Ventilation and Air Conditioning in the Workplace

Published July 26 2021

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Providing good ventilation in the workplace is considered to be a key factor in helping to reduce viral infection within the workplace along with good hygiene standards, a degree of social distancing and the wearing of face masks where close proximity to others is required to allow work to be done.

Ventilation allows for the replacement of stale, hot or humid air that has been caused by:

  • there being no immediate access to fresh air;
  • there being no means of moving the air in the workplace or part of it;
  • a work process;
  • the use of machinery / equipment.

Under the Workplace (Health, Safety and Welfare) Regulations 1992 (the Welfare Regs), employers in the United Kingdom are already required to ensure that all workplaces provide a healthy working environment, which includes providing sufficient ventilation, especially where there are enclosed spaces.

L24 is the Approved Code of Practice (ACoP) for the Welfare Regs which have their own legal status. This means that if an employer or other duty holder for the site are being prosecuted for breaches of health and safety law and it is proved that the relevant provisions of the Code were not followed, it would need to be demonstrable that the requirements have been met or exceeded in some other way or a Court will likely find the duty holder(s) at fault.

A risk assessment called for by the Management of Health and Safety at Work Regulations 1999 should be conducted to assess the ventilation requirements of the site to ensure all site users will be safe and conditions that could affect their health will be well managed.

Open doors and or windows are, in many workplaces, all the ventilation needed but employers must not shy away from the fact that if it is necessary, they must provide a mechanical means of ventilating the workplace whether in part or full. It is however, also required that workers are not then placed in harm’s way (subjected to working in an uncomfortable draught) and therefore controlling the direction and the velocity of the airflow, or the re-siting of workstations could be necessary.

Where mechanical ventilation is recirculating air, the recirculated air should be:

  • adequately filtered to replace impurities;
  • mixed with fresh air before being recirculated.

To determine what your actual rate of replacement should be the following should be considered:

  • the floor area per person;
  • the processes and equipment involved;
  • whether the work is strenuous.

Air pulled from the outside environment is considered to be “fresh air”, although it is necessary to ensure that any inlets are not placed where they could draw in contaminated air such as from a nearby flue, an exhaust ventilation outlet or where vehicles are known to manoeuvre regularly. It may also be necessary to consider the need for filters to be fitted to remove particulates.

It should also be understood that whilst it might not be possible to remove smells that come in from the outside it is required that reasonable efforts to minimise their effects are undertaken.

It should be recognised that some ventilation systems are water based. Where water is used or stored, and where there is a means of creating and transmitting water droplets that may be inhaled there is a risk of exposure to Legionella bacterium. It should be understood that if this is the case you will need to ensure that any necessary measures to prevent or “adequately control” the risk must be undertaken.

So, whether the workforce is just beginning to come back into the workplace, or the workplace never closed during the pandemic, take time to check if there are any areas where ventilation could be regarded as insufficient as well as if any provided ventilation / air conditioning system / equipment is in need of maintenance. Duty holders must keep any mechanical ventilation systems, in good working order by:

  • carrying out regular checks of the equipment;
  • keeping the equipment clean;
  • conducting maintenance as per the manufacturer’s instructions and;
  • ensuring repairs are made in a timely manner.

Finally, it is important not to confuse the need to provide adequate ventilation with the need to have local exhaust ventilation (LEV), as they are not the same thing. LEV is designed to control exposure to harmful materials such as asbestos, lead and other substances hazardous to health (dusts, mists, fumes, created by work processes) for which legislation has required the provision of LEV.

If this alert has raised questions or you need to discuss any other health & safety related issue do not hesitate to contact your health & safety consultant or the main office for advice / assistance.