Abstract

Interpretation Sheet 1 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"

General Information

Status: Published
Publication Date: 03-Feb-2022

ICS: 29.260.20 - Electrical apparatus for explosive atmospheres

Technical Committee: TC 31 - Equipment for explosive atmospheres
Drafting Committee: MT 60079-31 - TC 31/MT 60079-31

Current Stage: DELPUB - Deleted Publication
Start Date: 04-Feb-2022
Completion Date: 14-Feb-2026

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Revised: IEC 60079-31:2013 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"
Effective Date: 05-Sep-2023

Revises: IEC 60079-31:2008 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"
Effective Date: 05-Sep-2023

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IEC 60079-31:2008/ISH1:2022 - Interpretation Sheet 1 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"
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IEC 60079-31:2008/ISH1:2022 - Interpretation Sheet 1 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t" Released:2/4/2022

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Frequently Asked Questions

What is IEC 60079-31:2008/ISH1:2022?

IEC 60079-31:2008/ISH1:2022 is a standard published by the International Electrotechnical Commission (IEC). Its full title is "Interpretation Sheet 1 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"". This standard covers: Interpretation Sheet 1 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"

What is the scope of IEC 60079-31:2008/ISH1:2022?

Interpretation Sheet 1 - Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure "t"

What ICS categories does IEC 60079-31:2008/ISH1:2022 belong to?

IEC 60079-31:2008/ISH1:2022 is classified under the following ICS (International Classification for Standards) categories: 29.260.20 - Electrical apparatus for explosive atmospheres. The ICS classification helps identify the subject area and facilitates finding related standards.

What standards are related to IEC 60079-31:2008/ISH1:2022?

IEC 60079-31:2008/ISH1:2022 has the following relationships with other standards: It is inter standard links to IEC 60079-31:2013, IEC 60079-31:2008. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

How can I access IEC 60079-31:2008/ISH1:2022?

IEC 60079-31:2008/ISH1:2022 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

Standards Content (Sample)

IEC 60079-31:2008/ISH1:2022 - ...

© IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
IEC 60079-31
Edition 1.0 2008-11
EXPLOSIVE ATMOSPHERES –
Part 31: Equipment dust ignition protection by enclosure "t"

INTERPRETATION SHEET 1
This interpretation sheet has been prepared by IEC technical committee 31: Equipment for
explosive atmospheres.
The text of this interpretation sheet is based on the following documents:
DISH Report on voting
31/1605/DISH 31/1616/RVDISH
Full information on the voting for the approval of this interpretation sheet can be found in the
report on voting indicated in the above table.

___________
IEC 60079-31:2008 Edition 1.0, Explosive atmospheres – Part 31: Equipment dust ignition
protection by enclosure "t"
Question 1:
The requirements given in 5.2.2 of IEC 60079-31:2008 (Edition 1) permit threaded entries for
dust protected enclosures to be tapered threads or parallel threads with not less than five
threads, with a minimum tolerance of medium or fine according to ISO 956-1 and ISO 965-3.
Does the description of threads include other thread forms such as ISO 228-1 threads (these
threads are commonly referred to as BSPP or Type G threads and BSPT or Type R threads)?
Answer 1:
No, only metric and NPT threaded entries are permitted for enclosures having equipment dust
ignition protection by enclosure.
NOTE It has been determined that some sizes of Type G and NPT threads will engage but will result in a mismatched
thread engagement. The intention of the restriction to only metric and NPT
...

