BC(A)R SI.9 or… green alternative No 1

by Bregs Blog admin team

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In recent statements Minister Hogan confirmed that there would be no change to the technical standards or requirements under Building Control (Amendment) Regulation (SI.9 of 2014). This opinion piece ponders what if part of the cost of this “blizzard of red tape”, BC(A)R SI.9, was instead spent on technical improvements that would benefit the consumer, taxpayer and industry. In previous posts we have noted the current industry estimate for separate professional appointments under SI.9 at around €15k for a typical house (note: this excludes an further additional €20,000 self-builders may be paying for main contractors fees and costs for self-build projects).

BC(A)R SI.9 or…Water Conservation

One topical area where increased technical performance standards could be usefully applied is water consumption. With the creation of Irish Water and the impending introduction of €600- €1000 per annum water charges water consumption will become a very hot topic in the near future. Costs associated with infrastructure, supply, treatment etc. are considerable. In Ireland the situation is even more acute- we treat most water used for commercial and domestic consumption, including water used for toilet flushing. In parallel our storm water drains are overflowing as a result of years of under-investment, a prolonged building boom and more intense storm “events”.

Rainwater recycling has long been seen as a remedy for both of these problems. Straightforward rainwater recycling in a domestic situation can reduce potable (treated) water consumption by up to 30%, just catching, storing (typically 3,000- 4,000L) and re-using rainwater to flush toilets. In addition this provides localised rainwater attenuation storage, acting as a buffer to a local storm water drainage system during heavy downpours. This is a tried and tested technology and costs in the region of €3,500 for typical new-build houses, depending on size, type and location.

Greywater recycling also is a less popular but also well proven method for reducing potable (treated) water consumption. This involves catching greywater used in sinks and washing machines, short term storage (24 hours max and typically 200L) and re-using to flushing toilets. More popular in the UK a typical system would cost in the region of £2,000 (€3,500).

A simple filtration system (UV) to 5 microns with carbon filter will cost between €1000- €2000. This would treat rainwater to a standard suitable for all “working water”; this can supply water appliances, washing, showers, etc. An added advantage is that this water is naturally soft, reducing wear and tear on appliances. This type of filter also is well proven and is not new technology.

Although both systems are used for toilet flushing it is possible to combine both with a simple filter to reduce water consumption by over 60%. Greywater recycling caters for toilet flushing while rainwater is filtered to a standard to be used for all working water.

A study 2010 Dublin Institute of Technology noted that it was possible, using a combination of these three components, to reduce potable water consumption by over 90%, relying on mains treated water for drinking water only. Link to DIT research paper here: DIT research paper. This system could supply 94% of the water required for a typical house less with only 6%, drinking water, supplied by mains.

So for a little over half the cost of SI.9 for a typical house an owner could have a rainwater/greywater system installed that could reduce water consumption by over 90%. Not only would the projected mains water requirement for the next 20 years be reduced considerably by this, the impact of heavier and more intense storm events on our existing drainage system would be reduced considerably. No costly infrastructure projects importing riverwater to Dublin from the Shannon, environmental benefit, new “green” business stimulus- a “win/win” scenario.

If this requirement applied to, say, domestic extensions over 40Sqm, this method for rainwater conservation could make significant inroads to supply demands for existing housing stock. By stimulating this area considerable economies of scale could be achieved driving down capital costs and making payback periods even less. Based on anticipated annual water charges of over €600 per annum per household the payback period for a system like the above could be a little over 10 years. When the water charge increases to €1000 per annum the payback will become very compelling.

The above opinion piece was submitted by Maoilíosa Mel Reynolds on 20th March 2014.