Hyeong-Jin Kim

Heat release rates of burning items in fires

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, in terms of heat release rate vs time, are required to be specified by the user as input to single-room and multiroom structural fire computer codes such as CFAST, FASTLite, FPETool, and HAZARD. Data are given that permit burning items to be specified in a useful modeled way, taking a t 2 fire for the growth and decay periods, with a constant maximum heat release rate between these two periods. By the use of the given data, a user of a fire simulation program can simply and easily specify the initial fire of a typical burning item, rather than having to appeal to the original experimental data. In this way, the user does not need to search for and incorporate a complicated set of numbers into the fire simulation program.

Comparison of Criteria for Room Flashover

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 firegrowth rate, ventilation opening area, and room area. A comparison of flashover criteria is undertaken using the Thomas, Babrauskas, and the CFAST/FASTLite criteria, concentrating on the similarities and differences between the criteria in their assessment of the major parameters affecting the time to reach flashover.

Comparison of theories for room flashover

Flashover is characterized by the rapid transition in fue behavior from localized burning of fuel to the involvement of all combustibles in the enclosure. The objective of the present contribution is to calculate the development of flashover in a typical single room fire, and show the effect of ten key parameters on the time required to reach flashover conditions. It is found that the major parameters affecting flashover are fire growth rate, ventilation opening area, and room area. A comparison of flashover theories is then 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.

Flashover: A Study of Parameter Effects on Time to Reach Flashover Conditions

Flashover is characterized by the rapid transition in fire behavior from localized burning of fuel to the involvement of all combustibles in the enclosure. The objective of the present contribution is to calculate the development of flashover in a typical single-room fire and show the effect of key parameters on the time required to reach flashover conditions. It is found that the major parameters affecting flashover are fire growth rate, ventilation opening area, wall and ceiling material, and room area. Parameters with little effect on the time to reach flashover are vent height above the floor, ceiling height, fire location, and fire radiation heat loss fraction.

Models of fire development - A review

The ultimate goal of this study is to improve scientific understanding of fire behavior leading to flashover in structural fires. This document summarizes important information in five topic areas: burning rates, radiant ignition, fire spread rates, ventilation limit imposed by size of opening, and flashover criteria. These are the main components related to the scientific understanding of the fire growth and flashover problem involved in real-world structural tires. Main components of the study are to develop improved mathematical simulations so as to improve the accuracy of theoretical calculation and to develop and extend the range of knowledge and modeling capability so as to extend the range of available experimental data.

Computer Modeling of Developing Structural Fires

*† 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 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. Zone-type and field-type computational fluid dynamic CFD modeling approaches to multi-room structural fire modeling are reviewed in this study. Their background, methodology, applicability are discussed. Studies of this type assist in the understanding of structural fires, and the development of computer modeling studies, and assessment of their predictive capability.

Structural Fire Modeling With the Zone Method

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.Copyright

Fire Dynamic Calculations and Illustrations

The ultimate goal of this study is to improve scientific understanding of fire behavior leading to flashover in structural fires. This document summarizes important information in five key topic areas related to the modeling of fire development: burning rates, radiant ignition, fire spread rates, ventilation limit imposed by size of opening, and flashover criteria. These are the main components related to the scientific understanding of the fire growth and flashover problem involved in real-world structural fires. Main components of the study are to develop improved mathematical simulations so as to improve the accuracy of theoretical calculations. Hence, the study helps to develop and extend the range of knowledge and modeling capability so as to extend the range of available experimental data.

A criterion for the development of fires in multiroom structures

Modeling of multiroom structural fires is possible with a variety of available computer codes, thus permitting calculations of temperature and smoke level in different rooms as the fire progresses from one room to the next. The accuracy and applicability of the results is greatly enhanced though the comparison of the calculations with experimental data. A criterion is suggested and confirmed that permits fire spread from room to room on the basis of the initiation of the next rooms fire to be at the instant of flashover of the previous adjacent room (which is connected to the next room via an open doorway). An even simpler approach with single room calculations, each up to the onset of flashover, then the next room begins to fire up from cold, is also considered, and shown to provide very useful cost-effective results.

Accuracy of the Three-Room Simulation of a Ten-Room Large House Fire

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.Copyright