Air quality and natural ventilation in learning spaces

The department understands air quality is a key factor in the comfort of a learning space, and that the most effective method for minimising the spread of disease is to maximise natural ventilation.

Ventilation is the provision of fresh air to a room. Ventilation is measured in litres per second.

The World Health Organisation guidance specifies 10 litres per person per second. For a standard classroom, opening windows provided in accordance with the building code can deliver at least this.

We operate schools with a variety of ventilation systems, from entirely naturally ventilated to fully sealed supported by heating, ventilation and air conditioning (HVAC) or evaporative cooling systems to suit their local environment. The underpinnings of all these systems are the fresh air requirements specified in the National Construction Code, and Australian Standards. When operating properly this specification allows us to meet or exceed the World Health Organisation recommendations.

Our independent advice confirms that even on a still day, the vast majority of our classrooms have sufficient air changes through natural ventilation.

To support thermal comfort, schools may use heating or cooling in conjunction with windows and doors remaining open to continue to allow natural ventilation.

There will be times when maximising natural ventilation may not be the only suitable option to implement in teaching spaces – for example, due to bushfire smoke or poor air quality.

Although air purifiers do not replace the need to maximise natural ventilation through open windows and doors, they can play a role during times those times when maximising natural ventilation isn’t a suitable option for teaching spaces due to outdoor air quality in local areas. This may include times where backburning or bushfire smoke is impacting a school community.

Ventilation research and audit during COVID-19

During COVID-19, NSW Health advice, along with independent expert advice from Steensen Varming (PDF 6.8 MB)  and World Health Organisation guidance told us that maximising natural ventilation in our learning spaces was the most effective method for minimising the spread of COVID-19 as it was a very effective way to disperse particles in the air. This was best achieved by opening doors and windows.

What did the advice and research tell us?

This advice told us that maximising natural ventilation in our learning spaces was the most effective method for minimising the spread of COVID-19 as it is a very effective way to disperse particles in the air. This can be best achieved by opening doors and windows.

• Maximise natural ventilation.
• Open windows and doors.
• Ventilation is one part of a range of effective measures.

Our response to the research

During the COVID-19 pandemic, the department conducted a statewide review of all windows, fans and ventilation systems in more than 150,000 spaces across our more than 2,200 public schools, including preschools, to ensure our schools can operate them as intended. This included checking:

• 650,000+ windows
• 200,000+ ceiling and wall fans
• 19,000+ extractor fans.

As a result of this audit, the department made repairs to more than 75,000 windows and 2,000 ceiling fans.

The audit confirmed the majority of spaces in schools could be adequately ventilated through natural and mechanically assisted ventilation. Indoor spaces in individual schools were categorised and each school was provided with and supported by an individual ventilation audit report and their local Asset Services Officer.

Findings from the review enabled the department to provide individualised audit reports to be customised for individual schools. It is not generalised advice. The comprehensive nature of the audits that were undertaken was unprecedented in an asset portfolio of this size.

The department’s ventilation and asset use recommendations were informed by:

• NSW Health advice
• independent expert advice from Steensen Varming
• research from the Doherty Institute
• guidelines from the World Health Organisation.

The approach to ventilation in NSW is nation leading. No other jurisdiction has the in-depth knowledge of the ventilation status of their schools, including individual data for each learning space, such as the number of students that can safely be accommodated at any one time.

It is also important to note that this work was completed in consultation with other jurisdictions around the country and overseas, including New Zealand. The Department of Education’s response meets and, in many cases, exceeds the WHO metrics for fresh air flow.