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IEC

IEC 60079-29-0:2025(Main)

Explosive atmospheres - Part 29-0: Gas detection equipment - General requirements and test methods

IEC 60079-29-0:2025 specifies general requirements, test methods and acceptance criteria that apply to flammable, oxygen and toxic gas detection equipment intended to detect gases and vapours and to provide an indication, alarm or other output function for personnel or property protection in industrial and commercial applications.
This document applies to the following gas detection equipment:
– Gas detection equipment Type "FL" intended for the detection of flammable gases:
• Type FL-Group I, in mines susceptible to firedamp;
• Type FL-Group II, in locations other than mines susceptible to firedamp; and
• Type FL-OP, open path gas detection equipment for flammable gases.
– Gas detection equipment Type "O2" intended for the detection of Oxygen:
• Type O2-DE, detection of oxygen deficiency or oxygen enrichment; and
• Type O2-IN, inertisation as measuring function for explosion protection.
– Gas detection equipment Type "TX" intended for the detection of toxic gases:
• Type TX-SM, detection in areas for safety monitoring applications and typically using alarm signalling;
• Type TX-HM, occupational exposure measurement in the region of occupational exposure limit values; and
• Type TX-OP, open path gas detection equipment for toxic gases.
This document is not applicable to equipment:
– used for medical applications;
– used only in laboratories for analysis or measurement;
– used only for process monitoring or control purposes (such as a gas analyser);
– used in the domestic environment;
– used in environmental air pollution monitoring;
– used for flue gas analysis;
– used for sampling systems external to the gas detection equipment;
– with samplers and concentrators such as sorbents or paper tape having an irreversible indication;
– consisting of a passive optical receiver without a dedicated optical source;
– equipment within the scope of IEC 60335-2-40 and IEC 60335-2-89.
This first edition of IEC 60079-29-0 cancels and replaces the second edition of 60079-29-1 published in 2016 and its Amendment 1:2020, and the first edition of IEC 60079-29-4 published in 2009. In addition, IEC 60079-29-0 Type TX-SM cancels and replaces Type SM of the first edition of IEC 62990-1.

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IEC 60079-28:2025(Main)

Explosive atmospheres - Part 28: Protection of equipment and transmission systems using optical radiation

IEC 60079-28:2025 specifies additional requirements for Ex Equipment, Ex associated equipment or Ex Components containing optical systems emitting optical radiation, which is exposed to explosive atmospheres. These additional requirements are applicable for all equipment groups and all Equipment Protection Levels (EPL).
This document contains requirements for optical radiation in the wavelength range from 380 nm to 10 µm. It covers the following ignition mechanisms:
• Optical radiation is absorbed by surfaces or particles, causing them to heat up, and under certain circumstances this might allow them to attain a temperature which will ignite a surrounding explosive atmosphere.
• In rare special cases, direct laser induced breakdown of the gas at the focus of a strong beam, producing plasma and a shock wave both eventually acting as ignition source. These processes can be supported by a solid material close to the breakdown point.
• Annex A provides guidance when considering ignition mechanisms that influence the hazard of optics in explosive atmospheres.
This document applies to
a) laser equipment; and
b) optical fibre equipment; and
c) any optical system that converts light into convergent beams with focal points within the hazardous area only.
This document does not apply to:
d) laser equipment for EPL Mb, Gb, Gc, Db or Dc applications which complies with Class 1 limits in accordance with IEC 60825-1; or
e) Single or multiple optical fibre cables not part of optical fibre equipment if the cables:
1) comply with the relevant industrial standards for optical fibre cables, along with additional protective means, for example robust cabling, conduit or raceway (for EPL Gb, Db, Mb, Gc or Dc); or
2) comply with the relevant industrial standards for optical fibre cables (for EPL Gc or Dc); or
f) Optical radiation sources as defined in i) to iii) above where the optical radiation is fully contained in an enclosure complying with one of the following Types of Protection suitable for the EPL, or the minimum ingress protection rating specified:
1) flameproof "d" enclosures (IEC 60079-1); or
2) pressurized "p" enclosures (IEC 60079-2); or
3) restricted breathing "nR" enclosure (IEC 60079-15); or
4) dust protection "t" enclosures" (IEC 60079-31); or
5) an enclosure that provides a minimum ingress protection of IP 6X and where no internal absorbers are to be expected and complying with "Tests of enclosures" in IEC 60079-0.
This document does not cover ignition by ultraviolet radiation and by absorption of the radiation in the explosive mixture itself. Explosive absorbers or absorbers that contain their own oxidizer as well as catalytic absorbers are also outside the scope of this document.
This document supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this document conflicts with a requirement of IEC 60079-0, the requirement of this document takes precedence.
This third edition cancels and replaces the second edition published in 2015. This edition constitutes a technical revision

