Document MMQ5NZenD79VrB3QO1NjnqKEy

TABLE 43-C EXTINGUISHERS SUITABLE FOR CLASS B FIRES, FOR FIRES IN FLAMMABLE LIQUIDS V INCH AND UNDER IN DEPTH Type of Hazard Baste Minimum Maximum Extinguisher Travel Distance Rating to Extinguishers For Extinguishers Labeled Pnor to June t, 1969 Light 4B 50 ft Ordinary 8B 50 ft Extra 12B 50 ft For Extinguishers Labeled After June 1, 1969 Light SB 10B 30 ft 50 Ordinary 10B 20B 30 ft 50 Extra 20B 40B 30 ft 50 Note For flammable liquid hazards of depth greater than Vi in, Class B fire extinguishers shall be pro vided on the bass of one numerical unit of Class B extinguishing potential per square foot of flammable liquid surface of the largest tank hazard within the area From National Fire Protection Association Standard No 10, Table 4210 the availability of the extinguisher for such protection Scattered or widely separated hazards shall be individually protected if the specified travel distances m Table 43-C are exceeded Likewise, extinguishers in the proximity of a hazard shall be care fully located so as to be accessible in the presence of a fire without undue danger to the operator Extinguishers with Class C ratings are re quired where energized electrical equipment may be encountered which would require a nonconducting extinguishing media This will include fire either directly involving or sur rounding electrical equipment Since the fire itself is a Class A or Class B hazard the ex tinguishers are sized and located on the basis of the anticipated Class A or B hazard Whenever possible, electrical equipment should be deenergized before attacking a Class C fire. Extinguishers used for Class D protec tion and other special fires are installed ac cording to the size and type of the special hazard The type of combustible material, the quantity, and its physical form are all determining factors that must be considered when selecting the proper type of agent and the method of application Selection of extinguishers. Operating char acteristics that make one type of portable fire extinguisher suitable for certain fire hazards may make the same type dangerous for others The purchaser and user of extinguishers should secure on-the-job advice from fire in spection bureaus, fire insurance earners, and fire protection engineers Choosing the right extinguisher is extremely important All too frequently cost is given more consideration than adequate protection Remember, good extinguishers are worth their cost because of the protection they give Ob viously, only extinguishers listed by nationally recognized agencies such as Underwriters' Laboratones, Inc, or Factory Mutual En gineering Corp should be purchased Although suitable types and sizes are in stalled in conformance with NFPA Standard No 10, there is a certain flexibility that can be used to the purchaser's advantage For example, if a certain condition calls for B ex tinguishers, the required units could be ob tained by using various size dry chemical, foam or carbon dioxide (CO.) extinguishers The relative advantages and disadvantages of each of these units should be considered with respect to all the conditions in the area It is also wise to investigate the relative merits of any particular extinguisher available on the market, as the UL classification can vary widely for extinguishers of the same size but of different manufacture The design and operating features, ease of maintenance, and the availability of repair service should be considered too If possible, actually operating and testing the extinguisher may make a great deal of difference m the final selection The following discussion of portable ex- (Text continues on page 1350 ) 1347