Keep smelly air and water out

Blog Post

The primary function of an in-building drainage system is to remove soil and waste. In doing so, you must take care to prevent foul air and water from entering the building through water trap seals on appliances. Water movement within the system can create positive and negative air flows that can affect these seals.

Typically, in high rise buildings, a secondary vent is used to soften the effect that these momentary flows cause to trap seals. But it’s been proven that a secondary vent system can be slow to respond to these fluctuations, causing trap seals to break.

An engineered alternative method to secondary venting lies in Positive Air Pressure Attenuators (P.A.P.A.) and Pleura valves. Pleura valves respond quickly to negative pressures to allow air entrance to balance the system. P.A.P.A. valves activate under positive pressure and attenuate the pressure wave, allowing the system to return to balance in a controlled manner, protecting the trap seals from opening.

By replacing the secondary vent with the P.A.P.A. and Pleura system, there’s a reduced requirement for material and fire compartmentalisation. But the main benefit is your customer, who won’t have to worry about foul air or water entering the building.

Find out more about the Studor System / Terrain Pleura System LABC Registered Details certification by visiting

Published November 2015.

LABC Registered Details, now known as LABC Assured (as of March 2019), is a one-off certification process proving compliance with building regulations and standards across England, Wales & Scotland. Registering your product, system or house type with LABC increases industry confidence while also raising the profile of your company.

Please Note: Every care was taken to ensure the information was correct at the time of publication. Any written guidance provided does not replace the user’s professional judgement. It is the responsibility of the dutyholder or person carrying out the work to ensure compliance with relevant building regulations or applicable technical standards.


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