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ABSTRACTS AND REVIEWS 285 Nash, P., and Fittes, D. W. (Jomt Fire Research Organization, Boreham Wood, England) "Extmction of Industrial Fires by Foams," Fire Research Technical Paper No 24, London: Her Majesty's Stationery Office: 1970 Section: E Subjects: Extinguishment; Foams, Industrial fires Reviewed by R. L. Tuve This paper of general scope gives the applications, characteristics, necessary equipment needed (and its fundamentals of design), and U K specification test methods, for producing and using fire-fightmg foams of the following types Chemi- cal foam Mechanical or air foams Fortified mechanical foams (Fluoroprotem). All-purpose foams (Alcohol foams). "Light Water" foams. High expansion foams. The performance of ordmary protein based foams, all-purpose alcohol type foams and "Light Water" foams when applied to the burning surface of NBP (Narrow boihng range petrol), AVTUR (Aviation kerosene, JPl) , AVTAG (Wide-cut fuel, JP4), AVGAS (Aviation gasohne), AVPIN (Aviation starter fuel), and to burning surfaces of Industrial methylated spirit, methanol, iso- propanol, acetone and methyl ethyl ketone are also given. Comparative standards of 90 percent fire control time, the critical and optimum rates of apphcation, and the mmimum quantities (m gallons per sq. f t . ) necessary to control the test fires are used. The uses and governing characteristics which are involved with the surface apphcation of mechamcal foams and their subsurface apphcation (injection) m burmng flammable fuel storage tanks are outlined as are the elementary require- ments and uses of medium and high expansion foams (50 to 500 expansion range and 500 to 1200 expansion range respectively) for fire protection of fires within buildmgs of mixed Classes A and B The following comments are stated in this paper as general gmde lines m the consideration of foams for multiple uses in fire extmguishment The water retention of foam is a measure of its stability during and after extinction of fire and hence gives a gmde to post-extinction protection provided by the foam The simplest type of foam-making equipment for mechamcal, all-purpose or "Light Water" foams is the hand-held air induction branch pipe producing foams in the expansion range of 4 to 10 with a critical shear stress of 100-200 dynes per sq cm "Forcing type" aspiratmg foam makers operate at higher water pressures Other foam makers producing foam under pressure utilize separate pumps for air and foammg solution or vane-type, positive displacement rotatmg pumps. High expansion foams are produced m much larger self-aspiratmg portable branch pipes and m motor-driven air blower ducts where a mesh screen forms the separate bubbles. The design of the screen must be such that the air velocity through i t does not exceed 1 5 meters per second. Normal air foams are suitable for apphcation to the bummg surface of gaso- lines, kerosines, hght diesel and lubricatbg oils and other non-water-miscible fuels
