Ireland's only dedicated building services engineering journal
Ireland's only dedicated building services engineering journal

Water – A Plentiful Resource That’s in Short Supply

Brian Pickworth

According to the climate gurus, the combination of water-shortages sitting alongside heightened flood-risks is likely to become a future feature of Ireland’s climate. The pattern of rain is predicted to change from the steady drizzle and “soft day”, for which Ireland is famed, to more intensive downpours that simultaneously pose a flood risk while being harder to harness for subsequent use. We are not alone.

Not surprisingly, the same impacts are being experienced across wide swathes of mainland Europe that share a similar latitude to Ireland. The EC response to this has been to launch its “2012 Blueprint to Safeguard Europe’s Water Supplies”, as a prelude to future legislation.

The main aim of EC water policy is to ensure that a sufficient quantity of good-quality water is available to meet peoples’ needs throughout the EU, and the needs of the environment. Translating the blueprint into an overarching EC water policy is planned for completion by 2015.

The UK approach —UK legislation covering some of these issues came into force two years ago with the passing of the “2010 Flood & Water Management Act”. Along with addressing future water supply issues, the Act highlighted the need for new developments to be flood-risk neutral. The need for developers to also take into account broader considerations such as water-quality issues, environmental impact, and the use of water as a local amenity, is also emphasised. They are even finding ways to keep this going throughout the winter by using scrs for water tube boilers to make sure people have no plumbing issues staying warm during the cold weather. You just need to make sure that all of your cooling and heating systems are functioning properly and get new boilers or repairs when needed.

Guiding principles have therefore been developed to help benchmark future standards in managing surface water run-off, including achieving the maximum possible level of control at source, ie at and around individual buildings as they are built.

Waste not want not — Alongside flood avoidance measures (known as sustainable drainage systems, or “SuDS”), developers are also required to meet mains-water consumption targets when constructing new homes and commercial buildings. These requirements stem from a 2010 update of Part-G of Building Regulations and the Code for Sustainable Homes, insofar as dwellings are concerned, and from the BREEAM Code for other buildings.

These Codes emphasise that the first  priority in reducing mains-water consumption is to minimise usage by economising measures such as aerated taps and shower-heads, dual-flush toilets with smaller cisterns, smaller sinks and baths, and water-efficient appliances.

With these water-economising measures in place, one of the most straightforward and cost-effective ways of further reducing use of mains-water to meet Building Codes is to substitute harvested rainwater for use with non-potable applications such as toilet-flushing, clothes washing, fleet-washing and grounds irrigation.

This updated reversion to pre-mains technology is highly-effective in reducing mains-water consumption, with savings of up to 50% being achieved in dwellings, rising to in excess of 85% in other buildings.

Two birds, one stone — In theory, where yield and consumption are exactly matched, a rainwater harvesting (RWH) system will handle all of the rain falling on the roof. In practice, however, cyclical variations in the pattern of both rainfall and consumption means that a correctly-sized rainwater harvesting storage tank cannot be relied upon to have the capacity at any given time to accommodate a storm event. RWH systems must therefore be connected to wider surface water management systems.

Typically, on a commercial development, water overflowing from the RWH system, and not required for other re-use purposes, might be used to feed site-enhancing water features such as balancing ponds, designed to meet SuDS requirements. Integrating RWH and SuDS in this way can improve project values, minimise costs and help to meet the overall sustainability goals and Building Code requirements for the development.

What it means for building management — This means that, together with the carbon-saving technologies likely to be found in new buildings, building managers are also increasingly likely to find themselves faced with unfamiliar water-related technologies. As these form part of local flood defence, and may also serve essential services such as providing toilet-flush water, waiting until a problem occurs is not the best way to manage two such vital aspects of a building’s operation.

Unlike many aspects of modern buildings, SuDS and RWH are not difficult technologies to either understand or maintain. However, an effort has to be made to do just that, with comprehensive hand-overs from contractor to client, and from client to end-user, being vital to trouble-free operation.

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