ATEX vs. IECEx: Understanding Explosion Protection Certifications for Valve Applications

dofun 07 Aug / 26

In the global trade of industrial valves, few topics generate as much confusion as explosion protection certification. For engineers specifying valves in petrochemical, energy, mining, defense, and refrigeration applications, the question is no longer “Is explosion protection necessary?”—it is “Which certification framework applies to my project: ATEX, IECEx, or both?” At Dofun, from our modern facility of more than 30 acres in Liaocheng with over 10,000 square meters of workshop space, with more than 30 invention patents, and a product portfolio serving energy & chemicals, defense & security, heavy industry & resources, public welfare & health, and thermal control & refrigeration sectors across 100+ countries, we regularly guide engineers through this exact compliance landscape. This article clarifies the fundamental differences between ATEX and IECEx, explains how they apply to valve applications, and outlines what engineering teams should consider when specifying Dofun valves for hazardous areas.

💡 Scope note: This article provides a technical and regulatory framework for understanding ATEX and IECEx in valve applications. Dofun’s current publicly documented certifications include EU CE certification, Russian EAC certification, special equipment TS certification, ISO 9001 quality system certification, ISO 14001 environmental system certification, and OHSAS 18001 occupational safety and health system certification. Specific ATEX or IECEx certificates for individual Dofun valve models should be confirmed directly with our application engineering team for your target market and project requirements.

The Fundamental Question: Regulation vs. Certification Scheme

The most important distinction between ATEX and IECEx is their legal nature.

ATEX (from the French “ATmosphères Explosibles”) is the European Union directive 2014/34/EU governing equipment for potentially explosive atmospheres. It is mandatory law across all European Economic Area (EEA) member states. If you place a valve with electrical components into service within the EU, ATEX compliance is a legal requirement, demonstrated by CE marking.

IECEx (IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres) is a voluntary international certification scheme administered by the International Electrotechnical Commission (IEC), established in 1996. It has grown to include more than 60 approved certification bodies in over 35 countries. IECEx is not law anywhere—but it is increasingly recognized as the global “common language” of explosion protection, with certificates publicly searchable in the IECEx On-Line Certification System (OCS).

As the IECEx operational FAQ states plainly: “The targeted jurisdiction for ATEX is the European Union… The targeted jurisdiction for IECEx is the world, all countries. As such, IECEx is a true International Certification Scheme where full compliance with IEC International Standards are required.”

How ATEX and IECEx Differ in Practice

Legal Status and Geographic Scope

Dimension	ATEX	IECEx
Legal basis	EU Directive 2014/34/EU (mandatory)	Voluntary international scheme (IEC)
Governing body	European Commission	International Electrotechnical Commission
Geographic reach	Mandatory in EU/EEA; used voluntarily outside	Global recognition across 60+ member countries
Technical standards	EN versions of IEC 60079 series	IEC 60079 series (direct)
Acceptance	Legally required for EU market	Widely accepted; sometimes with local additions

Certification Procedure

ATEX pathway:

Manufacturer engages a Notified Body (ExNB)—an organization designated by an EU member state
ExNB conducts EU Type Examination and issues an EU Type Examination Certificate
For Category 1 and M1 equipment, ongoing quality surveillance is required
Manufacturer issues a Declaration of Conformity and affixes CE marking

IECEx pathway:

Manufacturer engages an IECEx Certification Body (ExCB)
ExCB issues an IECEx Test Report (ExTR) based on testing by an accredited ExTL (Test Laboratory)
ExCB issues a Quality Assessment Report (QAR) covering the manufacturer’s production facilities
ExCB issues an IECEx Certificate of Conformity (CoC)
The certificate is published on the IECEx website for public verification

Self-Certification: A Key Difference

One of the most consequential distinctions for valve manufacturers:

⚠️ Under ATEX, it is acceptable to rely solely on a manufacturer’s declaration for Zone 2 equipment (Ex ‘n’). Category 3 electrical equipment and Category 2 non-electrical equipment may be self-certified by the manufacturer.

