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Fire Safety Directorate

116 Ballarat Road, Maidstone

Fire Date: 21 October 2016

“Reducing the incidence and

impact of fire in the community”

Post Incident Summary Report

DocCentral #1181161-v4 of 21

DISCLAIMER

The Metropolitan Fire and Emergency Services Board and its employees accept no responsibility for any loss or damage, whether direct or consequential, suffered by any person as the result of or arising from the reliance on the statements, information or opinions in this document.

The MFESB is subject to the Information Privacy Principles in the Privacy and Data Protection Act 2014. Pursuant to that Act the MFESB note that this document may contain personal information and as such request that you do not discuss or distribute the contents of this report outside your organisation without first discussing this with the MFESB.

Furthermore, it is not the intention of this report to pass judgement on, or fix liability for, the loss of property or the effects upon the occupants, following the fire.

COPYRIGHT

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means–electronic, mechanical, photocopying, recording or otherwise–without the prior written permission of the copyright owner.

Copyrighted materials reproduced herein are used under the provisions of the Copyright Act (1968) as amended, or as a result of application to the copyright owner.


Document History

Version Draft Final

Comment Issued for internal review Public release

Date Issued 8 November 2016 21 November 2016

Document No. 1181161-v1 1181161-v4

Prepared by T Georgas & S Attard T Georgas

Checked by A Threadwell A Quinton


Table of Contents

1. The Incident ................................................................................................................... 5

2. Building Description ....................................................................................................... 5

3. Fire Cause and Origin .................................................................................................... 9

4. Issues ........................................................................................................................... 12

4.1 Separating wall construction ........................................................................................ 12

4.2 Cantilevered floor construction < 900mm from allotment boundary ............................. 13

5. Recommendations ....................................................................................................... 15

6. Conclusion ................................................................................................................... 16

7. Acknowledgments ........................................................................................................ 17

APPENDIX A ...................................................................................................................... 18

APPENDIX B ...................................................................................................................... 20


1. The Incident

At 7:36AM on the morning of 21 October 2016, the MFB fire-fighters responded to an exchange call for a confirmed structure fire within a recently completed two-storey townhouse development at 116 Ballarat Road, Maidstone. MFB Call History indicated that the adjoining neighbour contacted the MFB after hearing an explosion and witnessing a significant amount of smoke coming from the side of Unit 1. A subsequent caller to 000 also confirmed the visible presence of smoke and flames from the side of Unit 1.

Shortly after receiving notification of the fire incident, MFB fire-fighters were dispatched from Footscray (Station 47), Sunshine (Station 44) and Ascot Vale (Station 50) to the incident. Pumper 47 was first the first to arrive on scene at approximately 7:41AM, with appliances from Sunshine and Ascot Vale arriving shortly thereafter. Fire-fighters made a forced entry into the year yards of Units 1 and 3 and with the protection of charged hose lines and breathing apparatus, they undertook a search of Units 1 and 3 and determined that no residents were home. For precautionary purposes, fire-fighters also evacuated the residents of the adjoining units on the property.

The fire had spread extensively onto both levels of Unit 1 via the separating wall cavity as well as the first floor sub-structures of both Units 1 and 3. This prolonged fire extinguishment operations for almost 90 minutes, until it was brought under control at approximately 10:05AM. During the incident, Victoria Police were forced to block parts of Ballarat Road, being a major highway and vehicular thoroughfare from Melbourne’s west into the CBD, to support fire-fighting operations.

Owing to the severity of the damage sustained by Units 1 and 3, Maribyrnong City Council’s municipal building surveyor (MBS) was requested to attend the property. Subsequent to the MBS’ arrival and inspection, it is understood that both an Emergency Order and Building Notice were issued, which prohibited occupation of the fire affected units, as well as providing directions to make the structures safe.

Officers from the MFB’s Fire Investigation and Analysis Unit investigated the fire incident, which in turn resulted in the removal of the air conditioning compressor unit from Unit 1 for further examination and testing

Upon the restoration of power to the property, the occupiers of the unaffected units were allowed to return to their residences at approximately 12:53PM.

2. Building Description

The property consists of 5 double storey attached residential townhouses of a Class 1a building classification.

Access to the residential townhouses is provided via a privately owned pedestrian footpath that connects Ballarat Road to the south and a ROW to the north.


The townhouses are separated from each other using a proprietary autoclaved aerated concrete fire rated separating wall system that achieves a 60/60/60 fire resistance level (FRL). The roofing cladding materials mainly comprise sheet metal roofing. The floors are constructed on reinforced concrete slabs at ground floor level whereas the first floor structures are mainly proprietary timber trussed floors.

