How Does an Automatic Fire Sprinkler Head Operate

15 3 How Does an Automatic Fire Sprinkler Head Operate  

Many office buildings rely on ceiling sprinkler systems as effective means of extinguishing a fire. How are these systems activated The heat generated by a fire is the key to the operation of such water sprinklers. 

Alloys are mixtures of metals combined to obtain specific characteristics and enhanced properties for a particular application. The term fusible metals or fusible alloys denotes a group of alloys that have melting points below that of tin (232°C, 449°F). Most of these substances are mixtures of metals that by themselves have relatively low melting points, such as tin, bismuth (m.p. 275°C), indium (157°C), 

TABLE 15.1 Melting Points of Fusible Alloys of Variable Composition 

Note that all combinations of metals yield an alloy with a melting point significantly lower than that of any of the individual metals. Even more extensive listings of fusible alloy compositions and melting points are available. As a point of reference, paper will spontaneously begin to bum when heated to 451°F, just above the melting point of tin. 

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