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GB 50257-2014 English PDF (GB 50257-1996)
GB 50257-2014 English name.Code for construction and acceptance of electric device for explosion atmospheres and fire hazard electrical equipment installation engineering 1 General 1.0.1 This specification is formulated to ensure the construction and installation quality of electrical installations in explosion and fire hazardous environments, promote the progress of construction and installation technology, ensure the safe operation of equipment in explosion and fire hazardous environments, and ensure the safety of the country and people's lives and property. 1.0.2 This specification is applicable to the construction and acceptance of electrical installations in environments where gases, vapors, dust, explosive mixtures of fibers and fire-hazardous substances appear or may appear during production, processing, handling, transshipment or storage. 1.0.3 This specification does not apply to the construction and acceptance of electrical installations in the following environments. 1 Underground mine; 2 The environment for the manufacture, use and storage of gunpowder, explosives, primers, fuzes and the production of pyrotechnics; 3 Areas of electrical devices such as electrolysis and electroplating that use electric energy for production and are directly related to the production process; 4 The environment where strong oxidants are used and substances that can ignite by themselves without an external ignition source; 5 Water, land and air transportation vehicles and offshore and land oil well platforms; 6 Nuclear islands of nuclear power plants; 7 Heating, air conditioning, cooking, laundry and similar plumbing systems fueled by flavored natural gas; 8 medical room; 9 catastrophic accident. 1.0.4 The construction and acceptance of electrical installations in explosive and fire-hazardous environments shall not only comply with this code, but also comply with the current relevant national standards. 2 terms 2.0.1 Explosive atmosphere explosive atmosphere Under atmospheric conditions, the mixture of flammable substances in the form of gas, vapor, dust, mist, fibers or flying flocs and air, after being ignited, can maintain the environment in which the combustion propagates itself. 2.0.2 Explosive dust atmosphere explosive dust atmosphere Under atmospheric conditions, the mixture of combustible substances in the form of dust, fibers or flying flocs and air, after being ignited, can maintain an environment in which combustion spreads by itself. 2.0.3 Explosive gas atmosphere explosive gas atmosphere Under atmospheric conditions, the mixture of flammable substances in the form of gas or vapor and air, after being ignited, can maintain the environment in which the combustion propagates itself. 2.0.4 Hazardous area An area where explosive mixtures are present or are expected to be present in quantities sufficient to require precautionary measures for the construction, installation and use of electrical equipment. 2.0.5 zone 0 zone 0 Environments where explosive gas mixtures are present continuously or for a long period of time. 2.0.6 zone 1 zone 1 Environments where explosive gas mixtures may be present during normal operation. 2.0.7 zone 2 zone 2 An environment in which explosive gas mixtures are unlikely to occur during normal operation, or where explosive gas mixtures exist only for a short period of time if they occur. 2.0.8 zone 20 zone 20 Combustible dust clouds in the air are continuously or chronically or frequently present in areas with explosive atmospheres. 2.0.9 zone 21 zone 21 During normal operation, airborne combustible dust clouds are likely to occasionally occur in areas of explosive atmospheres. 2.0.10 zone 22 zone 22 During normal operation, combustible dust clouds in the air are generally unlikely to appear in areas with explosive dust atmospheres, and even if they do, the duration is short. 2.0.11 Explosion-proof type type of protection Various specific measures are taken for electrical equipment to prevent ignition of surrounding explosive atmospheres. 2.0.12 Intrinsic safety type "i" intrinsic safety "i" A type of explosion protection that limits exposure to electrical energy inside equipment and interconnecting wires in an explosive gas atmosphere to below that which could cause ignition by sparks or thermal effects. 2.0.13 Intrinsically safe circuit intrinsically-safe circuit Under normal operation and specified fault conditions, any electric spark or any thermal effect generated cannot ignite the circuit in the specified explosive gas atmosphere. 2.0.14 intrinsically safe electrical equipment intrinsically-safe electrical appa-ratus All internal circuits are electrical equipment with intrinsically safe circuits. 2.0.15 Associated electrical equipment associated electrical apparatus Electrical equipment equipped with intrinsically safe circuits and non-intrinsically safe circuits, and constructed so that non-intrinsically safe circuits cannot adversely affect intrinsically safe circuits. 