Explosion hazard assessment operating conditions

Most electrical equipment either sparks in normal operation or is liable to spark under fault conditions. Some electrical appliances such as electric heaters, are specifically designed to produce high temperatures. These circumstances create fire and explosion hazards, which demand very careful assessment in locations where processes capable of producing flammable concentrations of gas or vapour are used, or where flammable liquids are stored. 

For the practical application of safety characteristics, especially for the assessment of explosion hazards at pumping of explosive atmospheres with vacuum pumps, the different conditions for the determination of the safety characteristics and the operating conditions of the vacuum pumps have to be considered. 

In principle, each specific manufacturing operation must be analyzed to determine potential hazards in the gas or condensed phase. If they are present, experimental research or calculations are carried out, and safe conditions for conducting manufacturing operations are recommended on the basis of the information obtained. To make a probabilistic assessment of the occurrence of accident situations and their aftermath, one must determine the conditions under which a potential hazard may be realized, as well as the characteristics of combustion, decomposition, or explosion processes. 

Hydrojylamine salts have been shown by the Williams group to catalyse the selective transamidation of primaiy amides. Hydro)ylamine hydrochloride catalysed the transamidation of a variety of primaiy amides (Scheme 17.12), including amino acid derivatives, with the catalyst removed by aqueous washing. Secondary amides were found to be inert under the reaction conditions and acid salts of the catalyst were found to be necessary, as freebase hydro)ylamines showed little activity. Although operationally cheap and simple, hydroiylamine does have associated hazards, including the risk of explosion the thermal hazard of any reaction of this type would therefore need to be assessed before being undertaken on scale. 

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