VPELA Fire & Planning

Transcription

1 VPELA Fire & Planning Are We Better Prepared than 6 years ago? Regulations and the Costs of Building in Fire Prone Areas Ken Mival Senior Principal URS 25 November 2014

2 Introduction Content Implementation of New Bushfire Regulations Added costs to Residential Buildings Construction Options in High Danger Areas Actual Implementation in part of Kinglake Ranges Has this made us better Prepared than 6 years ago? 2

3 New Requirements Bushfire Management Overlay (BMO) Building Code Australia - Updated to Include Standards and State Variations - In Victoria only references AS Australian Standard AS Originated as AS Amendments in 2000; 2001; 2009; Feb 2011 and Nov Fire Danger Index taken as 100 throughout Victoria - Introduced concept of Bushfire Attack Levels - BALs Position in landscape; Proximity and type of vegetation; defendable space etc - Identifies suitable materials and construction methods for construction in Bushfire areas 3

4 Summary of Requirements for BAL Levels BAL-Low Very Low Risk - Minimal chance of attack by radiant heat and flames. Requirement for basic property preparation. BAL-12.5 Low Risk - Significant chance of attack by burning debris, such as embers, and radiant heat levels. Some specific construction requirements. BAL-19 Moderate Risk - Significant chance of attack by burning debris, such as embers, and increased radiant heat levels, threatening elements of the building. Construction requirements to protect against such threat. 4

5 Summary of Requirements for BAL Levels BAL-29 High Risk - Significant chance of attack by burning debris, such as embers, and increased radiant heat levels, threatening building integrity. Some flame contact possible. Specific construction requirements to protect against such threat BAL-40 Very High Risk - Increased chance of attack by burning debris, significant radiant heat levels, threatening building integrity. Potential flame contact. Specific construction requirements to protect against such threats. BAL-Flame Zone Extreme Risk - Radiant heat levels and flame attack significant enough to threaten building integrity and result in significant risk to residents. Building must be designed and constructed to withstand extreme heat and flame contact. 5

6 AS 3959 Appendix I added 2011 Tiled Roof 6

7 AS 3959 Appendix I added 2011 Tiled Roof 7

8 Materials Compliance In AS All Materials are now subject to testing under AS Tests on elements of construction for buildings exposed to simulated bushfire attack; Part 8.1 Radiant Heat and small flaming sources BAL 12.5 to 40 Part 8.2 Large Flaming Sources BAL FZ AS 3959 is segregated into sections dealing with each BAL Level Eg Sarking enclosing roof BAL shall have a flammability index of not more than 5 when tested under AS Eg - Timber (Bushfire Resisting Species) eg species that have been tested to satisfy AS/NZS 3837 are: Ash (Silvertop); Blackbutt; Red River Gum; Spotted Gum; Ironbark; Merbau and Turpentine. Wall construction varies with the BAL so for FZ - Non-combustible (eg Masonry; Pre-cast Concrete; Earthwalls including Mudbrick) or a system compliant with AS when tested from the outside. 8

9 Added Costs BAL 2009 Building Commission 2014 Projected Estimates ** Various other Estimates Actual Costs reported ,535 3,000 # 5-20,000 ^6-7, ,535 10,000 #10-20, ,783 20,000 ~12 30, ,615 50,000 * 50,000 ~20 50,000+ FZ 22,108 *100,000+ ~118,000+ Based on Average 3 to 4 Bedroom 2 Bathroom House, double brick, single level # Personal comments on web sites ^ Villawood for minimum protection in Bushfire Zone (2013) ** Projections from Ecotide Bushfire Assessment FAQs * NIBA estimates for likely rebuild costs in FZ after Blue Mountains fires (2013) ~ Reported Costs from Rebuild of destroyed houses ( ) 9

10 Example BAL 29 House Components with approximate added costs: Roofing Sarking Wrap - $ 3,000 Roof 6mm fibre cement panels over frame - $ 1,500 Windows 5mm toughened glass; steel framed - $ 6,500 Windows Fire wire screens - $ 1,000 Security (Self closing doors) - $ 2,000 Firewater storage Tank (min 10,000L) - $ 3,000 Firewater Pump & Generator - $4,000 TOTAL - $21,000 10

