Workplace gases monitoring in an industrial workplace

Gas monitoring

Workplace Gas Monitoring

Workplace gas monitoring and industrial gas monitoring measure toxic and flammable gases across process plants and workshops, benchmarked against EH40 exposure limits.

Method

EH40 / MDHS

Sampling

Personal & static

WEL (EH40)

ALARP / COSHH

Turnaround

5–10 working days

01

What is workplace gas monitoring?

Workplace gases monitoring measures the airborne concentration of toxic and flammable gases released or leaking from industrial processes that workers may breathe in during normal operations. It quantifies real personal exposure so employers can judge whether existing controls are adequate.

IndustrialAirMonitoring.uk provides independent workplace gas monitoring across chemical and process, manufacturing, utilities, food production, waste sites throughout the UK. Our occupational hygienists deliver defensible exposure data that demonstrates compliance with the Control of Substances Hazardous to Health Regulations 2002 (COSHH) and the workplace exposure limits set out in HSE guidance note EH40.

02

Why workplace gas monitoring matters

Under COSHH Regulation 10, employers must monitor exposure to hazardous substances where it is needed to protect health, where a workplace exposure limit could be exceeded, or where control measures need to be verified. Workplace gases monitoring provides the objective evidence that satisfies this duty.

Uncontrolled exposure to workplace gases is linked to acute poisoning, asphyxiation and explosion risk. Beyond the legal duty, robust monitoring protects your workforce, reduces the risk of enforcement action and civil claims, and gives insurers and clients confidence that exposure is being actively managed.

03

How we carry out workplace gas monitoring

We measure exposure using direct-reading electrochemical and infrared gas detectors, with sorbent sampling where time-weighted limits apply, following the recognised EH40 / MDHS methodology. Personal samplers are worn in the breathing zone for a representative full shift to derive an 8-hour time-weighted average, while static (background) samples help map contaminant sources across the workplace.

Samples are analysed by an accredited laboratory and the results compared with the relevant occupational exposure limit. Where short-term peaks are a concern we add 15-minute short-term exposure limit (STEL) sampling, so both the chronic and acute risk picture is captured.

04

Standards, limits and reporting

Workplace gases is controlled to as low as is reasonably practicable, with sampling benchmarked against published occupational and in-house standards. We assess compliance using the BS EN 689 statistical decision framework, which accounts for exposure variability rather than relying on a single result.

Your report sets out the measured concentrations, the compliance position, the adequacy of existing controls such as local exhaust ventilation, and a recommended re-monitoring interval. It is written to be understood by managers and to satisfy HSE inspectors, auditors and insurers.

05

Our workplace gas monitoring process

Our workplace gas monitoring programmes follow a structured, four-stage workflow so the results stand up to scrutiny. Request monitoring or book a site assessment to begin.

  1. 1Scoping & site survey. We review your processes, COSHH assessments and previous workplace gas monitoring data, then plan a representative sampling strategy using BS EN 689 similar exposure groups.
  2. 2On-site sampling. Qualified occupational hygienists carry out calibrated breathing-zone and static measurements across a representative shift, with full chain-of-custody documentation.
  3. 3Accredited analysis. Samples are analysed using the relevant MDHS / ISO laboratory method and the results are compared against the applicable workplace exposure limit.
  4. 4Reporting & recommendations. You receive a clear exposure report with compliance status, control recommendations and a re-monitoring interval — defensible evidence for HSE, insurers and auditors.
06

Frequently asked questions

What is the difference between gas detection and gas monitoring?

Gas detection alarms when a gas reaches a set level; gas monitoring quantifies exposure over time against occupational exposure limits. We provide both.

Can you measure time-weighted gas exposure?

Yes — for gases with an 8-hour or short-term limit, we use logging detectors or sorbent sampling to determine the time-weighted average.

Which gases can you monitor?

Carbon monoxide, hydrogen sulphide, ammonia, chlorine, nitrogen dioxide, sulphur dioxide, ozone and many process-specific gases.

Next step

Need workplace gas monitoring for your site?

Request monitoring