Water efficiency?

[David OLIVIER]

The journal Water, Energy and Environment (Dec 2005) reports on p 28 that a device "Interflush" which saves up to 47% of water in siphon flush toilets (almost all older UK toilets are siphon flush) is being attacked by the manufacturers and resisted by water companies. Since valve flush was legalised in the UK in 1999, the article states that siphon manufacturers have been decimated.

The article then quotes the inventor of this device as claiming that American Standard, Inc. (which has bought up most UK toilet manufacturers) is aware of the resulting water waste but couldn't care less; if valves leak more quickly, they sell more valves! It sounds scandalous if it's true but maybe there was some exagerration - that always makes a good story. (If there's no scandal, maybe this posting should be moved to another section of the forum.)

Do others know more? It seems to me that if the Interflush device works on any siphon flush WC it could potentially turn the 4 litre Ifo ES4 WC into a 3 litre or even 2.5 litre (average) toilet, because liquids don't need the full 4 litre flush.

David.

[Nick Grant]

I'd rule out conspiracies on this one but it is interesting how all the UK WC manufacturers did an about turn from favouring siphons to only offering valves despite growing evidence for problems with valves.

As you know, I did the opposite about turn when we set out to prove that the UK siphon was a dinosaur and the data proved us wrong.

I agree that dual flush (and interuptable flush) can offer savings in a domestic setting although in trials these are less than most manufacturers and enthusiasts claim.

Anyway you will be glad to hear that the toilet you mention is going through WRAS testing with 2.5 litre/4 litre dual flush. Even at 4 litres it used less that 2/4 dual in trials so I don't know what the reality will be (I'm a Director of Solution Elements Ltd which developed it with Ifo and Thomas Dudley).

The Thomas Dudley Duoflush Turbo is available for retrofitting to older WCs, a superb bit of kit!