HSE guidance on ventilation and air con during COVID-19

The HSE website states that: 

Its guidance will help you and your workers:

• identify poorly ventilated areas
• assess the risk from breathing in small particles of the virus (aerosol transmission) in enclosed areas
• decide on the steps you can take to improve ventilation

Adequate ventilation reduces how much virus is in the air. It helps reduce the risk from aerosol transmission. Aerosol transmission can happen when someone breathes in small particles in the air (aerosols) after a person with the virus has been in the same enclosed area.  The risk from aerosols is greater in areas that are poorly ventilated. 

Your ventilation is likely to be adequate to minimise the risk of COVID-19 aerosol transmission if the rooms or spaces in your building(s) are:

• used within the occupancy limits specified in the building design, and
• have a sufficient fresh air supply to meet the current minimum building standard. You can get advice from a competent ventilation engineer or, as a precautionary approach, operate your system on the maximum air flow rate

See the full guidance at https://www.hse.gov.uk/coronavirus/equipment-and-machinery/air-conditioning-and-ventilation/index.htm