IEC 60079-19 Explained: Repair, Overhaul and Reclamation of Ex Equipment

Repairing explosion-protected equipment requires attention to the construction features that maintain its protection.

Explosion-protected equipment can require repair or overhaul after years of operation because of wear, corrosion, electrical failure, or mechanical damage. However, repairing Ex equipment is not the same as repairing ordinary industrial equipment.

A change to a flamepath, enclosure, terminal arrangement, internal circuit, or other critical feature can affect the protection on which the equipment's certification depends. Restoring normal operation does not necessarily mean that the equipment remains suitable for use in a hazardous area.

IEC 60079-19 – Explosive atmospheres – Equipment repair, overhaul and reclamation addresses repair-related activities for equipment designed for use in explosive atmospheres. It provides a technical framework for evaluating and carrying out applicable work while maintaining the equipment's explosion-protection characteristics.

This guide explains the difference between repair, overhaul, and reclamation, the importance of manufacturer documentation, and the checks that asset owners and repair workshops should consider before returning equipment to service.

1. Where IEC 60079-19 Fits in the Equipment Lifecycle

IEC 60079-19 addresses a different activity from the standards covering equipment design, installation, and operational inspection.

Activity	Relevant standard
General Ex equipment requirements	IEC 60079-0
Design, selection, and installation	IEC 60079-14
Inspection and maintenance of electrical installations	IEC 60079-17
Repair, overhaul, and reclamation of applicable Ex equipment	IEC 60079-19

IEC 60079-17 focuses on inspection and maintenance of electrical installations. When equipment requires repair or overhaul that falls within the scope of IEC 60079-19, the repair activity needs to be assessed and controlled accordingly.

The applicable edition, equipment type, certification documentation, and nature of the work determine which requirements must be followed.

2. Repair, Overhaul, and Reclamation

These terms describe different types of work. Their precise application depends on the applicable standard and the equipment involved.

• Repair: work intended to restore equipment to a serviceable condition after damage or failure, while maintaining the relevant explosion-protection characteristics.
• Overhaul: a more extensive examination and restoration process that may involve disassembly, inspection, and replacement or restoration of components.
• Reclamation: restoration of damaged or worn components using an appropriate technical method, subject to the applicable requirements and limitations.

Not every routine maintenance task is automatically a repair activity under IEC 60079-19. The work must be classified according to its nature and the applicable requirements.

The distinction matters because a task involving a replaceable component may have very different technical implications from one that alters a flameproof joint, enclosure, or safety-critical electrical characteristic.

3. Why Ex Equipment Repair Requires Special Controls

Explosion-protected equipment relies on specific construction features and operating limits. These may include enclosure dimensions, flamepaths, electrical clearances, insulation systems, temperature limits, and circuit characteristics.

Potentially significant repair activities include:

• Machining or restoring a flamepath.
• Replacing components that affect explosion protection.
• Changing fasteners or enclosure parts.
• Adding or modifying cable entries.
• Changing internal wiring or circuit components.
• Altering enclosure dimensions or materials.
• Changing electrical ratings or thermal characteristics.
• Removing or altering protective components.

The key question is not only whether the equipment functions after repair. The repair must also preserve the relevant protection characteristics and comply with the applicable technical requirements.

4. Assessment Before Repair

Before work begins, the equipment and proposed repair method should be assessed. This helps establish whether the damage can be corrected using an acceptable method and whether sufficient technical information is available.

Review the following information where applicable:

• Equipment manufacturer, model, type, and identification.
• Complete Ex marking and available certification documentation.
• Original protection concept.
• Extent and location of the damage.
• Manufacturer drawings, instructions, and repair limitations.
• Availability and suitability of replacement components.
• Proposed repair method and required verification.

If critical dimensions or construction details cannot be established, the repair organization should not assume that a visually similar reconstruction is acceptable. Further technical information or assessment may be necessary before proceeding.

5. Manufacturer Documentation and Replacement Parts

Manufacturer documentation is particularly important when a repair involves characteristics that are not readily visible or cannot be inferred from the equipment's external appearance.

Depending on the equipment, useful documents may include:

• Assembly and component drawings.
• Certification drawings and relevant certificate conditions.
• Parts lists and component specifications.
• Critical dimensions and tolerances.
• Repair instructions and permitted restoration methods.
• Electrical ratings and applicable testing requirements.

Replacement parts should not be selected solely because they fit mechanically. Their material, dimensions, electrical characteristics, temperature capability, and other relevant properties must be suitable for the equipment.

Where the original component is unavailable, a proposed alternative needs a technical evaluation appropriate to its role. The repair organization should not assume that an ordinary commercial component is equivalent to a component used in certified Ex equipment.

