Which is safer for equipment: Flameproof (Ex d) protection or Intrinsic Safety (Ex i) protection? And how to choose between them? STS briefly explains the relationship and differences between Flameproof and Intrinsic Safety protection from the following aspects:

I. Common Grounds

Flameproof and Intrinsic Safety are two distinct types of Ex protection modes, both serving as measures to achieve explosion-proof performance for equipment.

II. Differences

1. Explosion-proof Principles

Flameproof Protection

Flameproof protection relies on a flameproof enclosure with sufficient thickness and strength. In the event of an internal explosion within the equipment, the flame will be extinguished due to the width, clearance, and roughness of the joint surfaces of the flameproof enclosure, preventing ignition of the external hazardous atmosphere. Conversely, the flameproof enclosure is also explosion-resistant, meaning it can withstand an external explosion in the hazardous area. In summary, a flameproof enclosure is both explosion-proof and explosion-resistant, but the equipment is typically bulky and heavy.

Intrinsic Safety (Ex i) Protection

Intrinsic safety achieves inherent safety by limiting circuit energy. Intrinsic safety products impose strict requirements on the equipment’s circuitry and operating power, and are generally suitable for handheld devices and low-power products.

2. Application Scenarios

Flameproof Protection

Owing to the strength and thickness requirements of the enclosure, this mode is typically applied to large or heavy electrical equipment that demands higher safety performance when operating in explosive atmospheres.

Intrinsic Safety (Ex i) Protection

This mode is more suitable for application scenarios with restrictions on equipment size, weight, and power, such as handheld devices and small instruments.

3. Applicable Environments

Flameproof Type: Suitable for all types of explosive gas atmospheres.

Intrinsic Safety (Ex i) Type: Applicable to both explosive gas and dust environments, including Zone 0 and Zone 20 locations.

Conclusion

In summary, Flameproof and Intrinsic Safety protection each have unique principles and application scenarios. If you have specific application scenarios or requirements, STS’s professional Ex engineers can provide you with more tailored advice and solutions.