Description Of The Assessment Procedure For Explosion Risk

All installations and functional units which come into operational contact with flammable material, have to be examined as to whether an explosible atmosphere may be present under normal operating conditions. These include times of inspection and maintenance as well as situations of minor process deviations. In a new plant this evaluation should be performed for the first time during process engineering activities and be available in documented form for the detail engineering. 

The assessment of an explosion hazard has to include the close vicinity of the installation or functional unit. In the case of in-house installations the complete room has to be considered. If an existing plant is evaluated, explosion protection measures already installed may not be accounted for in this analysis of an explosion hazard. If they were selected adequately in former times, then the result of the study will reconfirm their necessity. 

After the localization of places and areas with the possibility of a formation of an explosible atmosphere, the resulting hazard must be assessed. Corresponding to the probability of formation of an explosible atmosphere, which represents the endanger-ment, these localized areas are attributed zones . Within a building the boundaries of a zone are defined at concrete walls. The zone classification still in use in Germany was first published by the BG-Chemie. Some changes to this system are to be expected 

The result of this zone classification has to be documented in suitable maps, such as concession or set-up maps. If a new plant is being built, these activities should at the latest be part of the detail engineering. 

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