Reactive chemicals dust explosions

Damaging fires are uncontrolled chemical reactions, so fire hazards involving ordinary flammable and combustible materials could be included in the above definition of chemical reactivity hazards. However, this publication seeks to supplement basic fire prevention and protection measures by addressing how to successfully manage other chemical reactivity hazards in the work environment. Consequently, the use of the term "chemical reactivity hazards" in this publication will not include explosion, fire and dust explosibility hazards involving the burning of flammable and combustible materials in air. Storage and use of commercial explosives is also outside the scope of this publication. 

A particularly troublesome mixture is the hybrid, a mixture of combustible dust and flammable gas which can form an explosive mixture in air. Dow requires that reactive chemical testing be employed to determine the proper MF in this unique situation. 

EXPLOSION and FIRE CONCERNS combustible solid NFPA rating Health 2, Flammability 1, Reactivity 0 combustion will produce carbon dioxide, carbon monoxide, and hydrogen chloride emits toxic decomposition and hydrolysis products when in contact with steam capable of creating dust explosions incompatible with strong oxidizing agents, water, and alkali when heated to decomposition, emits toxic fumes of CF use dry chemical, water spray, mist, or carbon dioxide for firefighting purposes. 

Consequently, a temperature profile develops within the mass which is mainly determined by the substance specific heat conductivity. The temperature profiles of those two limiting cases are presented schematically in Figure 4-7, As the Semenov model is of greater importance to chemical transitions performed in their respective reactors, the following elaboration shall focus on this part of the explosion theory. The other limiting case should be applied when assessing the storage of solid substances with dust explosive or self-reactive properties. 

The Dow Fire and Explosion Index (FEI) (Dow, 1994 Van den Braken, 2002) and the Dow Chemical Exposure Index (CEI) have been developed and practiced hy Dow Chemicals for several decades. These tools measure process inherent safety characteristics, help to quantify the expected damage of potential fire and explosion incidents, and identify equipment that would likely contribute to the creation of the incident. The Mond Index was developed by ICI (UK) from the Dow Fire and Explosion Index. The Mond Index includes toxicity and covers a wider range of processes and storage installations than the FEI. The various aspects considered in the FEI are material factor (flammability and reactivity), general process hazards such as exothermic/endothermic reactions, and special process hazards such as toxic nature of the chemicals and dust explosion. For example. Table 8.6 shows the results of the FEI for various inventory levels of storage of ethyl acrylate. 

Environmental LC50 (golden orfe, 66 h) > 10,000 mg/l Precaution Wear safety glasses with side shields, particulate respirator, chemical resistant protective gloves, and impermeable protective clothing dust explosion hazard avoid strong alkalies HMIS Health 1, Flammability 1, Reactivity 0... 

Airborne particulate matter may comprise liquid (aerosols, mists or fogs) or solids (dust, fumes). Refer to Figure 5.2. Some causes of dust and aerosol formation are listed in Table 4.3. In either case dispersion, by spraying or fragmentation, will result in a considerable increase in the surface area of the chemical. This increases the reactivity, e.g. to render some chemicals pyrophoric, explosive or prone to spontaneous combustion it also increases the ease of entry into the body. The behaviour of an airborne particle depends upon its size (e.g. equivalent diameter), shape and density. The effect of particle diameter on terminal settling velocity is shown in Table 4.4. As a result ... 

During the development of a new facility or process, or when introducing a new process into an existing facility for the first time, an inherent safety review can be conducted to understand the chemical reactivity hazards and explore hazard reduction alternatives. The review need not be limited to chemical reactivity hazards. It can be used to address all other types of process hazards at the same time, including flammability/ combustibility dust or mist explosibility elevated or reduced pressures or temperatures phase differences and health hazards such as toxicity, corrosivity, and asphyxiation. 

Hazards of Combustion Products. Data not available Behavior in Fire Melts and may decompose to give volatile acetic vapors pf valeric acid and other substances. Dust may form explosive mixture with air Ignition Temperature (deg. F) 788 Electrical Hazard. Not pertinent Burning Rate. Not pertinent. Chemical Reactivity Reactivity with Water No reaction Reactivity with Common Materials Data not available Stability During Transport Stable Neutralizing Agents for Acids and Caustics Rinse with dilute sodium bicarbonate or soda ash solution Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

SAFETY PROFILE A poison by ingestion. See also BORON COMPOUNDS. A relatively inert metal except in the form of powder or when exposed to highly oxidi2ing agents. Amorphous boron is very reactive, sometimes violently. Flammable in the form of dust when exposed to air, or by chemical reaction. An explosion ha2ard in the form of dust, which ignites on contact with air. 

Exposure effects, toxicity, burns, bruises, biological effects Flammability, reactivity, explosiveness, corrosivity and fire-promoting properties of chemicals Wetted surfaces, reduced visibility, falls, noise, damage Dust formation, mist formation, spray... 

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