Changes of new IEC 60079-28:2025

Technical Changes for IEC 60079-28:2015 to the new version 2025

Generalities

The transition of IEC 60079-28 to the 2025 edition, involves:

several key technical revisions; and
structural clarifications;

the changes are aimed at:

improving consistency; and
relying more heavily on verification by “documented safety limits” rather than “testing”.

1. approaches in the new and withdrawn versions of standard
IEC 60079-28:2015	IEC 60079-28:2025

2. Scope
IEC 60079-28:2015	IEC 60079-28:2025
scope of the standard was applied broadly to "equipment emitting optical radiation intended for use in explosive atmospheres"	The scope specifies three distinct application criteria: laser equipment; optical fibre equipment. any optical system that converts light into convergent beams with focal points within the hazardous area only.
lighting fixtures and LEDs (including divergent light sources) were NOT clearly excluded from the scope.	almost all lighting fixtures and LEDs (with Divergent light sources) have been excluded from the scope.
All laser equipment were included in the scope.	certain low-power laser equipment has been excluded from the scope, entirely: “laser equipment intended for EPL Mb, Gb, Gc, Db, or Dc applications that already complies with Class 1 limits in accordance with IEC 60825-1”. Rationale: class one limits (below 15 mW measured at a specified distance) are not considered as “capable of igniting an explosive atmosphere”.
3. elimination of ignition tests in the new version Refer to section C1 of “b) Information about the background of changes” of “3) Major technical Changes” of “Explanation of the types of significant changes” of FOREWORD of IEC 60079-28:2025
IEC 60079-28:2015	IEC 60079-28:2025
In the 2015 edition, ignition tests were permitted in special cases (specified by 5.2.4 of IEC 60079-28:2015) for Group II equipment.	The most significant revision in the 2025 edition is the removal of the alternative option for ignition tests. However, this alternative method was removed in the 2025 edition, because: questions were raised concerning the repeatability of the verification test results across different test laboratories, and the method for defining and applying a safety factor to real test samples was not sufficiently defined. Compliance through the new version is achieved exclusively through compliance of below parameters: specified power and irradiance limits (Continuous wave); or energy limits (pulsed radiation) The values of the above parameters are outlined in the tables and calculation methodologies within the standard, ensuring a standardized, predictable compliance route.

4. Changes to Protected Optical Radiation ("op pr") for Enclosures (Clause 4.3.3)
IEC 60079-28:2015	IEC 60079-28:2025
	The scope for protected optical radiation ("op pr") concerning enclosures was clarified.
the clause of requirements for protected optical radiation "op pr" in the standard, referred to "Radiation inside enclosures".	The title "Radiation inside enclosures" has been modified to "Radiation entering or leaving enclosures", emphasizing that protection must be maintained at the boundary of the enclosure.
5. Restructured Verification and Testing
IEC 60079-28:2015	IEC 60079-28:2025
Some test and measurement procedures spread across requirements clauses	test and measurement procedures are consolidated under “Type verification and tests”, clause 5.
	a new subclause of 5.1 "Optical detector," has been added, with following highlights: it defines that an optical detector, as a measuring system, must consist of at least a semiconductor sensor and power meter, or a thermopile sensor and power meter, or a spectroradiometer. The mandatory of selection optical detectors based on the type of light source (e.g., thermopile or spectroradiometer for sources with multiple wavelengths).
6. Marking Requirements
IEC 60079-28:2015	IEC 60079-28:2025
The examples of the marking stated in clause 7, was a little general and misleading, so that the provided samples do not include the symbol of existing type of protection (other than Ex op). e.g. Ex op is IIC T6 Ga , Ex op pr IIC T4 Gb	The examples of the marking stated in clause 6, have been more effective, so that the symbol of existing type of protection (other than Ex op) has been included to the marking, so that both symbols for existing protection and optical protection, are mentioned in one marking line. e.g. Ex ia op is IIC T6 Ga , Ex db op pr IIC T4 Gb , Ex mb op is IIC T4 Gb
The marking example for the equipment which is installed outside hazardous area and provides optical radiation to the hazardous area was defined in this form: “[Ex op is IIA T3 Ga]”	The marking example for the equipment which is installed outside hazardous area and provides optical radiation to the hazardous area was corrected to this form: “[Ex op is Ga] IIA T3” A new example of marking is added for the equipment which is installed in a hazardous area (protected by Type of Protection 'm') and providing optical radiation to a different hazardous area: Ex mb op is [op is IIA T3 Ga] IIC T4 Gb
Checklist for Conformity assessment the Ex-products with optical protection according to IEC 60079-25:2028 click here to download

Changes of new IEC 60079-28:2025

Changes of new IEC 60079-28:2025

Technical Changes for IEC 60079-28:2015 to the new version 2025

Generalities

The transition of IEC 60079-28 to the 2025 edition, involves:

several key technical revisions; and

structural clarifications;

the changes are aimed at:

improving consistency; and

relying more heavily on verification by “documented safety limits” rather than “testing”.

