Mid-Rise Timber Buildings Boris Iskra Forest & Wood Products Australia National Manager Codes & Standards 2 nd MTC International Conference on Wood Architecture 9 November 2017
Introduction Mid-rise Timber Buildings Presenter: Boris Iskra BE (Civil), Grad Dip. Building Fire Safety & Risk Engineering Has worked in the timber industry for 30 years in a range of roles including Technical Director at the Timber Promotion Council (Vic). Currently the National Manager Codes & Standards for Forest & Wood Products Australia.
Introduction Speaker involved with: Development of the Proposal-for-Change (PFC) for Mid-rise Timber Buildings Stakeholder engagement to understand areas of concern and to address these during the PFC development phase Running of the fire risk-based model assessments for Class 2, 3 and 5 Buildings Undertaking required fire testing of building elements to support the PFC and use of timber products Development of educational resources Delivery of stakeholder workshops/seminars
NCC 2016 Proposal for Change: Timber Construction Prior to NCC 2016, timber construction systems in Australia have been restricted to 3 storeys under the Deemed-to-Satisfy (DTS) provisions with higher buildings requiring an Alternative Solution pathway for compliance purposes. Project: Forte Living Location: Docklands, Melbourne Project :: Ruskin St Townhouses Architect :: Marcus O Reilly Architect Location :: Elwood, VIC Photographer :: Dianna Snape
NCC 2016 Proposal for Change: Timber Construction 25 20 Maximum Storey Height for Timber DTS Buildings - 2013 Number of Storeys 15 10 5 0 Hungary Portugal Poland Switzerland Slovakia Finland Australia Japan Romania Czech Rep Canada Austria No Sprinklers Denmark Italy USA Germany UK With Sprinklers Globally however, many countries now allow construction of timber systems well above 3 storeys. Slovenia France Iceland Belgium Greece Ireland Netherlands New Zealand Norway Spain Sweden
NCC 2016 Proposal for Change: Timber Construction 25 20 Maximum Storey Height for Timber DTS Buildings - 2016 Number of Storeys 15 10 5 0 Hungary Portugal Poland Switzerland Slovakia Finland Australia Japan Romania Czech Rep Canada Austria No Sprinklers Denmark Italy USA Germany UK With Sprinklers Globally however, many countries now allow construction of timber systems well above 3 storeys. Slovenia France Iceland Belgium Greece Ireland Netherlands New Zealand Norway Spain Sweden
NCC 2016 Proposal for Change: Timber Construction To assist in bringing Australia in line with international practices Forest & Wood Products Australia (FWPA) has undertaken a detailed fire testing program and in Feb 2015 submitted a Proposal for Change (PFC) to the ABCB seeking the modification to the National Construction Code, Building Code of Australia Volume 1 (NCC), DTS provisions to allow the use of fire-protected timber construction systems.
NCC 2016 New Timber Construction Provisions The 2016 NCC, has been amended to now allow under the Deemed-to-Satisfy (DTS) provisions the use of fire-protected timber construction systems in Class 2 (apartments), Class 3 (e.g. hotels) and Class 5 (offices) buildings Mid-rise up to 25 metres in effective height (herein termed mid-rise construction ).
2016 NCC Compliance Pathways Two pathways are available under the NCC to demonstrate performance Image of new WS Design Guide
Maximum Timber Storey Height by Building Classification (NCC 2015) Rise in storey Type of Construction Class 2 Class 3 Class 5 Class 6 Class 9a Class 9b Apartments Hotels Office Shops Healthcare Schools & public buildings 4 or more A A A A A A 3 A A B B A A 2 B B C C B B 1 C C C C C C Low-rise
Maximum Timber Storey Height by Building Classification (NCC 2016) Mid-rise
Major New Opportunity Apartments (Class 2) eg Hotels (Class 3) Office Buildings (Class 5) O A major new opportunity for a wide range of timber products and systems
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.
