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There are the following parts under the general title Explosive atmospheres:
——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 room “p” and artificially ventilated room “v”;
——Part 18: Intrinsically safe electrical systems;
——Part 19: Fieldbus intrinsically safe concept (FISCO);
——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 EPL 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;
…
This is Part 17 of Explosive atmospheres.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB 3836.17-2007 Electrical apparatus for explosive gas atmosphere - Part 17: Construction and use of rooms or buildings protected by pressurization, and the following main technical changes have been made with respect to GB 3836.17-2007:
——The standard name is changed, with the pressurized room "p" defined and the artificially ventilated room "v” added;
——The types of protections pb, pc and vc are added;
——The equipment protection level (EPL) is added;
——The requirements related to dusts are added;
——The requirements for various doors are added to prevent explosive atmosphere from entering;
——The content that the air inlet may be located in Zone 2 under specific conditions is added.
This part has been redrafted and modified in relation to IEC 60079-13:2017 Explosive atmospheres - Part 13: Equipment protection by pressurized room “p” and artificially ventilated room “v”.
The main technical differences of this part from IEC 60079-13:2017 and their justifications are as follows::
——The adjustment on technical differences has been made on “Normative references” of this part to meet the technical specification in China; the adjustment situations are embodied in a concentrated way in Clause 2 - "Normative references" and the specific adjustments are as follows:
IEC 60050-426 is replaced by GB/T 2900.35 which is identical to the international standard.
IEC 60079-0 is replaced by GB 3836.1 which is modified in relation to the international standard.
IEC 60079-10-1 is replaced by GB 3836.14 which is identical to the international standard.
IEC 60079-29 (all parts) is replaced by GB/T 20936 (all parts), and the degree of consistency between various parts of the two standards is as follows:
GB/T 20936.1-2017 Gas detectors for explosive atmospheres - Part 1: Performance requirements of detectors for flammable gases (IEC 60079-29-1:2007, MOD);
GB/T 20936.2-2017 Gas detectors for explosive atmospheres - Part 2: Selection, installation, use and maintenance of detectors for flammable gases and oxygen (IEC 60079-29-2:2007, MOD);
GB/T 20936.3-2017 Gas detectors for explosive atmospheres - Part 3: Guidance on functional safety of fixed gas detection systems (IEC 60079-29-3:2014, MOD);
GB/T 20936.4-2017 Gas detectors for explosive atmospheres - Part 4: Performance requirements of open path detectors for flammable gases (IEC 60079-29-4:2009, MOD).
GB/T 3836.16 is added for reference.
——Annex A is adjusted from informative to normative to strengthen maintenance requirements so as to ensure protection of equipment after being put into use.
The following editorial changes have been made in this part:
——The part number in the standard name is modified.
This part was proposed by the China Electrical Equipment Industrial Association.
This part is under the jurisdiction of SAC/TC 9 National Technical Committee on Explosion Protected Electrical Apparatus of Standardization Administration of China.
The previous edition of this part is as follows:
——GB 3836.17-2007.
Explosive atmospheres -
Part 17: Equipment protection by pressurized room “p” and artificially ventilated room “v”
1 Scope
This part of Explosive atmospheres gives requirements for the design, construction, assessment, test and marking of rooms used to protect internal equipment:
——located in a Zone 1 or Zone 2 or Zone 21 or Zone 22 explosive atmosphere (an area normally requiring an equipment protection level (EPL) Gb, Gc, Db or Dc) without an internal source of gas/vapour release and protected by pressurization;
——located in a Zone 2 explosive atmosphere (an area normally requiring EPL Gc) without an internal source of gas/vapour release and protected by artificial ventilation;
——located in a non-hazardous area, containing an internal source of gas/vapour release and protected by artificial ventilation;
——located in a Zone 1 or Zone 2 or Zone 21 or Zone 22 explosive atmosphere (an area normally requiring EPL Gb, Gc, Db or Dc), containing an internal source of gas/vapour release and protected by both pressurization and artificial ventilation.
The term "room" used in this part includes single rooms, multiple rooms, a complete building or a room contained within a building. A room includes passages for facilitating the entry of personnel as well as the inlet and outlet ducts. An acoustic hood and other like enclosures designed to permit the entry of personnel may be considered as a room. This part also includes requirements related to safety devices and controls necessary to ensure that artificial ventilation, purging and pressurization are established and maintained.
