GB/T 3836.4-2021 Explosive atmospheres—Part 4：Equipment protection by intrinsic safety“i” English
This document is Part 4 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 liquid immersion “o”;
——Part 7: Equipment protection by powder filling “q”;
——Part 8: Equipment protection by type of protection “n”;
——Part 9: Equipment protection by encapsulation “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, reclamation and modification;
——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 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;
——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.
1 Scope
This document specifies the construction and testing of intrinsic safety apparatus intended for use in an explosive atmosphere and for associated apparatus, which is intended for connection to intrinsically safe circuits which enter such atmospheres.
This type of protection specified in this document is applicable to electrical equipment in which the electrical circuits themselves are incapable of causing an explosion in the surrounding explosive atmospheres.
This document is also applicable to electrical equipment or parts of electrical equipment located outside the explosive atmosphere or protected by another type of protection listed in GB/T 3836.1-2021, where the intrinsic safety of the electrical circuits in the explosive atmosphere may depend upon the design and construction of such electrical equipment or parts of such electrical equipment. The electrical circuits exposed to the explosive atmosphere are evaluated for use in such an atmosphere by applying this document.
The requirements for intrinsically safe systems are provided in GB/T 3836.18.
This document supplements and modifies the general requirements of GB/T 3836.1-2021, except as indicated in Table 1. Where a requirement of this document conflicts with a requirement of GB/T 3836.1-2021, the requirements of this document shall take precedence.
If requirements in this document are applicable to both intrinsic safety apparatus and associated apparatus, the term “apparatus” is used throughout the document.
This document is for electrical equipment only; therefore the term “equipment” used in the document always means “electrical equipment”.
If associated apparatus is placed in the explosive atmosphere, it shall be protected by an appropriate type of protection listed in GB/T 3836.1-2021, and then the requirements of that type of protection together with the relevant parts of GB/T 3836.1-2021 also apply to the associated apparatus.
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2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 3836.1-2021 Explosive atmospheres - Part 1: Equipment - General requirements (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 3836.18 Explosive atmospheres - Part 18: Intrinsically safe electrical systems (GB/T 3836.18-2017, IEC 60079-25:2010, 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 provided by enclosure (IP code) (GB/T 4208-2017, IEC 60529:2013, IDT)
GB/T 6109.2 Enamelled round winding wire - Part 2: Polyester enamelled round copper wire, class 155 (GB/T 6109.2-2008, IEC 60317-3:2004, IDT)
GB/T 6109.5 Enamelled round winding wire - Part 5: Polyesterimide enamelled round copper wire, class 180 (GB/T 6109.5-2008, IEC 60317-8:1997, IDT)
GB/T 6109.6 Enamelled round winding wire - Part 6: Polyimide enamelled round copper wire, class 220 (GB/T 6109.6-2008, IEC 60317-7:1997, IDT)
GB/T 6109.20 Enamelled round winding wire - Part 20: Polyester on polyesterimide overcoated with polyamide-imide enamelled round copper wire, class 200 (GB/T 6109.20-2008, IEC 60317-13:1997, IDT)
GB/T 7957 General requirements for construction, performance and explosion protected testing of caplights for use in mines susceptible to firedamp (GB/T 7957-2017, IEC 60079-35-1:2011, IEC 60079-35-2:2011, NEQ)
GB/T 9364 (all parts) Miniature fuses [IEC 60127 (all parts)]
GB/T 11021 Electrical insulation - Thermal evaluation and designation (GB/T 11021-2014, IEC 60085:2007, IDT)
GB/T 16657.2 Industrial communication networks - Fieldbus specifications - Part 2: Physical layer specification and service definition (GB/T 16657.2-2008, IEC 61158-2:2007, IDT)
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)
GB/T 16935.3 Insulation coordination for equipment within low-voltage systems - Part 3: Use of coating, potting or moulding for protection against pollution (GB/T 16935.3-2016, IEC 60664-3:2010, IDT)
ANSI/UL 248-1 Low-voltage fuses - Part 1: General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 3836.1-2021, and the following apply.
3.1
general
3.1.1
intrinsic safety “i”
electrical effect energy limited to a level that does not produce ignition
3.1.2
associated apparatus
electrical equipment which contains both intrinsically safe circuits and non-intrinsically safe circuits and is constructed so that the non-intrinsically safe circuits cannot adversely affect the intrinsically safe circuits
Note 1: Associated apparatus may be either:
a) electrical equipment which has another type of protection listed in GB/T 3836.1-2021 for use in the appropriate explosive atmosphere, or;
b) electrical equipment not so protected and which, therefore, is not normally used within an explosive atmosphere, for example a recorder which is not itself in an explosive atmosphere, but is connected to a thermocouple situated within an explosive atmosphere where only the recorder input circuit is intrinsically safe.
Note 2: In earlier versions of this document, the term was "associated equipment".
3.1.3
intrinsic safety apparatus
intrinsic safety equipment
electrical equipment in which all the circuits are intrinsically safe circuits
3.1.4
intrinsically safe circuit
circuit in which any spark or any thermal effect produced in the conditions specified in this standard, which include normal operation and specified fault conditions, is not capable of causing ignition of a given explosive atmosphere
3.1.5
simple apparatus
electrical component or combination of components of simple construction with well-defined electrical parameters and which is compatible with the intrinsic safety of the circuit in which it is used
Note: In earlier versions of this document, the term was "simple equipment".
3.2
coating
insulating material such as varnish or dry film laid on the surface of the assembly
Note: Coating and base material of a printed board form an insulating system that may have properties similar to solid insulation.
