Detail of GB/T 2900.35-2023

Introduction of GB/T 2900.35-2023

Electrotechnical terminology - Explosive atmospheres 1 Scope This document defines terms and definitions specifically relevant to explosive atmospheres. This document is applicable to communication within the industrial sector and its related fields, and is also applicable to the preparation of relevant standardization documents and other publications. As a basic document, this terminology is consistent with the terminology developed in the other specialized parts of the IEV. 2 Normative references There are no normative references in this document. 3 Terms and definitions The terms and definitions contained in this document were extracted from the Electropedia (www.electropedia.org). 426-01 General terms 426-01-01 equipment, apparatus, fittings, devices, and the like used as part of, or in connection with, an installation Note: Equipment incorporating a Type of Protection can be "Ex Equipment", or an "Ex Component". 426-01-02 Type of Protection, set of specific measures applied to equipment to avoid ignition of a surrounding explosive atmosphere 426-01-03 equipment grouping classification system of equipment related to the explosive atmosphere for which they are intended to be used Note: IEC 60079-0 identifies three equipment groups: ——Group I, equipment for mines susceptible to firedamp; ——Group II, which is divided into sub-groups, equipment for all places with an explosive gas atmosphere other than mines susceptible to firedamp; ——Group III, which is divided into sub-groups, equipment for all places with an explosive dust atmosphere other than mines susceptible to firedamp. 426-01-04 maximum surface temperature highest temperature which is attained in service under the most adverse conditions (but within the specified tolerances) by any part or surface of Ex Equipment Note 1: For Ex Equipment in an explosive gas atmosphere, this temperature may occur on an internal component or on the external surface of the enclosure, depending upon the Type of Protection employed. Note 2: For Ex Equipment in an explosive dust atmosphere, this temperature occurs on the external surface of the enclosure and may include a defined dust layer condition. 426-01-05 temperature class classification system of Ex Equipment, based on its maximum surface temperature, related to the specific explosive gas atmosphere for which it is intended to be used 426-01-06 explosive atmosphere mixture with air, under atmospheric conditions, of flammable substances in the form of gas, vapour, or dust, which, after ignition, permits self-sustaining propagation 426-01-07 explosive gas atmosphere mixture with air, under atmospheric conditions, of flammable substances in the form of gas or vapour which, after ignition, permits self-sustaining flame propagation 426-01-08 explosive dust atmosphere mixture with air, under atmospheric conditions, of flammable substances in the form of dust, which, after ignition, permits self-sustaining propagation 426-01-09 fixed equipment, equipment fastened to a support, or otherwise secured in a specific location, when energized 426-01-10 personal equipment equipment intended to be worn by and to be in contact with a person's body during its operation 426-01-11 portable equipment equipment intended to be carried by a person during its operation Note: Portable equipment carried by a person during its operation is sometimes referred to as hand-held equipment. 426-01-12 transportable equipment equipment not intended to be carried by a person during its operation, nor intended for fixed installation 426-01-13 Ex Component equipment intended to be part of Ex Equipment, marked with symbol "U", which is not intended to be used alone, and requires additional consideration when incorporated into Ex Equipment 426-01-14 Ex Equipment equipment with explosion protection Note: Such equipment often includes Ex Components, but additional evaluation is always required as part of their incorporation into equipment. 426-01-15 equipment protection level; EPL Level of Protection assigned to equipment based on its likelihood of becoming a source of ignition and distinguishing the differences between explosive gas atmospheres, explosive dust atmospheres, and the explosive atmospheres in mines susceptible to firedamp 426-01-16 EPL Ma equipment for installation in a mine susceptible to firedamp, having a "very high" Level of Protection, which has sufficient security that it is unlikely to become an ignition source in normal operation, during expected malfunctions or during rare malfunctions, even when left energized in the presence of an outbreak of gas 426-01-17 EPL Mb equipment for installation in a mine susceptible to firedamp, having a "high" Level of Protection, which has sufficient security that it is unlikely to become a source of ignition in normal operation or during expected malfunctions in the time span between there being an outbreak of gas and the equipment being de-energized 426-01-18 EPL Ga equipment for explosive gas atmospheres, having a "very high" Level of Protection, which is not a source of ignition in normal operation, during expected malfunctions or during rare malfunctions 426-01-19 EPL Gb equipment for explosive gas atmospheres, having a "high" Level of Protection, which is not a source of ignition in normal operation or during expected malfunctions 426-01-20 EPL Gc equipment for explosive gas atmospheres, having an "enhanced" Level of Protection, which is not a source of ignition in normal operation and which can have some additional protection to ensure that it remains inactive as an ignition source in the case of regular expected occurrences (for example failure of a lamp) 426-01-21 EPL Da equipment for explosive dust atmospheres, having a "very high" Level of Protection, which is not a source of ignition in normal operation, during expected malfunctions, or during rare malfunctions 426-01-22 EPL Db equipment for explosive dust atmospheres, having a "high" Level of Protection, which is not a source of ignition in normal operation or during expected malfunctions 426-01-23 EPL Dc equipment for explosive dust atmospheres, having an "enhanced" Level of Protection, which is not a source of ignition in normal operation and which can have some additional protection to ensure that it remains inactive as an ignition source in the case of regular expected occurrences (for example failure of a lamp) 426-01-24 Level of Protection subdivision of a Type of Protection, correlating with the Equipment Protection Level, that differentiates the likelihood of the equipment becoming a source of ignition Note: For example, Type of Protection intrinsic safety "i" is subdivided into Levels of Protection "ia", "ib", and "ic", which correlate with EPL Ga, EPL Gb, and EPL Gc (for explosive gas atmospheres). 426-02 Physical and chemical phenomena 426-02-01 auto-ignition temperature; AIT lowest temperature (of a hot surface) at which, under specified conditions, an ignition of a flammable gas or vapour in mixture with air/inert gas occurs Note: The conditions are specified in ISO/IEC 80079-20-1. 426-02-05 explosive test mixture specified explosive mixture used for the testing of equipment for explosive gas atmospheres 426-02-09 lower flammable limit; LFL concentration of flammable gas or vapour in air, below which an explosive gas atmosphere does not form Note 1: For the purposes of Ex Equipment, this was previously referred to as the lower explosive limit (LEL). Note 2: The concentration can be expressed as either a volume fraction or a mass per unit volume.

Contents of GB/T 2900.35-2023