A room assembled or constructed on site, may be either on land or off-shore. The room is primarily intended for installation by an end-user but could be constructed and assessed at a manufacturer’s facility, where the final construction such as ducting can be completed on site.
Rooms can be located in an explosive gas atmosphere requiring EPL Gb or Gc, or a combustible dust atmosphere requiring EPL Db or Dc.
This part does not specify the methods that may be required to ensure adequate air quality and temperature for personnel to work within the room.
Protection of rooms by using an inert gas or a flammable gas is outside of the scope of this part. It is generally recognized that such applications are special cases, which in part may be addressed using the principles from GB/T 3836.5, but in all probability will also be the subject of additional, stringent engineering standards, procedures and practices. Pressurized enclosures for equipment that are not intended to facilitate the entry of personnel are addressed in GB/T 3836.5, and are not in the scope of this part.
Maintenance recommendations are contained in Annex A.
This part supplements and modifies the general requirements of GB 3836.1, except exclusions as indicated in Table 1.
Table 1 Relationship between this part and GB 3836.1
Clause of GB 3836.1 GB 3836.1
application to
this part
Clause of
GB 3836.1
(2010 edition)
(Informative) Clause/subclause title
(Nominative)
4 Equipment grouping Applies
4.1 Group I Excluded
4.2 Group II Applies
4.3 Group III Applies
4.4 Equipment for a particular explosive atmosphere Applies
5.1 Environmental influences Applies
5.1.1 Ambient temperature Applies
5.1.2 External source of heating or cooling Applies
5.2 Service temperature Applies
5.3.1 Determination of maximum surface temperature Applies
5.3.2.1 Group I electrical equipment Excluded
5.3.2.2 Group II electrical equipment Applies
5.3.2.3 Group III electrical equipment Applies
5.3.3 Small component temperature for Group I and Group II electrical equipment Excluded
6.1 General Applies
6.2 Mechanical strength of equipment Excluded
6.3 Opening time of equipment enclosure Excluded
6.4 Circulating currents Excluded
6.5 Gasket retention Excluded
6.6 Electromagnetic and ultrasonic radiating equipment Applies
7.1 General Excluded
7.2 Thermal endurance Excluded
7.3 Resistance to light Modified
7.4 Electrostatic charges on external non-metallic materials Modified
7.5 Flame retardance Excluded
7.6 Screw hole Applies
8 Metallic enclosures and metallic parts of enclosures Excluded
9 Fasteners Excluded
10 Interlocking devices Excluded
11 Insulating bushings Excluded
12 Materials used for cementing Excluded
13 Ex components Excluded
14 Connection facilities and termination compartments Excluded
15 Connection facilities for earthing and bonding conductors Excluded
16 Entries into enclosures Excluded
17 Supplementary requirements for rotating electrical machines Excluded
18 Supplementary requirements for switchgear Excluded
19 Supplementary requirements for fuses Excluded
20 Supplementary requirements for plugs and sockets Excluded
21 Supplementary requirements for luminaires Excluded
22 Supplementary requirements for caplights and handlights Excluded
23 Equipment incorporating cells and batteries Excluded
24 Documentation Applies
25 Compliance of prototype or sample with documents Applies
26 Type test Excluded
26.1 General Applies
26.2 Test configuration Applies
26.3 Tests in explosive test mixtures Excluded
26.4 Tests of enclosures Excluded
26.5 Thermal tests Excluded
26.6 Torque test for insulating bushings Excluded
26.7 Non-metallic enclosures or non-metallic parts of enclosures Excluded
26.8 Test for thermal endurance to heat Excluded
26.9 Test for thermal endurance to cold Excluded
26.10 Test for resistance to light Applies
26.11 Test for resistance to chemical agents for Group I electrical equipment Excluded
26.12 Earth continuity Excluded
26.13 Surface resistance test of parts of enclosures of non-metallic materials Excluded
26.14 Electrification test Applies
26.15 Measurement of capacitance Excluded
27 Routine tests Applies
28 Manufacturers responsibility Applies
29.1 Location Modified
29.2 General Modified
29.3 Ex marking for explosive gas atmospheres Modified
29.4 Ex marking for explosive dust atmospheres Applies
29.5 Combined types of protection Applies
29.6 Multiple types of protection Excluded
29.7 Ga using two independent Gb types of protection Excluded
29.8 Ex components Excluded
29.9 Small equipment and small Ex components Excluded
29.10 Extremely small equipment and extremely small Ex components Modified
29.11 Warning markings Applies
29.12 Alternate marking of equipment protection levels (EPLs) Excluded
29.13 Cells and batteries Applies
30 Instructions Modified
Annex A Supplementary requirements for Ex cable glands Excluded
Annex B Requirements for Ex components Excluded
Annex C Special requirements for Group I electrical equipment Excluded
Annex D Inspection procedure for obtaining Ex certificate Applies
Annex E Introduction to an alternative risk assessment method encompassing "equipment protection levels" for Ex equipment Applies
Annex F Motors with converter supply Applies
Annex G Example of rig for resistance to impact test Excluded
Applies: this requirement of GB 3836.1 is applied without change.
