What does BAL-FZ mean?
This is the highest danger rating that a property can be given regarding bushfires. It also means that the property is likely to be exposed directly to flames from the fire front and is susceptible to attack from embers. Additionally, a heat flux of more than 40kW/m2 can be expected.
Installing flame zone bushfire shutters is the only way to meet the BAL-FZ standards on a property with standard windows.
While the majority of aluminium window shutters offer some level of protection against bushfires, bushfire shutters are specifically designed for this purpose.
Acting as a physical barrier against radiant heat, ember attacks and direct flames, these shutters actively prevent fire from penetrating a building’s interior.
Fire Safety Ratings Defined
Fire safety ratings quantify the performance of standard or bushfire shutters under specific fire conditions. In Australia, you will come across fire rating systems BAL (Bushfire Attack Level) and FRL (Fire Resistance Rating)
These ratings are determined through rigorous testing procedures conducted by accredited laboratories, following internationally recognised standards such as AS/NZS 1530.8.2 and AS 3959.
Window shutters are typically rated using the BAL system and home construction materials using the FRL system.
Bushfire Attack Levels (BAL)
Bushfire Attack Levels or BALs are used to categorise the severity of bushfire exposure that a property may face.
For example, a higher BAL rating would be attributed to a property located close to the bush whereas a property in the middle of the city would have a much lower rating as it is at lesser risk.
In terms of your home, the BAL rating assigned to its location dictates the minimum fire safety requirements for building materials used in its construction. This should also inform your choice of window shutters.
BAL ratings range from BAL–Low (least severe) to BAL–FZ (most severe), with corresponding fire safety standards for shutters.
BAL Ratings for bushfire shutters can be deciphered as follows:
BAL–LOW
Shutters with a BAL–LOW rating are suitable for areas with minimal bushfire risk. They typically have lower fire resistance requirements but still provide basic protection against ember attacks.
BAL–12.5
This rating indicates shutters designed to withstand low levels of radiant heat and ember attack, suitable for areas with moderate bushfire risk.
BAL–19
Shutters with a BAL–19 rating offer increased protection against ember attacks and moderate levels of radiant heat exposure.
BAL–29
Designed for high-risk bushfire zones, BAL–29 shutters provide enhanced resistance to radiant heat, ember attack, and direct flame contact.
BAL–40/BAL–FZ
These ratings signify shutters capable of withstanding extreme bushfire conditions, including intense radiant heat and direct flame impingement.
Fire Resistance Levels
Fire Resistance Levels (FRL) are used to indicate the duration and intensity of fire exposure that a home’s structural components can withstand without failing.
FRL ratings typically consist of three components:
Their capacity to preserve structural integrity in the face of fire is known as structural adequacy. Integrity: their ability to keep heat and flames from escaping Insulation's capacity to lessen heat transmission.
FRLs are expressed using a rating system that represents the fire resistance duration for each aspect and are commonly presented in the format of X/Y/Z, where:
X indicates the fire resistance duration for structural adequacy,
Y represents the duration for integrity, and
Z signifies the duration for insulation.
For example, an FRL rating of 90/60/30 can be interpreted as a shutter, during a fire, being able to maintain structural adequacy for 90 minutes, integrity for 60 minutes, and insulation for 30 minutes.
Shutters
Shutters, in contrast, are not considered an essential but rather an add-on, so a different rating system is applied.
Factors Influencing Fire Safety Ratings
Several factors influence the fire safety rating that can be attributed to standard and bushfire shutters.
This includes things such as the materials used in their construction, how well they are constructed and whether these comply with regulatory standards.
Compliance & Certification
It is important to remember that any shutter that is sold as BAL-rated needs to adhere to all applicable laws and industry standards. This illustrates their demonstrated dependability and effectiveness in the event of a fire. Always seek out businesses that have compliance certification from the appropriate authorized bodies to make sure you are spending your money on bushfire shutters that have been thoroughly tested and proven to be effective.
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