Limits for use of vent elements in building drainage systems considering the risks of infection spread by means of water-seal behaviour and integrity: the case of Brazilian systems

Considering the water conservation programmes that promote a reduction in WC flush volume, and given the concern with the safe use of new concepts and techniques to avoid the transmission of serious disease via the drainage system as in the case of SARS, this paper discusses the influences of said reduction on the behaviour of water-based trap seals in drainage systems utilizing different types of ventilation, as allowed by Brazilian standards. The paper shows that the venting system capacity to limit the internal pressure in the drainage system, in order to maintain the integrity of the water seals, reduces the risk of infection spread in buildings.