Ground Gas Risk Assessment

Targeted, risk-led assessments to protect development and avoid unnecessary costs.

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Ground gas can pose a serious risk to new or existing buildings and their occupants, but not all sites require intrusive monitoring. At Clear Environmental, we assess each site in stages — recommending gas monitoring only when there’s a credible source of risk.

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Step 1: Desk-Based Ground Gas Risk Assessment

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Initial screening to determine if monitoring is needed.

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✔ We review historical land use, geology, groundwater, mining history, and nearby sources of gas (e.g. landfills, made ground, organic soils).
✔ We consider your proposed development type and sensitivity (e.g. residential vs. commercial).
✔ Where no credible source–pathway–receptor linkage exists, no gas monitoring is needed — saving you time and cost.
✔ We provide a concise, planning-ready report explaining the rationale and outcome.

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Many sites do not require monitoring — we help you avoid unnecessary work.

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Step 2: Intrusive Ground Gas Monitoring (If Required)

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‍Only undertaken where there’s a valid risk.

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If the desk study identifies potential gas sources that could impact your site, we:

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✔ Design and install gas monitoring standpipes

✔ Undertake a monitoring programme in line with BS8485 / CIRIA C665

✔ Interpret results and assign a characteristic situation (CS1–CS6)

✔ Recommend appropriate gas protection measures if needed

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We ensure that the scope and duration of monitoring are proportionate to the level of risk and site constraints.