HVAC maintenance: the old weapon for new challenges

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There are a number of new recommended HVAC measures to address airborne COVID-19 and the climate crisis. But with so much out of our control, good maintenance is our best chance to be prepared, says Paul Robaard.

We have heard from several clients and people in the industry over the last two years, seeking guidance and advice on mitigating COVID-19 airborne spread. While the times are changing and there are new challenges and possibilities, our advice remains largely the same: keep up your maintenance.

Earlier in the pandemic, I spent a week investigating healthy air and COVID-19 with numerous people, companies, engineers, NSW Health Infection Control, and air quality companies. And we found that good maintenance, good practices and making sure things are working the way they were designed was your best protection. This, in combination with sanitising, distancing and wearing masks where distancing is difficult, will minimise the spread. If occupants are in risky areas, they should be encouraged to wear masks. Lifts, confined space, entries and exits to building as well as lunchrooms and bathrooms. As building managers and maintenance workers, we can play a part with good maintenance practices, though people also have some control in what they do to protect themselves and help the situation.

Much has been said in the media about increasing the intake of outside air to better naturally ventilate indoor spaces. But HVAC systems have been carefully designed by building engineers to manage a certain level of air changes per hour, based on the square metreage and the people occupancy in the building. So it’s not going to be as simple as introducing more outside air. In fact, it could mean your HVAC system won’t work properly, and won’t be able to maintain a comfortable temperature range. Or the air conditioning will have to work harder, using more energy – which will cost you money to run and affect factors like NABERS ratings. Many don’t consider these flow-on effects.

So, go back to making sure the system operates according to its original design. Determine if the outside air vents are working, check your flow rates, ensure your coils and fans are clean and your filters are replaced regularly. General housekeeping and maintenance activities can help decrease the risk of transmission.

Smarter technology makes these measures easier. A good building management system (BMS) can control plant operations. It will track carbon dioxide (CO₂) levels within a building, and identify if they’re over acceptable levels, it will help manage and control outside air quantities. Sensors can help you monitor temperature and examine some particles in the air.

Good BMS maintenance makes for far more efficient buildings. Your BMS should help you put strategies into place to choose the optimal times to flush air from the building without impacting energy usage, with options like night purges, for example. No matter the HVAC management strategy you choose, you can find technology and advancements to help you perfect HVAC maintenance procedures for your building

There are also other measures that can be taken, such as upgrading your filter to a higher-grade filter, if the fan has the capacity for the extra pressure drop across the filter. These catch more particles and make the air cleaner. We’re advising our clients: if the fan has enough capacity to support the upgraded filter, then certainly upgrade your filters to a better grade. If you’re sticking with what you’ve got, you must ensure you change them at the correct time to and keep up with cleaning and maintenance.

The future promises more viruses, harsher climates and threats to clean air like bushfire smoke and pollution. You can’t control what happens out there, but you can control the environment that you’re in. Good and proactive maintenance practices will help you navigate the current situation as well as prepare for the future – make sure you’re doing all the right things to achieve this.

Paul Robaard is National Service Line Manager – HVAC – at Grosvenor Engineering Group

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