What is a type of protection?
A type of protection describes the design and technical measures with which a device is designed so that it can be operated safely in an explosive atmosphere - without itself being a source of ignition.
The most important types of ignition protection at a glance
1. intrinsic safety (Ex i)
With this type of protection, the energy in the circuit is limited to such an extent that no ignition can occur even in the event of a short circuit.
- Typical applications: sensors, measurement and control technology, signal transmission
- Marking: e.g. Ex ia
Differences by zone:
| Level | Field of application | Security level | Typical use |
|---|---|---|---|
| Ex ia | Zones 0, 1, 2 | Two errors for sure | Sensors in gas rooms, tank farms |
| Ex ib | Zone 1, 2 | A error for sure | Industrial environments, process automation |
| Ex ic | Zone 2 | Only safe in normal operation | Building automation, simple monitoring systems |
💡 Practical tip: Intrinsic safety refers to the entire circuit - not just the field device!
2. Flameproof enclosure (Ex d)
Here, the device is installed in a pressure-resistant housing that withstands an internal explosion and prevents the explosion from escaping to the outside.
- Typical application: Motors, switches, lights - but also IT components such as access points
- Marking: e.g. Ex d
Advantages & practical knowledge:
- Devices without ATEX approval can also be operated in an Ex d enclosure.
- Example: WLAN access points in industrial environments.
- But beware: conditions apply:
- Electrical parameters (e.g. power, temperature development)
- Dimensions and thermal load
- No operation during operation - only open when de-energized!
3. Increased safety (Ex e)
Design measures are taken to prevent sparks or dangerous temperatures from occurring.
- Typical application: Junction boxes, terminals, lighting
- Marking: e.g. Ex e
4. Pressurized enclosure (Ex p)
The appliance is operated in an enclosure that is under positive pressure - this prevents the ingress of an explosive atmosphere.
- Typical application: analytical devices, control cabinets, label printers
- Labeling: e.g. Ex pxb
Variants:
| Variante | Zone | Description |
|---|---|---|
| px | Zones 0 | high protection, with shielding gas and flushing |
| py | Zone 1 | medium protection, limited irrigation |
| pz | Zone 2 | simple protection, often with ambient air instead of protective gas |
✅ Conclusion: In many devices – such as label printers – overpressure with ambient air is sufficient. Protective gas is not absolutely necessary!
5. encapsulation (Ex m)
Components are encapsulated in non-conductive material so that no ignition source can escape.
- Typical applications: sensors, electronic modules – but also portable devices!
- Marking: e.g. Ex mb
Criticism in practice:
- Is unfortunately also used for mobile devices.
- Repairs are hardly possible:
- Defective socket or display = total write-off
- No interchangeability of individual components
- Particularly annoying with high-priced ex-smartphones or hand scanners
6. Oil immersion (Ex o)
The ignition sources are located in an oil bath that shields heat and sparks.
- Typical application: transformers, switchgear
- Marking: e.g. Ex o
7. Sand encapsulation (Ex q)
Ignitable parts are fully embedded in fine-grained quartz sand to safely absorb heat and sparks.
- Typical applications: capacitors, resistors – and even portable devices!
- Marking: e.g. Ex q
Conclusion
Selecting the appropriate type of protection is not a mere formality, but crucial for safe and economical operation. Whether it's intrinsic safety, flameproof enclosure or pressurization – each method has its strengths and limitations.
🔍 Our tip: Make sure that your device can be repaired easily, especially if it is mobile. We at ATEXshop.de are happy to help!