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It is perhaps sobering to recall the concerns of the plumbing community at the end of the nineteenth century, as recorded by Hellyer who condemned 'oversized drains, insufficient flows to provide self cleansing, drains that run up hill, or through 90° bends and junctions, lack of trap seal retention, inefficient WC's and the eight minutes needed to refill a cistern' (Wright, 1980). |
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Water conservation was also an issue at this time, with the London Water Companies attempting to establish the flush volume at 9.1 litres, when up to 40 litres had been in use. The Builder journal at the time condemned this as a retrograde step (Billington and Roberts, 1982). This exchange of views parallels recent discussions in the UK concerning a reduction of flush volume from 9.1 to 6.0 litres, which has met an almost identical reaction from the modern ceramic industry (British Bathroom Council, 1988). |
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WC evaluation tests also date from this period: Robinson (Billington and Roberts 1982) recorded tests in 1893 at the Sanitary Institute where a 9 litre flush left 5 per cent of solids in the trap and 21 per cent along a 50 foot drain, these values reducing to 1 per cent and 5 per cent with a 13.5 litre flush volume. Such tests are now common, with their results being the subject of considerable discussion in the UK, USA and elsewhere. |
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Water conservation is a necessary and achievable objective. Forty per cent of domestic water in the UK is flushed via the WC. The WC is the one appliance where meaningful savings could be made by a careful synthesis of hydraulic and design methodologies. This chapter describes one such successful water conservation project. |
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13.1.2
Definition of Need and Project Background |
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The hydraulic parameters governing low water use WC designs were studied by the authors from 1978 to 1981, during the development of a 4.56 litre flush volume close-coupled WC for the UK market, funded by the UK Confederation of British Ceramic Sanitaryware Manufacturers (Uujamhan, 1981). In 1983 the authors initiated a 5-year research project, funded by the UK |
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