Ventilation and Air Purification

Using ventilation to improve indoor air quality

This chapter describes various strategies schools can use to improve air quality in indoor spaces using ventilation.

Ventilation using windows and doors

Schools can use the following strategies to improve ventilation using windows and doors:

• Keep all windows, doors, and vents open as much of the day as possible (even when unoccupied), if practicable.
• In inclement weather consider opening windows and doors at intervals for short durations only – for example, in between classes, including while using air purifiers.
• Keep windows and door openings clear of any obstruction to air flow.
• Open windows and doors on multiple sides of the room to draw air through a space. This is called cross ventilation and is more effective than if windows and doors are only open on one side of the room (single-sided ventilation).
• Where windows open at the top and bottom, open both parts.
• Open windows and vents that are higher or towards the ceiling during poor or windy weather.

Ventilation using air conditioning systems

Schools can use the following strategies to improve ventilation using air-conditioning systems:

• Some schools have a centrally controlled mechanical ventilation and air-conditioning system that brings in outside air. Where installed, these systems should be set to use as much outside air as possible. These systems should run during school hours, including when rooms are unoccupied and, ideally 2 hours before and after the use of a space.
• A large proportion of air conditioning systems in schools are split systems which use recirculated air and do not bring in outside air. However, split systems can improve natural ventilation by increasing air movement within a room. As such split systems should be used alongside open windows and doors to bring in outside air.
• Air conditioning filters should be maintained according to maintenance plans, checked and cleaned regularly.

Fans to assist air movement

Schools can use the following strategies to improve ventilation using fans:

• Increase air movement by turning on fans when windows and doors are open.
• Pedestal or desk fans must be used on an oscillating function (not continually pointing in one direction).
• Exhaust fans are to be used as much as possible (for example in kitchens, bathrooms and laboratories).
• Split system air conditioners can be used to assist with air movement within the room, even when not required for thermal comfort.

Demand-controlled ventilation systems

Some air conditioning and ventilation systems operate based on demand – this means they are responsive to indoor conditions, such as indoor temperature or occupancy. For example, some systems automatically open windows if a CO₂ monitor detects a reading reaching a pre-set threshold or turn on fans at a certain room temperature.

Demand controlled air conditioning and ventilation systems should be disabled. Mechanical ventilation systems should be operated on high, irrespective of demand, to maximise the amount of air going in to a room.

Poor outside air quality

Schools are to follow the below advice in instances of poor outside air quality, such as bushfire smoke or thunderstorm asthma:

• Monitor the VicEmergency and the EPA AirWatch sites for risk warnings and advice on events that may reduce outside air quality.
• Take action to protect students during periods of poor outside air quality.
• Take steps to close windows and doors, set air conditioners to re-circulate air and use air purifiers.
• Refer to Air Quality – Impact of Smoke on Health for further information on how to minimise potential health risks from poor air quality.

Implement measures for a comfortable learning environment

Learning spaces are places where health and safety measures are practiced and are also places where people need to comfortably learn and work. Factors that affect a comfortable environment include temperature and noise levels.

To maintain thermal comfort (or a comfortable room temperature), schools are encouraged to use heating and air conditioning systems – even when windows and doors are open. These can be systems that bring in outside air, or only use recirculated air. Schools can also introduce measures such as flexible uniform and seating arrangements to ensure thermal comfort is maintained.

Refer to the Noise Management Policy for more information about the risks associated with excessive and strategies to manage these risks.