- Long-term exposure limit (8-hr reference period) of 5000 ppm [Gas Safe Immediately Dangerous level]
- Short-term exposure limit (15 minute reference period) of 15000 ppm
Gas Safe and Health & Safety Executive (HSE) set limits on Carbon Dioxide (CO2) levels in commercial kitchens. These are tested as part of the gas safety certificate check, where all gas appliances are run at full power for 10 minutes and the air quality measured near the edge of the extract canopy:
- Levels above 2800 ppm CO2 are noted as AR At Risk.
- Levels above 5000 ppm CO2 will be ID Immediately Dangerous so kitchen will be closed until CO2 levels can be reduced.
An obvious sign of excessive CO2 is a discoloured ceiling.
Research indicates that repeated exposure to CO2 levels in excess of 5000 ppm for extended periods can cause long term health effects, this is why the HSE imposes their limits and they are particularly relevant to staff in commercial kitchens who are likely to spend 8+ hour shifts in exactly these conditions. If CO2 exceeds 5000 pm then unused burners can be capped, more powerful air extract fan fitted and/or improved fresh air provision will reduce CO2 back to safe levels.