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Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Boris Iskra Forest & Wood Products Australia
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
This Presentation
1. Fire Hazard Properties – Building Code of Australia Volume 1: Specification C1.10
(Floor, wall and ceiling linings)
2. MRTFC and Commercial Buildings
– Overview – Timber properties during fire – Connection performance during fire – Calculation methods to predict timber capacity
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
BCA Reference Description Section C Fire Resistance
Specifies community expectations regarding fire resistance of Class 2 -9 buildings.
Part C1 Fire Resistance and Stability
Deemed-to-Satisfy (DTS) Provisions regarding fire resistance and stability
Clause C1.10 Fire Hazard Properties
DTS Provisions for Fire Hazard Properties of materials and assemblies used in the building construction industry
Specification C1.10 Clause 3, 4 & 6 Fire Hazard Properties - Floors, Walls and Ceilings
A method of complying with the BCA requirements for floor coverings, walls and ceilings
Specification C1.10 Clause 7 Fire Hazard Properties – Other Materials
A method of complying with the BCA requirements for materials other than those used for floors, walls and ceilings
Fire Resistance in the BCA
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Topics
1. Fire Hazard Properties – Clause C1.10: Specification C1.10 – Clause 7 – Clause C1.10: Specification C1.10 – Clauses 3, 4 & 6
2. MRTFC and Commercial Buildings
– Overview – Timber properties during fire – Connection performance during fire – Calculation methods to predict timber capacity
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
No requirements yes
•Timber-framed window? • Solid timber handrail or skirting? • Timber- faced solid core door or fire door? • Joinery, cupboard shelving etc? • Paints, varnishes, etc or adhesives
Class 1 or 10
Class 2-9
Class of Building?
Clause C1.10
Other
Specification C1.10 - Clause 7 Specification C1.10 - Clauses 3, 4 & 6
Covering - Floor, Wall & Ceiling no
No Clause C1.10 requirements
Clause C1.10
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Flammability Index ≤ 5
Spread-of-Flame Index ≤ 9 and
Smoke-Developed Index2
≤ 8
Specification C1.10 – Clause 7
sarking All other materials,
including timber
Other Materials1?
1 There are additional requirements for fire isolated exits, public entertainment theaters, public halls, refer BCA
2 Only for materials with a Spread-of-Flame Index > 5
Specification C1.10 – Clause 7
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
More species can be found on: www.woodsolutions.com.au
Specification C1.10 – Clause 7 Fire Hazard Properties of Timber
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Topics
1. Fire Hazard Properties – Clause C1.10: Specification C1.10 – Clause 7 – Clause C1.10: Specification C1.10 – Clauses 3, 4 & 6
2. MRTFC and Commercial Buildings
– Overview – Timber properties during fire – Connection performance during fire – Calculation methods to predict timber capacity
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
No requirements yes
•Timber-framed window? • Solid timber handrail or skirting? • Timber- faced solid core door or fire door? • Joinery, cupboard shelving etc? • Paints, varnishes, etc or adhesives
Clause C1.10
Other
Specification C1.10 – Clause 7 Specification C1.10 – Clauses 3, 4 & 6
Coverings - Floor, Wall & Ceiling no
Class 1 or 10
Class 2-9
Class of Building? No Clause C1.10
requirements
Clause C1.10
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Floor
Critical Radiant
Flux
Critical Radiant Flux
and Smoke
Development Rate
≤ 750 percent minutes
Specification C1.10 - Clause 3 Floor linings and floor coverings
Wall / Ceiling
yes no
Sprinklered?
Lift
Specification C1.10
Clause 3
Additional requirement “… for any portion of the floor covering that is continued more than 150 mm up a wall” - Group number 1 or 2
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
BCA Requirements for flooring materials in a building not protected by a sprinkler system complying with specification E1.5, maximum smoke development rate of 750 percent-minutes is permitted.
Class of building Sprinkler Status Fire
Isolated Exit
No Sprinklers
Sprinklers
Class 2, 3, 5, 6, 7, 8 or 9b, Excluding accommodation for the aged
2.2 1.2 2.2
Class 3 Accommodation for the aged
4.5 2.2 4.5
Class 9a Patient care areas. Areas other than patient care areas.
4.5 2.2 4.5 2.2 1.2 4.5
Class 9c Resident use areas. Areas other than resident use areas
2.2 4.5
1.2 4.5
EFT Consulting
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
More species can be found on: www.woodsolutions.com.au
Specification C1.10 – Clause 3: Floors - Fire Hazard Properties of Timber
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Floor
Critical Radiant
Flux
Critical Radiant Flux
and Smoke
Development Rate
≤ 750 percent minutes
Group Number
Specification C1.10 - Clause 4 Wall and ceiling linings
Group Number and
smoke growth rate index ≤ 100
or average specific extinction area
< 250 m²/kg
Wall / Ceiling
yes no
Sprinklered?
yes no
Sprinklered?
