Spreading fires

The flame spread rate can be represented in terms of the pyrolysis front (xp) from Equation (8.7a)  

For concurrent spread, the growth rate can be much faster, and therefore the critical condition can be reached at lower compartment temperatures. The dependence of the concurrent flame spread area on both Q and the surface temperature of the material make this spread mode very feedback sensitive. 

The Semenov criticality diagrams for fire growth are useful to understand the complex interactions of the fire growth mechanisms with the enclosure effects. These diagrams can be used qualitatively, but might also be the bases of simple quantitative graphical solutions. 

Karlsson, B. and Quintiere, J. G., Enclosure Fire Dynamics, CRC Press, Boca Raton, Florida, 2000. 

Engineering Guide to Fire Exposures to Structural Elements, Society of Fire Protection Engineers, Bethesda, Maryland, May 2004. 

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Combustible Dusts Dusts are particularly hazardous they have a very high surface area-to-volume ratio. When finely divided as powders or (dusts, solids burn quite differently from the original material in the bulk. Dust and fiber deposits can spread fire across a room or along a ledge or roof beam very quickly. On the other hand, accumulations of dust can smolder slowly for long periods, giving little indication that combustion has started until the fire suddenly flares up, possibly when no one suspects a problem. 

Gas Temperature Approximate Scale EC) Figure 11.22 Surface spread fire growth... 

Combinations of photoelectric and ionization detectors are available that operate as describe above. They are used to detect either smoldering or rapidly spreading fires. 

Jettisonable Airplane Fuel Tank Bombs. Another type of US incendiary bomb was the coverted auxiliary airplane fuel tank of 75 to 300 gallon capacity. They were filled with jellied gasoline and provided with a fuse and an igniter. Such bombs spread fire over a large area and were very effective against Japanese targets (Ref 10, p 239 Ref 15, part IV)... 

The characteristics of a chemical or substance that would categorize it as a reactive material include (1) it reacts violently with water, (2) it forms potentially explosive mixtures with water, or (3) when mixed widi water or other chemicals, it generates toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment. Because water is the most common fire suppressant, the characteristic of reactivity is especially relevant since the application of water to eliminate or prevent the spread fires may be counterpro-ductive rather than helpful. Several categories of chemicals will be discussed from this standpoint however, several of these same chemicals also present additional hazards. 

Hasemi, Y., Experimental wall flame heat transfer correlations for the analysis of upward wall flame spread. Fire Science and Technology 1984,4, 75-90. 

Flame spread (opposed flow and wind-aided flame spread, fire growth rate, etc.)... 

Surprisingly, much less work has been conducted to predict burning rates of stationary fires (particularly on solid fuels) than spreading fires. The studies that have been conducted to date fall into two primary categories (1) prediction of burning rates in small-scale flammability experiments such as the Cone Calorimeter [85,86], and (2) prediction of burning rates in liquid pool fires [74-76],... 

Zhang, J., Dembele, S., Karwatzki, J., and Wen, J.X. Effect of radiation models on CFD simulations of upward flame spread. Fire Safety Science—Proceedings of the Eighth International Symposium, Vista, FL, 2005, pp. 421 132. 

Interior finish, decorations, furnishings, and other combustibles that contribute to fire spread, fire load, and smoke production... 

Hitting and friction of floating roofs Spreaded fire Open fire... 

N-Butyl Acetate 75 99 1.7 7.6 Foam, dry chemical, carbon dioxide Water in straight hose stream will scatter and spread fire and should be avoided Not pertinent 760 No ... 

EXPLOSION and FIRE CONCERNS flammable liquid dangerous fire hazard NFPA rating Health 2, Flammability 3, Reactivity 2 reacts violently with chlorosulfonic acid vigorous reaction with oxidizing materials vapors may travel to an ignition source and flash back liquid floats on water and may travel to an ignition source and spread fire sealed containers may rupture violently when exposed to heat use carbon dioxide, dry chemical powder, or alcohol foam for firefighting purposes. 

Backup or flooding in a municipal sewer may inconvenience motorists and may cause some property damage. Around a refinery or chemical plant unit, backup can cause serious fires of spread fires that are confined to one area. Thus, in sizing a branch sewer or lateral, it is very important to consider the probable amount of fire water which may be used in the event of fire. 

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