Fire Safety

Stronger fire protection requirements for external structures in NSW are being missed by some timber suppliers, but the Rural Fire Service is available to help.

Timber merchants are generally good about regulation. They know the product they sell has to be fit for purpose, and educate themselves on the relevant Australian Standards and other codes.

But in NSW, some suppliers have missed an amendment by the Rural Fire Service (RFS) that applies to decking among other external timbers.

Jason Israel of Toronto Timbers flagged the issue with TTN. He says, “We’re in the Newcastle area, so people up our way are quite aware of fire safety when it comes to timber for construction. But as I travel around the Greater Sydney area, I see a lot of people who are selling BAL-19 timbers for decking. They’re going by the Australian Standard, but they’re missing the fact there’s an RFS amendment that means all those timbers should be BAL-29 at least.”

Mark Hawkins, Development Planning and Policy officer at the Rural Fire Service, spoke with TTN to explain the situation.

“After the 2009 Victorian bushfires, the Australian Standard 3959 was changed to become the 2009 version of that standard. When it did, the RFS decided that some of the protection in the new standard had left out crucial protection components,” Hawkins says.

For certain elements, such as decking and other house-surrounding elements on the horizontal plane, it was decided that the protection afforded by the previous standard should be implemented.

“We prepared an Addendum Appendix (3) for our Planning for Bushfire Protection (PBP) guide,” says Hawkins, ”and ever since then we have asked for the requirements for certain elements of the Australian standards, largely decking timbers and some other ancillary items, in BAL-12.5 and BAL-19 to be raised to BAL-29 for compliance.

“We used our stakeholder relationships to have the National Construction Code, which sits above the building code of Australia and then sits above AS 3959, reference the PBP details because it provides a higher level of protections. The new NCC came in on 1 May and in NSW it has a state-specific variation which references the new PBP.”

The whys and hows

The reason for the focus on decking timbers is that they represent a particular risk to homes in the event of an approaching fire.

“There’s a real focus on the first 400mm above any horizontal surface,” says Hawkins. “The big provision with damage from bushfires is the ember attack. Embers fly through the air and at some point they drop out of the air and the wind is going to continue to push them. They become basically an ember shower, roughly within the first 400mm of the ground, and they’ll roll along the ground at terrific speed because if you’ve got a terrible bushfire, you’ve usually got a terrible wind.

“That first 400mm is where a lot of the damage has been recorded, and that’s why the standards focus on extra protection at that first 400mm.”

The legislation is confusing, particularly because some parts have not yet gone through the NSW parliament (see below) but for builders seeking to meet the standards, things are much simpler.

PBP has a deemed to satisfy process, or, for those who want to take the option of going by performance, RFS has the capacity within legislation to be able to send any performance measures for approval. “We have the pre-release of PBP-2019 on our website,” says Hawins. “A lot of it has changed, a lot of science has been put into it and it can be used as a performance solution.”

“We are currently working closely with the Department of Planning and Environment (DPE) to finalise and legislate PBP-2019 and anticipate that will occur in September 2019,” Hawkins says. “Until the new PBP is published and legislated, the current 2006 edition of PBP will remain in force. The transitional arrangements that were put in place when the pre-release version of PBP 2018 was published have been extended. Proposals that comply with the requirements of the pre-release version of PBP 2018 can still to be considered as a performance solution that complies with PBP 2006.

“The 2019 edition of the National Construction Code (NCC) came into effect on 1 May 2019 and references AS3959:2018. As PBP 2006 remains legislated in NSW, AS3959:2009 will continue to be referenced by PBP (as modified by Addendum Appendix 3). This means that currently, to comply with PBP 2006 the requirements of AS 3959:2009 will need to be satisfied. However for any Complying Development Certificates or Construction Certificate lodged on or after 1 May 2019, the plans and specifications will still need to show compliance with AS 3959:2009.”

Any questions about Planning for Bush Fire Protection can be sent to PBP2018@rfs.nsw.gov.au. The following is the wording from the soon to be available PBP-2019.

7.5 Additional construction requirements

To ensure the performance criteria for construction standards given in section 7.5.1.1 can be met, PBP adopts a suite of additional measures over and above AS 3959:2009 and the NASH Standard as follows:

construction measures for ember protection at the lower bush fire attack levels (BAL-12.5 and BAL-19) provided by AS 3959;
construction measures for development in the Flame Zone; and
requirements over and above the performance criteria contained within AS 1530.8.1 and AS 1530.8.2 apply in regards to flaming.

7.5.1 Ember protection

Based on a review of AS 3959 and through the findings from the 2009 Victorian Bushfires Royal Commission, PBP aims to maintain the safety levels previously provided by AS 3959:1999 in relation to ember protection at lower bush fire attack levels.

In particular, the areas addressed are in relation to:

sarking
subfloor screening
floors
verandas, decks, steps, ramps and landings
timber support posts and beams
fascia and bargeboards

7.5.1.1 NSW State Variations under G5.2(a) (i) and 3.10.5.0(c)(i) of the NCC

Certain provisions of AS 3959-2018 are varied in NSW based on the findings of the Victorian Bushfires Royal Commission and bush fire industry research.

The following variations to AS 3959 apply in NSW for the purposes of NSW G5.2(a)(i) of Volume One and NSW 3.10.5.0(c)(i) of Volume Two of the NCC.

(i) clause 3.10 of AS 3959 is deleted and any sarking used for BAL-12.5, BAL-19, BAL-29 or BAL-40 shall be:

a) Non-combustible; or
b) Comply with AS/NZS 4200.1, be installed on the outside of the frame and have a flammability index of not more than 5 as determined by AS 1530.2 and

(ii) clause 5.2 and 6.2 of AS 3959 is replaced by clause 7.2 of AS 3959, except that any wall enclosing the subfloor space need only comply with the wall requirements for the respective BAL; and

(iii) clause 5.7 and 6.7 of AS 3959 is replaced by clause 7.7 of AS 3959, except that any wall enclosing the subfloor space need only comply with the wall requirements for the respective BAL; and

(iv) Fascias and bargeboards, in BAL 40, shall comply with: