Choosing Air Filters for Temporary Accommodation During Bushfire Smoke Events

Bushfire smoke can create difficult conditions for temporary accommodation, especially where guests are staying in close quarters and moving through shared corridors, foyers and lift lobbies. For motel operators, short-stay apartment managers and emergency accommodation providers, the goal is to choose filters that suit the existing system, fit the space available and help capture smoke particles without causing unnecessary strain on the equipment.

The right choice depends on the type of air handling system, the room layout, the expected smoke load and how often the plant can be inspected during the event. In many buildings, the best outcome comes from using the existing ventilation system well, improving filtration where practical and checking that supply air, return air and corridor pressure relationships still make sense for the site.

Start with the building and the system

Before changing filters, it helps to identify exactly what equipment is serving the rooms and shared areas.

Temporary accommodation buildings can vary widely. Some rely on individual split systems, others use packaged units, fan coil systems or central air handling units with ducted supply air. Corridor systems may also be separate from guest room systems, which means the filter choice in one area may not suit another.

Useful questions include:

• •What filter sizes fit the existing frames or housings?
• •Is there enough fan capacity for a denser filter?
• •Are guest rooms and corridors served by the same air system or different systems?
• •Are there access panels that allow safe inspection and replacement?
• •Is the current filter bank in good condition, or does the frame need repair first?

If you are unsure what is installed, it is worth checking the equipment label, opening the access panel where safe to do so, or measuring the filter carefully before ordering. Our guide on how to measure an air filter can help when you need to confirm the dimensions before placing an order.

Match filtration to the smoke problem

Bushfire smoke is made up of fine airborne particles and odorous compounds, so filtration needs to be chosen with both particle capture and system practicality in mind. For many temporary accommodation sites, a staged approach is the most workable option.

Pre-filters and coarse filters

A pre-filter or coarse filter can help protect the main filter and capture larger dust and debris before it reaches the finer stage. This is useful where the building is also dealing with outside dust, open doors, high foot traffic or ongoing cleaning activity.

Common options may include EN 779 classes such as G3, G4 and F5-F9, although these classes have been superseded by ISO 16890. They are still widely used in Australia, so you may see them on existing plant, spare filters or equipment documentation.

Finer filters for smoke particles

Where the system can handle it, a higher-efficiency filter is often considered for smoke events because it can capture finer particles more effectively than a basic dust filter. The exact choice depends on airflow, pressure drop tolerance and the filter housing available.

In some central systems, a finer final filter may be used after a pre-filter. In smaller room units, a compact pleated filter may be the practical limit. The aim is not to overload the fan or reduce airflow to the point where the system no longer performs as intended.

HEPA where it is appropriate

HEPA filtration is sometimes used in specialised temporary accommodation settings, isolation spaces or dedicated clean-air rooms, but it is not suitable for every system. If HEPA is being considered, check whether the plant can accommodate the increased resistance and whether the housing can seal correctly.

For reference, H13 filters are at least 99.95% efficient and H14 filters are at least 99.995% efficient at the most penetrating particle size under EN 1822. Those ratings do not describe every aspect of performance in a real building, so the mechanical services engineer or building owner should confirm whether the site can support that type of filter arrangement.

Think about guest rooms and corridors separately

Guest rooms and corridors do not always need the same filter arrangement. In fact, treating them as different spaces can make the building easier to manage during a smoke event.

Guest rooms

In guest rooms, the main concerns are comfort, airflow and ease of maintenance. If rooms have individual fan coil units or split systems, filters should be selected to suit the specific unit and the available space in the return grille or internal cabinet.

For rooms used as emergency accommodation, it is especially important to keep the system simple for staff to inspect. Filters should be easy to access without complex tools, and spare stock should match the installed size exactly.

Corridors and common areas

Corridors often see more door movement and more air exchange between spaces. A suitable filter in the corridor air handling system can help capture smoke particles before air reaches guest rooms, but the overall pressure balance should still be checked.

If the building is trying to keep corridors under a slight positive or negative pressure for operational reasons, changing to a much denser filter may alter that balance. This is where the advice of the mechanical services engineer matters, along with reference to AS 1668.2:2024 where ventilation requirements are relevant to the site.

Odour control and activated carbon

Smoke management is not only about visible particles. Guests often notice the smell of smoke even when the air looks clearer. In some systems, filters with activated carbon are used to help adsorb odours, but they are not a substitute for particle filtration.

Carbon filters can be helpful where the air handling system has space for a multi-stage arrangement, or where a room unit can accept a compatible insert. They are best viewed as part of a broader response that may include outdoor air management, sealing obvious leakage points and keeping doors and windows closed when external smoke is present.

It is also worth noting that not every carbon product is suited to every application. Product construction, dwell time and the available filter area all affect how suitable it will be for a particular building.

Maintenance during smoke events

During a smoke event, filters can load up quickly, especially where the building is running longer hours or bringing in more outdoor air than usual. That is why inspection matters just as much as the initial filter selection.

Good practice includes:

• •Checking pressure drop where gauges are fitted
• •Inspecting filters more often when smoke loading is high
• •Watching for bypass around frames and seals
• •Replacing damaged or collapsed filters promptly
• •Following the filter and equipment manufacturer instructions

Inspection frequency depends on the system, site conditions and dust load. There is no single schedule that suits every motel, apartment building or emergency accommodation site.

Some filters are designed to be washable - check the product instructions before reusing any filter. If a washable product is not designed for reuse, do not attempt to clean it in a way that could damage the media or release trapped dust back into the system.

Practical stock planning for short-stay operators

Temporary accommodation providers often need a sensible spare-parts plan rather than a large inventory. Keep a small, well-labelled stock of the most common sizes used by the property, along with the details needed to reorder quickly.

It helps to record:

• •Filter dimensions
• •Media type and rating shown on the product
• •Frame style and seal type
• •Which system or room each filter serves
• •The supplier contact details for urgent replenishment

If you manage multiple properties, standardising where possible can reduce confusion during a smoke event, but only where the equipment allows it. Do not assume one filter will fit every unit simply because the dimensions look similar on paper.

Getting the right filters for your site

For motels, short-stay apartments and emergency accommodation, the best filter choice is the one that suits the equipment, the available airflow and the level of smoke control the building needs. If you need help identifying a replacement, discussing suitable media options or arranging a custom size, Total Air Filtration can supply or make the right filters for your site.

We are a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, and we work with hospitality and accommodation operators across a range of building types. To discuss your requirements, call 07 3800 3448 or request a quote. You can also view our products or explore custom air filters for non-standard sizes and applications.