11 Example Flame Zone House Components with approximate added costs: Fire Shutters (23) Supply and install - $56,000 One hour FZ Fire Door (Back Door) - $1,000 Roof compliant Fire Blanket (230m 2 ) - $42,000 Firewater Concrete Tank - $10,000 Plumbing Sprinkler system and fire hose points - $5,000 Pump & Generator - $4,000 TOTAL - $118,000* * Total does not include added cost of rammed earth construction chosen for aesthetics and energy saving as well as fire risk reduction 11

12 Building Fabric Options Decisions? Siting of building Slab on Ground (no fire entry below floors) Low Profile Single Story (Less profile to fire front) Flat Roof Single Piece (No angles to accumulate leaf debris and gutters easy to keep clear) Non Flammable Structure (eg Brick, Stone, Steel, Mud brick, Rammed Earth) Fire protection Measures: Fire Resistant Windows, Glass, Frames, Fire wire etc or - Fire Shutters Roof Construction Single piece steel (rather than tiles or multiple components) Roof Protection Sarking, Fire Blanket, & Non-flammable insulation (Rock Wool) Proximity of protected water supplies, generators, pumps with permanent sprinklers that can wet whole house and surrounding area; supplied by concrete/steel water tank close to house Landscaping, Paving, Gravel, Trees, Fire resistant vegetation etc 12

13 Bunkers are one option to save lives 13

14 Structure Options eg Rammed Earth 14

15 Structure Options eg Rammed Earth 15

16 Examples of Rebuilt Houses BAL? 16

17 Examples of Rebuilt Houses BAL? 17

18 Examples of Rebuilt Houses BAL? 18

19 Examples of Rebuilt Houses BAL? 19

20 Examples of Rebuilt Houses BAL - FZ 20

21 Flame Zone Roof 21

22 Flame Zone Roof 22

23 Flame Zone Roof 23

24 24

25 Whole House Fire Blanket Wrap! 25

26 Windows & Doors - Testing of BAL FZ Windows Paarhammer - Radiated heat through the window did not exceed 6kW,which is within the maximum allowed by AS This was reported to be partly due to the choice of fire rated Pyranova glass (by Schott). 26

27 Bal 40 Windows 27

28 BAL 40 Windows and Doors 28

29 Flame Zone Windows 29

30 FZ Windows and Construction 30

31 Fire Shutters Shutters designed by Sonnenschutz were the first to pass BAL-FZ Flame Zone requirements. - The shutters make it possible to use standard windows with 5mm toughened glass for BAL-FZ compliance - They meet AS and the AS test standards Shutters types include: - BAL-FZ shutters in steel for full Flame Zone protection; - BAL-40 compliant shutters in steel or aluminium; or - BAL-29 timber shutters for improved protection of exposed windows BAL-FZ shutters achieve the required compliance level of safety through: - Reinforced steel frame - Steel construction with insulating non-flammable core - Dedicated shutter hardware with multi-point lock/latching that remains intact throughout - Intumescent seals to prevent flame by-passing the shutters 31

32 BAL 29 - Shutters Wooden 32

33 BAL 29 Sliding Aluminium 33

34 BAL 40 and Flame Zone - Steel 34

35 BAL 40 and Flame Zone - Steel 35

36 Story of a Street Forest Road Hazeldene 2009 Black Saturday Flowerdale/Hazeldene 324 Houses 207 Destroyed Forest Road Hazeldene 14 Houses 10 destroyed One person Bob Harrop died defending his property 36

37 Houses Destroyed and those Rebuilt 37

38 BAL 19 to 40 38

39 Actual BAL Levels Rated 39

40 BAL Zones Forest Road Hazeldene Not all BAL determinations make sense Some were initially rated BAL 40 reduced to BAL 29 or 19 with removal of trees The landscape would still define as BAL 40 minimum Mostly BAL FZ avoided because of high costs to comply Much of the vegetation and trees have re-grown over the last 6 years Are we better Prepared? At least one house is. 40

41 Flame Zone Combined Fire Shutters, Roof Fire Blanket, & Rammed Earth Construction 41

42 Pumps, Generators and Sprinklers 42

43 Pumps, Generators and Sprinklers 43

44 References Building Commission A Guide to Building in Victoria after the Bushfires (2009) CFA - Landscaping for Bushfire Garden Design and Plant Selection Australian Building Codes Board National Construction Code Series Building Codes of Australia Standards Australia AS amended 2011 Standards Australia AS &2 44

45 VPELA Fire & Planning Are We Better Prepared than 6 years ago? Regulations and the Costs of Building in Fire Prone Areas Questions?