3.3
conformal coating
electrical insulating material applied as a coating to loaded printed circuit boards to produce a thin layer conforming to the surface in order to provide a protective barrier against deleterious effects from environmental conditions
3.4
control drawing
drawing or other document that is prepared by the manufacturer for the intrinsic safety or associated apparatus, detailing the electrical parameters to allow for interconnections to other circuits or apparatus
3.5
diode safety barrier
assemblies incorporating shunt diodes or diode chains (including Zener diodes) protected by fuses or resistors or a combination of these, manufactured as an individual apparatus rather than as part of a larger apparatus
3.6
entity concept
method used to determine acceptable combinations of intrinsic safety apparatus and associated apparatus through the use of intrinsically safe parameters assigned to connection facilities
3.7
faults
3.7.1
countable fault
fault which occurs in parts of electrical apparatus conforming to the constructional requirements of this document
3.7.2
fault
any defect of any component, separation, insulation or connection between components, not defined as infallible by this document, upon which the intrinsic safety of a circuit depends
3.7.3
non-countable fault
fault which occurs in parts of electrical apparatus not conforming to the constructional requirements of this document
3.8
fuse rating
In
current rating of a fuse as specified in GB/T 9364 series, ANSI/UL 248-1 or in the manufacturer's specification
3.9
fieldbus intrinsically safe concept (FISCO)
abbreviation of Fieldbus Intrinsically Safe Concept
3.10
infallibility
3.10.1
infallible component
infallible assembly of components
component or assembly of components that is considered as not subject to certain fault modes as specified in this document
Note: The probability of such fault modes occurring in service or storage is considered to be so low that they are not to be taken into account.
3.10.2
infallible connection
connections, including joints and interconnecting wiring and printed circuit board tracks, that are not considered according to this document as becoming open-circuited in service or storage
Note: The probability of such fault modes occurring in service or storage is considered to be so low that they are not to be taken into account.
3.10.3
infallible separation
infallible insulation
separation or insulation between electrically conductive parts that is considered as not subject to short circuits as specified in this document
Note: The probability of such fault modes occurring in service or storage is considered to be so low that they are not to be taken into account.
3.11
internal wiring
wiring and electrical connections that are made within the apparatus by its manufacturer
3.12
live maintenance
maintenance activities carried out while the associated apparatus, intrinsic safety apparatus and circuits are energized
3.13
electrical parameters
3.13.1
maximum input voltage
Ui
maximum voltage (peak a.c. or d.c.) that can be applied to the connection facilities of apparatus without invalidating the type of protection
3.13.2
maximum input current
Ii
maximum current (peak a.c. or d.c.) that can be applied to the connection facilities of apparatus without invalidating the type of protection
3.13.3
maximum input power
Foreword III
Introduction IX
1 Scope
2 Normative references
3 Terms and definitions
4 Grouping and classification of intrinsic safety apparatus and associated apparatus
5 Levels of protection and ignition compliance requirements of electrical apparatus
5.1 General
5.2 Level of protection “ia”
5.3 Level of protection "ib”
5.4 Level of protection “ic”
5.5 Spark ignition compliance
5.6 Thermal ignition compliance
5.7 Simple apparatus
6 Apparatus construction
6.1 Enclosures
6.2 Facilities for connection of external circuits
6.3 Separation distances
6.4 Protection against polarity reversal
6.5 Earth conductors, connections and terminals
6.6 Encapsulation
7 Components on which intrinsic safety depends
7.1 Rating of components
7.2 Connectors for internal connections, plug-in cards and components
7.3 Fuses
7.4 Primary and secondary cells and batteries
7.5 Semiconductors
7.6 Failure of components, connections and separations
7.7 Piezo-electric devices
7.8 Electrochemical cells for the detection of gases
8 Infallible components, infallible assemblies of components and infallible connections on which intrinsic safety depends
8.1 Level of protection “ic”
8.2 Mains transformers
8.3 Transformers other than mains transformers
8.4 Infallible windings
8.5 Current-limiting resistors
8.6 Capacitor
8.7 Shunt safety assemblies
8.8 Wiring, printed circuit board tracks, and connections
8.9 Galvanically separating components
9 Supplementary requirements for specific apparatus
9.1 Diode safety barriers
9.2 FISCO apparatus
9.3 Handlights and caplights
10 Type verifications and type tests
10.1 Spark ignition test
10.2 Temperature tests
10.3 Dielectric strength tests
10.4 Determination of parameters of loosely specified components
10.5 Tests for cells and batteries
10.6 Mechanical tests
10.7 Tests for intrinsic safety apparatus containing piezoelectric devices
10.8 Type tests for diode safety barriers and safety shunts
10.9 Cable pull test
10.10 Transformer tests
10.11 Optical isolator tests
10.12 Current carrying capacity of infallible printed circuit board connections
11 Routine verifications and tests
11.1 Routine tests for diode safety barriers
11.2 Routine tests for infallible transformers
12 Marking
12.1 General
12.2 Marking of connection facilities
12.3 Warning markings
12.4 Examples of marking
13 Documentation
Annex A (Normative) Assessment of intrinsically safe circuits
Annex B (Normative) Spark test apparatus for intrinsically safe circuits
Annex C (Informative) Measurement of creepage distances, clearances and separation distances through casting compound and through solid insulation
Annex D (Normative) Encapsulation
Annex E (Informative) Transient energy test
Annex F (Normative) Alternative separation distances for assembled printed circuit boards and separation of components
Annex G (Normative) Fieldbus intrinsically safe concept (FISCO) - Apparatus requirements
Annex H (Informative) Ignition test of semiconductor limiting power supply circuits
Bibliography
