【導(dǎo)讀】式滅火器的趨勢(shì)，而且這一趨勢(shì)正在增強(qiáng)。作者研究了使用泡沫方式對(duì)泡沫效率的影響，流散火災(zāi)對(duì)蛋白泡沫的滅火性能的影響已經(jīng)在多篇論文中論述解釋了。Tuve和Peterson在他們自己寫(xiě)的論文中很。泡沫的膨脹性和密度可以承受一定的效率變化，只要它超過(guò)最小臨界值。泡沫的黏度和它的水吸出率是密切相關(guān)的。在泡沫的應(yīng)用中，需要美制加侖每平方英尺的泡沫含水量用以平衡后大火中。在又有這樣一個(gè)趨向，既趨向于使用大容量的泡沫滅火器來(lái)保護(hù)油罐。超過(guò)600美制加侖的泡沫與水的混合物。調(diào)整噴射孔以便產(chǎn)生。了所允許的15分鐘預(yù)燒后實(shí)施的。試驗(yàn)使用了4%的泡沫溶液，這種泡沫溶液由兩種可獲得的已商業(yè)化的水解蛋白。中獲得的曲線(xiàn)非常接近的。熱區(qū)以每小時(shí)24到36英寸的速率形成，并且在熱區(qū)和冷油之間。實(shí)驗(yàn)中使用了兩個(gè)不同批次的燃料，蒸餾實(shí)驗(yàn)顯示了熱區(qū)在每種情況下所對(duì)應(yīng)

　　

【正文】 sec. From the results of the laboratory tests and the 18ft2 fire, one might have expected that the 400ft 2 test fire would have been controlled readilyunder test conditions by the two hydrolyzed protein foam pounds applied at an application density of gpm/ft 2. One difference in the400ft2 test fire was that only a 2in. fuel depth was used as pared with deeper fuel layers on the smaller fires. It could, however, be an extension of the scale effect that was thought to explain the differences obtained between the small laboratory test fires and the 18ft 2 test fire results. LIGHT WATER Investigations of new foaming agents at the . Naval Research Laboratory led to the development of Light Water foam pound. There are a number of reports 57 relating its performance on shallow fuel layers associated with its use on aircraft crash fires. There are no test results reported on its performance on deep fuel layers。 therefore, a test was made on the 18ft2 test fire with a 30min preburn time at an application rate near the critical rate for the fluoroprotein foam . 70 used in the test program. The results are given in Table 4 together with the results for the other foaming agents used in the test program. TABLE 4. Results of 18 ft2 Fire Test of Regular Grade 90 Octane Gasoline, 17 in. Deep, after 30 rain Preburn Time (Foam Applied in Straight Stream to Center of Fire Area at a Rate of gpm/ft2) Foaming agent Fire performance Light Water, 6 per cent solution Fluoroprotein . 70, 6 per cent solution Hydrolyzed protein A Hydrolyzed protein B 90 per cent control in 1 rain. Extinction in 5 rain* 90 per cent control in 2 rain. Extinction in 5 rain * No control after 15rain foam application No control after 15rain foam application *Although Light Water had a more rapid control time than . 70, the long extinction times in both cases were due to persistence of flames near the hot tank wall. CONCLUSIONS The following conclusions were drawn from the work described in this paper. ? Where normal proteinbased foams are applied forcibly to fires in Class A flammable liquids, their efficiency is greatly reduced pared with gentle application to the surface. ? Under operational conditions in the event of fire in a fuel storage tank containing gasoline, a hot zone at 70176。C to 80 176。 C is likely to form. Under these conditions, normal proteinbased foams are even less efficient, unless applied gently, and foam application at the present remended rates ( gpm/ft 2) would have no effect on the fire. ? Results on the 400ft2 test fire suggest that there could be scale effects for this type of foam application and point to higher values of the critical rate of application even for short preburn times. Further work is required at this and larger scales on fires in deep fuel layers with long preburn times in metal tanks. ? Foams made from the fluoroprotein foam and Light Water, applied at rates below the present remended rates of application, extinguished the test fires rapidly, even when a deep hot zone had been formed. REFERENCES [1] Tuve, R. L. and Peterson, H. B., A Study of Some Mechanical Foams and Their Use for Extinguishing Petroleum Fires, NRL Report 3725, 23 Aug. 1950, . Naval Research Laboratory [2] French, R. J., Hinkley, P. L., and Fry, J. F., The Surface Application of Foam to Petrol Fires, Fire Research Note No. 21, 1952, Department of Scientiiic and Industrial Research and Fire Offices39。 Joint Fire Research Organization. [3] Fry, J. F. and French, R. J., A Mechanical Foam Generator for Use in Laboratories, Journal of Applied Chemistry, Vol. 1 (1951), pp. 425429. [4] Burgoyne, J. H. and Katan, L. L., Fires in Open Tanks of Petroleum Products: Some Fundamental Aspects, ,Journal of the Institute of Petroleum~ Vol. 33 (1947), p. 158. [5] Tuve, R. L., et al, A New Vapor Securing Agent for Flammable Liquid Fire Extinguishment, NRL Report 6057, 13 March 1964, . Naval Research Laboratory. [6] Tuve, R. L., et al, Fullscale Fire Modelling Test Studies of 39。Light V~rater 39。 and Protein Type Foams, NRL Report 6573, 15 Aug. 1967, . Naval Research Labora tory. [7] Fittes, D. W. and Nash, P., Light Water, Fiie, Vol. 61, No. 759 (Sept. 1968)pp. 170171,195.