Excluded: this requirement of GB 3836.1 does not apply.
Modified: this requirement of GB 3836.1 is modified as detailed in this part.
Note: The applicable requirements of GB 3836.1 are identified by the clause title which is normative. This table was written against the specific requirements of GB 3836.1.
2 Normative references
The following referenced documents are indispensable for the application of this document. 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 3836.1 Explosive atmospheres - Part 1: Equipment - General requirements (GB 3836.1-2010, IEC 60079-0:2007, MOD)
GB 3836.14 Explosive atmospheres - Part 14: Classification of areas - Explosive gas atmosphere (GB 3836.14-2014, IEC 60079-10-1:2008, IDT)
GB/T 3836.16 Explosive atmospheres - Part 16: Electrical installations inspection and maintenance (GB/T 3836.16-2017, IEC 60079-17:2007, IDT)
GB/T 20936 (all parts) Gas detectors for explosive atmospheres [IEC 60079-29 (all parts)]
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.35 and GB 3836.1 and the following apply.
Note: Unless otherwise specified, the terms "voltage" and "current" mean the RMS values of an alternating, direct or composite voltage or current.
3.1
airlock
means of egress, consisting of two interdependent doors designed to maintain the internal pressure of the room in order to prevent the entry of a surrounding explosive atmosphere
3.2
alarm
piece of apparatus that generates a visual or audible signal that is intended to attract attention
3.3
clean air
air that is essentially free of combustible dust, flammable vapour or gas
3.4
dilution
mixing of flammable gas or vapour with air which, over time, will reduce the flammable concentration to a safe level
Note: For safety reasons, dilution to a level lower than the lower explosive limit (LEL) can be required if associated with the potential release there is an additional toxic or asphyxiant risk. Further guidance can be found in GB/T 29812.
3.5
internal source of release
point or location indoors from which a gas, vapour, mist or liquid may be released into the atmosphere such that an explosive gas atmosphere could be formed
3.6
limiting value
lowest concentration value of the lower flammable limit (LFL) of each component involved, taking account of the most onerous conditions of concentration that may occur from every internal source of release within the room
3.7
lower flammable limit; LFL
lower limit of the combustion concentration range of flammable gas or vapour in air below which an explosive gas atmosphere will not form
Note: This term is also known as the lower explosive limit (LEL).
3.8
opening
inlet, outlet, door or non-airtight fixed panel
3.9
pressurization
technique of guarding against the ingress of the external atmosphere into a room by maintaining clean air therein at a pressure above that of the external atmosphere
Note: The pressurization in this part is suitable for rooms.
3.10
pressurization system
grouping of safety devices and other components used to pressurize and monitor or control a pressurized room
3.11
restricted access door
door located in a hazardous area in Zone 2, which may be opened for no more than three times a day and for no more than 60s each time, gives an alarm when open or has an option of a time delay of no more than 90s if not completely closed
Note: Access-restricted doors include those that can be opened only with a work permit.
