BAL-19: meaning and requirements
BAL-19 is the third of the six Bushfire Attack Levels. It means a building could face radiant heat of more than 12.5 and up to 19 kilowatts per square metre, as well as more embers and burning debris. Its requirements are close to BAL-12.5, with stricter rules for some materials near the ground.
What BAL 19 means
Ember attack gets heavier and burning debris carried by the wind becomes likely. Radiant heat is higher than at BAL-12.5 but still below the point where ordinary building materials start to fail. So BAL-19 keeps BAL-12.5's ember protection and tightens up the parts of the house most likely to catch embers and debris.
What puts a site at BAL-19
Vegetation somewhat closer to the building than at BAL-12.5, or the same vegetation on steeper ground falling away from the house. For many blocks on the edge of bushland or grassland, BAL-19 is the level that comes up.
A BAL determines which construction requirements apply to the building. Your building surveyor or an accredited bushfire practitioner can tell you what they are.
How state rules differ
Same as BAL-12.5: AS 3959 sets the requirements, each state decides where they apply. NSW sets BALs under Planning for Bush Fire Protection. See the BAL calculator by state.
What BAL-19 costs
Usually only a little more than BAL-12.5. The main extra cost tends to be glazing near the ground. Ask your window supplier for BAL-19 rated options early, because it can change which ranges are available.
Getting to BAL-12.5
Moving the building further from the vegetation that sets the level, or siting it so that vegetation isn't on ground falling away from the house, can bring it down to BAL-12.5. See how to lower your BAL. The next level up is BAL-29.
BAL Buddy gives an indicative Bushfire Attack Level (BAL) only. It isn't a determination under any Act, and no council or building surveyor has to accept it. For a BAL you can rely on, use an accredited bushfire practitioner.
Questions people ask
What does BAL 19 mean?
The building could face radiant heat up to 19 kW/m², with heavier ember attack and burning debris. The construction requirements build on BAL-12.5.
What are the BAL 19 requirements?
The BAL-12.5 requirements, plus stricter rules for glazing, timber and other materials close to the ground and near decks. AS 3959 has the full detail.
Is BAL 19 much more expensive than BAL 12.5?
Usually not much. Glazing near the ground is the main difference. The big cost step comes at BAL-29 and above.
Can I use timber decking at BAL 19?
Often yes, with limits. Decking close to the house generally needs to be a fire-resistant timber or a non-combustible material. Check the product's BAL rating with the supplier.