Detail of GB/T 3836.5-2021

Introduction of GB/T 3836.5-2021

GB/T 3836.5-2021 Explosive atmospheres—Part 5：Equipment protection by pressurized enclosure “p” This document is Part 5 of GB/T 3836 Explosive atmospheres. The following parts of GB/T 3836 have been published: ——Part 1: Equipment — General requirements; ——Part 2: Equipment protection by flameproof enclosures "d"; ——Part 3: Equipment protection by increased safety "e"; ——Part 4: Equipment protection by intrinsic safety "i"; ——Part 5: Equipment protection by pressurized enclosure "p"; ——Part 6: Equipment protection by oil immersion "o"; ——Part 7: Equipment protection by powder filling "q"; ——Part 8: Equipment protection by type of protection "n"; ——Part 9: Equipment protection by type of protection "m"; ——Part 11: Material characteristics for gas and vapour classification — Test methods and data; ——Part 12: Material characteristics for combustible dusts — Test methods; ——Part 13: Equipment repair, overhaul and reclamation; ——Part 14: Classification of areas — Explosive gas atmosphere; ——Part 15: Electrical installations design, selection and erection; ——Part 16: Electrical installations inspection and maintenance; ——Part 17: Equipment protection by pressurized enclosure "p" and artificially ventilated room "v"; ——Part 18: Intrinsically safe electrical systems; ——Part 20: Equipment with equipment protection level (EPL) Ga; ——Part 21: Application of quality systems for equipment manufacture; ——Part 22: Protection of equipment and transmission system using optical radiation; ——Part 23: Group I, category EPIL Ma equipment intended to remain functional in atmospheres endangered by firedamp and/or coal dust; ——Part 24: Equipment protection by special protection "s"; ——Part 25: Requirements for process sealing between flammable process fluids and electrical systems; ——Part 26: Electrostatic hazards — Guidance; ——Part 27: Electrostatic hazards — Test; ——Part 28: Non-electrical equipment for explosive atmospheres — Basic method and requirements; ——Part 29: Non-electrical equipment for explosive atmospheres — Constructional safety "c", control of ignition source "b", liquid immersion "k"; ——Part 30: Equipment and components in explosive atmospheres in underground mines; ——Part 31: Equipment dust ignition protection by enclosure "t"; ——Part 32: Intrinsically safe systems with electronically controlled spark duration limitation; ——Part 33: Equipment in adverse service conditions; ——Part 34: Equipment assemblies; ——Part 35: Classification of areas for explosive dust atmospheres; This document replaces GB/T 3836.5-2017 Explosive atmospheres — Part 5: Equipment protection by pressurized enclosure "p" and GB 12476.7-2010 Electrical apparatus for use in the presence of combustible dust — Part 7:Type of protection "pD". Explosive atmospheres — Part 5: Equipment protection by pressurized enclosure "p" 1 Scope This document contains the specific requirements for the construction and testing of electrical equipment with pressurized enclosures, of type of protection "p", intended for use in explosive gas atmospheres or explosive dust atmospheres. It also includes the requirements for pressurized enclosures containing a limited release of a flammable substance. This document applies to electrical equipment protected by pressurized enclosure "p" and for use in explosive gas atmospheres or explosive dust atmospheres. This document is not applicable to: ——pressurized enclosures where the containment system may release the following substance: ● air with an oxygen content greater than normal; or ● oxygen in combination with inert gas where the oxygen is in a proportion greater than 21%. ——pressurized rooms or analyser houses; see GB/T 3836.17. ——pressurized enclosures used where "explosives" or pyrotechnics are present. ——pressurized enclosures used where hybrid mixtures of gas/vapor and combustible dust are present. ——pressurized enclosures used where pyrophoric substances such as explosives or propellants containing their own oxidizers are present. ——pressurized enclosures with an internal source of release of combustible dust. Note: When the user acts in the role of the manufacturer, it is typically the user’s responsibility to ensure that all relevant requirements of this document are applied to the manufacturing and testing of the equipment. This document supplements and modifies the general requirements of GB/T 3836.1. Where a requirement of this document conflicts with a requirement of GB/T 3836.1, the requirements of this document take precedence. 