Building a home in an area with high fire danger?Live near a national park or bushland? Or just generally want to improve your home’s resistance to the Australian risk of bushfire?
Brick could help you achieve your goal.
As the primary ingredient for a brick is clay, which is fired at around 1000 degrees Celsius to form the hardened shape that we know and love, brick is considered a non-combustible building material. This means that well-designed and constructed brick walls have an inherently high level of fire resistance when exposed to the extremely high temperatures and flames of a bushfire. Bricks also provide a number of other thermoregulation and energy efficiency benefits.
Adding to the many reasons to choose brick as your building material, insurance companies may even offer discounts on insurance cost for brick homes, due to the fundamental strength and durability of the building material.
With this in mind, lets take a closer look at how building with brick can increase your home’s resistance to the risk of structural damage caused by bushfires:
The Australian StandardsThe National Construction Code (NCC) dictates the requirements for construction in Australia and requires that clay masonry walls be designed and constructed in accordance with Australian Standard (AS) 3700 ‘Masonry Structures’ and that in bushfire prone areas, buildings be constructed in accordance with AS 3959 ‘Construction in bushfire prone areas’.
Understanding fire resistance levelsFire resistance levels (FRLs) are specified in the NCC. This system allows us to predict the ability of a wall to maintain its strength in a fire and to resist the spread of the fire. The FRL specifies the fire resistance periods (FRP) for structural adequacy, integrity and insulation.
The NCC requires that certain walls have a level of fire resistance, expressed as a fire resistance level (FRL) which is given in terms of time (minutes). The purpose of a wall having a high FRL is to help prevent collapse, to prevent toxins from passing through and to prolong the other side from getting hot, so that the occupants inside are given enough time to safely escape in the event of a fire. The FRL for masonry, including clay bricks, can be determined in accordance with AS 3700 ‘Masonry Structures’ or testing via AS 1530.4, Part 4.
PGH Bricks & Pavers’ clay masonry units are all purpose-built to comply with the FRL requirements determined in AS 3700. Also, with clay brick being non-combustible, the clay brick wall is more likely to remain intact after a fire.
Understanding bushfire attack levelsWhen constructing in bushfire prone areas, under AS 3959 the severity of the building’s predisposition to ember attack is expressed as a Bushfire Attack Level (BAL), with Flame Zone (BAL-FZ) being the most severe and having the most severe requirements. The BAL levels are determined by the region where you live, the vegetation type around your property, the distance from your home to individual vegetation types, as well as slope on the property.
When constructing in a BAL-FZ area, the external walls will be required to have an FRL of 30mins. A properly designed and constructed clay brick wall provides greater safety and is also likely to remain intact afterwards given its non-combustibility.
The non-combustibility of bricksDuring manufacture, clay bricks are fired at temperatures as high as or higher than those reached at the heart of a large bushfire and are in the kiln for longer than it takes for the front of a bushfire to pass a given point. It logically follows that bricks themselves are non-combustible, and the perfect choice for helping to protect a home from structural damage caused by bushfires.
The CSIRO survey of houses in the Otway Ranges in Victoria that were exposed to the 1983 Ash Wednesday fires, showed that masonry walls significantly reduced the chances of a house being destroyed by bushfire. The use of bricks also confers a number of other planning and design advantages. For example, full-brick construction is thermally comfortable and energy efficient, while at the same time minimising noise problems and maintenance costs.
For more information or help choosing the right brick for your project, get in touch with one of our friendly PGH staff here or call 13 15 79.
Alternatively, for more information regarding the non-combustibility of brick and how to use it to protect against bushfires, check out Manuals 5 and 15 from industry association, Think Brick Australia.