Windows and doors
This section describes a range of design and construction principles to maximise the bushfire resilience of your window and door systems.
Windows and doors are another vulnerable part of the house. They can allow flame and embers to enter by being left open, being blown open, or through breaks or gaps in their seals and surfaces. Window and door glazing is also vulnerable to breakages, caused by exposure to radiant heat, high wind loads, and direct flame contact. It is also common for debris to build-up around windowsills and door frames, which could ignite during a bushfire.
You should design your home to avoid windows and doors facing hazards. Your window and door systems (including their screen, shutters and glazing) should be designed to prevent collapse, displacement, breach and ignition. As a rule, all exposed components should be made of non-combustible materials, and all fixtures and fittings should be durable and resistant to heat and corrosion.
A home in its final stages of construction
- Face glazing away from hazards where possible.
- Use durable non-combustible materials for windows and doors. Class 1 durability timber could be used to protect against BAL-12.5 (as defined by Australian Standard AS 5604:2005 Timber–Natural durability ratings).
- Sliding windows and windows that extend to the floor must comply with the national building code (see AS 3959:2018 for more information).
- Openable windows should be protected with a metal mesh to protect against ember attack (apertures in the mesh should be less than 2mm).
- Consider installing non-combustible shutters to protect against flame contact, embers, and strikes from and flying objects.
- Doors should be protected with a self-closing screened security door (apertures in the mesh should be less than 2mm).
- Doors should be constructed using a solid core fitted with a metal outer cover.
- Doors and windows should be self-closing in case an unexpected fire threatens the home.
- To prevent occupants from becoming trapped, all doors and windows should be easily opened from the inside without a key.
- Keep windows and doors clear of vegetation and other objects that might burn or block access.
- Ensure that all window and door systems can withstand high wind loads,including the impact of flying debris.
- Seal all gaps larger than 2mm.
- Close all windows and doors when threatened by bushfire – openings provide an entry point for smoke and toxic gases, and will allow flames, embers and radiant heat to penetrate the building’s envelope.
- Do not use combustible cladding materials around windows and doors.
- Avoid combustible frames.
- Do not use combustible reveals between door/window and the wall frame.
- Avoid plastic shutters and flyscreens. These products will melt during a bushfire, creating an additional hazard.
- Do not rely on conventional sarking to protect against flame and ember attack. Conventional sarking products are not suitable as an ember or flame barrier, even if they are rated with a flammability index. The flammability index specifies the threshold at which the material will freely burn, rather than its ability to act as an effective barrier. A small number of specialised sarking products are available which can resist flame and embers attack; pay attention to what your product can do.
Construction and materials
The following table contains information on different window and door systems and the level of bushfire protection they provide. Consider the Bushfire Attack Level (BAL) at the site of your build and use window and door systems that will protect against the predicted level of exposure.
|Type of opening||Material||Frame||Exposure protection – BAL|
|Window||Annealed glass (i.e., standard glass)||Non-combustible material or Class 1 durability timber||BAL-12.5|
|Toughened glass||Non-combustible material||BAL-29|
|Fire rated glass||Non-combustible material||BAL-40|
|Non-combustible material with non-combustible shutter||BAL-FZ|
|Door||Non-combustible material or solid core Class 1 durability timber||Non-combustible material or Class 1 durability timber||BAL-12.5|
|Non-combustible material||Non-combustible material||BAL-29|
|30min fire rated material||30min fire rated material||BAL-FZ|
|60min fire rated material||30min fire rated material||BAL-FZ and consequential fire|