health and safety - hot water

Sparkpea

I'm looking a bit of advice. Theres a local open farm/kids adventure type place I take the child too - I also had my stag day there for quad biking so got talking to the owner and he knows I'm a plumber. Anyway was in today for something to eat and he was saying H&S where out and theres no HW at the WHB in the gents toilets. I had a quick look and seen a pipe had been blanked off and theres only the mains going to it. No big deal to pipe the hot however I was thinking to myself there should be a basin mixing valve on all basins so that water temp does not exceed 50-55 degrees for H&S reasons, especially when kids are using it all the time.

Now I was thinking to myself if I add a mixing valve at the draw off at the hot tank then that will do all the basins so only 1 is needed rather than one in male, female and disabled toilets. But once I had a look theres a pressurised HW system in place. Can I still do that and have mains running through the mixing valve or is there any other suggestions to stop the water getting too hot? IIRC there is normally a motorised valve on these so if the water temp was set to 50 degrees then the valve would close and water would no longer be heated? Or would the build up of heat exceed 50 degrees?

Opinions welcomed..

slavetothegrind

i wouldn't use the mains at the mixing valve, no guarantee the pressure will be high enough at all times and not good practice even with an nrv.
take a feed from the pressurised cold feed into the hw tank and use that at the mixer valve.

Sparkpea

slavetothegrind wrote: »

i wouldn't use the mains at the mixing valve, no guarantee the pressure will be high enough at all times and not good practice even with an nrv.
take a feed from the pressurised cold feed into the hw tank and use that at the mixer valve.

pressurised cold feed going into the tank is from the mains anyway tho? its a mains fed system - or am I missing the point here

slavetothegrind

apologies, i presumed a pumped system from a storage tank.

sullzz

in a hospital where I occasionally do plumbing we have had to re-do a lot of the plumbing so that each whb and shower has it's own tmv and it had to be at a maximum 1 meter away from the draw off point , apparently it's the regs now , possibly just in healthcare situations .

Sparkpea

No probs - I'm trying to get around the cost of fitting a valve under each basin - tho this is the way I see it done in most nursing homes etc. Mixing valve could be about £60, each basin is then £180 for the 3, whereas if I was able to do it with the 1 valve at the draw off it would keep costs done. But again I question myself saying why hasn't others done this? Why is 1 under each basin? Must be a reason apart from cost...

slavetothegrind

whats the temperature max allowable at the tap?
i think it's around 41 degrees

i suppose the individual tmv's guarantees the correct temp at each point

sullzz

What size is the hot supply from the cylinder if it's 1" your talking big money for a tmv if your thinking about fitting just the one , if I remember correctly a 3/4" one is about €150 , if I were you I'd fit one at each whb especially if you only have 3 to do ,

DoneDL

I would just go with one mixer to serve the hot water outlets, cheaper and easier to service.

Sparkpea

I'm pretty sure a 22mm mixing valve is about £50-60, if it was inch I would just use 28x22 compression reducing sets in the valve nuts

Joey the lips

Why dont you just keep it simple and use a water heater.That way you can set the temp

heinbloed

If health and safety is an issue for tapped (drinking) water only qualified staff should tackle the water system.

Mixing valves can be incorporate wherever one thinks it is necessary.
For different points of tapping supplied with 1 mixing valve it is recommended to insulate all pipes.
There are also thermostatic mixing valves available where the temperature can be set, be fixed at a chosen temperature,vandal proof.

Sparkpea

I've been looking at the reliance water controls - thinking one per basin might be better so if 1 fails then they aren't all down, and also I don't want the kitchen/cleaning water to be restricted

sullzz

Sparkpea wrote: »

I'm pretty sure a 22mm mixing valve is about £50-60, if it was inch I would just use 28x22 compression reducing sets in the valve nuts

Well that's a lot cheaper than the ones I was buying , the ones I was using were Horne tmvs you adjusted the temp with an Allen key , they were anti tamper , they would prob be the type you would need in your application .

sullzz

Joey the lips wrote: »

Why dont you just keep it simple and use a water heater.That way you can set the temp

Because there are already hot supplies at the basins , all he needs to do is fit a couple of tmvs , no need to repipe or run in power supplies