FIERAsystem Theory Report: Fire Spread Model

(FSPM)

Kashef, A.; Bnichou, N.; Reid, I.; Hadjisophocleous, G.

IRC-RR-134

www.nrc.ca/irc/ircpubs

FIERAsystem Theory Report: Fire Spread Model (FSPM) Ahmed Kashef, Noureddine Benichou, Irene Reid, and George Hadjisophocleous Research Report No. 134 May 2003 Fire Risk Management Program Institute for Research in Construction National Research Council Canada

Table of Contents Table of Contents ............................................................................................................................................. i List of Figures................................................................................................................................................... i 1. INTRODUCTION............................................................................................................................2

2. FSPM DESCRIPTION....................................................................................................................3

3. REFERENCES...............................................................................................................................4

List of Figures FIGURE 1 EXAMPLE OF FIRE SPREAD IN A MULTI-COMPARTMENT BUILDING .................................4

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1. INTRODUCTION

As Canada and other countries move from prescriptive-based building codes to performance/objective-based codes, new design tools are needed to aid in demonstrating that compliance with these new codes has been achieved. One such tool is the computer model FiRECAM, which has been developed over the past decade by the Fire Risk Management Program of the Institute for Research in Construction at the National Research Council of Canada (NRC). FiRECAM is a computer model for evaluating fire protection systems in residential and office buildings that can be used to compare the expected safety and cost of candidate fire protection options.

To evaluate fire protection systems in light industrial buildings, a new computer model is being developed. This model, whose current focus is aircraft hangars and warehouses, is based on a framework that allows designers to establish objectives, select fire scenarios that may occur in the building and evaluate the impact of each of the selected scenarios on life safety, property protection and business interruption. This model will assist engineers and building officials in evaluating, in a clear and concise manner, whether a selected design satisfies the established objectives for a building. The new computer model is called FIERAsystem, which stands for Fire Evaluation and Risk Assessment system [1].

FIERAsystem uses time-dependent deterministic and probabilistic models to evaluate the impact of selected fire scenarios on life, property and business interruption. The main FIERAsystem submodels calculate fire development, smoke movement through a building, time of failure of building elements, and occupant response and evacuation. In addition, there are submodels dealing with the effectiveness of fire suppression systems and the response of fire departments.

This report describes the theoretical framework of the Fire Spread Model (FSPM) of the FIERAsystem. The FSPM code was developed to evaluate the different scenarios involving the fire spreading from a fully-developed fire in the compartment of fire origin to adjacent compartments, corridors, or stairwells in a building. The fire spread from one compartment to an adjacent compartment depends on the fire resistance performance of the boundary element that separates them. The FSPM calculates the time of fire spread to adjacent compartments (delay time) and the heat release rates, temperatures and heat fluxes in the adjacent compartments.

The FSPM can be run independently, or in conjunction with other models to perform

a complete risk or hazard analysis. If used in a stand-alone mode, the user should input the fire characteristics in the compartment of fire origin (fire heat release rate, heat fluxes, temperatures) and the delay time.

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2. FSPM DESCRIPTION

The FSPM requires the following input: Compartment of fire origin, Type of fire, Fire characteristics, such as heat release rates, temperatures, and heat fluxes,

as functions of time, Whether or not the fire department will arrive if notified, Whether or not the suppression system will activate properly. In order to make fire spread calculations manageable, FSPM only considers fire

spread to adjacent compartments. For example, in Figure 1, where the compartment of fire origin is Compartment A, only fire spread to Compartments B and C would be considered. Fire spread to Compartment D would be ignored.

The FSPM shifts the fire characteristic curves (specified by the user, in a stand-alone

mode, or calculated by the Fire Development Model [2], in an integrated mode) by a delay time. The delay time is the time at which the boundary element of the compartment of fire origin would fail (fire resistance rating of the boundary element) or the compartment temperature reaches a critical value. For the current version of FSPM, the critical temperature is set as 1000oC. This temperature represents the expected temperature, from the standard time-temperature curves [3], at a time of 120 min. Different values of the critical temperature could be chosen depending on the level of conservatism required. The feature of setting the value of the critical temperature is not available for the user in the current version, however, it could easily be accommodated in future releases.

The delay time is an input by the user, in the stand-alone mode, or if the FSPM is run

in an integrated mode, is calculated automatically for the user. In which case, the delay time is the lesser of the failure time (predicted by Boundary Element Failure Model, BEFM [4]) and the time to reach 1000oC (predicted by the Smoke Movement Model, SMVM [5]). The FSPM main output is:

Time of fire spread to adjacent compartments. Heat release rates, temperatures and heat fluxes in adjacent compartments.

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Figure 1 Example of fire spread in a multi-compartment building

3. REFERENCES

1. Benichou, N., Kashef, A., Torvi, D.A., Hadjisophocleous, G.V., and Reid, I., FIERAsystem: A Fire Risk Assessment Model for Light Industrial Building Fire Safety Evaluation, IRC Research Report No. 120, Institute for Research in Construction, National Research Council Canada, Ottawa, ON, 2002.

2. Kashef, A., Benichou, N., Torvi, Raboud, D.W., D.A., Hadjisophocleous, G.V., and Reid, I., FIERAsystem Enclosed Pool Fire Development Model: Theory Report, IRC Research Report No. 121, Institute for Research in Construction, National Research Council Canada, Ottawa, ON, 2002.

3. Buhanan, A.H., Structural Design for Fire Safety, John Wiley & Sons, Ltd., Baffins Lane, Chichester, England, ISBN 0-471-88993-8.

4. Benichou, N., Kashef, A., and Reid, I., FIERAsystem Building Boundary Element Failure Model (BEFM): Theory Report, IRC Research Report No. 135, Institute for Research in Construction, National Research Council Canada, Ottawa, ON, 2003.

5. Fu, Z., Kashef, A., Benichou, N., and Hadjisophocleous, G.V., FIERAsystem Theory Documentation: Smoke Movement Model, IRC Internal Report No. 835, Institute for Research in Construction, National Research Council Canada, Ottawa, ON, 2002.

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134.pdfTable of ContentsList of FiguresINTRODUCTIONFSPM DESCRIPTIONREFERENCES