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The heating, ventilation and air conditioning (HVAC) system in my workplace was shut down while COVID-19 restrictions were in place. What are the risks to health and safety once it is restarted?

Restarting HVAC systems that have been temporarily shut down can carry significant risks to the health and safety of workers and other people that enter the building, if they have not been maintained and inspected in accordance with relevant regulations and standards prior to restarting. 

During periods of shutdown, cooling towers and condenser water systems in an HVAC system can build-up corrosion on the surfaces that have not been chemically treated.

When an HVAC system is shut down, the sections of the system that have been altered, abandoned or capped so that water cannot flow through (dead legs) can hold stagnant water. The bacterium Legionella can grow in the corrosion build-up and dead legs. Legionella can cause Legionellosis. This condition includes Legionnaires’ disease, a serious infection in the lungs that can be fatal.

For further information on Legionnaires’ disease, you can also refer to the website of the health department in your jurisdiction. You can find out more about the risk of Legionella in an HVAC system during a period of shutdown at the Australian Institute of Refrigeration, Air-conditioning and Heating (AIRAH) website.

Occupants and other visitors returning to the building may also face health risks from inferior indoor air quality and mould if the hygiene of the HVAC system has deteriorated while shut down. For more information on HVAC hygiene measures that can minimise this risk, refer to the AIRAH’s Best Practice Guideline.

As an employer, what steps should I take to eliminate or minimise risks arising from restarting an HVAC system?

Before workers and other people enter a building where the HVAC system has been temporarily shut down, you must take all reasonably practicable steps ensure risks to health and safety are eliminated or minimised. This includes any risks associated with the HVAC system being restarted. If you do not directly control or manage the HVAC unit you will need to liaise with the building owner or facilities manager to ensure this takes place. 

A working HVAC system is an essential safety measure for most buildings. Essential safety systems such as these must continue to be maintained in accordance with the relevant regulations to ensure ongoing building compliance, even during temporary restrictions such as those in place during the COVID-19 pandemic. To ensure this has taken place for the HVAC in your building, you should seek confirmation from the building owner or facilities manager that the HVAC system has been inspected and is properly maintained. HVAC maintenance must be carried out by a competent person and in accordance with all recognised standards. This will help ensure that all maintenance procedures are adhered to.

You may wish to request that the building owner or facilities manager produce a statement from a ventilation engineer that the system has been examined if available, You should ensure with the building owner or facilities manager that the HVAC system has been inspected and maintained during the shutdown period before you allow your workers to resume work.

If a complex HVAC system (those that can be found in large buildings that can transfer heating and cooling to secondary units or are integrated into the Building Automation System) has been shut down, the building owner or facilities manager should consult experts to implement the correct start-up procedures, to check control settings and to compare the system’s operation with commissioning baseline data. Before you allow your workers to resume work, you should confirm with the building owner or facilities manager that this has taken place if your building has a complex HVAC system installed.

You can refer to our guidance on COVID-19 Risk Assessments for information about how to determine what might be reasonably practicable in the current circumstances.

As an employer, do I have to personally check the HVAC system in my building before workers and others are allowed in?

No. You may not directly control or manage the HVAC system for your premises but you still have to take all reasonably practicable steps to ensure the system has been maintained and that risks to health and safety that arise from restarting the HVAC system are eliminated or minimised. Liaise with the building owner or facilities manager to ensure this takes place. You must do this before the building is reopened for business and workers and others are allowed in. 

A working HVAC system is an essential safety measure for most buildings. Essential safety systems must continue to be maintained in accordance with the relevant regulations to ensure ongoing building compliance, even during temporary restrictions such as those in place during the COVID-19 pandemic. To ensure this has taken place you should seek confirmation from the building owner or facilities manager that the HVAC system has been inspected and properly maintained by a competent person and in accordance with all recognised standards.

This will help ensure that all maintenance procedures are adhered to.You also confirm with the building owner or facilities manager that the HVAC system complies with relevant Australian standards.   

If a complex HVAC system (those that can be found in large buildings that can transfer heating and cooling to secondary units or are integrated into the Building Automation System) has been shut down, the building owner or facilities manager should consult experts to implement the correct start-up procedures, to check control settings and to compare the system’s operation with commissioning baseline data. Before you allow your workers to resume work, you should confirm with the building owner or facilities manager that this has taken place if your building has a complex HVAC system installed.