2 Normative references The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 2900.35 Electrotechnical terminology — Equipment for explosive atmospheres (GB/T 2900.35-2008, IEC 60050-426: 2008, IDT) GB/T 2900.83 Electrotechnical terminology — Electrical and magnetic devices (GB/T 2900.83-2008, IEC 60050-151: 2001, IDT) GB/T 3836.1 Explosive atmospheres — Part 1: Equipment — General requirements (GB/T 3836.1-2021, IEC 60079-0: 2017, 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 4207 Method for the determination of the proof and the comparative tracking indices of solid insulating materials (GB/T 4207-2012, IEC 60112: 2009, IDT) GB/T 4208 Degrees of protection provide by enclosure (IP code) (GB/T 4208-2017, IEC 60529: 2013, IDT) GB/T 4942.1 Degrees of protection provided by the integral design of rotating electrical machines (IP code) — Classification (GB/T 4942.1-2006, IEC 60034-5: 2000, IDT) GB/T 9364 (all parts) Miniature fuses [IEC 60127 (all parts)] GB/T 16935.1 Insulation coordination for equipment within low-voltage systems — Part 1: Principles, requirements and tests (GB/T 16935.1-2008, IEC 60664-1: 2007, IDT) 3 Terms and definitions For the purposes of this document, the terms and definitions given in GB/T 2900.35, GB/T 2900.83 and GB/T 3836.1 as well as the following apply. Note: Unless otherwise specified, the terms "voltage" and "current" mean the r.m.s. values of an alternating, direct or composite voltage or current. 3.1 alarm piece of equipment that generates a visual or audible signal that is intended to attract attention 3.2 containment system part of the equipment containing the flammable substance that may constitute an internal source of release 3.3 dilution continuous supply of a protective gas, after purging, at such a rate that the concentration of a flammable substance inside the pressurized enclosure is maintained at a value outside the explosive limits at any potential ignition source (that is to say, outside the dilution area) Note: Dilution of oxygen by inert gas may result in a concentration of flammable gas or vapor above the upper flammable limit (UFL). 3.4 dilution area area in the vicinity of an internal source of release where the concentration of a flammable substance is not diluted to a safe concentration 3.5 enclosure volume volume of the empty enclosure without internal equipment. For rotating electrical machines, the free internal volume plus the volume displaced by the rotor 3.6 flammable substance gases, vapors, liquids or mixtures thereof that are capable of being ignited 3.7 hermetically sealed device device which is so constructed that the external atmosphere cannot gain access to the interior and in which any seal is made by fusion Note: Examples of fusion include brazing, welding or the fusion of glass to metal. 3.8 ignition-capable equipment; ICE equipment which in normal operation constitutes a source of ignition for a specified explosive atmosphere 3.9 indicator piece of equipment that shows whether flow or pressure is adequate and which is intended to be monitored periodically, consistent with the requirement of the application

Contents of GB/T 3836.5-2021

Foreword i Introduction vi 1 Scope 2 Normative references 3 Terms and definitions 4 Protection levels 5 Constructional requirements for pressurized enclosures 6 Temperature limits 7 Safety provisions and safety devices (except for static pressurization) 8 Safety provisions and safety devices for static pressurization 9 Supply of protective gas 10 Pressurized enclosure with an internal source of release 11 Release conditions 12 Design requirements for the containment system 13 Protective gas and pressurizing techniques when there is an internal source of release 14 Ignition-capable equipment 15 Internal hot surfaces 16 Type verification and test 17 Routine tests 18 Marking 19 Instructions Annex A (Normative) Purging and dilution tests Annex B (informative) Examples of functional sequence diagram Annex C (informative) Examples of the changes in pressure in ducts and enclosures Annex D (informative) Information to be provided to the user Annex E (Nominative) Classification of the type of release within enclosures Annex F (Informative) Examples for the use of the dilution area concept Annex G (Nominative) Internal cells and batteries for level of protection "pxb" and level of protection "pyb" Annex H (Nominative) Internal batteries and battery packs applied to Level of Protection "pzc" Bibliography