Control and suppression of air pressure transients in building drainage and vent systems

Air pressure transients propagate within building drainage and vent systems due to the unsteady nature of the network flows. These low-amplitude transients may deplete the appliance water trap seals that prevent ingress of foul gases and odours into habitable space. The simulation of transient propagation and trap seal response is achieved via the method of characteristics solution of the St. Venant equations. The application of transient control and suppression methodologies to control both positive and suction pressure trap seal loss is demonstrated and the importance of trap seal retention to prevent cross contamination via the drainage network is emphasised.