2015-08-21
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In reference to standard «SNIP 24-86» all work areas are divided into 5 categories: «A», «Б», «В», «Г», «Д».
Work area is relevant to some category dependently on characteristics of substances stored or used in the area (table 5).
Table 5
Fire and explosion risk area categories
| Area Category | Characteristics of materials and substances stored in the area |
| «A» fire and explosion risk area | Inflammable substances with: lower limit of ignition 10% or lower; flashpoint lower or equal 28 deg C; in condition that mentioned substances can make explosive mixtures in volume covering 5 % of the total area volume. Such as: painting workshops, areas storing pressured gas. |
| Б fire and explosion risk area | Inflammable substances with: lower limit of ignition over 10%; flashpoint over 28 to 61 deg C; in condition that mentioned substances can make explosive mixtures in volume covering 5 % of the total area volume. Such as: areas using ammonia, and emitting flammable dusts. |
| «B» fire risk area | Inflammable substances with: flashpoint over 61 deg C; solid flammable substances liable only to catch fire but not explosion. |
| «Г» | Nonflammable substances in hot, molten and red-hot condition; And also substances which are burned as fuel. |
| «Д» | Areas using nonflammable substances in cold condition. |
The importance of accurate defining Category of fire-explosive risk for an area or a building is extremely high because the considered Category significantly defines requirements to building’s construction and floor plan, organization of fire safety and its technical equipment.
