Double check valves. Why? Where? Says who?

[ToughButterCup]

And just when I thought I was getting my plumbing well organised, I bumped into the terms 'check valve' and 'double check valve' in a YooChube video about fitting taps. 

Scheiße - schon wieder , verdammt noch mal !

 

At this stage of the game, I'm getting really tired: folks, could someone give me a quick sentence on where they should be fitted - and maybe a quick word or two of sageness about how not to use them?  Please?

Danke.

 

 

[Jeremy Harris]

A double check valve is required at the incoming supply and on any outside tap (because of the risk of back contamination from a hose etc into the potable supply).  Most outside taps have an integral double check valve, look for the small drain screw on the underside, that allows the space between the two check valve to be drained.

[ToughButterCup]

1 minute ago, JSHarris said:

[...]

required at the incoming supply and on any outside tap 

[...]

 

Thanks.

Is there a public document where I can read the rules?

[ProDave]

Up here a double check valve is also required on the pipe into the house and the pipe into our static caravan, as well as the outside tap.

 

I "discussed" this with the SW man at the time.  The incoming underground stopcock that SW proved has a single check valve.  The in line underground stopcock that I fitted has a single check valve.  But no, neither of these are any good, I also had to have three double check valves as well.

 

I did "suggest" to SW if they are that worried, why don't they supply an underground stopcock that has a double check valve fitted and I would not need to bother with this nonsense.

[Jeremy Harris]

I'm pretty sure they are somewhere within the WRAS stuff: https://www.wras.co.uk/consumers/advice_for_consumers/what_are_the_water_regulations_/

 

Sadly that's not a very user-friendly collection of documents.

 

 

 

[Construction Channel]

Make sure you get a full flow/ bore one for your incoming main. ??

[Pocster]

Water company forced me to install one outside because we are having rain water harvesting again as said to avoid contamination into the mains 

[Russell griffiths]

Ok people, my situation mains pipe coming in from street travels 180m to old house, no check valve installed, I knock down old house and build a new one and reconnect pipe, who will be coming to inspect my new check valve, if I haven’t got one what will happen???

am I likely going to end up on D wing being someone’s bitch or should I not be worried. ??

[Pocster]

1 minute ago, Russell griffiths said:

Ok people, my situation mains pipe coming in from street travels 180m to old house, no check valve installed, I knock down old house and build a new one and reconnect pipe, who will be coming to inspect my new check valve, if I haven’t got one what will happen???

am I likely going to end up on D wing being someone’s bitch or should I not be worried. ??

Prison then executed for certain .

Farewell 

 

[Ferdinand]

1 hour ago, JSHarris said:

I'm pretty sure they are somewhere within the WRAS stuff: https://www.wras.co.uk/consumers/advice_for_consumers/what_are_the_water_regulations_/

 

Sadly that's not a very user-friendly collection of documents.

 

 

 

 

Is @AnonymousBosch not a spcialist in online learning? It'll be sorted out before you can say Cinzano. ?

[Simplysimon]

2 hours ago, ProDave said:

Up here a double check valve is also required on the pipe into the house and the pipe into our static caravan, as well as the outside tap.

 

I "discussed" this with the SW man at the time.  The incoming underground stopcock that SW proved has a single check valve.  The in line underground stopcock that I fitted has a single check valve.  But no, neither of these are any good, I also had to have three double check valves as well.

 

I did "suggest" to SW if they are that worried, why don't they supply an underground stopcock that has a double check valve fitted and I would not need to bother with this nonsense.

exactly the same here

[PeterW]

DCV is required after the main stop tap and before any other filters or pressure reducing valves. After that; they are only required where contamination may occur. 

 

It is good practice to put single check valves on the feeds to showers 

[Ed Davies]

10 hours ago, PeterW said:

It is good practice to put single check valves on the feeds to showers 

 

Does doing that get rid of the requirement that the shower head can't reach within 50mm (or whatever it is) of the water level in the bath, basin, etc?

[PeterW]

3 minutes ago, Ed Davies said:

 

Does doing that get rid of the requirement that the shower head can't reach within 50mm (or whatever it is) of the water level in the bath, basin, etc?

 

Technically yes however as a single has no air gap it is not deemed to be sufficient ....