Guidance on the use of plastic membranes as VOC vapour barriers

Buildings are often constructed on sites where volatile organic compounds (VOC) are present in the ground. This publication provides guidance on the use of plastic membranes to reduce vapour migration into buildings. It discusses vapour transport mechanisms that occur in membranes, factors that influence this and the test methods available for determining the rate of vapour permeation. It then explains how to use the results in a risk assessment. Durability and resistance to damage when plastic membranes are exposed to VOCs is a concern and the guide considers the potential for degradation and which tests methods are suitable to assess performance. This guide should allow readers to make a robust evaluation of the contribution to membranes to reducing indoor inhalation risk from VOCs in the ground and to specify the most appropriate type of membrane for any given site. Further information on this subject can be found in CIRIA C735.