Effective gas detection and monitoring are essential, enabling food processing operators to protect personnel, minimise operational risk and meet the requirements of UK health and safety regulations, as Paul Davidson, Gas Safety Expert, Draeger Safety UK, describes here.
The use of gases is integral to many food processing operations, from beverage production and packaging to refrigeration and storage. However, gases such as carbon dioxide and ammonia can pose significant hazards to worker health and safety if leaks or elevated concentrations occur.
Portable gas detection devices are an essential tool in protecting employees by providing early warning of the presence of toxic or flammable gases. As food processing becomes increasingly automated and production more complex, having a solid grasp of this important safety issue enables greater understanding and potentially more informed decisions when deploying gas detection equipment across food production facilities.
What is a portable gas detector?
Portable gas detectors, sometimes referred to as personal or compliance monitors, are compact, battery-powered devices designed to be worn by workers, typically clipped to clothing within the breathing zone at chest height. They may also be handheld or used as standalone monitoring devices.
Their purpose is to provide early warning of hazardous gas concentrations or oxygen depletion in the wearer’s immediate surroundings, allowing workers to evacuate or take other appropriate action before conditions become dangerous.
Portable gas detectors are available as single-gas or multi-gas instruments. Multi-gas detectors are capable of simultaneously monitoring several hazards using multiple sensors within one device.
When a detector senses gas concentrations reaching a pre-set alarm threshold, it activates audible, visible and vibrating alarms to alert the wearer. This warning enables workers to leave the area quickly and initiate emergency procedures before exposure reaches dangerous levels.
Gas detection regulations in the UK
Gas detection is tightly regulated in the UK to ensure worker safety, and there are three key regulations which employers must adhere to in order to keep their employees safe.
1. EH40/2005 Workplace Exposure Limits (WELs)
EH40/2005 specifies WELs for many hazardous substances, including gases commonly encountered in food processing. Employers have a legal duty to prevent employees being exposed above these limits.
The WEL values are split into two parameters: Long-Term Exposure Limit (LTEL), which means maximum average exposure over an eight-hour working day (Time Weighted Average); and Short-Term Exposure Limit (STEL), where the maximum average exposure over a 15-minute period to protect against acute health effects.
Gas concentrations are measured using units including parts per million (ppm) and percentage by volume (%Vol). For example, a reading of 50 ppm carbon monoxide indicates there are 50 parts of carbon monoxide in every million parts of air.
2. COSHH
The Control of Substances Hazardous to Health (COSHH) regulations require employers to assess and control exposure to hazardous substances, including gases, vapours and airborne contaminants. COSHH makes compliance with WELs legally enforceable.
3. Flammable atmospheres
Food processing facilities may also need to consider explosive atmospheres where flammable gases are present. Understanding the Lower Explosive Limit (LEL) and Upper Explosive Limit (UEL) is fundamental. The LEL represents the minimum concentration at which a gas can ignite in air, while the UEL is the maximum concentration capable of supporting combustion.
Portable gas detectors typically alarm at around 10-20 per cent of the LEL, providing sufficient warning before an explosive atmosphere develops.
Why portable gas detectors are used
Portable gas detectors generally serve three key purposes:
- Personal safety: to protect workers from immediate or long-term exposure.
- Operational integrity: to identify leaks and prevent fires or explosions.
- Regulatory compliance: to meet occupational health and safety regulations.
Portable detectors often complement fixed gas detection systems rather than replace them.
Fixed gas detection provides continuous monitoring in locations such as refrigeration plant rooms, carbon dioxide storage areas and packaging halls.
Portable monitors provide personal protection for maintenance engineers, hygiene teams, contractors and workers entering confined spaces or areas where fixed monitoring may not be available.
Using both systems together provides a comprehensive approach to gas safety.
Effective gas safety procedures
Portable gas detectors are only effective when supported by robust procedures.
Every food processing site should undertake a suitable and sufficient risk assessment to identify potential gas hazards, determine appropriate control measures and establish emergency arrangements.
Essential elements of an effective gas safety programme include ongoing employee training to ensure employees understand gases present within their workplace, how detectors operate, alarms and how to respond and emergency evacuation procedures.
Regular emergency exercises are also crucial to help reinforce procedures and ensure employees understand evacuation routes, assembly points and re-entry controls.
Also essential is regular maintenance, testing and calibration of equipment; manufacturers generally recommend servicing every six to twelve months, although requirements vary according to equipment type and operating conditions.
Routine maintenance should include:
- Visual inspection before use
- Bump testing to verify sensors and alarms respond correctly
- Calibration at intervals specified by the manufacturer
- Replacement of consumable components where required.
Calibration is particularly important because gas sensors naturally drift over time. Without regular calibration, detectors may fail to alarm at the correct concentration, potentially placing workers at risk.
Conclusion
Portable gas detectors save lives every day, but only when used correctly and when an effective procedure is in place. By integrating portable gas detection into a wider gas safety management programme, understanding the key regulations and health impact of gas exposure, food processors can reduce risk, helping to ensure that everyone goes home safely at the end of every shift.
