4. Morten Valkvist

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fire fighting

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  • 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 societys 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

    rddetpre ttt +=

    rdt

    [Okamoto et al. (2009), Fire Safety Journal 44, pp. 301-310]

    Npers/Ntotal

    trdOffice

    1.0

    Shopping

    [EN 12101-5]:=4,000 kW

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  • 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

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    Horizontal vent

    Full vent, Ag=1.0 dh=1.0 ARv=1.0Full vent, Ag=1.2 dh=1.1 ARv=0.8Full vent, Ag=1.4 dh=1.2 ARv=0.7Full vent, Ag=1.6 dh=1.2 ARv=0.6Full vent, Ag=1.8 dh=1.3 ARv=0.6Full vent, Ag=2.0 dh=1.3 ARv=0.5Full vent, Ag=2.8 dh=1.5 ARv=0.4Full vent, Ag=4.0 dh=2.0 ARv=1.0Full vent, Ag=5.6 dh=2.3 ARv=1.4Full vent, Ag=3.9 dh=1.9 ARv=0.5Passive vent, Ag=1.0 dh=1.0 ARv=1.0Passive vent,Ag=1.2 dh=1.1 ARv=0.8Passive vent,Ag=1.4 dh=1.2 ARv=0.7Passive vent,Ag=1.6 dh=1.2 ARv=0.6Passive vent,Ag=1.8 dh=1.3 ARv=0.6Passive vent,Ag=2.0 dh=1.3 ARv=0.5Passive vent,Ag=2.8 dh=1.5 ARv=0.4Passive vent,Ag=4.0 dh=2.0 ARv=1.0Passive vent,Ag=5.6 dh=2.3 ARv=1.4Passive vent,Ag=3.9 dh=1.9 ARv=0.5

    Vena contracta

    No VC

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    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

    ( )f

    ( ) 0; = FSLRSETfASETFSL ( )f

    i

    in

    out

  • 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:%50:

  • 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 16Handrail 24

    ImprovedExisting

    Full-scale test 3 rep. tests with 200 pers. in each staircase

    FindingsLane Outer Centre InnerSpeed [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 AHJs 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

    =

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    ii

    L

    1

    1

    [Klote (2002)] - Other: 1E-5/hr[Klote (2002)] - Fan: 1E-6/hr

    L=23 months L=9 months