Assessment of the Risk of Inadequate Ventilation
As part of your legal duty to provide adequate fresh air, your workplace risk assessment should identify poorly ventilated work areas:
- Look for areas where there is no natural ventilation (windows, doors, or vents) or mechanical ventilation (fans or ducts bringing in outside air).
- identify areas that are stuffy or badly smelling
- consider using a CO2 monitor to identify inadequate ventilation
- Using floor plans can be helpful to list areas in your workplace or record how spaces are ventilated. Don’t forget to include areas like locker rooms and cafeterias used for breaks.
Understanding When To Take Action
Ventilation Rate;
The ventilation rate refers to the volume of air supplied to a room over a specific period of time. What is necessary for adequate general ventilation will depend on various factors such as the amount of floor area per person and the nature of the activities conducted.
HSE’s Approved Code of Practice and guidance states, “The rate of fresh air supply should not normally fall below 5 to 8 litres per second per person.” Some building guides recommend a value of 10 litres per second per person as appropriate for most commercial buildings.
In workplaces like windy workshops, it is evident that there is sufficient air. In other more enclosed environments, especially for natural ventilation, estimating the airflow in an area can be challenging. However, a useful way to determine if there is an issue is to use CO2 monitors when you suspect there might be a problem.
Complex Ventilation Systems
If your workplace has a complex ventilation system, for example, due to multiple floors, you can obtain more detailed guidance from the Chartered Institution of Building Services Engineers (CIBSE).
You may need a ventilation engineer to provide expert advice on the best system for your workplace.
Table or Ceiling Fans
In poorly ventilated areas, you should not rely solely on table or ceiling fans. They will not improve fresh air.
Local Exhaust Ventilation
You can use local exhaust ventilation (LEV) to control risks from workplace hazards such as dust or welding fumes. If an LEV system exhausts outside air, it will also improve general ventilation in the area.
Talk To our Workers!
Talking to your employees will help you assess the risk and take effective measures to improve ventilation.
Questions to ask them;
How do we bring clean air (ventilation) to our workplace?
Consider natural ventilation through fully or partially operable windows, doors, and vents.
If using mechanical ventilation, ensure it is correctly adjusted and maintained.
How can we improve ventilation?
Consider areas with stagnant or bad-smelling air – open windows, vents, and doors (excluding fire doors).
If we have recirculation systems, are we bringing in some fresh air?
What is the level and impact of temperatures in the workplace?
Discussing the results of your risk assessment and the identified measures will also help them understand how they can play a role in improving ventilation at the workplace.
