Flame Extinguishment Properties of Dry Chemicals: Extinction Weights for Small Diffusion Pan Fires and Additional Evidence for Flame Extinguishment by Thermal Mechanisms

Ewing, C. T.; Faith, Francis R.; Romans, J. B.; Hughes, J. Thomas; Carhart, Homer W.

doi:10.1177/104239159200400201

Cited by 36 publications

(23 citation statements)

References 5 publications

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“…In addition, the particle size was also found to be negatively correlated with the extinguishing time. This result agrees well with the fact that the particle size of suppressants generally governs their fire-extinguishing ability [28]; also, it suggests that the extinguishing time and dispersion stability might be improved by using smaller ferrocene particles. However, a comparison between the extinguishing times of S1 ferrocene/surfynol 465 and S1 ferrocene/ DTAC dispersions demonstrated that the surfactant had little influence on extinguishing time in this study; furthermore, systematically investigating the influence of the surfactant on the extinction ability using a large variety of surfactants is necessary.…”

Section: Fire Suppression Experimentssupporting

confidence: 77%

Fire extinguishing properties of novel ferrocene/surfynol 465 dispersions

Koshiba

Iida

Ohtani

2015

Fire Safety Journal

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a b s t r a c tThis paper reports a novel fire-extinguishing agent: an aqueous dispersion of fine ferrocene particles. In this study, the ferrocene-water-surfactant dispersions were prepared to optimize the gas-phase concentration of ferrocene, and their ability to extinguish heptane fires was examined. The fire-extinguishing efficiency was characterized by three parameters: the ferrocene concentration in the dispersion (0-175 ppm), the surfactant used, and the ferrocene particle size (d 50 ¼10.4, 11.4, 21.5, and 68.8 μm). The results indicated that (1) the ferrocene (d 50 ¼10.4 mm)-water-surfynol 465 dispersion is the most stable among the dispersions tested, (2) the ferrocene-water-surfynol 465 dispersions have an optimal value of ferrocene concentration regarding the extinguishing time, and (3) in the ferrocene particle size range of 10.4-21.5 μm, the minimum extinguishing time of the ferrocene-water-surfynol 465 dispersions is remarkably shorter (1.2 s) than those observed when using a conventional wet chemical agent (45 wt% aqueous solution of potassium carbonate, 12.9 s).

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Section: Fire Suppression Experimentssupporting

confidence: 77%

Fire extinguishing properties of novel ferrocene/surfynol 465 dispersions

Koshiba

Iida

Ohtani

2015

Fire Safety Journal

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“…(W/W )s8 = 2.275-1.270 X (3) where (W/Wg~sis the extinction weight ratio (2.32 m 2 pari) for the small-particle fraction, (< 38/am) without carrier; W is the real extinction weight (2.32 m 2 pan) for the (< 38/am) fraction, g/m2; W is the latent extinetion weight (2.32 m 2 pan) for the (< . Later in the article, we will use Equation 9 to predict the large-pan extinction ratio for any carrier extinguishant combination where the extinguishant fraction is equal to, or greater than, that of the aerodynamically optimal fraction.…”

Section: Experimental Extinction Ratio Curvesmentioning

confidence: 99%

“…3 The selected values of S in Table 2 were those that gare the highest degree of data correlation. Limit sizes for the same dry chemicals observed in small pan studies z3 are included in Table 2 for comparison.…”

Section: S C a L L N G F A C T O R Smentioning

confidence: 99%

Extinguishing class B fires with dry chemicals: Scaling studies

et al. 1995

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In a continuing study of flame extinguishment, ~, 2, 3, 4 we report on scaling studies for dry chemicals on larger heptane diffusion flames (0.29 m 2 and 2.32 m 2 pans). We demonstrate again that small particle sizes extinguish most effectively. Extinguishment is related to heat absorption by decomposing or vaporizing particles. We show that the limiting particle size for each dry chemical--that is, the maximum size which completely decomposes or vaporizes in the flame--is independent of flame size for the systems studied. We broaden and apply the concept of latent or maximum effectiveness 2,3 to pan fires of all sizes. Finally, we describe and characterize an aerodynamic effect in the transport of powders, where large particles with their higher momenturn entrain and drag smaller, more effective particles into the flame.We also show that extinction curves, involving the ratio of real-to-latent extinction weight and the proportion of small to large particles, have predictable shapes and predictable quantitative levels for most dry chemicals. We have developed the real-to-latent concept along with scaling equations for agent mixtures and for a wide spectrum of agents and particle sizes.

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“…For example, Krasnyansky [3] assessed the fire suppression performance of mixedphase agents of 5 μm ABC dry powder and nitrogen in combination with halon 2402 in a 100 m 3 chamber and a tunnel with a length of 180 m and a cross section of 3 m 2 . Ewing [4] studied the extinguishing performance of several kinds of dry powder using n-heptane diffusion flame in a 422-liter chamber. Adam [5] examined the performance of non-pyrotechnically generated aerosols fire suppressants in an 8 m 3 chamber.…”

Section: Introductionmentioning

confidence: 99%