Mid-rise Timber Buildings Proposal for Change Colin MacKenzie Technical Consultant
FWPA programs
Mid-rise Timber Buildings
Background New engineered timber products and building systems are now being used. FWPA and industry assisting with the development of new market opportunities for innovative timber building systems commercial buildings. FWPA and industry understand the need to work collaboratively with key stakeholders to ensure a consistent level safety (structural, fire, durability) across all building materials. Growing demand from specifiers and designers to use these innovative, sustainable timber products/systems.
Objective To provide a deemed-to-satisfy option for mid-rise timber buildings that: Enhances life safety and property protection compared to current deemed-to-satisfy provisions. Is economically viable. Facilitates consistent approaches to mid-rise timber buildings. Facilitates Sustainable Construction practices. Is compatible with existing BCA approaches. Achieves broad support from relevant stakeholders.
Maximum DTS Timber Storey Height by Building Classification (BCA 2013) Rise in storey Type of Construction Class 2 Class 3 Class 5 Class 6 Class 9a Class 9b Apartment s Hotels Office Shops Healthcar e 4 or more A A A A A A Schools & public buildings 3 A A B B A A 2 B B C C B B 1 C C C C C C
Maximum Timber Storey Height by Building Classification (BCA 2014) Rise in storey 4 or more Type of Construction Class 2 Class 3 Class 5 Class 6 Class 9a Class 9b Apartment s Hotels Office Shops Healthcar e A A A A A A Schools & public buildings 3 A A B B A A 2 B B C C B B 1 C C C C C C
How does Australia compare to the rest of world? Source: Timber Developments Association - NSW
How does Australia compare to the rest of world? 25 20 Number of Storeys 15 10 5 0 Hungary Portugal Poland Switzerland Slovakia Finland Australia Japan Romania Czech Rep Canada Austria Source: Timber Developments Association - NSW No Sprinklers Denmark Italy USA Germany UK With Sprinklers Slovenia France Iceland Belgium Greece Ireland Netherlands New Zealand Norway Spain Sweden
Fire Protection Two Methods Protected Timber Exposed timber Proposal For Change Alternative Solution
Calculations by AS 1720.4 Structural Only
Calculations by AS 1720.4
Fire Protection Fire protection provided by increased thickness to timber elements.
Char for FRL 90/90/90
2 minutes Steel framed test Timber framed test
30 minutes Steel framed test Timber framed test
Results Time to Failure Non-combustible frames 66 mins Timber 114 mins Average temperature of protected steel column thermocouples 500 450 Average Temperature ( o C) 400 350 300 250 200 150 100 50 0 0 10 20 30 40 50 60 70 80 90 Time (minutes) Control Test Timber Framed Test
Timber Construction Systems
Lightweight Construction Figure 1 Floor / Wall Junction Cavity Barrier Figure 2 Floor / External Wall Cavity Barrier Figure 3 Wall / External Call Timber Cavity Barrier Figure 3 Wall / External Call Mineral Wool Cavity Barrier
Overseas
Vancouver Canada
Portland Oregon 5 stories over 1 storey concrete
Skellefteå Sweden 7 stories
The Green Parkville, Victoria
Massive Systems
Cross Laminated Timber Multiple layers of laminated timber cross at each laminate i.e. Jumbo plywood
Forté Docklands, Victoria 807 Bourke St Victoria Harbour 10 storeys 23 apartments 4 townhouses Project: Forte Builders: Lend Lease Location: Melbourne, Vic
Post-tensioned timber frames
Post-tensioned timber frames
Post-tensioned timber frames
How high can we go?
Timber Tower Research Project 42 Storey Concrete Jointed Timber Frame Carbon footprint reduced by 60-75%. How high can we go?
WoodSolutions : Design Guides Available free by registering at: www.woodsolutions.com.au
WoodSolutions : Design Guides The following guides are related to fire engineering and developing Alternative Solutions.
Fires During Construction Only addressed to a limited extent in BCA More detailed approach considering broader range of issues required under WHS legislation Guide published June 2014 being used by some contractors
Mid-rise Timber Buildings XX Mid-rise Timber Buildings New Technical Guide detailing the DTS requirements for lightweight and massive systems Guide to be published by end of 2015
Mid-rise Timber Buildings Training Package New training package for use by registered training providers detailing the DTS requirements for lightweight and massive systems Training package to be completed by end of 2015
Robust Design YY Robust Design of Mid-rise Buildings Only addressed to a limited extent in the BCA and design standards A generic guide being drafted to assist engineers across all structural materials Guide to be published by end of 2015
FWPA has: Stakeholder Support engaged with stakeholders (e.g. AFAC, FPAA, SFS, fire protective product manufacturers) to inform and explain the Proposal For Change (PFC). undertaken a detailed and rigorous fire engineering analysis of the proposed DTS solutions; and submitted the PFC (2 February 2015).
Proposal for Change
Overview of Proposal for Change FWPA has submitted a Proposal for Change (PFC) to the Building Code of Australia (BCA) for the use of timber construction systems for Class 2 (apartments), Class 3 (hotels) and Class 5 (offices) buildings up to 25 metres in effective height (approximately 8 storeys). The proposed solutions will cover both timber construction and massive timber systems and will consist of the use of appropriate layers of fire-grade plasterboard and sprinklers. PFC accepted by ABCB for inclusion in draft BCA 2016
Overview of Proposal for Change The proposal: Building effective height of not more than 25m. Protected by automatic fire sprinklers complying with Specification E1.5 of the BCA. Fire-Protected Timber used in applications where the BCA DTS requires the element to be of non-combustible construction or concrete or masonry. Cavity barriers specified for timber framed construction to address risk of fire spread via cavities. No reductions in FRLs proposed despite provision of automatic fire sprinklers.
Fire-Protected Timber General Timber (High level of protection to timber) FRL lightweight timber-framed construction e.g. 90, 120, 140 x 45mm Additional precautions to reduce risk of fire spread to cavities e.g. Sprinkler system plus 2 x 13mm fire-grade plasterboard for walls, 2 x 16mm fire-grade plasterboard for ceilings Additional precautions to reduce risk if fire enters or starts in cavity e.g. cavity barriers Fire-grade plasterboard Timber framing
Fire-Protected Timber Massive Timber (Lower level of protection to timber) Minimum 75mm thickness of massive timber element, with required FRL, with no concealed spaces between plasterboard coverings and timber e.g. CLT, Glulam, LVL Precautions to reduce risk of timber ignition e.g. Sprinkler system plus 1 x 16mm fire-grade plasterboard for walls, 1 x 16mm fire-grade plasterboard for ceilings High inherent fire resistance of massive timber Comparable to minimum definition in US for heavy timber Fire -grade plasterboard Massive timber
Main components of Strategy Prevent Fully Developed Fires occurring fire sprinklers Reduce risk of timber structural members becoming involved in the low probability event of failure of fire sprinklers fire protective coverings If timber members involved in fire minimise impact Massive timber high inherent fire resistance General timber cavity insulation to be noncombustible All Cavities and concealed spaces provision of cavity barriers, larger cavities provided with sprinkler coverage robust structural design
Acknowledgements FWPA TDA Hyne Tillings
WoodSolutions : Design Guides Available for free by registering at: www.woodsolutions.com.au
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