Can anyone tell me where I can download a full piping library.
There is alot of standard parts online but not all of them are correct.
I want to download a proper "BSP" library which will be accurate.
To that, good luck.
You are right on that most of the stuff you find online isn't correct or is only partly correct. The problem is most of the standards have ranges and thus you will rarely find what you are looking for out of the box. This isn't just pipe, even the bolting library for solid edge is iffy at best and largely incomplete. I think the expectation from SE is that you make up your own parts and fill in what you need using the skeleton of a reference that they gave you to start with.
12Gage is right on that for USC dimension stuff, McMaster-Carr is hard to beat.
When it comes to things that are obscure for Americans like BSP threaded parts you are kinda out of luck often times as even the traceparts online being of a european origin still tends to lack non-metric european standards parts such as BSP.
McM-Carr does offer more BSP fittings than I thought they might. Can't vouch for their accuracy. Another problem with all their models is that threads are fully formed. I remove them and put in simple representations.