Lift
Specification C1.10
Clause 3 Clause 4
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
NCC PERMITTED WALL AND CEILING LINING MATERIALS GROUPS
Class of building Sprinkler Protection
Fire Isolated Exits & Fire Control Rooms Public corridors Specific areas Other areas
Walls Ceilings Walls Ceilings Walls Ceilings Walls Ceilings
Class 2 Residential Apartments
No 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Yes 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 3 Short term Accommodation
No 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Yes 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 3 Accommodation for Aged, disabilities and children
No 1 1 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 5 Office
No 1 1 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 6 Retail
No 1 1 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 7 Carpark
No 1 1 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 8 Factory or laboratory
No 1 1 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 9a Health-care
No 1 1 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 9b Schools
No 1 1 1, 2 1, 2 1, 2, 3 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 9b Assemble buildings other than schools
No 1 1 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3
Yes 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Class 9c Aged Care
Yes 1 1 1, 2 1, 2 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3
Lift Cars N/A - - - - - - 1, 2 1, 2
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
More species can be found on: www.woodsolutions.com.au
Specification C1.10: Walls / Ceiling Fire Hazard Properties of Timber
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Floor
Critical Radiant
Flux
Critical Radiant Flux
and Smoke
Development Rate
≤ 750 percent minutes
Group Number
Specification C1.10 – Clause 6 Lift cars
Group Number and
smoke growth rate index ≤ 100
or average specific extinction area
< 250 m²/kg
Wall / Ceiling
yes no
Sprinklered?
yes no
Sprinklered?
Lift Cars
Group Number
1 or 2
floor wall/ceiling
Floor, Wall/Ceiling?
Critical Radiant
Flux ≥ 2.2
kW/m²
Clause Specification C1.10: Lift Cars
Clause 3 Clause 4 Clause 6
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
More species can be found on: www.woodsolutions.com.au
Specification C1.10 – Clause 6: Floors - Fire Hazard Properties of Timber
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Topics
1. Fire Hazard Properties – Clause C1.10: Specification C1.10 – Clause 7 – Clause C1.10: Specification C1.10 – Clauses 3, 4 & 6
2. MRTFC and Commercial Buildings
– Overview – Timber properties during fire – Connection performance during fire – Calculation methods to predict timber capacity
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
– Multi – Residential – Timber – Frame – Construction
M R T F C
MRTFC - Overview
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Maximum storey height for timber DTS complying buildings
Australia Number of Storeys Without Sprinklers
Storey Max floor area (m2)
Single family Unlimited Unlimited Multi-residential 3 Unlimited Office 2 8,000 Retail 2 5,000 Industrial 2 18,000 Public (Assembly) 1 8,000
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
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
Maximum Storey Height by Building Classification
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
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
Maximum Storey Height by Building Classification
NCC 2014
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• MRTFC commonly deals with: – Class 1 buildings (houses or dwellings
attached side by side) – Class 2 buildings (flats and units above one
another as well as side by side) – Class 3 buildings (residential parts of hotels,
motels, accommodation for students, aged and disabled)
– Class 9c buildings (buildings for the aged) • Performance criteria in these classes focuses on:
– Fire resistance – Sound resistance
• This presentation focuses on Fire Resistance
MRTFC and Performance Requirements
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• In Class 2 and 3 residential buildings there is extensive use of “Sole occupancy units” (SOUs). This separates buildings into manageable units and provides protection to “other property”:
– A SOU is a part of a building that is occupied by one owner, lessee or other occupant
– SOUs must be designed to restrict fire and sound from affecting adjoining SOUs
SOU Concept
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
The extent of fire resistant construction required by the BCA depends on the Type of Construction:
Type A provides the highest level of passive protection e.g. structural elements must withstand burnout of the building contents
Type B provides lower passive protection e.g. less of the structure must be able to withstand burnout of the contents
Type C provides the lowest passive fire resistance e.g. only some elements have specified fire resistance intended to mainly restrict horizontal spread of fire to adjoining dwellings
Type of Construction
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• The BCA requires protection to be provided at the boundaries between compartments or SOUs
• The walls, floors and ceilings bounding compartments are constructed to meet “Fire Resistance Levels” (FRLs) to prevent spread of fire
• FRLs are expressed in minutes as follows:
FRL: 60 / 60 / 60 structure integrity insulation
• Columns have a FRL of 60/-/- or 120/-/- etc as they are not barriers • Partition walls are the exact opposite: barriers but non-loadbearing so
typically have a FRL of -/30/30 or -/60/60
Measuring Fire Resistance Levels
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• MRTFC details focus on meeting the combined requirements of fire, sound and structural performance for designated wall, floor and ceiling elements in Class 1, 2 and 3 buildings
• A systems approach is used to meet needs which can be broken up into: – Wall framing systems – Floor/ceiling framing systems
• Each system uses a number of common concepts to maintain continuity at intersections between elements and at penetrations, including: – Fire resistant joints – Cavity barriers – Fire stops
General Framing Requirements
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• The system features two stud walls with a separating cavity
• Load Bearing frames are typically made from 90x45 timber framing
• The frames can be prefabricated as required
• The system is easy to handle and erect on-site
• Insulation is used extensively between studs or in the cavity
• It must be non-combustible (BCA Requirement)
• Fire grade plasterboard is built up in layers to meet fire requirements
• Fibre cement sheet can be used in combination with plasterboard
• Other cladding or linings can be used over these components
Double Stud Walls in More Detail
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Depending on the type of construction, fire rated walls may need to continue through the roof and eaves cavities. In these areas:
– walls must extend at least to the underside of the roof
– walls may be single skin (not double) because sound resistance isn’t required in the roof or eaves areas
Treatment of Roof and Eave Cavities
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Floor/ceiling systems are required between sole occupancy units (SOUs)
• These systems consist of floor coverings, platform flooring, floor joists, sound insulation, resiliently mounted ceiling battens and ceiling linings
Floor/Ceiling Systems
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Timber joists dictate the load and spanning capacity of the floor
• Non-combustible sound insulation is placed within the joist depth
• Resiliently mounted ceiling battens are fixed transversely to the joists to isolate sound from the structure above
• Plasterboard is fixed to the sound resilient supports. A build up of layers is used to achieve sound and fire requirements (fire grade board required)
Summary of Floor/Ceiling System Components
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Care must be taken to ensure weak spots don’t occur at the interfaces between systems (e.g. intersections and penetrations)
• Methods of doing this include: – Fire resistant joints – Cavity barriers – Fire stops at gaps and penetrations (caulking)
Continuity of Systems
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Fire resistant joints are used at intersections between floor/ceiling elements e.g. where one element has a lower FRL than the other
• Some structural framing remains protected by the plasterboard and by the slow charring of the other framing at the junction.