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IEC/IEEE 60079-30-1:2025(Main)

Explosive atmospheres - Part 30-1: Electrical resistance trace heating - General and testing requirements

IEC/IEEE 60079-30-1:2025 is available as IEC/IEEE 60079-30-1:2025 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC/IEEE 60079-30-1:2025 specifies general and testing requirements for electrical resistance trace heaters for application in explosive atmospheres with the exclusion of those for Equipment Protection Levels (EPL) Ga, Da, Ma and Mb equipment. This document covers trace heaters that comprise either factory or field (worksite) assembled units, and which can be series trace heaters, parallel trace heaters, trace heater pads, or trace heater panels that have been assembled and/or terminated in accordance with the manufacturer's instructions.
This document also includes requirements for termination assemblies and control methods used with trace heating systems. The explosive atmospheres referred to in this document are those defined in IEC 60079-10-1 and IEC 60079-10-2.
Annex F and Annex G outline the application of this document for those users applying the Division method of area classification
This second edition of IEC/IEEE 60079-30-1 cancels and replaces the first edition of IEC/IEEE 60079-30-1 published in 2015. This edition constitutes a technical revision.
The significant technical changes with respect to the previous edition can be found n the foreword of this publication.

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IEC/IEEE 60079-30-2:2025(Main)

Explosive atmospheres - Part 30-2: Electrical resistance trace heating - Guidance on application for design, installation and maintenance

IEC/IEEE 60079-30-2:2025 is available as IEC/IEEE 60079-30-2:2025 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC/IEEE 60079-30-2:2025 provides guidance for the application of electrical resistance trace heating systems in areas where explosive atmospheres can be present, with the exclusion of those classified as requiring Equipment Protection Level (EPL) Ga or Da (traditional relationship to Zone 0 and Zone 20 respectively). This document also provides guidance for explosive atmospheres incorporating the Division method of area classification that can be applied by some users of this document.
This document provides recommendations for the design, installation, maintenance and repair of trace heating systems including associated control and monitoring equipment. It does not cover devices that operate by induction heating, skin effect heating or direct pipeline heating, nor those intended for stress relieving.
This second edition of IEC/IEEE 60079-30-2 cancels and replaces the first edition of IEC/IEEE 60079-30-2 published in 2015.
This edition includes the following significant technical changes with respect to the previous edition:
a) a general review and updating of the first edition;
b) the addition of Annex I – Other applications of trace heating in explosive atmospheres.
The significance of changes between IEC/IEEE 60079-30-2, Edition 1.0 (2015) and IEC/IEEE 60079-30-2, Edition 2.0 (this document) can be found on the foreword of this document.

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IEC 60079-45:2025(Main)

Explosive atmospheres - Part 45: Electrical ignition systems for internal combustion engines

IEC 60079-45:2025 is intended to enhance the safety of personnel by providing minimum requirements for electrical ignition systems for spark-ignited reciprocating internal combustion engines, parts of which provide Equipment Protection Level (EPL) Gc.
This document provides minimum construction and test requirements, in addition to manufacturer installation and maintenance recommendations, for the safe operation of ignition systems and components for spark-ignited reciprocating internal combustion engines providing EPL Gc for equipment Group IIB+H2, IIB or IIA. These requirements apply to systems rated for normal operation with secondary voltages less than or equal to 60 kV.
This document applies only to the ignition systems or the individual ignition system components used on reciprocating internal combustion engines that are stationary when in operation and mobile machinery where the internal combustion engine can be potential source of ignition. Applications addressed by the scope of this document include but are not limited to gas compressors, electric power generators, forklift trucks, and pumps.
This document does not apply to:
a) Engine ignition systems that utilize a breaker point or magneto type ignition systems as these would not be suitable for use in a hazardous area.
b) Road vehicles.
c) Low voltage parts and electrical installation that are not included in the ignition system, such as various sensors and thermocouples, throttle actuator(s), fuel control valve(s), human machine interface (HMI), respective harness and wiring and all the other items that might belong to the integrated control system besides the ignition system.
This document supplements and modifies the general requirements of IEC 60079-0 and the requirements of ISO/IEC 80079-41. Where a requirement of this document conflicts with IEC 60079 0 or ISO/IEC 80079-41, the requirement of this document takes precedence.