3.12
safety device
item used to implement or maintain the integrity of the type of protection
3.13
pressurized room
room volume protected by pressurization and of sufficient size to permit the entry of a person who may work or stay in the room
3.14
artificially ventilated room
room volume protected by artificial ventilation and of sufficient size to permit the entry of a person who may work or stay in the room
3.15
purging
operation of passing a quantity of clean air through the room and ducts in a pressurized or artificially ventilated room, so that the concentration of the explosive gas mixture is brought to a safe level
3.16
room volume
(of the pressurized or artificially ventilated room) volume of the empty room and including any associated ducting without internal equipment
3.17
pressurization pb
pressurized room that provides an equipment protection level Gb or Db
3.18
pressurization pc
pressurized room that provides an equipment protection level Gc or Dc
3.19
artificial ventilation vc
artificial ventilation of a room with or without an internal source of release, such that the room provides an equipment protection level Gc, which is only applicable to artificially ventilated rooms used in Zone 2
3.20
artificial ventilation
technique of guarding against an explosive atmosphere by the use of mechanical means to provide for the movement of air
3.21
ventilation system
complete installation required to produce artificial ventilation
4 Requirements for rooms
4.1 General
Protection by pressurization and protection by artificial ventilation are separately used but may be combined to protect against hazards where required. Where both techniques are combined, then requirements for both shall apply. Unless otherwise identified in Clauses 6 or 7, the requirements in 4.2 to 4.10 apply to both protection techniques.
Note: Annex C provides examples of applications and associated guidelines.
4.2 Type and level of protection
4.2.1 Pressurization "p"
Rooms with pressurization "p" shall be one of the following:
a) Level of protection "pb" (EPL Gb or Db). The pressurized room maintains an internal positive pressure reducing the risk of ingress of an explosive atmosphere and is suitable for use in an area requiring EPL Gb or Db, permitting unprotected equipment to be installed within the pressurized room except for pressurization safety devices (see 6.3.1).
b) Level of protection "pc" (EPL Gc or Dc). The pressurized room maintains an internal positive pressure reducing the risk of the ingress of an explosive atmosphere and is suitable for use in an area requiring EPL Gc or Dc, permitting unprotected equipment to be installed within the pressurized room except for pressurization safety devices (see 6.3.1).
4.2.2 Artificial ventilation "v"
The artificially ventilated room maintains artificial ventilation to dilute a release of flammable substance to reduce a hazardous area inside such that the required EPL is reduced from either Gb or Gc to non-hazardous or from Gb to Gc.
Rooms with artificial ventilation "v" shall be:
——level of protection "vc" (EPL Gc). The artificially ventilated room maintains artificial ventilation to dilute a release of flammable substance to reduce a hazardous area such that unprotected equipment can be installed within the artificially ventilated room, and is suitable for use in an area requiring EPL Gc.
Note: This permits equipment with a lower EPL to be installed within the artificially ventilated room except for ventilation safety devices (see 7.3.1).
Rooms may be protected by either general or local artificial ventilation. General artificial ventilation applies to an entire room or significant portion of a room and local artificial ventilation applies to restricted regions, for example an extraction hood.
4.3 Construction
The protected room shall, at a minimum, be designed to allow pressurization or artificial ventilation to be used in accordance with Clauses 6 or 7.
Note: The pressurized room construction requirements could be affected by the location, occupancy requirements, and functionality.
For pressurized rooms and rooms protected by artificial ventilation, provision shall be made to ensure adequate purging of dead air spaces created within the room, for example by avoiding suspended ceilings, trenches, or raised floors.
Foreword III
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements for rooms
4.1 General
4.2 Type and level of protection
4.3 Construction
4.4 Mechanical strength
4.5 Penetrations and seal
4.6 Personnel access doors
4.7 Inlets and outlets
4.8 Ducts
4.9 Purging and dust cleaning
4.10 Ignition prevention under system failure
5 Clean air supply
5.1 General
5.2 Source of clean air
5.3 Environmental and air temperature conditions
5.4 Heating, ventilation and air conditioning equipment
6 Requirements for pressurized rooms
6.1 General
6.2 Purging of rooms
6.3 Minimum safety provisions, safety devices and electrical disconnects
6.4 Test for pressurized rooms
7 Requirements for artificially ventilated rooms
7.1 General
7.2 Purging of artificially ventilated area
7.3 Minimum safety provisions, safety devices and electrical disconnects
7.4 Loss of artificial ventilation
7.5 Test for artificially ventilated rooms
8 Marking
8.1 General
8.2 Marking of pressurized rooms
8.3 Marking of artificially ventilated rooms
9 Instructions
9.1 General
9.2 Technical documentation for pressurized rooms
9.3 Technical documentation for artificially ventilated rooms
9.4 Technical documentation for rooms protected by pressurization and artificial ventilation combined
9.5 Modifications
Annex A (Informative) Maintenance
Annex B (Informative) Guidelines when pressurization or artificial ventilation is not immediately restored
Annex C (Informative) Examples of applications and associated guidelines
Bibliography
