On 23/12/2017 20:28, Andrew Mawson wrote:
I have some 3/4" brass bibcocks on the way to me - these are the bigger
version for a stand pipe (the more usual 1/2" ones are 1/2" BSP input
and 3/4" BSP where the water comes out)

Try as I may I cannot find the thread specification for the output side
of these bigger taps. Not yet to hand but I'd guess at 1" BSP logically

I've met 7/8" - but I've led a sheltered life as an office wallah so
that counts for little. I certainly don't suggest it is a (let alone
_the_) standard.

I think reducers to 3/4" can be bought - or contrived by cunning
artificers

--
Robin
reply-to address is (intended to be) valid