BRE water calculator

[Mike Jacob]

Any news on this yet? can 80l be acheived by efficiency measures alone yet?

[Nick Grant]

Hi Mike

http://www.planningportal.gov.uk/uploads/br/water_efficiency_calculator.pdf

Following the review the factors have been tweaked so that normal fittings don't give such silly results. I have emailed you a spreadsheet knocked together to play with this. Important to remember that the calculator principle is still flawed for reasons laid out in the review by Faber Maunsell (AECOM).

Seems that if we assume that a 4/2 litre WC actually does what the calculator suggests (which it won't) then a 4/2 WC, 6 l/min kitchen tap (probably acceptable), 4 l/min basin taps, 6 l/min shower (OK I think but others will want more) and no bath or waste disposal unit gives 80 litres according to the CSH version. Part G adds anther 5 litres/min for outdoor use which is meaningless.

I hope you will consider using the AECB Water Standards as a guide to a more robust spec'. With the revised calculator it is easy to meet the 105 litre targets.

Just don't forget that the calculator is no predictor of performance or water efficiency. even I start to believe it once in nice spreadsheet form with graphs!

Cheers

Nick

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