Selection of lighting fixtures for work in explosive and fire-hazardous areas and premises
Classification of premises with explosive and fire-hazardous areas
The wide assortment and different nature of premises and outdoor installations with explosive and fire-hazardous areas, common in all industries, as well as in public buildings with mass construction, limit the possibility of generalization and conclusions related to the lighting engineering part of lighting installations from these objects. At the same time, some of the characteristics inherent in many such premises can serve as a basis for a number of general recommendations aimed at improving the quality and efficiency of electric lighting.
In terms of lighting requirements, most of the premises and installations of industrial and auxiliary buildings and areas of open areas with explosive and fire-hazardous areas can be conditionally divided into several groups according to the main production characteristics.
To the first group can be attributed the premises and installations of enterprises of the chemical, oil, gas and other industries, where the production technology is based on the wide use of liquid, gaseous and powdery flammable and combustible substances with a high level of mechanization and automation of production processes.
The second group includes a wide range of workshops: painting, drying and impregnation, washing and steaming, preservation, antiseptic products and others, in which all kinds of paints and varnishes, impregnating masses, flammable solvents, thinners and oils are widely used.
To the third group Premises include the processing of primary raw materials (cotton, linen, wool, waste paper, wood waste, etc.) and the production of all kinds of fabrics, paper, cardboard and other fiber-based products.
The fourth group includes premises whose technological processes are related to the use and processing of solid combustible substances, for example woodworking workshops, electrical, plastic products and other enterprises.
The fifth group includes separate premises located in public and civil buildings where various combustible materials are stored and processed. These are, for example, the premises of archives, storage of books, drawings, customer services, packaging, various workshops, warehouses, etc.
The sixth group can be classified as explosion-hazardous and fire-hazardous areas in open areas. These are installations for storing flammable liquids and flammable liquids in tanks and tanks with valves, racks for loading and pouring flammable liquids and flammable liquids, open warehouses with coal, peat, timber, etc.
Lighting fixtures for explosive and fire-hazardous areas and premises
The range and number of lighting fixtures for lighting explosive and fire-hazardous areas produced by the lighting industry is constantly increasing. New types of explosion-proof lighting fixtures for explosive areas of classes BI, B-Ia, B-Ig and B-II and lighting fixtures for severe environmental conditions, whose designs allow their use in explosive areas of classes BI and B-IIa and fire-hazardous areas of classes P-I, P-II and P-III. The assortment and production of lighting fixtures designed for lighting industrial premises with normal environmental conditions, suitable for lighting some fire-hazardous areas of classes, is also increasing P-II and P-IIa under certain conditions.
The classes of explosive and fire-hazardous areas and the nature of the environment determine the use of lighting fixtures of different designs and designs, the correct choice of which is the main factor determining the reliability, energy efficiency and optimal cost of lighting installations.
It should be borne in mind that the complexity of the design and protective equipment (glass, grids, grids, etc.) of the lighting fixtures have a negative impact on their lighting characteristics and efficiency, therefore the selection of lighting fixtures for the considered conditions requires a comprehensive assessment of the factors , which determine the quality and efficiency of electric lighting.
The table contains data on the minimum permissible levels of explosion protection and the degree of protection of lighting fixtures depending on the classes of dangerous areas.
Minimum permissible levels of protection and degrees of protection lighting fixtures depending on the classes of dangerous areas
Explosive zone class
Explosion protection level
V-Me
V-Azorana
V-Azb
V-I
V-IIa
V-Me, V-Me
V-Azb, V-AzG
V-II
V-IIa
Stationary lighting fixtures
Explosion-proof
Increased reliability against explosion
Without explosion protection. Degree of protection AzP5X
Increased reliability against explosion
Without explosion protection. Degree of protection 1P5X
Portable lamps
Increased reliability against explosion
Explosion-proof
Increased reliability against explosion
In explosive areas of classes B-II and B-IIa, it is recommended to use lighting fixtures designed for explosive areas with mixtures of combustible dusts or fibers with air. In the absence of such lighting fixtures, it is allowed in B-II class areas to use explosion-proof lighting fixtures for work in an environment with explosive mixtures of gases and vapors with air, and in B-IIa class areas - general purpose lighting fixtures ( without explosion protection) but with suitable enclosure protection against dust ingress.
Portable lighting fixtures in fire-hazardous areas of any class must have a degree of protection of at least IP54; glass covers must be protected with metal mesh.
The design of light fixtures with gas discharge lamps in these areas must prevent the lamps from falling from them. Incandescent light fixtures must have hard silicate glass to protect the lamp. They must not have reflectors and diffusers made of combustible materials. In fire-hazardous areas of any class of storage rooms, lamps with gas discharge lamps must not have reflectors and diffusers made of combustible materials.
The selection of permanently installed lighting fixtures for ignition of fire and explosion-hazardous premises must be made in accordance with the table.2 and taking into account the characteristics of the environmental conditions in the premises.
The following lighting methods are also allowed for explosive areas, subject to compliance with the requirements PUE and the Production of Explosion-Proof Electrical Equipment (PIVRE) Regulations:
a) lighting fixtures removed from the hazardous environment and installed behind glazed windows, as well as niches or openings in walls or ceilings;
(b) ventilated lamps or lamps mounted in ventilated boxes;
c) with the help of slit lamps - light guides.
Portable lighting fixtures used in fire or explosive areas must have:
d) in fire-hazardous rooms of all classes — the degree of protection is IP54, and as a rule, the glass of the lighting unit must be covered with a protective metal mesh;
e) in explosive rooms of all classes, except for B-1b, -explosion-proof or special design, as a rule, the lamps must be equipped with a metal mesh;
f) in explosive rooms of class B-1b and in outdoor installations of classes B-1g - any explosion-proof version for the relevant categories and groups of explosive mixtures.
The selection of permanently installed lighting fixtures for ignition of fire and explosive areas
Premises
Light sources ¾ lamps
incandescence
DRL, DRI and sodium2
luminescent
Fire hazard
Production and warehouse classes:
P-I; P-II
IP5X
IP5X
IP5X; 5'X
P-IIa as well as P-II with general ventilation and local bottom suction waste
2'X3
IP2X4
IP2X5
Class P-IIa warehouse with valuable materials, combustible or combustible packaging
2'X3
IP2X4
IP2X5.6
Class P-III outdoor units
2’33
IP234
IP235
Explosive
classes:
B-I
Design of lighting fixtures1 according to PIVRE, GOST 13828¾74 and GOST 14254¾69
Fire-resistant for the relevant groups and categories of explosive mixtures
B-Ia; B-II
All explosion protection for the relevant groups and categories of explosive mixtures
B-Ib; B-IIa
IP5X
Foreign bodies V-Ig
All explosion protection for the relevant groups and categories of explosive mixtures