6. Repairing Ex d Equipment

Ex d protection relies on a flameproof enclosure designed to withstand an internal explosion and prevent flame transmission to the surrounding explosive atmosphere. The enclosure and its flamepaths are therefore important features during repair.

Depending on the equipment and damage, assessment may involve:

• Flamepath dimensions and surface condition.
• Joint geometry and threaded interfaces.
• Fasteners and enclosure closure arrangements.
• Corrosion, wear, and mechanical deformation.
• Cable entries and other enclosure interfaces.
• Manufacturer-specified dimensions and tolerances.

Machining, grinding, welding, or other restoration methods must not be selected simply because they remove visible damage. The permitted method and acceptance criteria must be established from the applicable technical requirements and equipment documentation.

For the underlying protection concept, see IEC 60079-1 Explained: Flameproof Enclosures "d".

7. Repairing Ex e Equipment

Ex e equipment relies on construction and protective measures intended to prevent unacceptable temperatures, arcs, and sparks under the applicable requirements. Repair must preserve the relevant characteristics of that construction.

Depending on the equipment, review may include:

• Electrical clearances and creepage distances.
• Terminal construction and connection integrity.
• Insulation materials and systems.
• Component suitability and temperature limits.
• Enclosure integrity and ingress protection.
• Wiring arrangements and electrical ratings.

Replacing terminals, insulation, or other components with parts of a different design can affect the original protection characteristics. Such changes require an appropriate technical assessment rather than an assumption that the equipment remains compliant because it operates normally.

See IEC 60079-7 Explained: Increased Safety "e" for the protection concept itself.

8. Repairing Ex i Equipment

Intrinsic safety relies on limiting the electrical and thermal energy capable of causing ignition. Changes to circuitry or components can alter the characteristics on which that protection depends.

Potentially relevant repair activities include:

• Replacing electronic components.
• Modifying printed circuit boards.
• Changing components that affect energy limitation.
• Changing the characteristics of associated apparatus.
• Altering electrical parameters relevant to intrinsic safety.

A repair that changes safety-relevant circuit characteristics may require additional engineering evaluation. Depending on the change and applicable certification arrangements, further certification-related action may also be necessary.

For more information, see IEC 60079-11 Explained: Intrinsic Safety "i".

9. Inspection and Testing After Repair

Successful operation alone is not sufficient evidence that a repair has preserved explosion protection. The repaired equipment should undergo the inspections and tests applicable to the work performed.

Depending on the equipment and repair, verification may include:

• Visual examination of the completed work.
• Dimensional checks against the applicable requirements.
• Electrical tests and continuity checks where relevant.
• Verification of enclosure or joint characteristics.
• Pressure testing where specifically applicable and required.
• Functional testing.
• Verification of equipment identification and markings.
• Review of repair records and test results.

These are examples, not a universal test list. The repair method, protection concept, equipment documentation, and applicable requirements determine which checks are necessary. Pressure testing, for example, must not be applied indiscriminately to equipment for which it is not specified.

10. Repair Documentation and Traceability

Repair records provide evidence of what was found, what work was performed, which components were used, and how the completed repair was verified.

Records may include:

• Equipment identification and Ex marking.
• Description of the original defect or damage.
• Repair method and procedures followed.
• Replacement components and their identification.
• Measurements and inspection results where applicable.
• Electrical, functional, or other test results.
• Repair organization and responsible personnel.
• Date of repair and final disposition.

Records should be retained according to the applicable requirements and the organization's procedures. Good traceability helps future maintenance personnel understand the equipment's repair history and identify recurring problems.

11. When a Repair Becomes a Modification

Repair is intended to restore equipment, but some proposed work changes its original configuration or characteristics. This distinction is important because a modification may affect the basis on which the equipment was assessed or certified.

Examples include:

• Adding cable entries to an enclosure.
• Changing enclosure dimensions or construction materials.
• Substituting components with different characteristics.
• Changing electrical ratings or internal circuitry.
• Altering thermal characteristics or protective features.
• Changing construction details covered by certification documentation.

Not every modification automatically requires the same certification action. The correct response depends on the nature of the change, the applicable conformity or certification scheme, and the equipment documentation.

Repair organizations should identify these issues before carrying out the work. They should not assume that a requested modification can be treated as a routine repair merely because it is mechanically feasible.

