API RP 2021:2001 pdf download

API RP 2021:2001 pdf download.Management of Atmospheric Storage Tank Fires.
6.8 FIRE SUPPRESSION AGENTS
6.8.1 General
Fire suppression is achieved by cooling. inhibiting sapor formation, eliminating oxygen or interfering with the freer.idwjl uhemistrs of ci,iithustk,n (see Appendix II t. The eftectiveness and usefulness of various agenLs is a function of the type of tirc and the fuel insolvcd. The planning phase is the appropriate lime to review the proper agents tor cacti tank- specifIc scenario.
6.8.2 Water
Water is the ideal tire suppression agent as discussed in Appendix H.2 (although it cannot he used alone to extinguish ulainmahle liquid pool tires); it absorbs heat very effectively thus inhibiting vajsr formation. Steam generated by flame contact expands and tends in blanket and exclude air. kter is the primary ingredient in foam. The logi.tics of delivering sufficient quantities of’ water for a major tank tire can be challenging, as discussed in 7.4.3. Section 8.5.6 explains the need for using water carefully to avoid causing problems. Appendix M pros ides a brief review of hydraulics, explaining why there are significant benefits accompanying the use of large diameter hose (LDH).
6.8.3 FIre FightIng Foam
Fire fighting foam canes waler to a burning fuel surface and makes it buoyant on a hydrocarbon stirl’acc. even with specific gravity less than 1, With good heat resistance, it keeps the water where it is needed and maximizes its eflectiveness. Foam is the primary fire-suppression agent used to put out hydrocarbon fires by cooling, exclusion of oxygen and vapor inhibition. The expanded tisim can be delivered to the burning surface by injection at the base of the tank from where it floats to the surface, by foam chambers permanently attached to the tank, by monitors permanently fixed to the periphery of the tank or by portable ground monitors. Current technology allows portable monitors to be built with the capacity to deliser volumes of expanded foam to a tire surface essentially limited only by the amount of water and foam concentrate asailahk. Monitors commercially asailable from several sources have very large capacities. 4.000 gimin (15.000 1mm) to over I 0.0(x) g/min (40,(X)() I/mm) or more.
In choosing how to deliver expanded foam to a burning tank the potential impact of the method chosen and equipment available should he considered. Sonic portahk systems have fixed delivery rates. If used for tanks smaller than intended this fixed rate will deliver loam at a rate significantly above the theoretical (calculated) amount for a specific densitv in that diameter tank. Using the higher foam application rate. NFPA II allows the specified time to he reduced proportionately. but not to less than 70% of the standard time. In such cases, the total amount of foaiii concentrate and water.