Plywood on Steroids: Exploring Potential Building Code Amendments to Enable 6 Storey Mid-rise Wood-Frame Buildings

Transcription

1 Ministry of Municipal Affairs and Housing Ministère des Affaires municipales et du Logement Plywood on Steroids: Exploring Potential Building Code Amendments to Enable 6 Storey Mid-rise Wood-Frame Buildings Northern Ontario Municipal Association Northwestern Ontario Regional Conference Thunder Bay, September 30, 2010 Michael de Lint

2 Outline of Presentation Context and Ontario Government Direction Growth Plans Wood as a Green Building Material Potential Ontario Building Code Changes: 6 Storey Mid-Rise Buildings British Columbia Building Code Changes Enabling 6 Storey Buildings Preliminary Stakeholder Views Technical Analysis and Consultation Other Jurisdictions Next Steps 18/10/2010 2

3 Context and Ontario Government Direction Increasing Use of Wood in Buildings: Jurisdictions in Canada and around the world are looking at policies to increase the use of wood in building construction Use of wood framing not limited to low rise residential There is a long history of tall wood or timber frame buildings 18/10/2010 3

4 Examples of Taller Wood Buildings 67.1m Sakyamuni Pagoda in Yingxian, China (1056), tallest wood building in the world. 18/10/2010 4

5 Examples of Taller Wood Buildings Downtown Toronto, 8-Storey Post & Beam (timber) building with masonry walls, /10/2010 5

6 Context and Ontario Government Direction Current Ontario Building Code restrictions: Structural wood framing not allowed for buildings over 4 storeys (the limit for combustible construction) Except through alternative solutions British Columbia: Effective April 6, 2009, BC amended its Building Code to allow 6 storey wood frame residential buildings 18/10/2010 6

7 Context and Ontario Government Direction Ontario government is: Exploring how the Building Code might be amended to facilitate greater use of wood in buildings including potentially increasing the maximum height limit of wood frame buildings from four to six storeys Main focus in BC is wood frame buildings (e.g. platform framing based on wood studs) rather than timber frame buildings 18/10/2010 7

8 Context and Ontario Government Direction Ministry of Municipal Affairs and Housing (MMAH) is working with: Ministry of Northern Development Mines and Forests (MNDMF); Ministry of Infrastructure (MOI); and Ministry of the Community Safety and Correctional Services (MCSCS) - responsible for Ontario Fire Marshal s Office (OFM) Rationale for exploring potential enabling Code amendments: Support flexible and cost effective mid-rise construction Promotion of sustainable building materials Supports Northern and Greater Golden Horseshoe Growth Plan 18/10/2010 8

9 Growth Plans Mid-rise wood frame buildings support both: Growth Plan for the Greater Golden Horseshoe Proposed Growth Plan for Northern Ontario. Potential synergy between North and South economic embrace Proposed Growth Plan for Northern Ontario released for public consultation, outlined the following actions: Recognize wood as renewable resource and increase its use in construction Showcase the use of wood in public buildings Amend building codes and construction standards to allow for the use of wood in mid rise construction 18/10/2010 9

10 Growth Plans The Growth Plan for the Greater Golden Horseshoe contains policies to.. Build compact, complete communities including policies for intensification in built-up areas and creating transit supportive, pedestrian oriented neighbourhoods Mid-rise construction supports implementation of these policies by integrating new, more intensive uses within existing neighbourhoods, making better use of existing infrastructure and services 18/10/

11 Growth Plans Mid-rise buildings also supports Toronto s Official Plan Toronto population forecast to grow by 500,000 over next 20 years Toronto s OP supports intensification including mid-rise buildings on avenues/mainstreets. A significant proportion could be mid-rise wood buildings 18/10/

12 Examples of Mid-Rise Wood Buildings Left: Older brick and beam mid-rise buildings, Vancouver, typically between 20 and 24 meters high Right: New 6 storey mid-rise wood frame building on concrete under construction in BC. Concrete slab acts as fire barrier with up to two- three hours fire separation ratings, ground floor can be used for offices, commercial and retail or as garages for parking, upper floors for housing 18/10/

13 Wood as a Green Building Material Some Key Attributes of Wood: Strong and durable: centuries old timber structures still sound Easily adaptable: amendable to renovation and retrofit Natural insulator: cellular structure of wood reduces thermal bridging Reusable and recyclable: Wood can be reused in new buildings Renewable: Wood is the only major building material that is harvested 18/10/

14 Wood as a Green Building Material Wood is a green (environmentally friendly), renewable building material. Wood performs well compared to major building materials (steel, concrete) when considering: Life cycle assessment (LCA) Carbon capture LCA measures environmental impact of wood over its life covering: Resource extraction, manufacturing, distribution, use and end of life disposal Recent LCA studies suggest that wood performs well compared other building materials in regards to: Emissions of green house gasses and pollutants Embodied energy (energy to produce) 18/10/

15 Wood as a Green Building Material Wood as a carbon sink : Through photosynthesis, chlorophyll in leaves convert carbon dioxide from the air to carbon - wood is 50% carbon by weight Managed forests are efficient carbon sinks - Canadian law requires prompt reforestation after harvesting on public lands If trees are harvested before they burn or decay, carbon is stored indefinitely in wood products (including recycled wood products) Planting trees begin the cycle again rapid sequestration in early, middle years of tree growth Every cubic meter of wood product sequesters tones of carbon About 5 years of car emissions are sequestered in typical wood home 18/10/

