Water demand of commercial buildings 2

[ImroZ]

Hi,

At first, I am sorry for my grammar mistakes. Unfortunately my English is not the best...

I need some information about the methods and standards are used in UK for calculating or estimating the water demand of commercial buildings.

I got an estimation - made by an English expert- about a water supply of a shopping centre. It determines the daily water demand by the area of the building in this way:

- the area is about 100.000. m2
- the calculaton says there are one person in every ten m2
- the water demand is 45 l/person

In this way he got (100.000 / 10) x 45 = 450 m3/day.

We - in Hungary - use an absolute different method. Because of that I would like to be sure about the correctness of this result, because I have not any idea about the 45 l/person or the 0,1 person/m2 is a good estimation or not.


I would like to ask you to send me some pieces of information about the ways of calculating this demand in your country, and if it is possible, an issue of the current standards would be great.

Thanks,

 

[TGLG]

Basing daily water demand on population density can work for large developments, where things tend to average out, but for a smaller development it may not be appropriate.

Are there published standards for wastewater generation in your municipality?
If so, you can use the wastewater flow rate as a good estimate of daily potable water demand. After all, almost all of the potable water that comes into a building goes back out as wastewater.

 

[steamdog]

I am not sure this will help, as I think you are looking at more of a 'macro' view rather than an actual building usage. When I size booster pumps or hot water heaters for buildings I do a fixture count of all of the uses of water in the building then use the ASHRAE modified Hunters curve to determine water usage. Some say this overestimates the usage, but I have not yet had a problem with a system.
If you Google "Modified Huters Curve" you will get many hits of reprints of this method.