as 3959 bushfire attack level (bal) compliance report ... bal rating recommended setback to achieve

Download AS 3959 Bushfire Attack Level (BAL) Compliance Report ... BAL rating Recommended setback to achieve

Post on 15-Oct-2020

0 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Level 1, 50 Subiaco Square Road, Subiaco, WA 6008 P.O. Box 243, Subiaco, WA 6904 Phone: (08) 9380 3100 Fax: (08) 9380 4606 177 Spencer Street, Bunbury, WA 6230 P.O. Box 287, Bunbury, WA 6231 Phone: (08) 9792 4797 Fax: (08) 9792 4708

    Email: info@strategen.com.au Web: www.strategen.com.au ABN: 32 056 190 419

    To: Daniel Calderwood Date: 13 July 2018

    Company: Cedar Woods Properties Limited Project No: CED18260.01

    Email: Daniel.Calderwood@cedarwoods.com.au Inquiries: Zac Cockerill

    AS 3959 Bushfire Attack Level (BAL) Compliance Report Stage 1B Millars Landing, Baldivis

    Site Details

    Address: Lots 1–36 and 38–42, Stage 1B Millars Landing

    Suburb: Baldivis State: Western Australia Local Government Area: City of Rockingham Description of building works: Class 1a buildings with associated Class 10a buildings

    Report details

    Report/Job number: CED18260.01 Report reference: CED18260_01 R002 Rev A Assessment date: 10 May 2018 Report date: 13 July 2018 Endorsement/Review Zac Cockerill BPAD Level 2: 37803

    Introduction

    This Bushfire Attack Level (BAL) compliance report has been prepared for 41 residential lots within Stage 1B Millars Landing (hereon referred to as the project area), located in Baldivis, City of Rockingham.

    This report provides a post-subdivisional works update of the BAL ratings for individual lots within the project area and has been prepared for the benefit of the developer, future lot purchasers and decision- makers. BAL certificates for each individual lot have been prepared based on the final site compliance check and are appended to this report for use at the building permit stage.

    The BAL assessment outlined in this report is the most up to date assessment relating to the project area and therefore supersedes any previous BAL assessments undertaken within the project area, including previous BAL contour mapping contained in Bushfire Management Plans (BMPs) prepared by RUIC Fire (2017) to accompany both the Structure Planning and Stage 1B subdivision planning applications.

    This BAL compliance report also takes into consideration the proposed landscaping, drainage and planting regime detail outlined in the most up to date versions of the relevant landscape concepts for POS Areas 1 and 2 to account for the reintroduction of classified vegetation and associated BAL response.

    The approach for preparation of this BAL compliance report is consistent with Section 4.2 and Appendix 3 of Guidelines for Planning in Bushfire Prone Areas.

    The BAL compliance assessment has been completed by a Level 2 accredited Bushfire Planning and Design practitioner (Zac Cockerill, BPAD37803) in accordance with Method 1 of AS 3959–2009 Construction of Buildings in Bushfire-prone Areas (AS 3959) and results are consistent with on-ground conditions observed at the time of inspection on 10 May 2018.

    Should subdivision design or the classified vegetation extent be further modified prior to building construction, then an updated BAL assessment for the affected lots may need to be undertaken to account for these changes.

  • AS 3959 Bushfire Attack Level (BAL) Compliance Report

    CED18260_01 R002 Rev A

    13-Jul-18 2

    BAL compliance assessment

    Results of the BAL compliance assessment are provided in Figure 1 in the form of a BAL contour map and a summary of assessment inputs are provided in the following subsections.

    Fire Danger Index

    A blanket rating of FDI 80 is adopted for Western Australian environments, as outlined in AS 3959 and endorsed by Australasian Fire and Emergency Service Authorities Council.

    Classified vegetation

    The spatial extent of classified vegetation and exclusion plots are depicted in Figure 1, along with site photo points to validate site observations. The photo points depicted in Figure 1 relate to the georeferenced site photographs provided in Appendix 1.

