is fitted to with enough force that it is able to withstand pressure. Sealant is used to ensure that the two components are sealed together properly.
If BSPT is what you’re after, Anglo Stainless stock a comprehensive range of quality stainless steel BSPT fittings.
NPT (National Pipe Thread)
NPT is also a tapered thread often used in pipes transporting liquids and gases, mainly in the oil and gas industry. It is the standard thread in the United States and cannot be sealed together with a BSPT fitting. NPT only requires a small amount of sealant, as too much can cause the seal to leak, and can be prone to over-tightening.
BSPP (British Standard Parallel Pipe)
BSPP comes from the same family as BSPT, but does not share its tapered design. As the name suggests, the thread has a straight shape and is the same width all the way along. A bonded seal ring is therefore needed to make the seal and secure the connection.
If you’d like more information on steel fittings, or want to browse our extensive range of stainless steel BSPT fittings, the team at Anglo Stainless have over 40 years of knowledge and experience and are happy to help. Feel free to give us a call on 01924 430 044.