lund university / faculty of engineering / department of fire safety engineering and systems safety...

Lund University / Faculty of Engineering / Department of Fire Safety Engineering and Systems Safety

SIMULATION OF CRITICAL EVACUATION CONDITIONS

FOR FIRE SCENARIOS INVOLVING CABLES AND

COMPARISON OF DIFFERENT CABLESPatrick van Hees & Daniel Nilsson

Lund University – Department of Fire Safety Engineering and Systems Safety


Outline• Background and Scope• Choice of building• Fire modelling• Evacuation modelling• Tenability assessment• Conclusions• Future research


•Is a cable fire dangerous in a realistic

building environment?

•Is cable A better then cable B?

•Suitable methods for assessment?

Background


Background• Prescriptive rules

• Example:

Exit must be 1 m wide

• Performance based rules

• Example:

Everyone must be able to evacuate before conditions become critical


• Prescriptive rules

• Example:

Only cables of class X are allowed in evacuation routes

• Performance based rules

• Example:

A specific cable is allowed in evacuation paths if safety can be demonstrated

Background


•Fire Safety Engineering

(FSE) methods

Background


•Develop feasible technique using FSE

•Compare 2 cables with the technique

Scope


Layout of the procedure


•Requirements

•a public building

•a realistic building - FSE possible

•existence of fire risk related to cables

•data available – evacuation or fire

•possible exposure to gases

Choice of the building


Choice of the building


•Possible locations

•Cable cabinet – under balcony

•Cables in appliances - kitchen

•Vertical cable tray – in atrium

Fire scenario


Fire scenario•Possible locations:


•Choice fire position:

Vertical cable tray – in atrium

from pre-simulations

Fire scenario


Fire scenario•Design fire

•Data from cable tests – prEN 50399

•2 cables - Euroclass D

•Cable I

•Cable M

•FIGRA value => growth rate up to 0.5 MW


•Design fire

•Product yields from fire tests

•Cable I – carbon monoxide, carbon

dioxide, soot

•Cable M – carbon monoxide, carbon

dioxide, soot, acrolein, formic aldehyde,

hydrogen chloride

Fire scenario


•Design fire

Fire scenario


Fire modelling

•Computational Fluid Dynamics (CFD)


•FDS 5 software –

parallel version on cluster

Fire modelling


Fire modelling


•Evacuation experiment – input data

•Time to start (pre-movement)

•Exit choice

•Flow on stairs

Evacuation scenario


•Evacuation experiment – input data

Evacuation scenario


•Evacuation scenarios – 6 scenarios

•Number and location of occupants

•Exit choice

•One scenario selected for tenability

assessment (based on 450 occupants)

Evacuation scenario


•Simulex software

Evacuation modelling


•FED and FEC – ISO TS 13571

•FED – accumulated dose

•FEC – momentary concentration

•Combination of results

•FDS – Fire simulations

•Simulex – Evacuation simulations

•Matlab – FED and FEC calculations

Tenability assessment


Property Cable I Cable M

FED > 0.3

0 0

FEC > 0.3

0 41

Tenability assessment

Based on 450 occupants


•Feasibility of the method was demonstrated in

this case study

•Cable M worse than Cable I

for this case study

Conclusions


•Develop method further

•Compare cables with other characteristics

•Test method for other buildings and cases

•Sensitivity of input data from fire tests

•Extend to other materials/products

Future Research


Acknowledgments

• Report available at www.brand.lth.se/publikationer

• Video available at http://safety-during-fire.com/library.html


www.brand.lth.se/english

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