Can COVID-19 be transmitted through the HVAC system in my building? 

There is currently no evidence that COVID-19 can be spread through HVAC systems. However, having your HVAC system set to allow more air circulation in common areas and limiting or not using recirculated air and increasing outside air intake, if possible, may help minimise the risk of COVID-19 spreading in your workplace. If you consider it is reasonably practicable to avoid using recirculated air, you should speak to your building owner or facilities manager to organise to have the recirculation dampers closed. If the HVAC system in your building does not have a setting that allows for recirculation of air to be stopped or limited, you may wish to consider working with the building owner and/or facilities manager to organise for doors and windows to be opened to increase the intake of fresh air within the building, so far as this is reasonably practicable .

Current evidence suggests COVID-19 most commonly spreads from close contact with someone who is infectious. It can also spread from touching a surface that has recently been contaminated with the respiratory droplets (cough or sneeze) of an infectious person and then touching your eyes, nose or mouth. 

The most effective way to minimise the risk of infection with COVID-19 is through ensuring physical distancing requirements are complied with at your workplace and encouraging staff and any visitors to maintain good hygiene

Our webpage on cleaning and our cleaning guide also provide useful information on cleaning and disinfecting measures that may help limit the spread of the virus in your workplace.

Are there other things I should talk to my building owner or facilities manager about?

Yes. Working with your building owner or facilities manager is a very important step to successfully minimise the risks of exposure to COVID-19 and meet your work health and safety (WHS) duties at the workplace.

COVID-19 spreads through respiratory droplets produced when an infected person coughs or sneezes. A person can acquire the virus from close contact with an infectious person and/or by touching a surface or object that has the virus on it then touching their own mouth, nose or eyes. 

The most effective way to minimise the risk of infection with COVID-19 is through ensuring physical distancing requirements are complied with at your workplace and encouraging staff and any visitors to maintain good hygiene

If your business operates in a shared premises you must work with other employers, the building owner and facilities manager to ensure that these measures are implemented appropriately taking into account all those on site. Think about shared facilities such as lifts, changerooms and common meeting spaces to ensure everyone is on the same page and that the measures you are each putting in place will be complementary (e.g. discuss plans for staggering arrival and departure times). You may also wish to discuss with your building owner or facilities manager whether the evacuation and other safety processes for the building have been reviewed to implement good hygiene and physical distancing so far as reasonably practicable, such as at designated assembly points. 

You may also wish to consider working with the building owner and/or facilities manager to organise for doors and windows to be opened to increase the intake of fresh air within the building, so far as this is reasonably practicable .

One of my workers has been diagnosed with an illness that might have been caused by my HVAC system. Can my workers continue to work in the building?

If you or any of your workers are suspected or confirmed to have an illness that may have been contracted from a recently restarted HVAC system such as Legionellosis, you must immediately inform the building owner or facilities manager and organise testing of the HVAC system. The person diagnosed should also request to be tested for COVID-19. If the test is positive for COVID-19 see our infographic on what to do if a worker has COVID-19

If it is found a worker has likely contracted Legionellosis, which can include Legionnaires’ disease from the HVAC system at the workplace, follow relevant guidelines for Legionella control. You can also contact your local Public Health Unit for advice. You can put in place arrangements to work from home or temporarily relocate to other premises. You can find more information on your obligations when workers are working from home on our Working from home webpage. You may also wish to refer to the model Code of Practice: Managing the work environment and facilities if you need to set up a temporary office or workspace. If a worker has confirmed Legionellosis and the HVAC system is considered to be a likely cause of infection, you must notify your WHS regulator.

I own an HVAC maintenance business, are there additional safety measures that I should implement to protect my workers when they are working on HVAC systems?

Workers involved in servicing HVAC systems should continue to abide by all industry safety requirements, including wearing all necessary personal protective equipment.

Current evidence suggests COVID-19 most commonly spreads from close contact with someone who is infectious. It can also spread from touching a surface that has recently been contaminated with the respiratory droplets (cough or sneeze) of an infectious person and then touching your eyes, nose or mouth. 

The most effective way to minimise the risk of infection with COVID-19 is through physical distancing and encouraging workers and visitors to maintain good hygiene

For further guidance on how to help minimise the spread of COVID-19, you can refer to our guidance for the Trades and home maintenance sector or the Energy and utilities sector.
 

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