DEV Community

Andreas Parr Bjørnsund
Andreas Parr Bjørnsund

Posted on

ATEX Certification for Mobile Devices: What Engineers Need to Know About Zone 1 and Zone 21

If you work in oil and gas, chemical processing, mining, or pharmaceuticals, you have probably encountered the term ATEX. It refers to a set of EU directives governing equipment used in potentially explosive atmospheres. Getting ATEX certification for electronic devices — especially smartphones — is a complex process that touches on electrical engineering, materials science, and regulatory compliance.

This article breaks down the key concepts behind ATEX certification, with a focus on what it means for mobile devices deployed in hazardous areas.

What is ATEX?

ATEX comes from the French "ATmosphères EXplosibles." It encompasses two EU directives:

  • Directive 2014/34/EU (ATEX Equipment Directive): Covers equipment and protective systems intended for use in explosive atmospheres.
  • Directive 1999/92/EC (ATEX Workplace Directive): Covers the safety and health of workers potentially at risk from explosive atmospheres.

For device manufacturers, the Equipment Directive is the one that matters. It mandates that any electrical or mechanical equipment used in classified hazardous zones must meet specific safety requirements and carry appropriate markings.

Zone Classification

Hazardous areas are classified based on the type of explosive substance and how often it is present:

Gas/Vapor Zones

  • Zone 0: Explosive gas atmosphere present continuously or for long periods. Equipment must be Category 1.
  • Zone 1: Explosive gas atmosphere likely to occur during normal operations. Equipment must be Category 2.
  • Zone 2: Explosive gas atmosphere not likely to occur, and if it does, only briefly. Category 3 equipment is sufficient.

Dust Zones

  • Zone 20: Combustible dust cloud present continuously. Category 1 required.
  • Zone 21: Combustible dust cloud likely during normal operations. Category 2 required.
  • Zone 22: Combustible dust cloud unlikely, and if present, only briefly. Category 3 sufficient.

Most industrial environments where smartphones are needed fall into Zone 1 (gas) and Zone 21 (dust). This is the sweet spot where mobile communication is needed but standard consumer electronics are prohibited.

Why Smartphones Are Difficult to Certify

Smartphones present particular challenges for ATEX certification:

  1. Battery energy: Lithium-ion batteries store significant energy. A short circuit or thermal runaway could produce sparks or heat sufficient to ignite flammable gases.
  2. Wireless transmissions: RF energy from cellular, Wi-Fi, and Bluetooth radios must be evaluated against ignition thresholds.
  3. Camera flash: LED flash circuits can produce localized heating.
  4. Touchscreen: Capacitive touchscreens carry voltage across their surface.
  5. Rapid product cycles: New phone models release annually, each requiring fresh certification.

The traditional approach was to build purpose-built "intrinsically safe" (IS) phones from scratch. These were typically slow, outdated, and expensive. A newer approach is to design certified protective cases that limit the energy available to ignition-capable circuits while preserving full smartphone functionality.

Protection Concepts

ATEX certification uses several protection concepts. The most relevant for portable electronics:

  • Ex ia (Intrinsic Safety, Level a): The circuit cannot produce sufficient electrical or thermal energy to cause ignition, even with two faults. This is the gold standard for Zone 0.
  • Ex ib (Intrinsic Safety, Level b): Safe with one fault. Suitable for Zone 1.
  • Ex ic (Intrinsic Safety, Level c): Safe under normal operation. Zone 2 only.

For a smartphone case designed for Zone 1, the protection must ensure that:

  • Battery terminals are isolated from any conductive path that could cause sparking
  • The device meets temperature class requirements (typically T4: max 135°C surface temperature)
  • IP rating is sufficient (typically IP65 or higher for dust and water protection)

IECEx: The International Equivalent

While ATEX is an EU directive, IECEx is the international certification scheme managed by the International Electrotechnical Commission. IECEx certificates are recognized in over 30 countries including Australia, Singapore, South Korea, and across the Middle East.

For manufacturers targeting global markets, dual ATEX/IECEx certification is the standard approach. The technical requirements are largely harmonized, but testing and documentation must satisfy both schemes.

Gas and Dust Group Ratings

Equipment is further classified by the types of gas or dust it can safely operate around:

Gas Groups

  • IIA: Propane and similar
  • IIB: Ethylene and similar
  • IIC: Hydrogen and acetylene — the most demanding group

Dust Groups

  • IIIA: Combustible flyings (fibers)
  • IIIB: Non-conductive dust
  • IIIC: Conductive dust — the most demanding group

A device rated for Gas Group IIC and Dust Group IIIC can be used in virtually any industrial environment, from hydrogen processing facilities to coal mines.

Real-World Application

Companies like Xshielder are tackling this problem by designing ATEX and IECEx certified protective cases for current-generation iPhones. Their approach certifies the case itself as the protective barrier, which means users get a real smartphone (iPhone 15 Pro Max, iPhone 16 Pro Max) that is certified for Zone 1 gas and Zone 21 dust environments with IIC/IIIC group ratings.

This approach has significant advantages for industries where workers need modern mobile capabilities — high-resolution cameras for inspection documentation, LiDAR for measurements, and reliable connectivity — in areas where those devices would otherwise be banned.

What to Look For

If you are evaluating ATEX-certified mobile devices for your operation, check for:

  1. Zone rating: Zone 1/21 is the standard for most oil and gas applications. Zone 2/22 is less restrictive and may not be accepted in many facilities.
  2. Gas and dust groups: IIC/IIIC covers the widest range of environments.
  3. Temperature class: T4 (135°C max) covers most applications.
  4. IP rating: IP65 minimum for dust and water protection.
  5. Certificate validity: Ensure the certificate covers the specific phone model you intend to use.
  6. Notified Body: ATEX certificates must be issued by an EU Notified Body. IECEx certificates come from accredited ExCBs.

Conclusion

ATEX certification for mobile devices is a specialized but increasingly important field. As industries push for digital transformation in hazardous environments, the demand for certified smartphones will only grow. Understanding zone classifications, protection concepts, and certification schemes helps engineers make informed decisions about which devices to deploy.

For more information on ATEX-certified smartphone solutions, visit xshielder.com.

Top comments (0)