BS 8485:2015 is now available. Buy it now
When building/developing on or adjacent to brownfield sites, sites where degradable materials are present within the ground, and in areas of mineworkings, there is a potential risk of the generation of ground gases and accumulation of these gases within buildings. Under adverse circumstances, methane and carbon dioxide gases can build up to hazardous concentrations within confined spaces giving rise to a potential risk of explosion or asphyxiation.
Guidance up to the date of this British Standard has generally focussed on the occurrence and methods of measurement of ground gases and the incorporation of protection measures into buildings to mitigate the risk of building on sites affected by ground gas. The issue of how to undertake assessment of gas monitoring data in order to determine suitable parameters to be used in the design of protection measures has, until recently, not been developed to any significant degree. As a result, design solutions often lack a rigorous assessment of data and have often resulted in overly conservative solutions or insufficient measures being adopted.
BS 8485:2007 gives recommendations and describes methods for the investigation and assessment of the ground gases methane and carbon dioxide during new development of affected sites. BS 8485 is not intended for the assessment of completed developments.
BS 8485 details a process that can be used to effectively demonstrate that risks posed by the potential presence of ground gas have been adequately considered and addressed.
This document presents the assessment and decision making stages in the form of a process flowchart, accompanying information and explanatory guidance and, where appropriate, references to other guidance and information.
Please note BS 8485 does not consider ground gases other than methane and carbon dioxide.
