Enhanced guidance on the management of risks posed by ground gas has been issued by the National House-Building Council (NHBC).
Following on from the Council’s ‘Guidance on Evaluation of Development Proposals on Sites where Methane & Carbon Dioxide are Present’, published in 2007, the new ‘Technical Extra’ focuses on common design, workmanship and verification essentials (both documents can be downloaded from www.nhbc.co.uk).
The NHBC says its experience suggests particular attention to managing ground-gas risks must be paid on construction sites. The gas membrane should be protected as soon as possible after installation and commissioned installers should be selected based on ability to offer the quality and competency of service and standards required.
It adds that installed measures should comply with National Occupational Standards (VR612 & 613) and, with regard to competence of installers, it points out that the Construction Skills Council now offers assessment against these national standards. It is envisaged that by 2013 operatives holding an NVQ level 2 Diploma in sub-structure work occupations (construction) – installation of gas membranes should install on high gas-risk sites.
Regarding the Basic Installer’s Card, automatic renewals for this ceased in January 2012 and will only remain valid until 2017, from when the NVQ will be required (for further details, visit www.cskills.org)
The NHBC has also announced that it is collaborating with CIRIA on further new guidance on the various approaches to verifying quality assurance of installations. It is scheduled to be published in March 2013 – in the meantime, details of this work can be obtained from CIRIA by visiting www.ciria.org
