Extinguishants carbon dioxide

If a fire occurs in a power generator, fire water is not needed to extinguish. Carbon dioxide or Halon 1301 is used. 

In this fire extinguisher, carbon dioxide is produced by the action of sulfuric acid on a saturated solution of sodium bicarbonate. It has an iron cylinder with a flexible tube. An iron cylinder is filled almost full with sodium bicarbonate solution. Sulfuric acid, in a small glass bottle, is kept in the upper part of the cylinder. The bottle is well supported. 

Carbon dioxide is a molecule in which a carbon atom is bonded to two oxygen atoms (Fig. 4.23). It is heavier than air (for the more scientific minds its density is higher than the density of air), so it can be poured like an invisible liquid to some extent. A common demonstration of this property is when carbon dioxide is poured onto a burning candle, which is immediately extinguished. Carbon dioxide should definitely not be confused with carbon monoxide (not even under pressure from ill-informed journalists), which is the other common oxide of carbon, highly toxic, and has the same density as air (— 4.19). 

Class B For fires involving flammable liquids and similar materials, use type BC or ABC dry powder extinguishers. Carbon dioxide (COj) extinguishers may also be used. 

Carbon dioxide extinguishers. Carbon dioxide is a common extinguishing agent for Class BC fires. They are relatively inexpensive. In this instance, the propellant and the extinguishing agent are the same substance. It is not effective for Class A fires since these fires usually contain enough heat to reignite after the carbon dioxide has dissipated. 

Portable fire extinguishers (carbon dioxide or chemical types), or other fire protection or suppression systems or devices must be available for fire emergencies at storage installations. Only trained personnel should be allowed to operate fire extinguishers. A flame-producing device must never be used for detection of flammable gas leaks. Either a flammable gas detector or compatible leak detection solution should be used. 

Carbon dioxide is used in the manufacture of sodium carbonate by the ammonia-soda process, urea, salicyclic acid (for aspirin), fire extinguishers and aerated water. Lesser amounts are used to transfer heat generated by an atomic reactor to water and so produce steam and electric power, whilst solid carbon dioxide is used as a refrigerant, a mixture of solid carbon dioxide and alcohol providing a good low-temperature bath (195 K) in which reactions can be carried out in the laboratory. 

It is usually better to use a fire extinguisher charged with carbon dioxide under pressure this produces a spray of solid carbon dioxide upon releasing the pressure intermittently and is effective for extinguishing most fires in the laboratory. 

Production and Shipment. Estimated adiponitrile production capacities in the U.S. in 1992 were about 625 thousand metric tons and worldwide capacity was in excess of lO metric tons. The DOT/IMO classification for adiponitrile is class 6.1 hazard, UN No. 2205. It requires a POISON label on all containers and is in packing group III. Approved materials of constmction for shipping, storage, and associated transportation equipment are carbon steel and type 316 stainless steel. Either centrifugal or positive displacement pumps may be used. Carbon dioxide or chemical-foam fire extinguishers should be used. There are no specifications for commercial adiponitrile. The typical composition is 99.5 wt % adiponitrile. Impurities that may be present depend on the method of manufacture, and thus, vary depending on the source. 

Shipment. The DOT/IMO shipping information is shown in Table 6. Approved materials of constmction for shipping, storage, and associated transportation equipment are lined carbon steel (DOT spec. 105 S 500W) and type 316 stainless steel. Water spray, carbon dioxide, chemical-foam, or dry-chemical fire extinguishers may be used. 

Flash points and autoignition temperatures are given in Table 11. The vapor can travel along the ground to an ignition source. In the event of fire, foam, carbon dioxide, and dry chemical are preferred extinguishers. The lower and upper explosion limits are 1% and 7%. 

C depending on the reference consulted). Fires may be controlled with carbon dioxide or dry chemical extinguishers. Recommended methods of handlings loadings unloadings and storage can be obtained from Material Safety Data Sheets and inquiries directed to suppHers of acetone. 

There are explosion hazards with phthahc anhydride, both as a dust or vapor in air and as a reactant. Table 11 presents explosion hazards resulting from phthahc anhydride dust or vapor (40,41). Preventative safeguards in handling sohd phthahc anhydride have been reported (15). Water, carbon dioxide, dry chemical, or foam may be used to extinguish the burning anhydride. Mixtures of phthahc anhydride with copper oxide, sodium nitrite, or nitric acid plus sulfuric acid above 80°C explode or react violently (39). 

Isophthahc acid dust forms explosive mixtures with air at certain concentrations. These concentrations and other information on burning and explosiveness of isophthahc acid dust clouds are given in Table 27 (40,41). Fires can be extinguished with dry chemical, carbon dioxide, water or water fog, or foam. 

Portable fire extinguishers are classified according to appHcabiHty Class A for soHd combustibles Class B for flammable Hquids Class C for electrical fires that require a nonconducting agent and Class D for combustible metals. Water frequently is used for Class A extinguishers bicarbonates for Class B and Class BC carbon dioxide or Freon for Class C ammonium phosphate for Class ABC and powdered salt, sodium chloride, for Class D. 

Butylenes are not toxic. The effect of long-term exposure is not known, hence, they should be handled with care. Reference 96 Hsts air and water pollution factors and biological effects. They are volatile and asphyxiants. Care should be taken to avoid spills because they are extremely flammable. Physical handling requires adequate ventilation to prevent high concentrations of butylenes in the air. Explosive limits in air are 1.6 to 9.7% of butylenes. Their flash points range from —80 to —73° C. Their autoignition is around 324 to 465°C (Table 2). Water and carbon dioxide extinguishers can be used in case of fire. 

When heated to about 60°C, nickel carbonyl explodes. Eor both iron and nickel carbonyl, suitable fire extinguishers are water, foam, carbon dioxide, or dry chemical. Large amounts of iron pentacarbonyl also have been reported to ignite spontaneously (189). Solutions of molybdenum carbonyl have been reported to be capable of spontaneous detonation (190). The toxicity of industrial chemicals including metal carbonyls may be found in references 191-194. 

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