Book Description

This part of GB 3836 specifies the general requirements for construction, testing and marking of electrical equipment and Ex components intended for use in explosive atmospheres. Unless modified by one of the standards supplementing this standard, electrical equipment complying with this standard is intended for use in hazardous areas in which explosive atmospheres exist under normal atmospheric conditions of Temperature: -20℃ to +60℃; Pressure: 80kPa to 110kPa; Air with normal oxygen content (Volume ratio): 21%. The application of electrical equipment in atmospheric conditions outside this range requires special consideration and may require additional assessment and testing. Note 1: Although the normal atmospheric conditions above give a temperature range for the atmosphere of -20℃ to +60℃, the normal ambient temperature range for the equipment is-20℃ to +40℃, unless otherwise specified and marked, see 5.1.1. Note 2: In designing equipment for operation in explosive atmospheres under conditions other than the atmospheric conditions given above, this standard may be used for guidance. However, additional testing related specifically to the intended conditions of use is recommended. This is particularly important when the types of protection 'flameproof enclosure "d"' (GB 3836.2-2010) and 'intrinsic safety "i"' (GB 3836.4-2010 or GB 12476.4-2010) are applied. Note 3: Requirements given in this standard result from an ignition hazard assessment made on electrical equipment. The ignition sources taken into account are those found associated with this type of equipment, such as hot surfaces, mechanically generated sparks, thermite reactions, electrical arcing and static electric discharge in normal industrial environments. Note 4: It is acknowledged that, with developments in technology, it may be possible to achieve the objectives of the GB 3836 series of standards in respect of explosion prevention by methods that are not yet fully defined. Where a manufacturer wishes to take advantage of such developments, this International Standard, as well as other standards in the GB 3836 series, may be applied in part. It is intended that the manufacturer prepare documentation that clearly defines how the GB 3836 series of standards has been applied, together with a full explanation of the additional techniques employed. Under such circumstances,, the designation "Ex s" has been reserved to indicate a type of protection that is not defined by the GB 3836 series of standards, Note 5: Where an explosive gas atmosphere and a combustible dust atmosphere are, or may be, present at the same time, the simultaneous presence of both should be considered and may require additional protective measures. This standard does not specify requirements for safety, other than those directly related to the explosion risk. Ignition sources like adiabatic compression, shock waves, exothermic chemical reaction, self ignition of dust, naked flames and hot gases/liquids, are not addressed by this part. Note 6: Such equipment should be subjected to a hazard analysis that identifies and lists all of the potential sources of ignition by the electrical equipment and the measures to be applied to prevent them becoming effective. This standard is supplemented or modified by the following standards concerning specific types of protection: GB 3836.2-2010 Gas-Flameproof Enclosures "d; GB 3836.3-2010 Gas-Increased Safety "e; GB 3836.4-2010 Gas-Intrinsic Safety "i; GB 3836.5-2004 Gas-Pressurized Enclosures "p; GB 3836.6-2004 Gas-Oil Immersion "o; GB 3836.7-2004 Gas-Powder Filling "q; GB 3836.8-2003 Gas-Type of Protection "n; GB 3836.9-2006 Gas-Encapsulation "m; GB 12476.7-2010 Dust-Pressurization "pD; GB 12476.4-2010 Dust-Intrinsic Safety "iD; GB 12476.6-2010 Dust-Encapsulation "mD; IEC 61241-1 Dust-Protection by Enclosures "tD. This standard is supplemented or modified by the following equipment standards: ——GB 3836.18-2010 "Explosive Atmospheres-Part 18: Intrinsically Safe System"; ——GB 3836.20-2010 "Explosive Atmospheres-Part 20: Equipment with Equipment Protection Level (EPL) Ga"; ——GB 7957-2003 "General Requirements for Safety of Cap Lamp"; ——GB 19518.1-2004 "Electrical Apparatus for Explosive Gas Atmospheres Electrical Resistance Trace Heating Part 1: General and Testing Requirements"; ——IEC 60079-28 "Explosive Atmospheres-Part 28: Protection of Equipment and Transmission Systems Using Optical Radiation. This part of GB 3836 together with other parts in the GB 3836 series and the additional standards mentioned above, are not applicable to the construction of electro-medical apparatus, shot-firing exploders, test devices for exploders, and shot-firing circuits. Note 7: "Flameproof enclosures" and "Flameproof type" in this part of GB 3836 are synonym.