Bushfire Management Overlay mysteries revealed.

Responding to comments and questions raised by my posting concerning garden sheds and the BMO on 18 February 2014, I decided that my response may interest others grappling with the BMO.

The issues raised were: 

• We have been informed that the current BMO will stop us from building all together! Not even a shed. 
•  We cannot meet current guidelines for defendable space so cannot even obtain a BAL rating.

On not being able to meet "current [BMO] guidelines":

Concerning not being able to meet "current [BMO] guidelines", how did you learn that, did you have a permit application with BMO statement formally refused? Or did someone tell you that without actually responding to a draft BMO statement e.g. council planner or CFA representative? Did a well-intended neighbour pass on their experience or was it based on "Chinese whispers"? 

There are two (2) methods to achieving the defendable space, hence the bushfire attack level (BAL); refer to Mandatory Standard BF6.1 in clause 52.47 Bushfire Protection:Planning Requirements (click here) in a Planning Scheme — defendable space is defined (page 4) in the CFA’s “Planning for Bushfire Victoria”

Both assessment options are explained in Appendix 1:Bushfire Site Assessment, page 6 in the Department of Planning and Community Development “Practice Note 65, November 2011, Bushfire Management Overlay and bushfire protection: planning requirements”(click here).

CFA representatives across Victoria, including the CFA head office element, vary in their acceptance of the use of the "alternative method".

Unfortunately, a refusal to accept the "alternative method" allowed in BF6.1 may deny approval where a site specific-approach could see an acceptable BAL achieved where defendable space according to Table 1 in clause 52.47 (page9) cannot be achieved.

Another reason to apply the "alternative method" could be where bushfire has not affected vegetation over many years and the natural state of that vegetation does not require the extent of the default defendable space. Here, the "alternative method" of assessment could assist when seeking to comply with the requirements of Standard BF4 under the heading 52.47-4 Siting and layout objective (click here) concerning “avoiding or minimising the removal of vegetation”.

Calculating the actual fire intensity at various approaches to the dwelling site, taking into consideration the effect of slope and actual fuel load (vegetation) can reduce the area of defendable space required in some circumstances. An example is where there is significant upslope above the dwelling site. Fire travels downhill slower and its intensity is reduced compared to when it crosses flat ground or runs up a hill. Hence the value of the “alternative method” according to Mandatory Standard BF6.1 in clause 52.47.

On a permit for a shed:

Concerning a shed, I refer to this paragraph in the second last paragraph of my 18 February posting:

On page two of Practice Note 65 under the heading “How does the BMO regulate new development?” the first paragraph:

Where the BMO applies to land, a planning permit is required to construct a building or construct or carry out works associated with land uses that are likely to increase the number of people in the overlay area.

If there is a formal refusal to an application for a permit to erect a shed without any dwelling on the land then there's probably a suspicion that you want to use the shed as a dwelling. But only an assumption on the part of the planner in my view, as the shed could have been required to house equipment to maintain your land and not increase the number of people on the land on a permanent basis.

Mode of bushfire attack

To conclude, it's important to understand that some land may never see a fire front to the extent I suspect was envisaged by the architects of the BMO and that's an issue in itself.

This story “Mountain highs” in a recent edition of The Age (click here) by a new resident in the bushfire-notorious Dandenong Ranges has a comment by a member of the CFA concerning bushfire on the resident's land:

The inspection wasn't all bad news. Apparently, we're unlikely to ever face a fire front. But the embers. The embers. They could fly up from anywhere around these parts, including from nearby Devil's Chimney. We cringed at that name and tried to listen to Dan's advice.

Without knowing the exact location or status of the land referred to in The Age story, there will be many locations across Victoria covered by a BMO that may never see a fire front and that's the advantage of the "alternative method" of assessment.

I’ll come back to the mythological "Devil’s Chimney" in a future posting on fire behaviour and also discuss matters in the CFA's "Planning for Bushfire Victoria" that seem to unnecessarily complicate and add cost to satisfying the BMO requirements when seeking a planning permit.

As always, the above are my views that others may disagree with. Consequently, you should use what I have said above as a guide and do your own research. To help I have given useful links to "government" documents applying to the BMO.