New DTS Provisions The new DTS provisions cover both traditional lightweight timber framing and new massive timber systems such as cross laminated timber (CLT) Fire resistant plasterboard Lightweight timber framing and consist of the use of appropriate layers of fire resistant plasterboard to provide fire- protected timber and the use of compliant automatic sprinkler systems. CLT
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 firegrade 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 firegrade 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
Summary of General Fire Design Principles Firstly, Mid-Rise the use Timber of automatic Buildings fire have sprinklers a number of critical layers of fire protection to suppress a fire before the timber structure is threatened Secondly, the use of fire-protected timber Protects timber in the low probability event that the sprinklers fail Thirdly, the use of cavity barriers to prevent fire or smoke spread through the cavities if the fire-protection is breached or cavity fire occurs Fourthly, the use of non-combustible insulation to minimise fire spread in cavities if the fire-protection is breached or cavity fire occurs
Design of Mid-Rise Timber Buildings Timber Construction Options for Mid-rise Timber Buildings
Building Form Class 2 or 3: Multi-residential or Hotels Class 2 Apartments and Class 3 e.g. Hotels tend to be honeycombed type structures with many closely spaced walls. There are a number of ways these could be constructed
Building Form Class 2 or 3: Multi-residential or Hotels Multi-Res Apartments Multi-Res Apartments 1-6 Storeys Lightweight Timber Conventional framing upper walls closer stud centres lower walls 6 8 Storeys Lightweight Timber + Massive Timber Multi-Res Apartments 6-12 Storeys Massive Timber (CLT)
Massive Wood Panel Systems Massive Panel Construction (min. 75mm thickness) LVL Cross Laminated Timber Glued/nail Laminated Timber
Typical Construction Approaches - Apartments Apartment floors Lightweight timber systems Massive timber systems, or Combination Podium level Often concrete (certainly basement)
Building Form Class 5 Offices Heavy Timber Post & Beam (Glulam) Portal Frames
Efficiencies & Cost Benefits of Timber Systems Direct savings from faster methods of construction compared to traditional steel and concrete structures due to both: increased scope for off-site prefabrication lighter and more easily manipulated and installed materials Reduced foundation requirements due to lighter above-ground structure; Reduced on-site costs & OH&S issues, particularly with a shift to more prefabricated solutions; Increased ability to commence follow-on trades earlier in the construction process, reducing the overall construction program time to completion; Reduced on-site construction infrastructure (preliminary costs) such as fixed cranes, site accommodation, storage areas, scaffolding and edge protection, hoists and so on ; and Increased accessibility of the construction site and far lower impacts on noise and site activities on local neighbourhoods (less truck movements & workers); a major benefit for suburban multi-residential developments.
WS Design Guide: Costing Case Studies See costing case study guides available from woodsolutions.com.au web site
Research Test Program
Demonstration of performance of Fire Protected Timber Approx. dimensions 4 m x 4 m x 2.4 m. Opening of 2 m width x 1.2 m height. Fire Load 740 MJ/m 2 enclosures
Fire resistant wall construction Control 2 layers of 13mm fire-grade plasterboard steel studs non-combustible insulation Timber Construction 2 layers of 13mm fire-grade plasterboard timber studs combustible insulation
30 minutes Control test Timber framed test
Enclosure Temperatures
Protected Steel Column Temperatures
Average Temperature Non-Fire Side of Walls
Fire Resistance Level (FRL) NCC Part A1.1 Definitions FRL means the grading periods in minutes determined in accordance with Specification A2.3, for the following criteria (a) structural adequacy; and (b) integrity; and (c) insulation, and expressed in that order. Structural adequacy ability of a loadbearing element to support an applied load Integrity ability of an element of construction to resist the passage of flames and hot gases from one space to another Insulation ability of the surface of an element of construction, on the non-fire side of the element, to maintain a temperature below the specified limits
FRL 90/90/90 RISF 60 lightweight engineered timber floor system being prepared for test
Ceiling System 2 x 16mm fire grade plasterboard fixed to furring channels. Channel spacing 600mm
Non-fire side 2 minutes after end of 90 minute test
Fire Exposed Face after test
Timber Buildings Australian Case Studies
The Green Design Team IrwinConsult TimberTruss & SmartStruct Timber Systems TecBeam Floor Cassette & Prefabricated Wall Frames Build Period Floor System 1.5 Days per Level Wall System 5.0 Days per Level Project :: The Green Builders :: Frasers Property (prev. Australand) Location :: Parkville, Vic
Forté 807 Bourke St Victoria Harbour 10 storeys 23 apartments 4 townhouses Project :: Forté Living Builders :: Lend Lease Location :: Melbourne, Vic
The Gardens Architect :: Strongbuild Engineer :: AECOM Builder :: Strongbuild Height :: 6, 7 & 8 storey CLT Location :: Macarthur Gardens, NSW
International House Sydney Image Credits: Dijana Tasevska Image Credits: Dijana Tasevska Architect :: Tzannes Architects Engineer :: Lend Lease Builder :: Lend Lease Height :: 7 storey office building Location :: Barangaroo, Sydney Image Credits: Jonathan Evans Image Credits: Jonathan Evans
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