The Terrain P.A.P.A is a positive air pressure attenuator, designed to mitigate the affects of positive air fluctuations in the drainage pipework system.

As water descends down the drainage stack it creates a negative pressure; if that flow is interrupted or is approaching a change of direction, the negative pressure changes to a positive pressure and moves up the pipe. This low amplitude air wave travels typically at 320m/s, the speed of sound. As the positive air fluctuation approaches the branch-off point for the Terrain P.A.P.A then becomes the path of least resistance and the majority of the positive air pressure is absorbed within the unit.

As the transient air pressure within the pipework starts to equalise, the bladder slowly releases the small volume of air into the pipework system to only 12m/s which will have no effect on the trap seals.