✅ Under IECEx, there is no such shortcut. “For IECEx we do not discriminate between Zone 0, 1, 2. All equipment under IECEx must be independently tested and certified.” Every product—regardless of zone—must go through a full ExCB-led certification process.

This makes IECEx, in practice, a more rigorous and universally consistent scheme, even though it lacks ATEX’s legal mandate.

Marking and Identification

ATEX marking appears as: CE [Notified Body Number] ⚠ II 2 G Ex d IIC T4 Gb

CE: European Conformity mark
Notified Body Number: Four-digit identifier
⚠: Hexagonal ATEX symbol
II 2 G: Group II (surface industries), Category 2, Gas
Ex d IIC T4 Gb: Technical protection method

IECEx marking appears as: ⚠ Ex d IIC T4 Gb IECEx SIR 12.0123X

IECEx: Shows it is an IECEx certification
SIR: Identifies the ExCB that issued the certificate
12: Last two digits of the year of issue
0123: Running certificate number for that year
X: Indicates conditions of use apply

The technical portion (Ex d IIC T4 Gb) is identical in both systems because both reference the IEC 60079 series.

Applying ATEX & IECEx to Valve Systems

Valves themselves are primarily mechanical devices. However, in modern industrial systems, valves are rarely standalone—they integrate electrical and electronic components that bring them firmly within the scope of explosion protection regulations.

Which Valve Components Require Certification?

When specifying Dofun valves for hazardous areas, engineers must assess the entire valve assembly:

1. Valve Actuators (Electric)

Dofun’s Motor Valve Series integrates electric actuators for precise modulation. Any electric actuator installed in a Zone 1 or Zone 2 area requires ATEX (for EU) or IECEx (for global) certification appropriate to the zone classification.

2. Solenoid Valves

Dofun’s Solenoid Valve Series incorporates electrical coils. These are squarely within the scope of both ATEX and IECEx—the coil and enclosure must be certified for the target zone.

3. Pneumatic Actuators with Electrical Accessories

Dofun’s Gas Powered Valve Series and Pressure Regulating Valve Series may incorporate limit switches, position transmitters, or solenoid pilots. Each electrical accessory requires its own certification, or must be housed in a certified junction box.

4. Valve Positioners and Transmitters

Smart positioners and digital feedback devices on Dofun control valves are electronic and fall under explosion protection requirements.

5. The Valve Body Itself

Purely mechanical valve bodies—such as Dofun’s Manual Operation Valve PN40/PN63 Series or Stainless Steel Valve Series—are generally considered “non-electrical equipment.” Under ATEX, non-electrical equipment can, in certain cases, be self-certified. However, the materials, sealing systems, and static electricity risks must still be evaluated. Dofun’s six-level sealing structure using imported materials, and our NANO surface treatment achieving Ra ≤ 0.03 μm, contribute to safe operation by preventing leakage and minimizing friction-induced ignition risks.

Zone Classification and Valve Selection

Zone	Definition	Typical Dofun Valve Application	Certification Requirement
Zone 0	Explosive atmosphere present continuously or for long periods	In-tank valves for ammonia/CO₂ refrigeration	Highest integrity; IECEx CoC mandatory; ATEX Cat 1
Zone 1	Explosive atmosphere likely to occur in normal operation	Process valves in petrochemical plants	ATEX Cat 2; IECEx mandatory
Zone 2	Explosive atmosphere not likely, or only briefly	Auxiliary systems, pump house valves	ATEX allows manufacturer declaration; IECEx still mandatory
Zone 20/21/22	Dust explosive atmospheres (equivalent to 0/1/2)	Grain handling, powder processing valves	Same as above, with ‘t’ protection

Dofun’s Approach to Hazardous Area Applications

While Dofun’s publicly documented certifications include CE, EAC, TS, ISO 9001, ISO 14001, and OHSAS 18001, our product portfolio is engineered with the realities of hazardous environments in mind:

1. Material Compatibility

Dofun valves are “made of various materials” and “widely used in… petrochemical, refining, chemical, metallurgical, mining, medicine, food, national defense, military and other fields”. Our Stainless Steel Valve Series provides corrosion resistance essential in chemical processing hazardous areas.