1. approaches in the new and withdrawn versions of standard

IEC 60079-28:2015

IEC 60079-28:2025

2. Scope

IEC 60079-28:2015

IEC 60079-28:2025

scope of the standard was applied broadly to "equipment emitting optical radiation intended for use in explosive atmospheres"

The scope specifies three distinct application criteria:

laser equipment;

optical fibre equipment.

any optical system that converts light into convergent beams with focal points within the hazardous area only.

lighting fixtures and LEDs (including divergent light sources) were NOT clearly excluded from the scope.

almost all lighting fixtures and LEDs (with Divergent light sources) have been excluded from the scope.

All laser equipment were included in the scope.

certain low-power laser equipment has been excluded from the scope, entirely: “laser equipment intended for EPL Mb, Gb, Gc, Db, or Dc applications that already complies with Class 1 limits in accordance with IEC 60825-1”.

Rationale: class one limits (below 15 mW measured at a specified distance) are not considered as “capable of igniting an explosive atmosphere”.

3. elimination of ignition tests in the new version

Refer to section C1 of “b) Information about the background of changes” of “3) Major technical Changes” of “Explanation of the types of significant changes” of FOREWORD of IEC 60079-28:2025

IEC 60079-28:2015

IEC 60079-28:2025

In the 2015 edition, ignition tests were permitted in special cases (specified by 5.2.4 of IEC 60079-28:2015) for Group II equipment.

The most significant revision in the 2025 edition is the removal of the alternative option for ignition tests.

However, this alternative method was removed in the 2025 edition, because:

questions were raised concerning the repeatability of the verification test results across different test laboratories, and

the method for defining and applying a safety factor to real test samples was not sufficiently defined.

Compliance through the new version is achieved exclusively through compliance of below parameters:

specified power and irradiance limits (Continuous wave); or

energy limits (pulsed radiation)

The values ​​of the above parameters are outlined in the tables and calculation methodologies within the standard, ensuring a standardized, predictable compliance route.

4. Changes to Protected Optical Radiation ("op pr") for Enclosures (Clause 4.3.3)

IEC 60079-28:2015

IEC 60079-28:2025

The scope for protected optical radiation ("op pr") concerning enclosures was clarified.

the clause of requirements for protected optical radiation "op pr" in the standard, referred to "Radiation inside enclosures".

The title "Radiation inside enclosures" has been modified to "Radiation entering or leaving enclosures", emphasizing that protection must be maintained at the boundary of the enclosure.

5. Restructured Verification and Testing

IEC 60079-28:2015

IEC 60079-28:2025

Some test and measurement procedures spread across requirements clauses

test and measurement procedures are consolidated under “Type verification and tests”, clause 5.

a new subclause of 5.1 "Optical detector," has been added, with following highlights:

it defines that an optical detector, as a measuring system, must consist of at least

a semiconductor sensor and power meter, or

a thermopile sensor and power meter, or

a spectroradiometer.

The mandatory of selection optical detectors based on the type of light source (e.g., thermopile or spectroradiometer for sources with multiple wavelengths).

6. Marking Requirements

IEC 60079-28:2015

IEC 60079-28:2025

The examples of the marking stated in clause 7, was a little general and misleading, so that the provided samples do not include the symbol of existing type of protection (other than Ex op). e.g. Ex op is IIC T6 Ga , Ex op pr IIC T4 Gb

The marking example for the equipment which is installed outside hazardous area and provides optical radiation to the hazardous area was defined in this form: “[Ex op is IIA T3 Ga]”

The marking example for the equipment which is installed outside hazardous area and provides optical radiation to the hazardous area was corrected to this form: “[Ex op is Ga] IIA T3”

A new example of marking is added for the equipment which is installed in a hazardous area (protected by Type of Protection 'm') and providing optical radiation to a different hazardous area: Ex mb op is [op is IIA T3 Ga] IIC T4 Gb

Checklist for Conformity assessment the Ex-products with optical protection according to IEC 60079-25:2028

click here to download

The values of the above parameters are outlined in the tables and calculation methodologies within the standard, ensuring a standardized, predictable compliance route.