New regulations apply to roof-mounted evaporative coolers to prevent bush fire attack

Bushfire planning regulations in Western Australia changed from 8 April 2016. If you live in a bushfire-prone area, a significant number of new regulations have been implemented which you must now comply with. WA BAL Report can assess your requirements and advise you on how to protect your home from bushfire attack.

Included as part of the new regulations is the requirement that new roof-mounted evaporative coolers installed on residential buildings located in bushfire-prone areas must now be fitted with non-combustible covers. Although it is not mandatory to upgrade existing roof-mounted evaporative coolers, it is recommended you consider retrofitting options for non-combustible covers. The Department of Fire and Emergency Services (DFES) has identified that roof-mounted evaporative coolers are at risk of catching fire if burning embers penetrate unprotected gaps and ignite the air conditioner’s cooling pads. Once this occurs, there is a strong chance that the fire burning in the ceiling will spread to the rest of the house.

The installation of roof-mounted evaporative coolers in bushfire-prone areas must comply with Australian Standards AS3959. If you are installing a roof-mounted evaporative cooler in a bushfire-prone area, you must have your property assessed for its level of risk from bushfire attack, to determine the required level of protection for your evaporative cooler. The following requirements apply based on your bushfire attack level (BAL):

  • BAL-Low – no requirements
  • BAL-12.5 to BAL-29 – the cooler must be fitted with non-combustible butterfly closers as close as practicable to roof level, or alternatively be fitted with a non-combustible cover with a mesh or perforated sheet with a maximum aperture of 2mm, made of corrosion resistant steel, bronze or aluminium. The unit must be adequately sealed to the roof with non-combustible material to prevent gaps greater than 3 mm.
  • BAL-40 and BAL-Flame Zone – you must obtain a building permit from the permit authority to install a roof-mounted evaporative cooler, as the Building Code does not permit the installation of a roof-mounted evaporative cooler unless it meets test criteria or an alternative solution has been developed. You should discuss these requirements with a registered building surveyor.


Whether a cover is acceptable depends on the material of the body of the evaporative cooler, which is usually either plastic (combustible) or metal (non-combustible). If the unit is plastic and does not have a butterfly closer, it must be fully encased in non-combustible covers, not simply covering the air intake areas. A butterfly closer is a valve fitted inside the unit that opens when the unit is running and closes when the fan is turned off. It prevents any fire from an ignited evaporative cooler from entering the roof. A metal unit not fitted with a butterfly closer must be fitted with non-combustible ember protection screens covering the air intake areas.

For more information

WA BAL Report are experts at conducting Bushfire Attack Level Assessments, Bushfire Attack Level Reports and bushfire prevention strategies in general in Perth and Western Australia. For more information, contact our friendly staff on 08 6114 9356 or at

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