Can anyone help with regards to American threads?

[knave_brewery]

Hi all,

I imported a wort chiller and a few other plumbing fixtures from the US to South Africa not realizing that the thread standards are completely different. In SA most of our plumbing threads are still British Standard. My question is this....NPT has a tapered thread, right. Does MPT ( male pipe thread) and FPT ( female pipe thread) have a taper or are they straight threads? If some kind person could please enlighten me I would be ever so grateful.

 

[Whsoj]

Imperial and US customary systems are closely related, there are a number of differences between them. Units of length and area (the inch, foot, yard, mile etc.) are identical except for surveying purposes. So the pipes should be same weather you have tapered or parallel depends, parallel is used on none pressure conduit but taper is for fluid pipe to get tighter with out bottoming out. I think

 

[Homercidal]

MPT and FPT are simply the male and female version of NPT, which is tapered, so they are all tapered.

Wikipedia seems to indicate that the British Pipe Thread differs from National Pipe Thread in this quote; "...adopted internationally for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) thread and has been adopted as a standard scale used in plumbing fittings, except in the United States where NPT is the standard used."

So it seems NPT and BPT are different, but to what extent I do not know. I did not research closely enough to know. There are numerous variable that make up a thread type, so you would have to compare these to know which are different and whether the two could be forced to mate.

I wonder if something as simple as an adapter might get you by to connect to your supply?

 

[hvjackson]

If this is for a wort chiller, you might have better luck taking off the existing fittigns and using compression fittings you buy locally. That way you'll be able to pick up parts at your local stores. (Compression fittings clamp around a pipe, so there are no threads to match up.)

E.g. here's a 3/8" compression x 1/2" MPT fitting: http://morebeer.com/products/stainless-38-comp-12-mpt.html?site_id=5

If you buy a 3/8" compression x 1/2" British Pipe Thread fitting locally, you could just swap it out.

 

[Felixio]

NPT stands for National Pipe Thread and is a US standard for threads. This is a tapered thread with a 60 degree threadform. The taper is 3/4" per foot. BPT stands for British Pipe Threads and is a standard in many countries of the United Kingdom. This is a 55 degree untapered threadform. BPST stands British Standard Pipe Taper and is the same threadform as BPT, but includes a taper. BP thread connections usually use a male tapered side and then a tapered or untapered female side. Obviously NPT and BP threads are not compatible.

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