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Explosive atmospheres - Part 18: Equipment protection by encapsulation "m"

IEC 60079-18:2025 gives the specific requirements for the construction, testing and marking of electrical Ex Equipment, parts of electrical Ex Equipment and Ex Components with the Type of Protection encapsulation "m" (hereinafter referred to as "m" Equipment) intended for use in explosive gas atmospheres or explosive dust atmospheres. For Levels of Protection "mb" and "mc", this document applies where the rated voltage does not exceed 11 kV ACRMS or DC. For Level of Protection "ma", this document applies where the rated voltage does not exceed 1 kV ACRMS or DC. This document does not take account of any hazard due to an emission of flammable or toxic gas from the dust. This document supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this document conflicts with a requirement of IEC 60079-0, the requirement of this document takes precedence. This fifth edition cancels and replaces the fourth edition published in 2014 and Amendment 1:2017. This edition constitutes a technical revision. This International Standard is to be used in conjunction with IEC 60079-0, Explosive atmospheres - Part 0: Equipment - General requirements. Users of this document are advised that interpretation sheets clarifying the interpretation of this document can be published. Interpretation sheets are available from the IEC webstore and can be found in the "history" tab of the page for each document. Please see the foreword to this document for the list of significant technical changes with respect to the previous edition.

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IEC TS 60079-44:2023(Main)

Explosive atmospheres - Part 44: Personal competence

IEC TS 60079-44:2023, which is a Technical Specification, is to provide guidance to establish recommended minimum criteria to determine roles, establish expectations of the necessary skills and evidence of competence to assess and manage the competence of personnel conducting work in or associated with hazardous areas. The purpose of this document is to provide guidance to establish:
• recommended minimum criteria to determine roles,
• expectations of the necessary skills, and
• evidence of competence
in order to assess and manage the competence of personnel who are conducting work in or associated with hazardous areas.
This document provides examples and recommendations of minimum levels of competence for typical roles associated with hazardous areas by addressing the knowledge, skills, or abilities that is expected of personnel. Additionally, examples of the evidence of competence expected for each role are provided.
The aim of tThis document is to assist in defining, assessing, and managing unique requirements for the competence of individuals working in or associated with installations where an explosive atmosphere could be present. Such a programme could be specific to a facility or used in conjunction with other regulatory requirements where they exist. The competencies for conducting work in a hazardous area are in addition to any competencies which may apply for the general type of work being undertaken (for example, professional credentials, electrical, non-electrical, operations, design).
This document applies to both electrical and non-electrical applications.
This document identifies the minimum level of knowledge and skills required to work in hazardous areas and the specific competence required for work associated with equipment for explosive atmospheres (commonly termed ‘Ex Equipment’) and the standards to which competence is to be assessed and attributed.
The purpose of this document is to provide guidance to establish:
• recommended minimum criteria to determine roles,
• expectations of the necessary skills, and
• evidence of competence
The principal application of this specification document is for personnel dealing with explosion-protected and associated equipment for use in explosive atmospheres, including the following work functions:
• Classification of areas;
• Producing, processing or servicing functions in a hazardous area and not directly involved in installing, maintaining or repairing explosion-protected equipment and systems;
• Designing, commissioning and maintaining explosion-protection strategies and equipment;
• Selecting, installing, testing and maintaining explosion-protected equipment and systems in hazardous areas;
• Inspecting hazardous area equipment, systems and installations;
• Overhauling, repairing and modifying explosion-protected equipment;
• Management of the Ex aspects of the facility.