Figure 1 – Ground floor plan & point of fire origin

UNIT 1

UNIT 2

UNIT 3

UNIT 4

UNIT 5

Point of origin: Air-conditioning compressor unit

Boundaries between

units

Units 4 & 5 –First Floor Overhang

Unit 3 – First Floor

Overhang

NORTH

Unit 2 – First Floor

Overhang


A combustible polystyrene cladding appears to have been used along the ground floor levels all 5 residential townhouses as indicated in Figures 2 and 3. The external wall cladding material that was used on the first floor levels of the townhouses appeared to constitute a non-combustible proprietary walling system.

Figure 2 – A photo of the exposed combustible polystyrene external wall cladding following the fire.

One of the unique features of the townhouses at the property is that they have a cantilevered first floor structure that overhangs the rear yards.

The layout of the first floor levels of Units 1-5 and the eastern elevation of Units 1, 3, 4 and 5 are contained within Appendix B.

Polystyrene external wall

cladding

Non-combustible proprietary external

wall cladding


Figure 3 – Example of cantilevered first floor overhang & soffit.

Approximate location of separating walls & property boundary indicated by the red line

Combustible polystyrene external wall cladding fixed continuously across the townhouses and over the 60/60/60 separating wall


3. Fire Cause and Origin

Visual observations and the examination of burn patterns and charring of the timber fence and the intersecting wall structure generally indicated that point of origin was more than likely to be the air conditioning compressor unit serving Unit 1, which is indicated in Figure 4 below.

Figure 4 – Point of fire origin outside of Unit 1

Fire spread into Unit 1 via the separating wall cavity and the first floor substructure was quite severe, which is evidenced by Figures 5 and 6.

The damage to Unit 1 caused by the fire was initially estimated to be $200,000. The costs associated with relocating the occupiers, the replacement of Unit 1’s contents, the repair of Unit 3 and the potential replacement of the external cladding to all units at the property are estimated to be in the vicinity of $800,000.

Point of origin


Figure 5 – Fire damaged first floor sub-structure of Unit 1


Figure 6 – Fire damaged timber walls adjoining the separating wall cavity of Unit 1


4. Issues

Following the fire, inspecting officers from the MFB’s Fire Safety Directorate visited the property and examined aspects of the common wall separating Units 1 and 2, soffit of the first floor overhang of Unit 2 and the type of external wall cladding that was used. Based on the inspecting officers’ observations, the following issues are highlighted.

4.1 Separating wall construction

MFB Comment: Clause 3.7.1.8 of the Building Code of Australia – Volume 2 requires separating walls between Class 1 buildings to maintain an FRL of 60/60/60. In this instance, the separating wall that was used was a proprietary separating wall that achieved a 60/60/60 FRL, however it did not completely separate Units 1 and 2. The proprietary wall appeared to have been terminated at the concrete floor slab’s edge and combustible polystyrene cladding material was fixed over it and the adjoining timber framed wall to form the basis of an external wall, which is illustrated in Figure 7.

Figure 7 – Sketch diagram of the separating wall being crossed over.

Typically, tested proprietary separating wall systems require the ends of autoclaved autoclave concrete (AAC) walls to be wrapped with a fire resistant mineral wool fibre before being covered over with a non-combustible wall cladding system. The details of a tested system and the expectation of Australian Standard 5146 are included within Figures A1 and A2 of Appendix A.

Autoclaved aerated concrete 60/60/60 FRL separating wall

Timber stud wall

Polystyrene external wall cladding

Boundary line

Unit 1 Unit 3


Note: A sample of design details for tested separating wall to external wall junctions is provided within Appendix A.

In this instance and in many more domestic construction projects, external walls often comprise alternative materials that are not masonry veneer and fall outside of the scope of Clause 3.7.1.8 (e) of the BCA 2016 – Volume 2, which is replicated below.

The fire, which originated from the air conditioning compressor unit from the rear yard of Unit 1, quickly spread to the adjoining combustible polystyrene wall, which spanned across the ground floor levels Units 1 and 3. Noticeably, the fire did not spread in a vertical direction externally as the external wall cladding material at the first floor level of Unit 1 appeared to be a proprietary non-combustible external wall assembly.

Had non-combustible wall cladding or a masonry veneer wall been used at the junction of the separating wall and external wall, the likelihood of fire spread between the units would have been minimised or prevented, as evidenced by the performance of the first floor level’s external wall cladding.

4.2 Cantilevered floor construction < 900mm from allotment boundary

MFB Comment: Part 3.7.1 of the BCA – Volume 2 does not appear to contain any specific requirements for cantilevered or overhanging floor structures that are situated within 900mm of an allotment boundary.

In this instance, the first floor level of Unit 3 contained a cantilevered overhang, of which an example of an adjoining unit appears in Figure 8. Direct flame impingement upon the first floor’s soffit also caused the cement sheet lining to fail, thus exposing one of the main structural floor members as indicated in Figure 9.

