Closures or partial shutdowns of commercial or public buildings during COVID-19 must be carefully managed, a leader in property risk management says.

In a recent interview, David Hauser, Team Manager- Property Risk at Greencap, a health, safety, property & environment risk management company, cautioned that several things could go wrong during COVID-19 where buildings are not shut down correctly.

First, there is the Heating, Ventilation and Air Conditioning (HVAC) system and the increased risk of diseases such as legionella.

Commonly, Hauser says, buildings which require a large volume of air-conditioning such as offices and retail outlets, commonly use a water-based HVAC system incorporating cooling towers which use water as a heat exchange medium. The water in these systems is generally maintained at a temperature which is conducive to growth of legionella and other bacteria. When these systems are running, fans induce air flow through the system and, if bacteria such as legionella is present within the system, these microorganisms may also be dispersed into the atmosphere.

With these systems, prevention of growth of harmful bacteria is usually managed through a program of regular maintenance, servicing, monitoring and through the use of chemicals to manage bacterial growth and corrosion. This includes regular water testing and reviews of system risk such as stagnant water within the system.

Where buildings are shut down, however, correct management of these systems is paramount with two common options available.

First, there is a complete shutdown of the HVAC system.

Where this happens, Hauser says problems can arise where water may stagnate throughout the system and the water treatment chemicals may not be adequately dispersed to manage bacterial growth.

To address this, one approach is to drain the water completely out of the system. This, however, is costly, can have detrimental environmental consequences (as chemically treated water is drained out of the system) and can create time delays prior to reoccupation of buildings where the system needs to be restarted (as towers and pipework are refilled) and water needs to be chemically treated.

The alternative is to partially shut down the HVAC system and to run the system either intermittently or on a low use setting. This approach is similar to what might typically be done during quiet periods such as over the Christmas holidays.

Under this approach, water continues to circulate, and the chemical treatment and maintenance programs are maintained. When the building is reoccupied, the system can be reinstated to full capacity without major delays.

When doing this, however, Hauser cautions that careful management is needed as it is possible for water to still stagnate over time and for legionella and other bacteria to grow.

Beyond HVAC, Hauser says concerns can arise elsewhere.

First, there are other water-based systems such as fountains and water features. Whilst these are not usually operated at temperatures which are favourable to legionella and bacteria growth specifically, Hauser cautions that they can also harbour bacteria when they are not managed correctly and have the potential to generate aerosols and cause infections. The potential may increase as these fountains or water features are commonly located near building windows, doors, air intakes, balconies and patios, increasing potential human exposure.

Next, a further risk can occur where cleaning regimes are not maintained during periods where the building is not occupied. Where this happens, food scraps or other waste left whilst the building is empty, can attract pests such as cockroaches and vermin. This is particularly the case where the building is not cleaned properly, and waste is not removed when a shutdown commences.

Another risk may be chemical leakage, which can occur where storage spaces for chemicals such as cleaning products are not inspected and maintained. This can lead to a greater risk of unsafe chemical exposure, mixing of incompatible chemicals and potential environmental impacts if chemicals enter stormwater or sewage systems.

Finally, there is underground carparks. In these areas, there is a risk that vehicle emissions such as oil or coolant could leak from vehicles such as fleet cars which are left unattended for extended periods during shutdown. This can lead to slip hazards, environmental contamination or ground surface damage.

Asked about strategies which should be adopted, Hauser says building owners and managers should plan how they will prepare for shutdown and what needs to happen when buildings are not occupied.

First, it is important to decide on a strategy for their building’s HVAC. As mentioned above, this can be either fully or partially shut down.

Where a full shutdown is used, Hauser says maintenance tasks such as chemical analysis and water testing are not needed whilst the system is drained, cleaned and kept in a dry condition. Nevertheless, it is advisable to perform general maintenance and inspection to identify additional rectification works, for example, pipework may have become loose when left empty for a period of time.

As well, owners and managers should talk with their maintenance contractors about the specific process to be followed to comply with their respective state’s legislation. In New South Wales, for example, Hauser says legislative requirements specify a defined shutdown procedure is to be observed and implemented for any system shutdown.

By contrast, systems which are only partially shutdown or operated at reduced capacity still need to be maintained. This might involve regular inspections and maintenance, chemical analysis, water testing, documentation of actions and subsequent remedial work.

Next, the building’s cleaning regime should be reviewed to ensure that this is adequate. A common misconception, Hauser says, is that cleaning is not necessary when buildings are not occupied. For reasons outlined above, this is not correct. Whilst it may be possible for cleaning to be wound back, he says regular cleaning is still needed to prevent infestations of pests and ensure a clean workplace is available if and when it is reoccupied.

Before reopening, building owners and managers should engage with cleaning contractors to ensure that cleaning regimes and methodologies are adequate to address risks associated with COVID-19 and other harmful bacteria which can be present on surfaces. Particular attention should be paid to high-touch areas such as handles, doors and seating.

Finally, general inspections of buildings undertaken by the building manager, security, cleaners, etc. are still needed to identify issues such as the carpark related matters referred to above.

Throughout Australia, many buildings have had to be fully or partially shut down.

Whilst this is happening, care is needed to manage and address risks which may occur.