Solar panels in WA bushfire-prone zones: BAL ratings and installation requirements

If your Perth or WA property sits in a mapped bushfire-prone area, your solar installation has to meet Bushfire Attack Level (BAL) requirements under Australian Standard AS 3959, on top of the normal WA building rules everyone else follows. In practice this mostly changes what goes under and around your panels: how the mounting gap is sealed, whether ember-resistant mesh is fitted, and how cables and junction boxes are protected. The higher your BAL rating, the more of this applies, from BAL-12.5 (some ember protection) up to BAL-FZ, the flame zone, which is the most restrictive band.

None of it rules out solar. Three things decide what you actually need: your BAL rating, which requirements apply at that rating, and whether your installer already works in bushfire zones. Sort those out before comparing quotes and you sidestep the two costliest surprises: a system that needs partial rework, or a Certificate of Compliance your insurer won't accept.

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What is a Bushfire Attack Level (BAL)?

BAL ratings measure how exposed a building is to ember attack, radiant heat, and direct flame contact during a bushfire. Four things drive the calculation:

• Vegetation type and proximity
• Slope of the land
• Local fire weather, which WA's climate factors into
• Distance from the property boundary to vegetation

BAL ratings, from lowest to highest risk:

For solar installations, BAL-12.5 and above bring specific requirements into play.

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How do I check my property's BAL rating?

Step 1: Check your building permit documentation. If your home was built more recently within a mapped bushfire-prone area, its original building permit is more likely to already reference a BAL rating. Dig out those documents before assuming you need a fresh assessment.

Step 2: Use local government planning maps. Many Perth Hills and outer metropolitan councils (Kalamunda, Mundaring, Armadale, Serpentine-Jarrahdale, Swan) publish bushfire hazard maps online. Search "[council name] bushfire hazard map" to find the relevant planning portal.

Step 3: Commission a BAL assessment. A formal BAL assessment has to be carried out by a competent person under AS 3959, usually a bushfire consultant or your local planning authority. If your property sits in a designated bushfire-prone area, planning approval requires one.

Which Perth areas usually need a BAL assessment?

• Perth Hills suburbs: Kalamunda, Mundaring, Roleystone, Byford, Serpentine, and similar
• South-West towns: Margaret River, Dunsborough, Bridgetown, Manjimup, and similar
• Any property next to unmanaged vegetation reserves
• Homes on elevated slopes facing the prevailing fire weather direction

Central Perth metropolitan areas are generally BAL-LOW. Ratings climb as you move into the Hills.

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What solar installation requirements apply at each BAL rating?

BAL-LOW. No specific solar requirements. A standard installation applies.

BAL-12.5 to BAL-29. AS 3959 requires panels at these ratings to limit the gap between the panel and the roof surface, with ember guards preventing debris building up in that gap. In practice, that means:

• Non-combustible mounting materials. Aluminium rails are standard and typically compliant.
• Restricting the gap between the panel underside and the roof cladding, so embers can't lodge there.
• In some interpretations, mesh guards under the panels to stop leaf and debris buildup that could catch embers.

BAL-29 to BAL-40. More stringent ember-entry prevention applies. Installations at this band typically add:

• Non-combustible wire mesh under all panels, covering the panel-to-roof gap.
• Sealed conduit and cable entry points, so embers can't get in through them.
• Non-combustible junction boxes.

Ember guard mesh, defined: non-combustible wire mesh with a gap no larger than 2mm, fitted under panels and over roof penetrations to stop wind-blown embers lodging in the gap during a fire.

BAL-FZ. Solar installation gets significantly harder. Standard construction requirements for the building itself are already extremely demanding at BAL-FZ, and a solar install may be impractical or need significant engineering assessment. BAL-FZ properties are relatively rare, but WA has some.

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What should solar buyers in bushfire zones actually expect?

Raise BAL compliance at the quoting stage. Not every Perth solar installer works in bushfire-prone zones regularly. If your property sits above BAL-LOW, confirm your installer knows AS 3959 solar compliance and can deliver a compliant install.

Ember mesh is common practice, and it adds to the price. Installers working in BAL-29 and BAL-40 zones typically fit non-combustible mesh under the panels to stop embers building up behind them. Whether mesh under solar panels specifically is a strict AS 3959 requirement, or standard installer practice applying the standard's general ember-entry principle, is interpreted differently across the industry, so ask your installer and building surveyor to confirm what applies to your rating. Either way, budget for it: expect a few hundred to around a thousand dollars on top of the base install, depending on system size, roof access, and the mesh spec used.

Panel location on the roof matters. Roof cladding requirements under AS 3959 vary by BAL zone. Tile roofs, terracotta or concrete, carry their own requirements at higher ratings, on top of the usual mounting considerations for tile roofs. Roofing condition matters too: cracked or missing tiles near panels can create gaps that fail ember protection requirements.

Battery placement matters here as well. A battery kept in a garage or on an external wall in a BAL zone should follow the same ember-and-fire-construction thinking as the rest of the build, kept clear of direct ember exposure. Our guide to where to install a home battery in Perth covers the wider placement rules, and home battery safety in Perth goes deeper on the fire-safety side. Ask your installer how bushfire-zone rules interact with that general placement guidance.

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Does home insurance affect solar in a bushfire zone?

Several major Australian insurers restrict where solar batteries can sit inside homes, garages, or relative to a dwelling, particularly for properties in bushfire-prone areas. Our guide on does home insurance cover solar panels in Perth covers the wider policy picture; the points below are specific to bushfire zones. Check your home and contents policy before installation:

• Is your battery's brand and model listed as approved?
• Does the policy set a minimum clearance between the battery and anything combustible? Clearance rules vary by insurer and by the installation standard applied, so check the figure in your own policy rather than assuming a distance.
• Does the policy require a fire-rated enclosure for battery storage?
• Does adding solar or a battery require you to notify your insurer?

Failing to notify your insurer of a solar or battery installation can affect a claim.

Bushfire risk is one of several WA weather factors worth checking before you sign. For the hail and wind side of things, see our guide to solar panels and storms in Perth.

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What should I ask installers if I'm in a BAL zone?

When you're getting quotes for a property in a bushfire-prone zone:

1. Confirm your property's BAL rating, even an approximate one, before installer visits.
2. State the BAL rating explicitly in your quote request.
3. Ask whether the quoted price includes AS 3959 ember guard provisions.
4. Request confirmation that the installer will certify compliance on the Certificate of Compliance (the electrical safety certificate).

A quote that doesn't mention BAL compliance for a rated property is probably not pricing it in, which can mean rework costs later or a non-compliant installation.

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This guide covers the general framework. BAL assessment and AS 3959 compliance are property-specific. Always confirm requirements with a licensed installer and your local government's planning authority before proceeding.