    Subdivisional and landscaping works have or will result in the following classified vegetation and exclusions within and adjacent to the project area:

    • Class B woodland (Plot 1) occurs to the west, northwest and southwest of the project area comprising mixed open canopy eucalypts or banksias over low shrubs or grass

    • Class G grassland (Plot 2) occurs to the southwest of the project area throughout cleared, unmanaged areas

    • Class D scrub (Plot 3) occurs to the far southwest of the project area comprising revegetated verge areas of Baldivis Road

    • POS 1, situated east and southeast of the project area, is currently excluded from classification under a combination of Clause 2.2.3.2 (b) for the central wetland area (Plot 5) and Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

    • following full implementation of POS 1 landscaping works as per Appendix 2, future exclusions for POS 1 will include a combination of Clause 2.2.3.2 (b) for the central wetland area (Plot 5), Clause 2.2.3.2 (c) for the two small drainage basins situated either side of the central wetland area (Plot 6) and Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

    • POS 2 situated north of the project area is currently excluded from classification under a combination of Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

    • following full implementation of POS 2 landscaping works as per Appendix 2, future classified vegetation for POS 2 will include Class G grassland throughout planted drainage areas (Plot 2) and future exclusions will include a combination of Clauses 2.2.3.2 (e) and (f) for any non- vegetated or low threat managed areas (Plot 4)

    • all proposed residential lots and road reserves are in a cleared, non-vegetated state and are excluded from classification under Clause 2.2.3.2 (e) (Plot 4)

    • 100 m wide staging buffers, as documented in the RUIC (2017) BMP, have been implemented where possible within future development areas adjacent to the project area and are excluded from classification under a combination of Clauses 2.2.3.2 (e) and (f) for any non-vegetated or low threat managed areas (Plot 4)

    • adjacent land beyond the 100 m wide staging buffer (particularly to the north), has been classified as Class G grassland (Plot 2) due to the unmanaged status of these areas.

    Effective slope

    All current and future areas of classified vegetation occur on flat land (i.e. effective slope of 0 degrees) as depicted in Figure 1.

  • AS 3959 Bushfire Attack Level (BAL) Compliance Report

    CED18260_01 R002 Rev A

    13-Jul-18 3

    BAL calculations

    The BAL impact to the project area has been assessed in the form of BAL contours, utilising assessment results as outlined above. Results of the BAL contour assessment are outlined in Table 1 and depicted in the BAL contour map (Figure 1).

    Table 1: BAL contour assessment Classified vegetation Effective slope BAL contour width (m) BAL rating Comment

    Class B woodland Flat/ upslope

  • AS 3959 Bushfire Attack Level (BAL) Compliance Report

    CED18260_01 R002 Rev A

    13-Jul-18 4

    Lot number

    Current separation distance

    Current BAL rating Recommended setback to achieve lower BAL

    New BAL rating*

    28 14 m BAL-29 6 m front setback BAL-19

    29 14 m BAL-29 6 m front setback BAL-19

    *The new BAL rating in Table 2 can only be confirmed once the building plan for the relevant lot has been prepared to demonstrate compliance with the recommended setback. Once the setback has been confirmed, a new BAL certificate for the lower BAL rating can be prepared and issued to accompany the building permit application.

    Conclusion and recommendations

    This BAL compliance report has been prepared for 41 residential lots within Stage 1B Millars Landing to provide a final BAL check for individual lots for use at the building permit stage. Assessment results are consistent with current on-ground conditions observed at time of inspection on 10 May 2018 and account for future areas of classified vegetation within POS. From these results, Strategen can confirm that the existing BMPs over the site (RUIC 2017) have been implemented as intended throughout the duration of subdivisional works to achieve the bushfire management outcome as planned for in these documents.

    In the absence of any change in development design or post-development classified vegetation extent that has not already been accounted for, Strategen considers that the BAL assessment and BAL certificates outlined in this report are accurate to inform individual lot building permit applications.

    Should the extent of classified vegetation change or new vegetation be introduced within 100 m of proposed development that has not already been accounted for, then the BAL should be reassessed at the building permit stage to ensure accuracy with on-ground conditions.

    Should it be determined through demonstration on the building plan that compliance with the recommended building setbacks has been achieved and subsequently a lower BAL rating has been achieved (as per Table 2), then the lower BAL rating should apply and be reflected in an updated BAL certificate prepared at that time.

    The BAL assessment outlined in this report is the most up to date assessment relating to the project area and therefore supersedes any previous BAL assessments undertaken within the project area.

    Ongoing r

Recommended

View more >