Download - Fire Sub-Group
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Fire Sub-Group
Xiao LiWith,Alejandro MedinaProf. George Hadjisophocleous Andrew HarmsworthChristian Dagenais
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Tall Wood Building Project
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Fire Risk Modeling using CUrisk The objective is using CUrisk to
compare the fire risk of the proposed combustible building with the fire risk of a non-combustible building.
Buildings for comparison:• The proposed combustible construction
• 15% of total room surface area non-protected (1 wall exposed)
• A comparable non-combustible construction
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Fire Risk Modelling
In the 2nd meeting:• Results of fire risk analysis based on fires
on the 2nd floor.• Fire growth in the fire room• Effects of sprinklers and fire department on
fire development• Effects of CLT wall exposure areas on fire
development• Effect of reliability of fire sprinklers on the
fire risk of the building
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Outline
CUrisk modeling results today• Fire Scenarios covering all the floors
• Normal scenarios in the residential floors• Extreme fire scenarios (lobby fire and night
fires)• Response and Evacuation process
• Probability of evacuation following response • Remaining percentage of building occupants• Occupants Evacuation times
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Floor Plan
Ground floor planResidential floor plan 2nd to 20th storey
2-BedRmApt.
2-BedRmApt.
1-BedRmApt.
2-bedroomApt. 2-BedRm
Apt.
1-BedRmApt.
Corridor
Commercial Rooms
Lobby Lobby
Commercial Rooms
Commercial Rooms
Commercial Rooms
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Occupant loads According to building code
Dwellings: 2 person per sleeping roomMercantile uses: 3.7 m2 /person
Occupant loadsFirst storey: 124 personsResidential storey: 20 persons
Totally in the building: 504 occupants
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4 p
4 p
4 p
4 p
2 p
2 p
31 p 31 p
31 p 31 p
First storey
other storey
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Fire Scenarios Residential Fires in
all the residential storeys• Apt 11 on 2nd floor• Apt 18 on 3rd floor• Apt 25 on 4th floor• …• Apt 137 on 20th
floor Extreme scenarios
• Fire In the lobby on the first floor
• Night fires without fire suppression
fire
Scissor stairs
Apt.11
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Occupant response to fire
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Probability of evacuation following occupant response timewhen fire occurs in room 11 on the 2nd floorNo fire suppression and detection and alarms (solid and dash lines)
0 2 4 6 8 10 12 14
0.0
0.2
0.4
0.6
0.8
1.0
Proposed combustibleconstruction Non-combustible
construction
Ave
rage
Pro
babi
lity
of E
vacu
atio
n
Time (minutes)
Proposed combustible constructionWhen detectors/alarmsare available
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Evacuation Remaining percentage
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Occupant remaining percentage in the building versus timewhen fire occurs in room 11 on the 2nd floorNo fire suppression and no detectors and alarms (red and black)
0 5 10 15 200
20
40
60
80
100
Occ
upan
t Rem
aini
ng P
erce
ntag
e in
the
Bui
ldin
g
Time (minutes)
Proposed building, when Detectors /Alarmsare available
Non-combustible building
Proposed building
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Occupant evacuation times
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Average evacuation time for each occupant (among 504)when fire occur on 2nd storey room 11A comparison of the proposed combustible building and a non-combustible building
1 101 201 301 401 5040
2
4
6
8
10
12
14
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Ave
rage
Eva
cuat
ion
Tim
e (m
inut
es)
Occupant Number
Storey number
124 pon 1st floor
Non-Combustible building
2nd floor
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
20 p on each residential floor
Proposed buildingwhen detectors and alarms are available
Proposed building
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Fire risk comparison
Considering possible fire senarios on each residential floor
• Same probability occurring on each floor
Considering reliability of • sprinklers, • detector/alarms and,• Fire Department actions
Totally 152 fire scenarios for each type of building
• The proposed building • Comparable non-
combustible building
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Scenario Probability
Fire Depart.
0.7
Detector and Alarm
0.8
Sprinkler
0.95
Room fire1/19
A Fire on each
residential floor
19 storeys
Yes
Y Y 0.024
N 0.016
N Y 0.006
N 0.004
No
Y Y 0.0013
N 8.4e-4
N Y 3.16e-4
N 2.1e-4
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Expected fire risk comparison
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Expected Casualties (person)
0
0.1
0.2
0.3
0.4
Non-CombProposed building
Expected Fire Loss (k$)
0
2
4
6
8
10
Expected Casualties when a fire occur on any residential storeys among all the occupants (504)
Expected Fire Loss when a fire occur on any residential storeys in the whole building
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Extreme fire scenarios
Low probability of occurrence Fires in the lobby Night fires where fire suppressions systems
are not available Earthquake induced fires are not considered
due to its complexity, but comments may be provided.
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Fire in the lobby CUrisk results showed that: Fire in the lobby can cause
hundreds of casualties and a lot more damages due to fire spread to adjacent heavy-loaded shops
Smoke and heat block all the exits
However, fire spread to upper storeys may be limited in the podium because of its non-combustible construction and remote window openings from upper storeys (vertical external fire spread)
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LobbyLobby
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Fires at night without fire prevention
Worst scenarios when no fire suppression and detection system
Compared with daytime fires without fire prevention
Expected overall risk by considering possible scenarios on every residential floors (19 fire scenarios)
Results show fire losses are same but night fires may cause lots more casualties than daytime fires.
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Casualties (person)02468
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Fire Losses (K$)0
50100150200250
Daytime Night Fires
Comparison of Expected risk between daytime fire and night fires in the proposed building.
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Reliability of Sprinklers
Last meeting showed that reliability of sprinklers is the most important factor in reducing the fire risks.
When sprinklers are installed and work reliably (P_Sprinkler = 1) :
Risk (proposed building) ≈ Risk (Non-combustible building)
Possible solutions: • Fast response sprinklers with high reliability and
suppression efficiency• Reliable fire detectors and alarms that can
provide quick fire cues to occupants.
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Summary Possible fire scenarios are simulated on all the residential
storeys, and results showed that fire risk of the proposed building is close to (or slightly higher) than the non-combustible building.
Evacuation simulation results showed that occupants can evacuate out of the building with a reasonable time frame; and occupant evacuation times in the proposed combustible building are slightly shorter than a comparable non-comb. building.
Again, high reliability sprinklers (good efficiency) can prevent the fire in its infancy, thus can avoid faster fire growth in the combustible compartment (especially in the case of wood panel exposure).
Fire in extreme scenarios may cause significant life risks and fire losses, though occurrence probabilities are low.
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