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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> pipe for outside tap https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1115827941 Message started by nyck on May 11^th, 2005, 5:12pm

Title: pipe for outside tap
Post by nyck on May 11^th, 2005, 5:12pm

I got to fit a outside tap to the back of my house .The pipe will have to run on the outside wall to the tap.Is it best to run in copper or polyplumb pipe.

nyck

Title: Re: pipe for outside tap
Post by Bahco on May 11^th, 2005, 8:27pm

Copper will look better than plastic pipe.

Don't forget the DCV and the drain off point outside. ;)

Title: Re: pipe for outside tap
Post by JerryD on May 11^th, 2005, 9:55pm

DCV = dual check valve

You'll also need an isolating valve inside the house for winter (or whenever) isolation. That's when you drain it off too.

Title: Re: pipe for outside tap
Post by Plumber on May 11^th, 2005, 10:33pm

The DCV and isolating valve should both be within the thermal envelope of the building, you should also insulate the external pipework with 25mm insulation, this should be closed cell and UV resistant, if it is not it will need to be boxed in

Title: Re: pipe for outside tap
Post by billythekid on May 12^th, 2005, 11:52am

Nothing more to add, use copper and clip every 1000mm. fit drain cock at the lowest point and insulate well. Jobs a good un.

btk

Title: Re: pipe for outside tap
Post by nyck on May 13^th, 2005, 12:45am

Confused now
What do double check valves do why do we need them.

I'm now going to put a tap at the front and back of the house
is the right set up

Cold water feed pipe
isolation valve
pipe
dcv
pipe to outside wall
T-piece + pipe to both taps
taps(check valve or not)

nyck

Title: Re: pipe for outside tap
Post by billythekid on May 13^th, 2005, 9:23am

Double check valves stop water flowing in the wrong direction in the pipe. These are one of the main reasons you can drink from the tap in the UK. Imagine you have a garden hose on a tap, sitting in a puddle of water, which is there because the drain is blocked after the rain. Further down the line theres a guy using his pressure washer for half an hour, thing is you dont have very good mains pressure where you live, so the pressure washer "sucks" the mains through, as you are on the same run it sucks your supply back towards his own. Just then you go to turn on the outside tap, hmmm no water, meanwhile just opening the tap has meant the guy down the street can suck all the water from your hose into the building, all the drain water is now flowing thru the (potable) water pipes in your house. The guy just stopped using his pressure washer now, jast as the last drop from the hose gets into your drinking water. fancy a coffee?? lol
Double check valves stop all that happening! lol

You have the right idea for running your taps, try to keep as much pipework as you can inside the building though. Nothing wrong with feeding both taps from one valve&check valve.

btk