Using Flow Restrictors to achieve schedule G" of the BRegs

[TerryE]

We've discussed this general issue as an aside on various topics but AFAIK from my search of the forum,  we don't have a topic covering this specifically.  BReg part "G2 and Regulation 36" states:

 

Quote

"The potential consumption of wholesome water by persons occupying a dwelling to which this regulation applies must not exceed 125 litres per person per day, calculated in accordance with the methodology set out in the document “The Water Efficiency Calculator for New Dwellings”, published in September 2009 by the DCLG*.

 

The Water Efficiency Calculator is available as an Excel or OpenOfiice Calc spreadsheet and IMO is easy to use.  The challenge is filling in the data in a way that the BInsp will believe.  As Jeremy and others have mentioned, the easiest way to have a demonstrable confidence in estimating flow rates is to fit flow restrictors on all taps.  @JSHarris post

covers this well.  In our case we have a 3 Bar direct system, so the flow rate at all of our taps is high.  I see little point in having any of the hand basins at more that 4 ltr / min.  This is more than enough for hand washing and limits the splash-back that would otherwise occur for fully open taps.  6 ltr/ min for our utility sink and 6 or 8 ltr/ min for our kitchen sink; 8 ltr/ min for our showers.

 

So much for the theory, but now the implementation.  The challenge that we have is the non-standardisation of tap aerator fittings.  We've standardised our taps during initial purchase, but we still have 4 different types:

   

 

some have a male thread, some female; some flanged some not.  Some simple through flow; some proper aerator.  None have the sort of negative feedback restrictor that gives a reasonably constant flow over a range of static pressures.  (Note that most require a minimum pressure of 1 bar to work correctly.)  Finding decent datasheets is difficult but this is the one for some Pegler restrictors.  Jeremy kindly provided a link to QS Supplies: all Eco Home Restrictors which seems to give a complete range at competitive prices.  If anyone has good alternatives then please post the links to the topic.

 

Note that the flow restrictors seem to follow a colour coding convention -- I suppose to allow any inspector a simple visual inspection of the faucet to determine flow rate.  The main challenge seems to be (i) choosing the right flow rate for you and (ii) choosing the correct sizing spec to match your tap outer.  For that reason many seem to replace the whole body as the threads usually come in one of two sizes.  The restrictors are easy to fit and to remove (so long as you remember to keep the original fitting) ?

 

In terms of estimating what 1.7 or 4 or whatever ltr/min flow rate feels like, the easiest way is to use a ½ltr jug and counting to adjust the flow rate on your exisiting tap and to ask yourself whether this is enough to wash your hands or whatever.  But remember that fitting an aerator (if your taps don't currently have them) effectively doubles the perceived flow rate as the water is mixed roughly 50:50 with an air-bubble stream.

 

Edited December 3, 2018 by TerryE
Get the title spelled correctly

[Jeremy Harris]

The flow restrictors I used fitted to the supply to the tap, so inline with the hot and cold feeds, except for the shower where they can fit on the shower mixer outlet.  The washer-type restrictors just replace the rubber seal in the tap connector.

 

I found we had a wide range of aerators, so chose not to fit restrictors there.  In practice, having the washer-type restrictors on some taps does make them a lot easier to use, with less splashing and a finer degree of control from the tap itself.

[TerryE]

@JSHarris I suspect that the washer type will fit well with the type but not the domed  aerator type. 

These last will be easier to swap out and we'll need to do this, as they flow about 8-10 l/min..

Edited December 2, 2018 by TerryE

[Jeremy Harris]

The washer type ( https://www.qssupplies.co.uk/bathroom-furniture-shower-taps/12664.htm ) aren't designed to be fitted at the tap outlet/aerator, they are designed to replace the washer in the tap connector; the junction between the pipework supplying the tap and the threaded portion of the tap to which it connects.  If you have taps with flexi tails, then you just replace the washers in the flexi tails with the restrictor washers.

[Gone West]

I quite like these where they fit.

 

https://www.screwfix.com/p/strom-maxi-flow-tap-flow-restrictor-aerator/3344r

 

 

[TerryE]

@PeterStarck Just ordered 5.  Collect tomorrow.

Edited December 2, 2018 by TerryE