16 Potential Ontario Building Code Changes: 6 Storey Mid-Rise Buildings Ontario is reviewing recent BC Code Changes to allow 6 storey residential mid-rise buildings But Ontario is exploring potential changes beyond those in BC: Mercantile (commercial) occupancies Office occupancies 18/10/

17 Preliminary Stakeholder Views In May the Ministry held a stakeholder information session with over 40 representatives from the building industry and regulators. Objective of the information session was to: Outline BC changes to allow 6 storey residential wood frame buildings Outline MMAH proposal to explore interest in commercial, office, mixed use, hybrid wood-frame buildings Assess initial industry interest and regulatory/fire safety community reactions Outcome of the information session: Strong support from designers, developers and builders and planners Fire safety concerns from fire safety stakeholders Ministry met with fire safety stakeholders in April, August to understand their concerns with more meetings planned 18/10/

18 BC Changes Enabling 6 Storey Wood Frame Buildings In April 2009, BC introduced Building Code changes enabling 6 storey wood frame residential buildings Previously BC (as Ontario) limited wood frame Buildings to 4 storeys sprinklered Some BC changes in addition to 1hr fire separation, included: Enhanced mandatory sprinklering - including concealed spaces such as attics, crawl spaces (more robust than for 4 storey sprinklered) Limits on building area - up to 20% of that allowed for non-combustible buildings of similar height Limit on height 18 meters Exterior cladding mandatory combustion-resistant and non-combustible cladding Shear wall alignment - structural design requirements to address seismic (earthquake) loads through alignment of shear walls Guideline on shrinkage - Requirement to consider wood shrinkage in the structural design of the building as outlined in a guideline 18/10/

19 Seismic Test of Wood Building Structure Earthquake simulation based on the Kolbe Shake Test conducted in Six storey wood frame building constructed with high capacity mid-ply wood frame construction reinforced with continuous rods connecting base of the building to the uppermost floor. Building performed very well with minimum damage resisting a major (magnitude 7.5) earthquake 18/10/

20 Technical Analysis and Consultation MMAH is engaging technical Code Consultant to recommend Code changes The technical consultant has expertise in: the fire safety and structural aspects of the Building Code; and BC changes Consultant will consult with building industry, fire service etc. 18/10/

21 Technical Analysis and Consultation The Consultant s technical analysis will include 4 elements: 1. Review of recent British Columbia changes, projects, - Review adequacy of the BC changes. - Review other jurisdictions (Seattle, Portland, Quebec, Europe) 2. Technical Parameters and issues - Parameters correspond to building code objectives - fire safety - structural sufficiency - noise etc 18/10/

22 Technical Analysis and Consultation 3. Recommended Code changes and rationale. - Recommend specific Code changes and supporting rationale - Mid-rise wood buildings should not be less safe than reference building - Key parameters are fire, structure - Accomodate conventional and pre-engineered, prefabricated components 4. Recommendations related to process issues. - Supportive recommendations related to: - qualifications of designers, contractors, building officials, - guidelines 18/10/

23 Technical Analysis and Consultation Fire safety related technical parameters being considered include: 1. Risk of ignition 2. Risk of fire spread beyond point of origin 3. Risk of fire spread to neighbouring buildings 4. Risk of failure of sprinkler system to control or suppress fire 5 Risk of occupants not being able to recognize fire 6. Risk of occupants not being able to evacuate the building 7. Risk of fire service unable to conduct effective operations (e.g. Rural capacity, etc) 8. Risk of building damage from water 9. Fire safety during construction 18/10/

24 Other Jurisdictions British Columbia: 20 Mid-rise projects in BC (planned, under construction) for 31 buildings Some are 6 storey wood, some hybrid (5 storeys wood on one storey concrete) Seattle, Portland 5 or more storeys on concrete base Quebec 6 storey office building (timber, concrete core, using alternative solutions provisions in Building Code) which are solutions that meet the objectives of the Code and performance implicit in prescriptive requirements UK, Europe 9 storeys in the London (market, affordable housing, with Cross Laminated Timber (CLT plywood on steroids ), no sprinklering Norway plans the world s tallest wood frame building (20 storeys) 18/10/

25 Examples of Mid-Rise Wood Buildings Seattle: Mixed use 6 storey wood frame building 18/10/

26 Prefabricated Wood Panels Pre-fabricated wood frame panels 18/10/

27 Examples of Mid-Rise Wood Buildings Berlin: Glulam Post and Beam 7 storeys 18/10/

28 Cross-Laminated Timber (CLT) Cross Laminated Timber (CLT) plywood on steroids for future potential code changes 18/10/

29 Cross-Laminated Timber Buildings (CLT) Left: 9 storey CLT building in London, UK Right: 8 storey CLT building in Vaxjo, Sweden 18/10/

30 Building Code-Public Consultation Rounds First consultation expected Fall 2010: Certain national building code changes Proposals from Ontario stakeholders Second consultation on key Ontario priorities, expected Early 2011: Enhanced energy and water conservation Enhancing barrier-free accessibility requirements Qualification maintenance requirements for building practitioners Potential changes enabling 6 Storey wood frame construction

31 Next Steps Consultant to complete final report by December 6 Subject to government direction, MMAH develops consultation proposals Public consultation on key Ontario priorities in next edition of Code - in winter 2011 (January - February) Review of consultation results by Technical Advisory Committees (TACs) Subject to government direction - Mid-rise wood frame provisions may be included in Building Code released in late 2011 or early /10/

32 Thank You Questions? 18/10/