Detail of GB/T 3836.2-2021

Introduction of GB/T 3836.2-2021

GB/T 3836.2-2021 Explosive atmospheres—Part 2：Equipment protection by flameproof enclosures “d” English 1 Scope This standard contains specific requirements for the construction and testing of electrical equipment with the type of protection flameproof enclosure “d”, intended for use in explosive gas atmospheres. This standard is applicable to electrical equipment protected by flameproof enclosure "d" to be used in explosive atmospheres. This standard supplements and modifies the general requirements of GB/T 3836.1. Where a requirement of this standard conflicts with a requirement of GB/T 3836.1, the requirement of this standard will take precedence. 2 Normative references The following documents, in whole or in part, are normatively referenced in this standard and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 197 General purpose metric screw threads—Tolerances (GB/T 197-2018, ISO 965-1: 2013, MOD) GB/T 1406.2 Types and dimensions of lamp caps—Part 2: Pin lamp caps (GB/T 1406.2-2008, IEC 60061-1: 2005, MOD) GB/T 2516 General purpose metric screw threads—Limit deviations (GB/T 2516-2003, ISO 965-3: 1998, MOD) GB/T 3836.1 Explosive atmospheres—Part 1: Equipment—General requirements (GB/T 3836.1-2021, IEC 60079-0: 2017, MOD) GB/T 3836.3 Explosive atmospheres—Part 3: Equipment protection by increased safety "e” (GB/T 3836.3-2021, IEC 60079-7: 2015, MOD) GB/T 3836.4 Explosive atmospheres—Part 4: Equipment protection by intrinsic safety "i” (GB/T 3836.4-2021, IEC 60079-11: 2011, MOD) GB/T 3836.8 Explosive atmospheres—Part 8: Equipment protection by type of protection “n” (GB/T 3836.8-2021, IEC 60079-15: 2017, MOD) GB/T 5163 Sintered metal materials, excluding hardmetals—Permeable sintered metal materials—Determination of density, oil content, and open porosity (GB/T 5163-2006, ISO 2738: 1999, IDT) GB/T 5249 Permeable sintered metal materials—Determination of bubble test pore size (GB/T 5249-2013, ISO 4003: 1977, IDT) GB/T 5250 Permeable sintered metal materials—Determination of fluid permeability (GB/T 5250-2014, ISO 4022: 1987, IDT) GB/T 9364 (all parts) Miniature fuses [IEC 60127 (all parts)] GB/T 19148.2 Types and dimensions of lampholders—Part 2: Pin lampholders (GB/T 19148.2-2008, IEC 60061-2: 2004, MOD) ANSI/ASME B1.20.1 Pipe threads, general purpose (inch) 3 Terms and definitions For the purposes of this standard, the terms and definitions given in GB/T 3836.1 and the following apply. Note: Additional definitions applicable to explosive atmospheres can be found in GB/T 2900.35. 3.1 flameproof enclosure “d” enclosure in which the parts which can ignite an explosive gas atmosphere are placed and which can withstand the pressure developed during an internal explosion of an explosive mixture, and which prevents the transmission of the explosion to the explosive gas atmosphere surrounding the enclosure Note: "Flameproof type" is defined as an explosion-proof type of electrical equipment in which the enclosure can withstand the explosion of an explosive mixture entering the interior of the enclosure through any joint surface or structural gap of the enclosure without damage, and does not cause ignition of an explosive atmospheres formed by one or more gases or vapors outside. The two terms have the same meaning. 3.2 volume total internal volume of the enclosure Note 1: For enclosures in which the contents are essential in service, the volume to be considered is the remaining free volume. Note 2: For luminaries, the volume is determined without lamps fitted. 3.3 flameproof joint or flamepath place where the corresponding surfaces of two parts of an enclosure, or the conjunction of enclosures, come together and which prevents the transmission of an internal explosion to the explosive gas atmosphere surrounding the enclosure 3.4 width of flameproof joint L shortest path through a flameproof joint from the inside to the outside of an enclosure Note: This definition does not apply to threaded joints. 3.5 distance l shortest path through a flameproof joint, when the width of the flameproof joint L is interrupted by holes intended for the passage of fasteners for assembling the parts of the flameproof enclosure 3.6 gap of flameproof joint i distance between the corresponding surfaces of a flameproof joint when the electrical apparatus enclosure has been assembled Note: For cylindrical surfaces, forming cylindrical joints, the gap is the difference between the diameters of the bore and the cylindrical component. 3.7 maximum experimental safe gap (for an explosive mixture) MESG maximum gap of a joint of 25 mm in width which prevents any transmission of an explosion during 10 tests made under the conditions specified in GB/T 3836.11 3.8 shaft part of circular cross-section used for the transmission of rotary movement 3.9 operating rod part used for the transmission of control movements which may be rotary or linear or a combination of the two 3.10 pressure-piling results of an ignition, in a compartment or subdivision of an enclosure, of a gas mixture pre-compressed, for example, due to a primary ignition in another compartment or subdivision 3.11 quick-acting door or cover door or cover provided with a device which permits opening or closing by a simple operation, such as the movement of a lever or the rotation of a wheel Note: The device is arranged so that the operation has two stages: ——one for locking or unlocking, and ——another for opening or closing. 3.12 door or cover fixed by threaded fasteners door or cover, the opening or closing of which requires the manipulation of one or more threaded fasteners (screws, studs, bolts or nuts) 3.13 threaded door or cover door or cover which is assembled to a flameproof enclosure by a threaded flameproof joint 3.14 breathing device device which permits an exchange between the atmosphere within an enclosure and the surrounding atmosphere and which maintains the integrity of the type of protection 3.15 draining device device which permits liquids to flow out from an enclosure and which maintains the integrity of the type of protection 3.16 Ex equipment blanking element blanking elements that are tested separately from the equipment enclosure, have an equipment certificate, and are intended to be fitted to the equipment enclosure without further consideration Note 1: This does not preclude a component certificate for Ex component blanking elements in accordance with GB/T 3836.1. Examples of blanking elements are shown in Figure C.1. Note 2: Non-threaded blanking elements are not equipment for Group II applications. 3.17 Ex equipment thread adapter thread adapter tested separately from the enclosure but having an equipment certificate and which is intended to be fitted to the equipment enclosure without further consideration Note: This does not preclude a component certificate for Ex component thread adapters in accordance with GB/T 3836.1. Examples of thread adapters are shown in Figure C.3. 3.18 Ex component enclosure empty flameproof enclosure provided with an Ex component certificate, without the internal equipment being defined, so as to enable the empty enclosure to be made available for incorporation into an equipment certificate without the need for repetition of type testing