2.0.16 Positive pressure shell type "P" pressurization "P" An explosion-proof type that prevents the entry of external explosive gases by maintaining the pressure of the protective gas inside the enclosure or in the room higher than the external atmospheric pressure. 2.0.17 Oil immersion type "o" oil immersion "o" A type of explosion protection in which electrical equipment or components of electrical equipment are immersed in a protective liquid so that the equipment cannot ignite explosive gases on the liquid surface or outside the enclosure. 2.0.18 "n" type electrical equipment type of protection "n" An explosion-proof type, the explosion-proof type of electrical equipment, in normal operation and under some abnormal conditions specified in this part, can not ignite the surrounding explosive gas. 2.0.19 flameproof enclosure "d" flameproof enclosure "d" An explosion-proof type of electrical equipment, the shell of which can withstand the internal explosion of the explosive mixture entering the shell through any joint surface or structural gap without damage, and will not cause an explosive explosion formed by one or more gases or vapors outside. Ignition of gaseous atmospheres. 2.0.20 Increased safety type "e" increased safety "e" An explosion-proof type of electrical equipment, that is, some additional measures are taken for electrical equipment to improve its safety and prevent the possibility of dangerous temperatures, arcs and sparks under normal operation or specified abnormal conditions. Note. 1 This form of protection is denoted by "e", and additional measures are those that comply with the requirements of this standard. 2 The definition of increased safety "e" does not include equipment that produces sparks or arcs under normal operating conditions. 3 Basic Regulations 3.0.1 The installation of electrical devices in explosive and fire-hazardous environments shall be carried out in accordance with the approved design documents. 3.0.2 The transportation and storage of equipment and equipment shall meet the requirements of product technical documents. 3.0.3 The equipment and equipment used shall have qualified certificates. The equipment should have a nameplate, and the explosion-proof electrical equipment should have an explosion-proof mark. 3.0.4 After the equipment and equipment arrive at the site, they shall be inspected for acceptance and shall comply with the following regulations. 1 The packaging and sealing should be good; 2 Open the box for inspection and inventory. The model, specification and explosion-proof mark should meet the design requirements, and the accessories, accessories and spare parts should be in good condition; 3 The technical documents of the product should be complete; 4 The nameplate of the explosion-proof electrical equipment shall be marked with the "explosion-proof certificate number" issued by the national inspection unit; 5 The appearance inspection of the equipment should be free from damage, corrosion and moisture. 3.0.5 Construction safety technical measures shall meet the requirements of this code and product technical documents. In expansion and reconstruction projects, safety regulations related to construction in the safety production (operation) regulations of the production plant should be followed. For important processes, special safety technical measures and construction operation instructions should be formulated in advance. 3.0.6 The construction of construction projects related to the installation of electrical installations in explosion and fire hazardous environments shall comply with the following regulations. 1 The engineering quality of buildings and structures shall comply with the relevant provisions of the current national standard "Unified Standards for Construction Quality Acceptance of Construction Engineering" GB 50300.When there are special requirements for equipment or design, the special requirements shall be complied with. 2 Before the equipment is installed, the construction project shall meet the following conditions. 1) The foundation and structure should meet the design requirements and pass the acceptance check; 2) The indoor ground foundation should be constructed, and the ground elevation should be marked on the wall; 3) The embedded parts and reserved holes shall meet the design requirements, the embedded electrical pipeline shall not be missed or blocked, and the embedded parts shall be firm; 4) The plastering and decoration works that may damage or seriously pollute electrical installations should be completed; 5) The site should be cleaned up; 6) Doors and windows should be installed. 3 After the electrical installations in explosion and fire hazardous environments are installed, before they are put into operation, the building installation project shall comply with the following regulations. 1) Defect repair and dec...... Similar standards: GB 50254-2014 GB 50255-2014 GB 50256-2014 Similar PDFs (Auto-delivered in 9 seconds): GB 50254-2014 GB 50303-2015 GB 50168-2018 GB 50093-2013 |
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