Fire Resistant Floor Junctions
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Needed at intersections between wall/wall elements such as when one element has a lower FRL than the other
• The joint is made by adding extra pieces of timber to the joint between the elements
• The extra timber adds fire resistance because when it burns it forms an insulative char layer on the surface – this slows burning in the core of the timber and in doing so provides fire resistance for a period of time
• In general, the more pieces of timber added to the joint, the longer the joint will last.
• In some cases light gauge steel angles are also used to slow char at corners
Fire Resistant Floor Junctions
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Cavity barriers restrict the passage of flame, smoke and gasses in cavities that bypass wall/floor/ceiling intersections
• Typical example: intersection between a wall separating SOUs and a non-fire rated external brick veneer wall
• Cavity barriers can be made by: – timber battens – appropriate sheet linings – moisture repellent mineral wool – Light gauge steel profiles
Example prior to brick veneer being laid
Cavity barrier using sheet lining
Cavity Barriers
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Use fire shafts as a means of avoiding services in fire/sound rated walls
Fire Rated Shafts
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Topics
1. Fire Hazard Properties – Specification C1.10 – Specification C1.10a
2. MRTFC and Commercial Buildings
– Overview – Timber properties during fire – Connection performance during fire – Calculation methods to predict timber capacity
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Unprotected Timber Exposed to Fire
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Char can also occur within a wall or floor when protected by linings.
• Experiments show it is at a slower rate and commences later
• Distribution of char different
Protected Timber Exposed to Fire
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Topics
1. Fire Hazard Properties – Specification C1.10 – Specification C1.10a
2. MRTFC and Commercial Buildings
– Overview – Timber properties during fire – Connection performance during fire – Calculation methods to predict timber capacity
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Connections usually limit the capacity of a timber element
• AS1720.4-2006 – Fire Resistance and Structural Adequacy of timber members also provides guidance for the design of connections
Connections
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Unprotected metal fasteners may limit FRLs of unprotected timber
• Protection of fixings is required and can be via: o surface protection
or o embedment of
fixings under plugs
• Other protection measures need test data to support their use
Connections and AS 1720.4
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Topics
1. Fire Hazard Properties – Specification C1.10 – Specification C1.10a
2. MRTFC and Commercial Buildings
– Overview – Timber properties during fire – Connection performance during fire – Calculation methods to predict timber capacity
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Charring Rate for Unprotected Timber
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
Depth of Char for Unprotected Timber
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Calculation to achieve effective load-bearing capacity of the section
• Dependant on timber density
• FRLs achieved using effective depth of charring for a typical unprotected 3-sided exposed hardwood beams (650 kg/m3) are shown opposite
FRL Effective depth of charring- mm
30/-/- 25
60/-/- 43
90/-/- 60
120/-/- 78
Example of the Fire Resistance of Unprotected Solid Hardwood
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Narrow section timber directly exposed to fire has a low FRL in accordance with AS 1720.4.
• Large member sections can have significant FRLs however the connections are sometimes not protected or embedded to the same degree, hence limit the FRL to potentially a relatively low values.
• Protection may be needed for these connections.
Interpretation of AS 1720.4 design rules
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Protect the timber with plasterboard
Alternative Method
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• Timber can be effectively used in buildings that are exposed to fire
• The key to the correct use of timber is the detailing in accordance with relevant Australian standards and industry manuals (e.g. Technical Guides)
Conclusions
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
woodsolutions.com.au The knowledge building website.
Fire Safety and Performance of Wood in Multi-Residential and Commercial Buildings
• WoodSolutions Technical Guides
• Improvements include details for columns in walls and improved junction details
• Available for free by registering at www.woodsolutions.com.au
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