Hydrogeo provides several options for evaluating the hazards from ground gases, including a desk-based evaluation of potential sources, measurement of organic carbon concentrations and assessment in accordance with CL:AIRE RB17, or the installation of standpipes and monitoring over time in accordance with BS8485:2015.
When there is a viable channel through the subsurface soils that permits gases to move into structures and concentrate in confined areas, ground gas, whether it is produced by mining, landfilling, or other natural sources, can represent a risk to a development.
To identify the risk posed by ground gases, a Phase I Desk Study looking to identify any potential sources, pathways, and receptor is progressed looking to develop a solid conceptual site model.
The installation of Gas Monitoring standpipes may be appropriate where potential off-site sources, such as infilled ground or landfill sites, are identified to gather readings over time to develop a representation of the ground gas regime. We can offer guidance on potential mitigation action, such as ventilation, barrier membranes, and pathway intervention, where a risk to the site is determined.
