New CIRIA Guidance Published C735 & C748

CIRIA C735 and C748.

CIRIA have just released new guidance documents on the installation and verification of ground gas protection measures for new buildings, and the use of membranes as VOC barriers, the documents are as follows:

  • Good practice on the testing and verification of protection systems for buildings against hazardous ground gases – CIRIA C735; and
  • Guidance on the use of plastic membranes as VOC vapour barriers – CIRIA C748.

The first guidance on the installation of gas protection systems for buildings was published in the early 1990s. Since then the frequency of installation and variety of systems has increased considerably. However, there is evidence that the installation of many of these systems has failed to meet an acceptable standard.

The publications provide best practice guidance for the designer, installer, verifier and regulator on the verification and integrity testing of gas protection systems, and options for vapour barriers. For verification the guidance sets out a flexible, risk based and practicable framework that can be adapted to provide site specific advice on the need for and scope of verification activities (including any integrity testing).

Recommendations are presented for the promotion of the best practice described in this publication and for recognition of the important role that local authority (LA) regulators play in its increased acceptance and application throughout the industry.

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