13 July 2020

Respiratory Viruses & Indoor HVAC Systems

respiratory virus

The World Health Organisation (WHO) have recently acknowledged growing concerns surrounding the possible airborne transmission of the coronavirus COVID-19.  Australian medical officials are closely monitoring the outcome of pending investigations, however, there are no changes to current Australian Government recommendation at this time.

Infectious respiratory viruses are typically spread from person to person through close physical contact with one another or through respiratory droplets (produced when an infected person coughs or sneezes) which may be inhaled or come into close contact with the eyes, nose or mouth of another person.

Respiratory droplets are very small, often invisible to the eye, with a particle size ranging from less than 0.5 micron to 15 micron, and standard measures to help mitigate these droplets within indoor HVAC systems include:

  • Providing sufficient and effective ventilation
    • supply clean outdoor air
    • increase outdoor air ventilation rates
    • minimise recirculating air
  • Supplementing general ventilation with airborne infection controls
    • local exhaust ventilation
    • opening outdoor air dampers
    • high efficiency air filtration, subject to fan capacity limitations
    • portable room air cleaners/purifiers
    • germicidal ultraviolet lights
  • Ongoing HVAC system maintenance
    • Regular changing of air filters
    • Cleaning /disinfection of cooling and heating coil surfaces, using approved methods and chemicals

Office Spaces/Commercial Buildings

Upgrading to higher efficiency air filters (F9 or ePM1 85%) is recommended for HVAC systems with AHU’s, however due to increased resistance to airflow and space restrictions, this may not be practical for every commercial HVAC system.

Please Note: Upgrading particulate air filters will also result in:

  • Shorter air filter life
  • Higher energy costs of air filtration
  • A higher pressure drop that existing fans may not be able to handle (reduced airflow countering the higher efficiency by reducing air change rates)

The next best option is to select the highest-rated air filter your HVAC system can handle, and/or run the system on an economy cycle (with 100% outside air) where possible.

Portable in room air cleaners/purifiers may also assist with reducing viral load.  Especially where supplementary localised controlling is needed.

Further Information

An interesting US based article regarding how modifications to heating, ventilation, and air conditioning systems might help reduce the spread of the coronavirus COVID-19 by purifying air, improving ventilation and managing airflows has recently been published to the McKinsey and Company website.  This article was written collaboratively by the Advanced Industries Practice, and published to the site on July 9, 2020.

See article link below:

Can HVAC systems help prevent transmission of COVID-19?

Camfil Airepure

Camfil Airepure have a comprehensive range of high efficiency air filters in stock, ready for you HVAC filtration needs.  Please contact us for assistance with selecting the most suitable upgraded air filter that your existing HVAC system can handle.

We also offer the Camfil range of portable air purifiers and air cleaners, or customised solutions.

Contact Camfil Airepure for further information.

*Purchased image from iStockPhoto. 


Airepure Australia
Ph: 1300 886 353
Email: info@airepure.com.au

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