12. Common Ex Equipment Repair Mistakes

Repair practices that are not supported by the applicable technical requirements can compromise the equipment's protection. Common examples include:

• Machining flamepaths without verifying permitted dimensions and methods.
• Replacing fasteners with unsuitable materials or specifications.
• Installing components without confirming their suitability.
• Changing motor winding or electrical characteristics without appropriate assessment.
• Adding cable entries without considering the certified enclosure construction.
• Modifying internal circuits without evaluating protection implications.
• Changing or removing identification and certification markings without authorization.
• Failing to document the work performed.
• Returning equipment to service without the required verification.

These mistakes can result in equipment that appears functional but no longer maintains the intended explosion protection. The repair decision must therefore be based on technical compliance, not only operational performance.

13. Repair Organization Competency and Quality Control

Repairing Ex equipment requires suitable technical knowledge, procedures, tools, and verification capability. The organization performing the work should have competence appropriate to the equipment and repair activities involved.

When evaluating a repair organization, consider:

• Knowledge of the relevant Ex protection concepts.
• Documented repair procedures and work controls.
• Access to applicable manufacturer information.
• Personnel competence for the specific repair activity.
• Suitable measuring and inspection equipment.
• Testing capability appropriate to the work.
• Control of replacement components and materials.
• Records, traceability, and quality management procedures.

The required capability depends on the equipment and the work being undertaken. A workshop capable of repairing conventional motors is not automatically competent to perform every type of Ex equipment repair.

14. How to Evaluate an Ex Equipment Repair Workshop

For asset owners and maintenance teams, workshop selection should include a review of its technical capability and controls rather than relying only on cost or turnaround time.

Evaluation item	Why it matters
Ex repair competence	Confirms relevant knowledge of the equipment and protection concept.
Repair procedures	Shows that work is performed using controlled methods.
Technical documentation	Supports decisions on dimensions, components, and permitted restoration methods.
Measurement capability	Supports dimensional and other required verification activities.
Testing capability	Allows the applicable post-repair checks to be performed.
Replacement-part control	Helps prevent unsuitable components from being installed.
Repair records	Provides traceability of the work and its results.
Quality management	Supports consistency and control throughout the repair process.

Where the project or applicable scheme requires specific approvals or certifications for repair organizations, those requirements should be verified separately. A general claim of workshop experience is not a substitute for checking the required evidence.

15. IEC 60079-19 and Equipment Certification

Repair does not automatically mean that equipment must be recertified, nor does a successful repair automatically establish that all certification conditions remain satisfied.

The outcome depends on the work performed and the applicable certification or conformity arrangements. Particular attention is needed where:

• Critical dimensions or construction details have changed.
• Components outside the original specifications have been installed.
• Unauthorized modifications have been introduced.
• Required inspections or tests have not been completed.
• The repair cannot be supported by adequate technical documentation.

When a repair affects features covered by the equipment's certification, the implications must be assessed under the applicable requirements. Do not assume either that every repair requires recertification or that no repair can affect certification.

16. Practical Ex Equipment Repair Workflow

A controlled repair process can be organized around the following sequence:

1. Identify the equipment. Record its manufacturer, model, rating, Ex marking, and available certification details.
2. Assess the damage. Establish what has failed or deteriorated.
3. Identify the protection concept. Determine which construction or circuit characteristics must be preserved.
4. Review the documentation. Check applicable drawings, parts information, tolerances, and repair instructions.
5. Define the repair method. Confirm that the proposed work is technically appropriate and permitted.
6. Control replacement parts. Verify their suitability for the equipment.
7. Perform the work. Follow controlled procedures using appropriate tools and competent personnel.
8. Inspect and test. Complete the checks applicable to the equipment and repair.
9. Document the results. Record the repair, parts, inspections, and test results.
10. Approve return to service. Confirm that the applicable repair and verification requirements have been satisfied.

This workflow is a practical overview. The detailed procedure and acceptance criteria must be taken from the applicable edition of IEC 60079-19, equipment documentation, and the repair organization's approved procedures.

Related Reading

• IEC 60079 Series Explained
• IEC 60079-14 Explained: Design, Selection and Installation of Electrical Installations
• IEC 60079-17 Explained: Inspection and Maintenance of Electrical Installations
• IEC 60079-1 Explained: Flameproof Enclosures "d"
• IEC 60079-7 Explained: Increased Safety "e"
• IEC 60079-11 Explained: Intrinsic Safety "i"
• What Is Ex d Flameproof Protection?
• What Is Ex e Increased Safety Protection?
• What Is Ex i Intrinsic Safety Protection?

References

• International Electrotechnical Commission (IEC) — consult the official catalogue for the applicable edition of IEC 60079-19.
• IECEx — information on equipment used in explosive atmospheres and the IECEx certification system.

This article is an engineering overview, not a substitute for the applicable standard, equipment certification documentation, manufacturer's instructions, or repair procedures.