Before starting an Ex i assessment, manufacturers should provide complete technical information to enable evaluation of the intrinsic safety concept in accordance with IEC 60079-11 and applicable ATEX or IECEx requirements.

Typical documentation includes a detailed product description, intended use, hazardous area classification, circuit diagrams, component specifications, safety-related parameters (such as voltage, current, capacitance, and inductance), and information on energy-limiting components. Documentation for associated equipment, barriers, and interconnecting wiring may also be required.

Additional information such as environmental conditions, installation requirements, and existing test reports or certificates can support the assessment. An initial technical review is usually performed to define the scope and confirm whether further data or design adjustments are necessary before testing or certification begins.

Ex e, Ex d, Ex i, and Ex t are different explosion protection concepts defined under the IEC 60079 series, each using a different technical approach to prevent ignition in hazardous areas.

Ex d (flameproof enclosure) is based on containing an internal explosion within a robust enclosure and preventing its transmission to the surrounding atmosphere. It is typically used for equipment such as motors, control boxes, and junction boxes.

Ex e (increased safety) focuses on eliminating ignition sources by applying enhanced design measures, such as improved insulation, secure connections, and controlled temperature limits, to prevent sparks or overheating.

Ex i (intrinsic safety) limits electrical energy in the circuit to a level too low to cause ignition, even under fault conditions. It is commonly used in instrumentation and control systems such as sensors and measuring devices.

Ex t (protection by enclosure for dust) is used in areas with combustible dust atmospheres and relies on enclosure design to prevent dust ingress and control surface temperatures to avoid ignition.

Each protection concept is selected based on the equipment design, operating conditions, and the type of hazardous atmosphere. A technical assessment is required to determine the most appropriate protection method for a specific product.

Yes. Ex i (intrinsic safety) assessments can cover both field devices installed in hazardous areas and associated apparatus located in safe areas, provided they are part of the same intrinsically safe system.

Field devices are typically designed to operate within explosive atmospheres with energy levels limited to prevent ignition. Associated apparatus, such as barriers or isolators, are installed in non-hazardous areas and are used to limit the electrical energy supplied to the field equipment.

The conformity assessment evaluates the complete intrinsic safety system, including interconnection parameters, entity parameters, and system compatibility between devices. Proper coordination of all components is essential to ensure that the overall system remains intrinsically safe under normal and fault conditions.

A system-level technical review is typically required to confirm correct pairing of associated apparatus and field devices in accordance with IEC 60079-11 requirements.

Product variations such as different power supply options, component substitutions, circuit modifications, or firmware changes can have a significant impact on Ex i (intrinsic safety) compliance, as they may alter the energy levels within the circuit or affect safety-related parameters.

In Ex i systems, compliance is based on strictly defined electrical parameters (such as voltage, current, capacitance, and inductance) and the overall system configuration. Even small design changes may influence the intrinsic safety assessment and require re-evaluation to ensure that ignition risks remain adequately controlled under both normal operation and fault conditions.

Where multiple product variants are intended, they may sometimes be included within a single assessment scope if the intrinsic safety parameters remain equivalent and clearly defined. However, significant differences typically require separate analysis, additional calculations, or supplementary testing.

A technical review is necessary to determine whether variations can be grouped under one Ex i certification or whether they require individual assessment.

Yes. Ex i evaluation can begin before the final design is completed, and early involvement is often recommended to reduce development risks and avoid redesign later in the project.

An initial assessment can be performed based on preliminary circuit diagrams, conceptual design data, and expected operating parameters. This allows identification of critical intrinsic safety aspects such as energy limitation, component selection, safety barriers, and compliance with IEC 60079-11 requirements.

However, the final conformity assessment and certification can only be completed once the design is finalized and all relevant documentation, calculations, and (if applicable) test results are available. Any design changes made during development may require reassessment to ensure continued compliance.