Whilst Clause 3.7.1.7 of the BCA-Volume 2 identifies allowable encroachments, soffits of cantilevered floor structures are not listed nor do they appear to have any association with any of the allowable encroachments.


Figure 8 – Example of cantilevered first floor overhang & soffit.

Figure 9 – Fire affected structural floor member in first floor overhang of Unit 2.

First floor soffit

Cantilevered first floor overhang

Separating wall

Fire affected structural floor member


5. Recommendations

As the reporting agency, the MFB has made the following recommendations after considering the building’s classification and the intent of the fire safety performance requirements of the BCA. The MFB believes that if the following recommendations are implemented, a greater degree of passive fire resistance will be afforded to townhouse buildings of this nature, thus protecting the people who occupy them, the fire-fighters who respond to them as well as minimising fire related property damage.

(a) Where cantilevered floors of all Class 1 buildings are proposed to be constructed within 900mm of the allotment boundary, the floor structure should be afforded the same degree of passive protection as a separating floor under Clause 3.7.1.11 of the BCA-Volume 2. Alternatively, walls achieving a 60/60/60 FRL should be constructed to protect the exposed floor soffits that extend to the ground; and

(b) That clause 3.7.1.8 of BCA – Volume 2 be amended to include both specific requirements and diagrams that emphasise the need for the junctions of separating wall to external walls to be constructed to the same requirement as masonry veneer walls as provided by sub-clause (e). Additionally, the amendment should also emphasise that the external wall will need to be of non-combustible construction need to extend no less than 450mm either side of the separating wall; and

(c) The mandatory notification stages for inspection, which are contained within Regulation 901 of the Building Regulations 2006, should be expanded to require an additional inspection where the use of proprietary fire resistant construction systems is proposed. The purpose of this inspection is to ensure that walls have been constructed in accordance with the approved design documentation and to ensure that the integrity of the separating wall is not compromised by the external wall junction.

Note: These recommendations are tendered to the Victorian Building Authority, the Australian Building Codes Board, the Housing Industry Association and the Australasian Fire and Emergency Service Authorities Council (AFAC) member agencies for their consideration and implementation at a legislative and strategic policy level.

6. Conclusion

This fire event has demonstrated how the installation of combustible wall cladding material over a fire rated common wall in a townhouse development can quickly spread to adjoining townhouses. This event has also demonstrated how quickly fire can spread in a vertical direction via the soffit lining of a cantilevered floor that is located next to the allotment boundary. Whilst Unit 3 appears to have suffered repairable damage, the residents of Unit 1 have been displaced and it is likely that Unit 1 will need to be reconstructed . It is also likely that the external wall cladding material of the entire site will need to be surveyed , replaced and reconstructed in accordance with the manufacturer's specifications of the proprietary separating wall ing system.

Ta s Ge rgas MAIB AffiiiEAust

Manag & Senior Engineer

~o-r-~ Damian O'Toole Station Officer

Community Safety Technical Department Fire Investigation & Analysis Unit

Please note: In order to assess the effectiveness of this report and to make reports of this type more meaningful, written/verbal contact may be made with the occupiers/owners, Maribyrnong City Council and the Victorian Building Authority in the future. The time frame of this follow-up will be dependent upon the issues highlighted and the complexity of the recommendations made.

DocCentral #11 81161 -v4 of 21


7. Acknowledgments

The MFB’s Fire Safety Directorate wishes to acknowledge the contribution of the following entities in the compilation of this report. Mr Alex Sekuloski of LOXO Cladding Systems Pty Ltd Ms Anita Dorfer-Mehanic of Maribyrnong City Council

PIA Circulation List

Jarrod Edwards, Victorian Building Authority Andrew Andreou, Country Fire Authority Gil King, Housing Industry Association Rob Llewellyn, AFAC Adam Dalrymple, Fire Services BRAC Representative Anita Dorfer-Mehanic, Maribyrnong City Council Building Owner/Occupier MFB Library Chief Technical Officer, FPAA Alex Sekuloski, LOXO

Chairperson, Society of Fire Safety (Victorian Chapter) President, Victorian Municipal Building Surveyors Group President, Australian Institute of Building Surveyors (Victorian Chapter) President, Australian Institute of Building (Victorian Chapter) Brian Ashe, Australian Building Codes Board Builder MFB Community Resilience Commanders MFB Officers 44 & 47 (A, B, C & D Platoons)


Figure A2 – External wall junction for reinforced AAC inter-tenancy discontinuous wall systems (Figure 5.3(K) – AS5146.3:2015 ©)


APPENDIX B

Figure B1 – First Floor Layout

Approximate boundary locations shown by broken

blue lines NORTH


Figure B2 – Eastern Elevation Extract – Units 1, 3 & 4

Approximate boundary locations

Extent of flame damage to external walls (shown in red)

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