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15.2 Classification of the Category of Buildings, Structures and

Premises for Fire and Explosion Hazards

The fire and explosion hazard areas and warehouse purposes, regardless of
their functionality are divided into the following categories:
1) high explosive (A);
2) explosive (B);
3) fire risk (C);
4) a moderate fire risk (D);
5) reduced fire risk (E).

Categories of premises for fire and explosion hazards are based on the
premises of the type of flammable substances and materials, their quantity and fire
properties, and based on the space-planning decisions and premises characteristics.
Definition of the categories of premises should be carried out by sequential testing
facilities belonging to the categories of the most dangerous (A) to the least
dangerous (E).
The category A includes areas in which there are (treated) flammable gases,
flammable liquid with a flash point of more than 28 degrees Celsius in a quantity
that can form explosive mixtures steam and gas, in the ignition which develops the
design pressure of explosion in the room of more than 5 kPa, and (or) substances
and materials that can explode and burn at contact with water, oxygen, or with
each other, in a such amount that the design pressure of explosion in the room is
more than 5 kPa.
The category B includes areas in which there are (treated) combustible dust
or fibers, flammable liquid with a flash point above 28 °C, flammable liquids in
such a quantity that can form explosive dust-air or vapor-air mixture, which, when
ignited, develop the design pressure of explosion in the room of more than 5 kPa.
The category C are the areas in which there are (treated) flammable and
nonflammable liquids, solids flammable and nonflammable materials and supplies
(including dust and fibers), substances and materials capable of contact with water,
oxygen, air, or with each other only to burn, provided that the premises in which
they are located, are not category A or B.
The category D includes the areas in which there are (treated) non-
combustible substances and materials in the hot or molten state, the processing of
which is accompanied by radiant heat, sparks and flame, and (or) fuel gases,
liquids and solids that are burned or recycled as fuel.
The category E also includes the areas in which there are (treated)
combustible media and materials in a cold state.
Common fire hazards are:
1) electrical systems that are overloaded, resulting in hot wiring or
connections, or failed components;
2) combustible storage areas with insufficient protection;
3) combustibles near equipment that generates heat, flame, or sparks;

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