BUILDING IN BUSH FIRE ZONES - FIRE RESISTANCE LEVELS - FRL
When assessing materials for use in building in bush fire zones architects, engineers and designers are guided by the fire resistance levels given for such materials. Fire resistance levels are determined when materials are tested in accordance with AS 1530 4-1990 and are expressed as Fire Resistance Level (FRL) SA/INT/INS or (for example) 60/60/60.
SA refers to structural adequacy; the ability of a material to maintain its stability and load bearing capacity expressed in minutes. In the above example if the SA is 60 then the particular material will theoretically last for 60 minutes in a fire before collapsing. INT refers to Integrity; the ability of a material to resist flame in a fire. In the above example if the INT is 60 then the material will last for 60 minutes before flames penetrate through it. INS refers to Insulation; the ability of a material to maintain a certain temperature below specified limits on the opposite side of a fire. In the above example if the INS is 60 then the opposite side of the material to the fire or flame or heat will remain at non dangerous levels for 60 minutes in a fire.
While these testing methods and procedures appear to be adequate for testing the potential of materials to resist heat and flame the question has to be asked about the ability to resist impact loads when, for example, a roof catches fire and the structural members collapse?
When a bush fire is raging the rate of travel is determined by the prevailing wind conditions. In high winds the fire moves fast with flames, embers and heat moving forward of the main fire. When a building is exposed to a moving fire and the embers created by the fire, the roof is usually the first part of the building to catch fire. Embers ingress via openings and gaps in the eaves structure and via openings and gaps in the cladding joints, ridges, hips, valleys, flumes and other penetrations. When the roof starts to burn the structural members such as the rafters, hips, valleys and struts are immediately weakened and in a short period of time begin to twist, craze and burn before eventually collapsing.
Once this happens the ceiling system and ceiling linings are exposed to impact loads from falling debris. As a consequence they too collapse or fail and the resulting outcome is that the fire literally falls into the habitable areas of the building where more fuel is available for the fire to burn out the inside of the building.
The consequences of this can be quite devastating. Property is lost and even lives can be lost. When designing a home for building in bush fire zones contact us for a free appraisal of your design.
BUILDING IN BUSH FIRE ZONES FROM THE ROOF DOWN
FIRE BARRIER CEILING
By using a fire rated ceiling barrier the incidences of roof collapse resulting in fire ingress into the habitable areas of a building are greatly reduced, if not eliminated. Using a fire rated ceiling barrier in terms of structural adequacy can be achieved to FRL 240 minutes which is four times greater than most conventional fire rated framing and lining systems.
When designing buildings and new homes that are to built in high risk fire zones the people at Quantec utilize a diverse and wide range of ceiling barriers to protect against destruction from fire. The designs incorporate aesthetic properties so that to the eye they look no different from conventional systems and are easy to install and require little maintenance.
If you are thinking about build in bush fire zones and you want to limit the risk associated with losing property and even lives in the event of a bush fire then fill out a contact form below to see how we can assist you.
You can also call us on 0434 089 871