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Building Products March 2018

DRAINAGE, PLUMBING AND WATER SUPPLY MAKING THE Direct RWH with stormwater infiltration MOST OF RWH Matthew Rolph, managing director at water management specialist, Graf UK, looks at the benefits of combinable rainwater harvesting and stormwater attenuation for large-scale commercial premises – and highlights the business opportunity for specifiers who are up to speed with this fast-growing market. context of BREEAM, which assesses a building’s environmental, social and economic sustainability performance. Nowadays, most commercial premises are built to meet BREEAM criteria, and to achieve a sought-after ‘excellent’ rating (the highest accolade possible), a number of energy consumption, sustainability and water-saving standards must be met. There are up to three BREEAM credits available for RWH, and those points are often crucial in reaching the highest possible score. The rating is based on the percentage of the total hard surface of the site (i.e. both roof and hard-standing) that is designed to allow the harvesting of rainwater for re-use around the building. To fully comply, the yield should off-set non-potable water demand MARCH 2018 | BUILDING PRODUCTS 47 Severe weather events such as droughts, storms and flash floods have become more and more commonplace in the UK over the past decade. This has highlighted a crucial need for effective and reliable water management solutions that can cope with such extremes – both now and for the long-term. What’s more, larger buildings in particular are under increasing pressure to comply with ever-tightening environmental regulations around flood protection. Against this backdrop, it’s no surprise that demand for solutions which can safely manage, store and reuse water is growing in the commercial sector – and large-scale rainwater harvesting (RWH) systems, especially ones with stormwater attenuation capabilities, do just that. Uptake of these is especially high in densely populated urban areas such as London, where water authorities are encouraging it as a way to reduce pressure on the mains supply. This particularly applies to businesses which rely on large amounts of water to run their operations, such as hotels and manufacturing plants. All of this is creating an unprecedented opportunity for commercial RWH specifiers. But what do they need to know about the benefits of RWH, the products shaping today’s market, and the legislation driving uptake in order to make the most of it? Why RWH? First of all, it’s important to understand why RWH is becoming so popular. From an environmental point of view, there is a clear case for collecting and reusing rainwater on a large scale (as opposed to simply letting it drain away) – especially in the Continued on page 48 >>>


Building Products March 2018
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