Stopcocks?

[The Medway Handyman]

Given that a full bore, quarter turn, top brand ball valve is about the same price as a stopcock - which will either seize or leak in a short time - why do we bother with stopcocks?

[Nightjar]

From memory, I have a feeling it is to do with what is approval marked for what purposes.

Colin Bignell

[Skipweasel]

Which is of no damned use when it's the primary means of shutting off the water.

Yes - allegedly you can turn it off at the board's stopcock outside, but these are often in worse shape than the one to hand.

[TheScullster]

"The Medway Handyman" wrote

Stopcocks tend to be used to control the flow in domestic situations. Ball valves are not designed to do this (although I'm sure some will be used in this way). If you partially open a ball valve, it exposes part of the internal seat (which provides the sealing for the ball) to the process flow. This wears the seat, particularly in high pressure/flow/abrasive situations and leads to leaks.

Phil

[Skipweasel]

Do they? None that I've see have. They're full on and backed off a quarter turn to allow you some waggle-room when they inevitably sieze.

[Nightjar]

Having looked at the WRAS approval directory, only about half are marked as meeting the requirements of a stop valve. So, you could legally use one, but you would first need to check that it is approved for use as a stop valve.

Colin Bignell

[TheScullster]

"Skipweasel" wrote

Presumably the water mains pressure is rather higher here! Opening the stopcock full bore would turn every cloak room into a shower/wet room

Phil

[John Williamson]

Not with the correct design of tap. The stopcock has no effect on the static pressure, and properly specified taps will work correctly.

Now, I remember one place where there was a couple of hundred feet of static head on the main supply, so the user had to fit a pressure regulator. They didn't need to pay extra for pumped power showers...

[Skipweasel]

Ah - I use the service valves on each outlet to control that problem. Crude, but better than turning the whole lot down en-masse.