Extinguishing systems

Fire-detection devices such as flame-sensing or ioni2ation-interference types operate much more rapidly than sprinkler heads and are used extensively both as alarms and to activate fixed fire-extinguishing systems. 

Halon 1301 Fire Extinguishing Systems, NFPA 12A, paragraph 1-5.3, National Fire Protection Association, Boston, Mass., 1992. 

NPPA 12 Standard on Carbon Dioxide Extinguishing Systems, 1998 edition. National Eire Protection Association, Quincy, MA. 

A eombination of deteetors may be appropriate. They may aetivate an alarm only, or aetuate a eombined alarm/extinguishment system. With a bank of deteetors a voting system may be used to inerease reliability and reduee the frequeney of spurious alarms. Deteetion/alarm systems may also be interlinked with, e.g., fire-eheek doors held baek on eleetromagnetie eatehes sueh that the doors elose automatieally upon aetivation of the deteetion system. 

Table 6.13 General requirements for fixed fire-extinguishing systems (Activation may be automatic by a detection system, or manual)...

Table 12.15 General requirements for fixed fire extinguishing system...

Gaseous fire extinguishing systems precautions for toxic and asphyxiating hazards (withdrawn) General fire precautions aboard ships being fitted out or under repair Eire precautions m pressurized workings Access to road tankers... 

Extinguishing system A system designed to extinguish fires by means of certain chemicals, gases, or water, either manual or automatic. 

Fire extinguishing systems can include foam, carbon dioxide and dry chemical. Wetting agents and high e.xpansion foam have been used in some plant protection systems. All fire extinguishing systems should be evaluated for the potential health risks as well as overall effectiveness before incorporation into a plant. 

Foam extinguishing system-Available in automatic and manual systems, foam has the ability to adhere to surfaces, and thus provide a blanketing as well as cooling effect. 

Dry chemical extinguishing systems-This is used primarily for flammable liquid fires since they provide a rapid flame knockdown and e.xtinguishment. 

Halogenated extinguishing systems-This system can be used to protect flammable liquid storage and processing units. It is used with caution since, in the appropriate concentration, the products of decomposition are... 

Combination extinguishing systems-Combining dry chemicals and foam agents unites the fast flame control of the dry chemical with the cooling and sealing ability of foam to provide an efficient portable extinguishing system. 

Some alloys are softer than the component metals. The presence of big bismuth atoms helps to soften a metal and lower its melting point, much as melons would destabilize a stack of oranges because they just do not fit together well. A low-melting-point alloy of lead, tin, and bismuth is employed to control water sprinklers used in certain fire-extinguishing systems. The heat of the fire melts the alloy, which activates the sprinklers before the fire can spread. 

A combination of detectors may be appropriate. They may activate an alarm only, or actuate a combined alarm/extinguishment system. 

GS16 Gaseous fire extinguishing systems precautions for toxic and asphyxiating hazards. 

The solvent water reliably averts the risk of fire, which was inherent in the old cobalt-based process as a result of leaking highly flammable, metal carbonyls. The technique with its "built-in extinguishing system" reliably prevents such fires, and the painstaking... 

Steciak, J., and Zalosh, R.G., "Preliminary Reliability Study of Halon 1301 Extinguishing Systems," 1989, Factory Mutual Research Corporation, Norwood, MA, Technical Report J.I. 0N1J7.RU/ 0Q4R5.RU. 

Sprinklers and fire protection systems are required by NFPA Codes, but are often dependent on the overall size of the facility and quantity of stored flammable/combustible material. The wisest course of action is to provide heat and smoke detectors in each laboratory and provide a sprinkler system at least in the hallways. Each laboratory should have at least one ABC portable fire extinguisher. Computers have become more important to laboratories than ever. Halon fire extinguishing systems are available which are nondestructive to both electronic equipment and human life. These should be employed for fire protection. 

Activate fixed fire extinguishing systems or vapor dispersion mechanisms (i.e., water sprays). 

National Fire Protection Association (NFPA), NFPA 17, Dry Chemical Extinguishing Systems. NFPA, Quincy, MA, 1990. 

Sodium bicarbonate- and borax bicarbonate-based dry chemicals were among the first dry agents used in portable fire extinguishers. About 1960, the sodium bicarbonate dry chemical was modified to make it compatible with protein-based, low-expansion foam to create a dual agent extinguishing system. Shortly thereafter, the more effective Purple K based extinguishers replaced sodium bicarbonate extinguishers. 

Clean agent systems can also be used for explosion prevention and suppression where flammable materials are confined. Clean agent fire extinguishing systems are used primarily to protect hazards that are in enclosures or equipment enclosures. Some typical hazards that could be protected by clean agents are ... 

Where a detection system is part of an automatic, fixed fire extinguishing system, complete compatibility between the systems is essential. 

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