Fire-extinguishing materials

Most dry-chemical fire-extinguishing materials also function by inhibiting combustion rather than by cooling or by reducing oxygen concentration. The usual dry-chemical material is a bicarbonate, but some phosphates, eg, ammonium, provide a coating that makes the material suitable for use on fires involving soHd combustibles such as mbber tires, wood, and paper. 

Fire To control small fires use dry chemical, sand, soda ash or lime or fight fire around the biological agent or weapon with normal fire extinguishing materials, but do not spread or scatter infectious substance. If without risk, move any containers containing anthrax or any other infectious substance from the area of the fire. 

Table 5.3 covers agricultural chemicals (including pesticides, both inorganic and organic) Table 5.4 covers fire-extinguishing materials. 

In fact, graphite powder is a class D fire extinguishing material for combustible metals, including zirconium. For the GT-MHR (and the PBMR for that matter), the oxidation resistance and heat capacity of graphite serves to mitigate, not exacerbate, the radiological consequences of a hypothetical severe accident that allows air into the reactor vessel. 

Water is the most widely used fire extinguishing material because it is both economical and effective. Offshore, seawater is always available (although equipment... 

D Class D fire extinguishing material only metal fires. 

Sand. Buckets of dry sand for fire-extinguishing should be available in the laboratory and should be strictly reserved for this purpose, and not encumbered with sand-baths, waste-paper, etc. Most fires on the bench may be quickly smothered by the ample use of sand. Sand once used for this purpose should always be thrown away afterwards, and not returned to the buckets, as it may contain appreciable quantities of inflammable, non-volatile materials e.g., nitrobenzene), and be dangerous if used a second time. 

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. 

Potassium bicarbonate is used in foods and medicine. It is approximately twice as effective as NaHC03 in dry-powder fire extinguishers, perhaps because the potassium affects the free-radical mechanism of flame propagation. However, the material does not have good handling characteristics. 

Threshold limit values for the components of cemented carbides and tool steels are given in Table 14 (176). There is generally no fire or explosion hazard involved with tool steels, cemented carbides, or other tool materials. Fires can be handled as metal fires, eg, with Type D fire extinguishers. Most constituents of tool materials do not polymerize. 

Fire Hazard. Although chlorosulfuric acid itself is not dammable, it may cause ignition by contact with combustible materials because of the heat of reaction. Open fires, open lights, and matches should not be used in or around tanks or containers where hydrogen gas may be collected because of the action of chlorosulfuric acid on metals. Water, carbon dioxide, and dry-chemical fire extinguishers should be kept readily available. 

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