Cold water tank needed in commercial property?

[Carrerahill]

Hi guys, 

 

Got a question I think one of you guys might be able to answer albeit not really a build related question: Do I need this cold water tank in my commercial property? Here is the background...

 

I have a business premises which is basically a commercial unit that has had offices/kitchen/storage built into it, so when it was built in the early 00's it was just an open plan unit with a male and female WC, above this "toilet block" is a cold water tank, it must be about 200/250litres (based on it's size compared to an oil drum which is 205litres). 

 

We would like to develop the area above the toilet block to tie it into the mezz storage level we already have but the tank is bang smack in the middle for weight loading reasons and it really makes the space useless. All that is fed from this tank is the two toilets. It would be a simple case of cutting the two pipes that go to the tank and join them somewhere downstairs thus making the toilets mains fed.

 

Apart from the obvious issue of if the water supply is cutoff we would only have a cistern full of water for each toilet to flush is there any reason why we could not remove this tank? I can think of no logical engineering reason other than that the valves in the cistern might not take mains pressure (although they should) but I am fitting a PRV to the system due to a new 15litre Ariston water heater we have installed which requires the incoming pressure to be no higher than 3bar so I can reduce the supply to the whole property with the Honeywall valve I have already purchased.

 

The reason I am asking and not just doing, is because this is a commercial property and occasionally Scottish Water do make system checks of our water system to ensure we are in compliance (non-return valves before water heaters and so on). If anything I see a tank as a liability for many reasons. Is this tank a throwback to an older plumbing code?

[Mr Punter]

No reason to keep the tank.  Drinking water needs to come from the main in any case.

[Russell griffiths]

The only drawback would be the same as our house, we have a mains fed toilet and the condensation on the cistern is terrible, as the water is so cold. 

[Nickfromwales]

The reason it's there is because the copper tank that original,y would have provided dhw would have typically been gravity fed, and the cold taps would have all been cold mains for drinking water, and then gravity cold for everything else. I think the system has simply been scaled back to the point where just the WC's are fed now, so that's just one stop short of doing away with it altogether. Probably retained just for convenience and nowt else IMO. 

Another reason for having the WC's fed from the tank was that the water then has a chance to acclimatise to ambeint, so it was no longer icy cold, the main cause of the WC cisterns accumulating very high levels of condensation, particularly in the colder parts of the year when the incoming cold mains gets so much colder. 

More 'modern' systems featured all cold mains feed to everything, and then a cold feed to a combination copper tank up top. That had an integral CWS at its head, then the stored hot water underneath it, heated by a simple immersion in most cases, which came out at gravity force. Simple and straightforward. 

Id dread to think what the levels of crud are like in that tank, so you are certainly better off without that one. 

Choices. 

Go all mains and suffer the condensation issue. 

Fit a new, sealed ( smaller ) coffin tank and keep the WC's on gravity, and then position the tank where it's convenient. I'd say above the rooms you develop. 

Pro's and con's either way.