Contents of GB/T 3836.2-2021

Foreword i Introduction ix 1 Scope 2 Normative references 3 Terms and definitions 4 Level of protection (equipment protection level, EPL) 5 Flameproof joints 6 Sealed joints 7 Operating rods 8 Supplementary requirements for shafts and bearings 9 Light-transmitting parts 10 Breathing and draining devices which form part of a flameproof enclosure 11 Fasteners and openings 12 Materials 13 Entry devices for flameproof enclosures 14 Verification and tests 15 Type tests 16 Routine tests 17 Switchgear for Group I 18 Lampholders and Iamp caps 19 Non-metallic enclosures and non-metallic parts of enclosures 20 Marking 21 Instructions Annex A (Normative) Additional requirements for crimped ribbon elements and multiple screen elements of breathing and draining devices Annex B (Normative) Additional requirements for elements, with non-measurable paths of breathing and draining devices Annex C (Normative) Additional requirements for flameproof enclosure entry devices Annex D (Normative) Empty flameproof enclosures as Ex components Annex E (Normative) Cells and batteries used in flameproof enclosures Annex F (Informative) Mechanical properties for screws and nuts Annex G (Normative) Additional requirements for flameproof enclosures with an internal source of release (containment system) Annex H (Normative) Requirements for machines with flameproof “d” enclosures fed from converters Annex I (Normative) Supplementary requirements for Group I electrical equipment Annex J (Informative) Examples of supplemental mechanical means of securing the cemented joint Bibliography