BAL stands for Bushfire Attack Level and represents a scale used to determine a building’s risk of catching on fire. However, as the name suggest, the scale is specifically concerned with bushfires. A BAL is used in the assessment of constructing buildings in areas which are likely to experience bushfires. In basic terms, when a proposed building BAL rates low on the scale there are no related restrictions on construction. However, each rating after BAL Low will mean that you must adhere to construction requirements. There are six BAL ratings in all, which are detailed below.
BAL Ratings Explained
BAL ratings dictate both the construction methods and materials used in bushfire prone areas. The purpose of BAL ratings is to help prevent bushfires from destroying buildings and spreading to other areas. Each BAL rating is assumed to carry the same risks as the previous rating, as well as additional risks. As such, it is important to ensure that new and existing buildings are constructed according to BAL rating requirements.
BAL Low – No significant risk. No Construction requirements
BAL Low suggests that there is insufficient risk of fire from embers, radiant heat or flames. There are no construction requirements for a BAL Low rating; however, you can use BAL 12.5 construction requirements if you are still concerned that your home may be at risk.
BAL 12.5 – Ember Risk
This rating carries a sufficient enough risk of fire from embers or burning debris to warrant construction requirements. However, BAL 12.5 does not signify enough heat to affect windows or other building elements.
BAL 19 – Increased heat flux, and possibility of debris igniting due to increased embers
When BAL 19 is reached, there is sufficient cause for concern due to increased radiant heat and ember attack. Building elements are subject to construction requirements to prevent damage and spread of fire. BAL 19 can be reduced by removing elements which increase the risk of radiant heat.
BAL 29 – Increased heat flux, burning debris and risk to building integrity
Buildings which are rated as BAL 29 are at serious risk of catching on fire due to burning debris and increased heat flux. There is also a risk of the building becoming exposed to flames. Ember and radiant heat protection are required in the construction of buildings that are rated BAL 29.
BAL 40 – Increased exposure to flames
BAL 40 carries all the risks of BAL 29 except that the risk of exposure to flames is now significantly increased. Construction requirements include using materials that are highly resistant to flames. Eliminating elements which promote the spread of flames, embers and radiant heat is also recommended.
BAL FZ – Direct contact with flames
BAL FZ – or Flame Zone – represents a direct threat to buildings and residents. Significant protection is required to reduce the threat, such as radiant heat barriers and modifications to the building and surrounding property. If at all possible, it is recommended that you do not build your home in a designated Flame Zone.
You can find out more about BAL ratings on the New South Wales Rural Fire Service website. Each BAL rating is also linked to a specific building code. Houspect building inspectors can provide construction advice in line with BAL rating requirements. Bushfires represent a serious risk to buildings and residents in New South Wales. Before you begin construction in a bushfire prone area, contact Houspect that that we can carry out a preconstruction inspection. The more buildings that are protected from bushfires, the less risk to there is for everyone.