Aug 25th, 2021
3 mins
In line with keeping workplaces safe the law says employers must make sure there’s an adequate supply of fresh air (ventilation) in enclosed areas of the workplace. The priority for any risk assessment is to ensure poorly ventilated areas are identified. There are some simple ways to identify poorly ventilated areas:
- Look for areas where people work and where there is no mechanical ventilation or natural ventilation such as open windows, doors, or vents
- Check that mechanical systems provide outdoor air, temperature control, or both. If a system only recirculates airand has no outdoor air supply, the area is likely to be poorly ventilated
- Identify areas that feel stuffy or smellbad
The use of CO2 monitors can help identify areas of inadequate ventilation. The most appropriate type for use in the workplace are non-dispersive infrared (NDIR)
The HSE has provided guidance on their use and amount of CO2 in the air is measured in parts per million (ppm). CO2 measurements should be used as a broad guide to ventilation within a space rather than treating them as ’safe thresholds’. Outdoor levels are around 400ppm and indoors a consistent CO2 value less than 800ppm is likely to indicate that a space is well ventilated. An average of 1500ppm CO2 concentration over the occupied period in a space is an indicator of poor ventilation. You should take action to improve ventilation where CO2 readings are consistently higher than 1500ppm.
For the full HSE guidance, please see below link:
Identifying poorly ventilated areas and using CO2 monitors (hse.gov.uk)
