12-6-2009 1
Morten ValkvistCompetence Director, Niras Safety, Denmark
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 2
• Basic intention in PB design verification:
• Verify society’s risk acceptance levels
• Danish approach
• Equal design
• Meet deterministic acceptance criteria
− E.g. objects discernible within 10 m etc.
− Sensitivity studies (failure)
• Risk accep. levels are important in PB design
Performance-Based Designs - Verification
Risk
Bldg.classAssembly
Acceptance Risk Level?
Compare
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 3
Performance-Based Designs - Documentation
Mathematical Model
Knowledgeable
User
Methodology of Use
• Fire design triangle [Beard, A., (Heriot Watt Uni.(UK)]:
• Requirements to PBFC system:
• Control over the risk levels induced by the
three factors
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 4
Mathematical Model
• Fire modelling in PB design
• A priori modelling
• Leads to unclear risk levels
• PBFC system must control math. assumptions
45 kg/s
75 kg/s
60 kg/s - 4. diff. math. models
- Identical design fire
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 5
Knowledgeable User
• Round-robin study of fire modelling
• Dalmarnock Fire Tests [Uni. of Edinb. et al.]
• A priori modelling (8xFDS+2xCFAST)
• Common test description and initial HRR
• HRR of initial fire was provided
• Pre-flashover well-ventilated round-robin studies
[Rein et al. (2009), Fire Safety Journal 44, pp. 590-602]
+500%Texp
-30%Texp
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 6
• Design fire uncertainty – e.g. car fire
• DK: Same building owner may be met with different design fires
• Premovement time
• Fixed: ~30 s => ~300 s
• Distribution of :
Methodology of Use
rddetprettt +=
rdt
[Okamoto et al. (2009), Fire Safety Journal 44, pp. 301-310]
Npers/Ntotal
trdOffice
1.0
Shopping
[EN 12101-5]:
=4,000 kW
Q&
fQ&
DK
: G
reat
variation
with
in g
roup
of
FS
Es a
nd
with
in g
rou
p o
f A
HJs
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 7
Methodology of Use
Vena
contracta
No VC
0 0.5 1 1.5 2 2.50
0.5
1
1.5
2
2.5
3
Froude no. [1]
dm
’’/dt [k
g/(
s*m
2)]
Horizontal vent
Full vent, A
g=1.0 d
h=1.0 AR
v=1.0
Full vent, Ag=1.2 d
h=1.1 AR
v=0.8
Full vent, Ag=1.4 d
h=1.2 AR
v=0.7
Full vent, Ag=1.6 d
h=1.2 AR
v=0.6
Full vent, Ag=1.8 d
h=1.3 AR
v=0.6
Full vent, Ag=2.0 d
h=1.3 AR
v=0.5
Full vent, Ag=2.8 d
h=1.5 AR
v=0.4
Full vent, Ag=4.0 d
h=2.0 AR
v=1.0
Full vent, Ag=5.6 d
h=2.3 AR
v=1.4
Full vent, Ag=3.9 d
h=1.9 AR
v=0.5
Passive vent, Ag=1.0 d
h=1.0 AR
v=1.0
Passive vent,Ag=1.2 d
h=1.1 AR
v=0.8
Passive vent,Ag=1.4 d
h=1.2 AR
v=0.7
Passive vent,Ag=1.6 d
h=1.2 AR
v=0.6
Passive vent,Ag=1.8 d
h=1.3 AR
v=0.6
Passive vent,Ag=2.0 d
h=1.3 AR
v=0.5
Passive vent,Ag=2.8 d
h=1.5 AR
v=0.4
Passive vent,Ag=4.0 d
h=2.0 AR
v=1.0
Passive vent,Ag=5.6 d
h=2.3 AR
v=1.4
Passive vent,Ag=3.9 d
h=1.9 AR
v=0.5
Vena
contracta
No VC
avg
hvv
avv
fdsvfdsg
hvg
fdsg
fdsv
AC
CCA
A
AC
,
,
,
,,
,
,
,
=
=
• Buoyancy-driven vent modelling
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 8
• Fire safety factors
• is adressing uncertainties
– The more freedom => the more
• What should control
− Risk based approach reflecting societal risk
levels within each bldg. class
– : Uncertainties in input parameters
and assumptions
– Reflected in sensitivity study
– Guideline on sensitivity study
– : Mathematical model assumptions and numerical precision
– Can be model dependent
Proposed Control Measures
( )γf
( ) 0; ≥−= FSLRSETfASETFSL γ
( )γf
iγ
inγ
outγ
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 9
• Fire safety factors
• IMPLICATIONS for model uncertainty:
− Risk based approach
− Clear height [EN 12101-5] compared to 2
m height of person:
– Public: 3 m =>
– Non-public: 2.5 m =>
– Not coupled to a certain model
• Intentions behind PBFC should still be met
− Fire protection costs should be reduced
• The good FSE should not be punished
− Verify proposed fire safety design
− Example: Evac. modelling of spiral stairs
Proposed Control Measures
%25:γ%50:γ
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 10
• Capacity of spiral stairs
• AROS Museum of Modern Art, Aarhus (DK)
• Hand rail in 1/3 point to improve capacity
Full-Scale Testing and Verification
[Olafur Eliasson]
ImprovedExisting
Handrail
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 11
Full-Scale Testing and Verification
Staircase Flow
[pers/10 s]
No handrail 16
Handrail 24
ImprovedExisting
• Full-scale test
• 3 rep. tests with 200 pers. in each staircase
• Findings
Lane Outer Centre Inner
Speed
[m/s]
1.3 0.8 0.6
Up
50%
Compares to 0.7 m/s
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 12
Proposed Control Measures
• Knowledgeable user/Methodology
• Fire strategies and documentation
− Know your audience (AHJ, eng., arch.)
− Assumptions must be clearly stated
− Increased requirements to AHJ training
• Engineering guidelines should be applied
− Ensures conformity in PB design
− DK: Task force on CFD guideline
• Fire safety engineers must be certified
− National standards of minimum competence
− Education alone does not cut it
− Sanctions can be imposed
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 13
Approval and Peer-Review
• The approval process must:
• Enforce societal risk control
− Approved by building AND fire authorities
– Design parameters (e.g. design fire)
− Requires trained and experienced AHJ’s and third party peer-reviewers
– Certified FSE reviewers in knowledge
centres
– DK: Big difference in training
• Prevent the ”Boiling Frog Syndrome” [Senge, P. M., 1993]
− GLOBAL: Bldgs. with unkown risk level
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 14
End of Presentation
THANK YOU!
[NRCC/MTQ: Full-scale fire test, Ville-Marie Tunnel, Montreal (CA)]
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 15
Commissioning, Operation and Management
• Commissioning:
• Complete test of the fire safety design
− Capacity of sprinklers and SHEVS
− Verify fire protection system operation
matrix (FP-SOM)
− Test report should accompany design
documentation
− DK: FSE contract typically terminates at this point
Safety
I:\inf\pr-toolbox\over heads\Firmapres entation_nov2005.ppt 16
Commissioning, Operation and Management
• Operation:
• Design compliance should be ensured
throughout the building lifetime
− System mean life time, L:
− Regular verification of FP-SOM by testing
∑=
=n
i
i
L
1
1
λ
[Klote (2002)] - Other: 1E-5/hr
[Klote (2002)] - Fan: 1E-6/hr
L=23 months L=9 months