Electrical installations in fire hazardous areas. Definitions. General requirements

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Encyclopedia of radio electronics and electrical engineering / Electrician

Section 7. Electrical equipment of special installations

Electrical installations in fire hazardous areas. Definitions. General requirements

Free technical library

Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

Comments on the article

7.4.2. A fire hazardous zone is a space inside and outside the premises, within which combustible (combustible) substances constantly or periodically circulate and in which they can be located during a normal technological process or during its violations.

Classification of fire hazardous areas is given in 7.4.3 - 7.4.6.

7.4.3. Zones of class П-I - zones located in rooms where flammable liquids with a flash point above 61ºС are circulated (see 7.3.12).

7.4.4. Class P-II zones - zones located in rooms in which combustible dust or fibers are emitted with a lower concentration limit of ignition of more than 65 g / m3 to the volume of air.

7.4.5. Class P-IIa zones - zones located in rooms in which solid combustible substances circulate.

7.4.6. Zones of class P-III - outdoor areas in which flammable liquids with a flash point above 61ºС or solid combustible substances circulate.

7.4.7. Zones in rooms and zones of outdoor installations within 5 m horizontally and vertically from the apparatus, in which combustible substances constantly or periodically circulate, but the technological process is carried out using open fire, hot parts, or technological apparatuses have surfaces heated to the self-ignition temperature of combustibles vapours, dusts or fibres, are not flammable in terms of their electrical equipment. The class of the indoor environment or the environment of outdoor installations outside the specified 5-meter zone should be determined depending on the technological processes used in this environment.

Zones in rooms and zones of outdoor installations, in which solid, liquid and gaseous combustible substances are burned as fuel or disposed of by combustion, are not classified as fire hazardous in terms of their electrical equipment.

7.4.8. Zones in the rooms of exhaust fans, as well as in the rooms of supply fans (if the supply systems operate using air recirculation) serving rooms with fire hazardous zones of class P-II, also belong to fire hazardous zones of class P-II.

Zones in the premises of fans of local exhausts belong to fire hazardous zones of the same class as the zone served by them.

For fans installed behind external enclosing structures and serving fire hazardous zones of class P-II and fire hazardous zones of any class of local exhausts, electric motors are selected as for a fire hazardous zone of class P-III.

7.4.9. Determination of the boundaries and class of fire hazardous zones should be carried out by technologists together with electricians of the design or operating organization.

In premises with industries (and warehouses) of category B, electrical equipment must, as a rule, meet the requirements of Ch. 7.4 to electrical installations in fire hazardous areas of the corresponding class.

7.4.10. When single fire hazardous equipment is placed indoors or outdoors, when special measures against the spread of fire are not provided, the zone within 3 m horizontally and vertically from this equipment is fire hazardous.

7.4.11. When choosing electrical equipment installed in fire hazardous areas, environmental conditions (chemical activity, atmospheric precipitation, etc.) must also be taken into account.

7.4.12. Fixed contact connections in fire hazardous areas of any class must be made by welding, crimping, soldering, screwing or other equivalent method. Collapsible contact connections must be equipped with a device to prevent self-unscrewing.

7.4.13. Protection of buildings, structures and outdoor installations containing fire hazardous zones from direct lightning strikes and its secondary manifestations, as well as grounding of equipment installed in them (metal vessels, pipelines, etc.) containing flammable liquids, powdery or fibrous materials, etc. etc., to prevent sparking caused by static electricity, must be carried out in accordance with the current standards for the design and installation of lightning protection of buildings and structures and the protection of installations from static electricity.

In fire hazardous areas of any class, measures must be provided to remove static charges from the equipment.

7.4.14. Grounding of electrical equipment in fire hazardous areas must be carried out in accordance with Ch. 1.7.

See other articles Section Rules for the installation of electrical installations (PUE).

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

A New Way to Control and Manipulate Optical Signals 05.05.2024

The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>

Primium Seneca keyboard 05.05.2024

Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Random news from the Archive

crab toothpaste 03.01.2003

Specialists from the University of Portsmouth (UK) have developed a new toothpaste that sticks to the teeth.

Microscopic capsules filled with a disinfectant antimicrobial agent - triclosan are mixed into the main substance of the paste. Gradually breaking down, they release triclosan on the tooth enamel, killing the microorganisms that cause caries. In order to keep the effect of brushing your teeth as long as possible, it was important to choose a material for the microcapsules so that they firmly adhere to the teeth.

Of the proposed options, chitosan turned out to be the best. This is a derivative of chitin, which is used in the shells of crabs, crayfish, lobsters, shrimp and other crustaceans. Thousands of tons of chitin annually go to waste after processing these seafood. The production of paste with chitosan will start in 2003.

Other interesting news:

▪ Viltrox AF 35/1.8 Z full frame lens

▪ Smart watch Qualcomm Toq

▪ Thyristor protection components

▪ Asphalt cleans the air

▪ alien plants

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Electrician's Handbook. Article selection

▪ article The smile of the augurs. Popular expression

▪ article How Do Oysters Eat? Detailed answer

▪ article Flax fiber sorter. Standard instruction on labor protection

▪ article Amplifier according to the Loftin-White scheme by Anatoly Manakov. Encyclopedia of radio electronics and electrical engineering

▪ article Soft inclusion of powerful loadings. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews