Understanding Fire

Fire creates a very rapid chemical reaction between oxygen and a combustible material. This reaction results in the release of heat, light, flame, and smoke. Fire needs a sufficient amount of oxygen to sustain combustion and a sufficient amount of heat to raise the material to its ignition temperature. Fire also needs some type of fuel or combustible material to burn (Table 7.1). 

Incipient stage—during this stage, no smoke, flame, or significant heat buildup is visible, but a large quantity of combustion particles created by chemical decomposition can rise 

Smoldering stage—as the incipient stage continues, the combustion particles increase until they become as smoke with no flame or significant heat source. 

Flame stage —as the fire condition develops further, ignition occurs and flames appear, 

Heat stage—at this point, large amounts of heat, flame, smoke, and even toxic gases become apparent. This stage develops very quickly, usually in seconds. 

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Understanding fire hazards is essential to risk reduction and fire protection decision-making. A fire hazard analysis (FHA) is a tool used to understand fire hazards. The process of quantifying the fire hazard is typically motivated by the need to determine the overall hazard of a process or facility or to have a decision-making tool for fire protection systems (Chapter 6). An FHA is an important element of a risk assessment and can also be used as a stand-alone hazard evaluation tool. 

Understanding Fire Behavior and Fire Retardancy Mechanisms.405... 

UNDERSTANDING FIRE BEHAVIOR AND FIRE RETARDANCY MECHANISMS... 

The focus of this program was to evaluate the environmental profiles of chemical flame-retardant alternatives for use in low-density polyurethane foam.93 The program was a joint venture between the Furniture Industry, Chemical Manufacturers, Environmental Groups, and the EPA to better understand fire safety options for the furniture industry. It assessed 14 formulations of flame-retardant products most likely to be used in this application. The project began in December 2003 and the report was issued in September 2005.94... 

Firefighters learn about fire behavior as part of their basic training in order to have a better understanding of fire. Fire behavior is part of the chemistry of fire, which is really a chemical chain reaction. Understanding fire and how it behaves helps firefighters extingnish fires safely and effectively. 

Understand fire and life safety rules, procedures, and policies. 

We can think of a chemical reaction profile to help us understand fire better. Figure 5.1.2.4 shows an exothermic reaction with a moderately high activation energy barrier. To start the fire, some ignition source is needed to overcome E, but once the fire is burning, the heat released can supply the... 

There are seemingly endless programs to better understand fire tests and continually develop more realistic fire tests. Ohio State University has one with specific heat limits. The NIST has a cone calorimeter for heat release that is more sophisticated than the OSU one. And the National Institute of Building Science has an evolutionary version of the NIST smoke and toxicity test [361]. 

Morgan, A.B. Bundy, M. Cone calorimeter analysis of UL-94 V rated plastics qualitative correlations and heat release rate understanding. Fire and Materials. In review. 

These tests at ORNL have produced extensive data on the release of the volatile fission products ftom high-bumup LWR fuel under accident conditions. Although the release data obtained for the less-volatile spedes are less extensive, they contribute to understanding fire behavior of less-volatile spedes and to evaluating the assodated hazards. All of these results, including fiiel behavior, are summarized in Table 5. 

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