The global explosion protection industry is entering a new stage of technological development. For decades, safety has relied mainly on proven passive protection methods, such as flameproof enclosures, known as Ex d, and increased safety, known as Ex e. These methods remain essential, but modern industrial environments are becoming more digital, automated, and complex.

Smart equipment, advanced control systems, and dynamic production processes create risks that may change during operation. In some applications, passive barriers alone are no longer sufficient to achieve the required level of protection. This is where IEC 60079-42 becomes strategically important.

The final draft of IEC 60079-42, formerly known as IEC TS 60079-42:2019, introduces a new type of protection: “f”, or Electrical Safety Devices. This represents an important shift in explosion protection philosophy, moving from purely structural protection toward active, function-based safety.

A New Approach to Explosion Protection

The “f” type of protection introduces a functional safety approach to ignition source control. Instead of relying only on physical barriers, it allows safety devices to monitor equipment, detect dangerous conditions, and bring the system into a safe state before an ignition source becomes effective.

In this concept, the equipment under control, referred to as ExEUC, and the safety device operate together as an integrated safety system. This provides a more intelligent and responsive method of explosion protection, especially for complex electrical and electronic equipment used in hazardous areas.

How the “f” Type of Protection Works

The main purpose of an “f” protection system is to identify a developing ignition risk at an early stage and prevent it from becoming hazardous.

This function may be performed by sensors, logic solvers, programmable controllers, or other electronic safety systems. For example, a temperature sensor may detect abnormal heating, while a controller may process the signal and initiate shutdown or another predefined safe action.

This makes the “f” type of protection especially relevant for modern industrial equipment, where risks are often dynamic, process-dependent, and closely connected to automation systems.

Technical Flexibility and Functional Safety

One of the strengths of IEC 60079-42 is its flexibility. The standard distinguishes between simple safety devices, such as temperature sensors, and more complex devices based on programmable electronics.

It also creates a methodological link with functional safety standards such as IEC 61508 and IEC 61511. A key element is Ignition Hazard Assessment, or IHA. During this assessment, residual ignition sources are identified and evaluated, and the required Risk Reduction Factor, or RRF, is determined for each remaining risk. This ensures that the safety function is based on a structured risk reduction process.

Scope of Application

IEC 60079-42 focuses on active ignition source management through electrical safety devices. It does not apply to gas detection systems, fire suppression or explosion mitigation systems, mechanical safety devices, ventilation systems, or inerting systems.

This clear scope positions the “f” type of protection as a dedicated method for controlling ignition risks, not as a universal replacement for other explosion protection techniques.

Conclusion

IEC 60079-42 does not replace existing IEC 60079 standards. Instead, it complements them by introducing a recognized framework for active electronic safety functions.

The new “f” type of protection gives Ex-equipment manufacturers and industrial safety engineers greater design flexibility. It helps achieve the required Equipment Protection Levels, or EPL, where traditional passive methods may be insufficient.

In practical terms, IEC 60079-42 brings explosion protection closer to modern industrial automation. It supports safer, smarter, and more adaptable equipment for hazardous areas and represents a logical step toward a new generation of intelligent and reliable explosion protection systems.

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