Structural Fire Calculations

Author(s):  
David G. Lilley

Abstract Information and calculations are given for estimating fire growth in structural fires. Heat release rates from flames, fire growth, ignition of nearby items, and the possibility of flashover are all topics of concern. Empirical equations are given and calculations are exhibited to illustrated these aspects of structural fire behavior.

Author(s):  
Hyeong-Jin Kim ◽  
David G. Lilley

Abstract Heat release rates of typical items in fires are needed as a prerequisite for estimating fire growth and temperatures in structural fires. That is, these burning rates are required to be specified by the user as input to single-room and multi-room structural fire computer codes like FPETool, FASTLife and HAZARD. Data are given here that permit burning items to be specified in a useful modeled way, taking a t2-fire for the growth and decay periods, with a constant maximum heat release rate between these two periods.


Author(s):  
Hyeong-Jin Kim ◽  
David G. Lilley

Abstract In structural fires, flashover is characterized by the rapid transition in fire behavior from localized burning of fuel to the involvement of all combustibles in the enclosure. Major parameters affecting flashover are fire growth rate, ventilation opening area, and room area. A comparison of flashover theories is undertaken using the Thomas, Babrauskas and the FASTLite theories, concentrating on the similarities and differences between the theories in their assessment of the major parameters affecting flashover.


Author(s):  
David G. Lilley

Abstract A computer-based fire model is a scientific mathematical representation of a fire. Computer simulations incorporate to some degree the many chemical and physical processes taking place. Structural fire behavior is considered with emphasis on fire development (burning rates, radiant ignition, flashover and backdraft), experimental studies and fire modeling (field and zone models).


Author(s):  
Hyeong-Jin Kim ◽  
David G. Lilley

The development of the fire analytical modeling has accelerated over the last 30 years. As a result, fire modeling can often be used to appraise the effectiveness of the protective measures proposed when one designs a building. Fire behavior is extremely important in fire protection engineering and building design engineering. The ultimate goal of modeling studies is to improve scientific and technical understanding of fire behavior leading to flashover in structural fires. The zone modeling approach to multi-room structural fire modeling is emphasized in this study. This paper also summarizes the theory and methodology of the CFAST (Consolidated Model of Fire Growth and Smoke Transport) model, and its simpler variant the FASTLite model, which are zone type approaches being widely used by the authors. Studies of this type assist in the understanding of structural fires, and the development of computer modeling studies, and assessment of their predictive capability.


Author(s):  
Hyeong-Jin Kim ◽  
David G. Lilley

Calculations (with a 10-room and a simpler 3-room simulation of the large house fire) of temperature and smoke levels in several rooms of a structural fire are possible with the CFAST computer code. The accuracy and applicability of the results is greatly enhanced though the comparison of the calculations with experimental data. Experimental work thereby assists in understanding fire behavior in structural fires. Temperature measurements at different locations during a house fire provide necessary data for the development of mathematical models, which attempt to simulate the fire on a computer. In this paper, a large 170 square meter single-level house was subject to a complete experimental burn, with temperature measurements and fire observations during the entire burn, and subsequent modeling via a detailed 10-room simulation and a simpler 3-room simulation. The CFAST (Consolidated Model of Fire Growth and Smoke Transport) computer code is used to calculate temperatures and smoke levels in the various rooms of the house during the burn (with 10 different rooms). Four fire scenarios are considered in the simulation, with increasing realism regarding the actual fire specification. A simpler calculation (with 3 different rooms) has also done to see if the similar results would be shown with the 10-room simulation. It was found that results for smoke temperature and smoke layer heights were very similar, leading to the conclusion that a 3-room simulation of a 10-room building gives adequate modeling capability of the real structural fire. Computation results give the expected trends (deduced from local point temperature measurements) of initial temperature surge and decay, peak and leveling off temperatures, especially with respect to the northwest bedroom with a closed door. The effect of whether a door of a room would have been open was investigated computationally, with results illustrating far more dangerous smoke temperature and smoke level in the room when its door is open.


1991 ◽  
Vol 83 (3-4) ◽  
pp. 325-332 ◽  
Author(s):  
E.E. Zukoski ◽  
J.H. Morehart ◽  
T. Kubota ◽  
S.J. Toner

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