Ground gases can be produced from a variety of natural sources including coal, peat, alluvial deposits and rock (Radon), plus a range of man-made sources such as landfills, in-filled ponds, made ground and spillages of fuel and volatile organic compounds (VOCs).

GRM provides risk assessments to identify and quantify ground-gas risks to specified receptors based on current guidance and regulations including:

• CIRIA C665
• BS8576:2013
• BS8485:2015+A1:2019
• BR211:2015 Radon: Guidance on Protective Measures for New Buildings

Monitoring installations will typically be put in place based on the type of site proposed, proximity to gas sources (often landfills), and the strata revealed during the ground investigation. Once the gas monitoring is complete ground-gas protection measures can be designed and put in place such as a ventilated sub-floor and gas resistant membrane.

On some occasions, the concentrations of landfill or soil gas is such that additional measures might be necessary to protect a development. Typical additional measures might include:

• Vent trenches
• Venting boreholes
• Engineered low permeability trenches and layers
• Search and removal of source areas

Examples of recent GRM news stories related to ground gas assessments can be found via the following links:

• New Radon Gas Data has Implications for Landowners, Developers & Homeowners
• Increasing Importance of Ground Gas Assessments & Membrane Verification
• New Gas Monitor ‘Detected’ at GRM Offices

To discuss any requirements you might have for Environmental Services, or any other service, please complete the contact form below or call us directly on 01283 551249.