BSP standard - plumbing4home

There's a lot confusion for non-plumbers to pick correct plumbing fittings size. All plumbing threads are provided in according to BSP (British Standard Pipe) standard which is also used in whole Europe but called ISO standard.

From our sellers experience we can say that the most common misunderstanding of this system is when customers are measuring diameter of the pipe thread which they require to work on and then trying to match the closest BSP size to it, which is of course wrong way to do it.

The BSP standard sizing was originally based on the inner diameter measured in inches of a steel tube for which the thread was intended. And this is the main cause of big confusion, as people think the size refers to the outside diameter of the male thread.

These day you can find many tables and articles in internet giving exact dimensions for each BSP size, but we would like to give you two very simple and easy to use methods for quick and correct thread sizing. Then you can make sure that for all our plumbing fittings range you will pick correct size:

1. Take a diameter measurement from your thread, if it's approx 1 inch then buy 3/4 inch product, if it approx 3/4 inch then buy 1/2 inch product, if it's approx 1/2 inch then buy 3/8 inch product and finally if it's approx 3/8 inch then buy 1/4 inch product. This should cover majority of sizes used in plumbing.

2. 1/2 inch thread is very similar in size to one pence coin, 3/4 inch BSP size thread is very similar in size to 2 pence coin.

We hope this will help to avoid the confusion and let you pink correct product size. Enjoy!