2. Low-Temperature Alloy Innovation

Dofun has “jointly developed a new type of alloy steel material capable of withstanding temperatures as low as −196°C”—extending the operational envelope of valves in LNG and cryogenic refrigeration applications where explosive atmospheres may be present.

3. Leakage Prevention

Our six-level sealing structure and documented 5,000-cycle no-leakage test record minimize fugitive emissions—a critical safety factor in hazardous areas where even minor leaks can create explosive mixtures.

4. Modular Design for Safe Maintenance

The DOFUN-CTP modular shared platform enables “quick switching of modules without the need for pipeline disassembly”. In hazardous areas, this means maintenance can be performed with minimal exposure and faster isolation—reducing the window of risk.

5. Defense & Security Applications

For “specialized valves with exceptional performance and absolute reliability under extreme conditions for the defense and military sectors”, Dofun’s engineering team works to specific project requirements, including applicable explosion protection frameworks.

The Engineering Decision Framework

When specifying valves for hazardous areas, Dofun’s application engineers guide clients through this structured process:

Step 1: Determine Geographic Market

EU/EEA destination → ATEX (CE marking) is legally mandatory
Global destination / international EPC project → IECEx certificate strongly preferred
Both markets → Pursue dual certification (often streamlined because both reference IEC 60079)

Step 2: Classify the Hazardous Zone

Conduct proper zone classification (0/1/2 for gas, 20/21/22 for dust)
Determine gas group (IIC for hydrogen, acetylene, etc.) or dust characteristics
Establish temperature class (T1–T6)

Step 3: Identify Electrical Components

Inventory all electrical elements: actuators, solenoids, switches, transmitters
Purely mechanical elements (handwheels, pneumatic-only operators) follow different rules

Step 4: Select Protection Method

Common methods per IEC 60079:

Ex d (flameproof enclosure)—typical for motor actuators
Ex e (increased safety)—for terminal boxes and wiring compartments
Ex i (intrinsic safety)—for low-energy sensors and transmitters
Ex m (encapsulation)—for solenoid coils
Ex p (pressurized enclosure)—for large enclosures

Step 5: Verify Certification Status

For ATEX: Confirm EU Type Examination Certificate and CE marking
For IECEx: Verify certificate number on the IECEx On-Line Certification System (OCS)
Engage Dofun’s engineering team to confirm specific model certifications

Step 6: Integrate into Valve Assembly

Ensure the complete valve assembly—including actuator, accessories, and body—meets the zone requirements
Dofun’s DOFUN-CTP platform facilitates configuration of compliant assemblies

Common Misconceptions

⚠️ Misconception #1: “ATEX certification equals IECEx certification.”

False. While both reference IEC 60079 technical standards, they are distinct schemes with different legal standings, certification procedures, and marking requirements. A product with ATEX certification is not automatically IECEx certified, and vice versa. However, “if the testing under ATEX has been done and satisfies all requirements of the relevant IEC Standard(s), then it is a case of transferring the test data into the IECEx Test Report format”—streamlining dual certification.

⚠️ Misconception #2: “IECEx is mandatory somewhere.”

False. IECEx is a voluntary scheme. No country legally mandates IECEx. However, an increasing number of national regulators accept IECEx certificates as evidence of compliance with local requirements, making it the de facto global standard for multinational projects.

⚠️ Misconception #3: “A mechanical valve doesn’t need any explosion protection consideration.”

False. Even purely mechanical valves in hazardous areas must be evaluated for static electricity, material compatibility, and potential ignition sources. Under ATEX, non-electrical equipment can sometimes be self-certified; under IECEx, all equipment requires independent certification regardless of zone.

⚠️ Misconception #4: “Once certified, a valve design is permanently compliant.”

False. “If a manufacturer makes changes to the design of IECEx Certified Equipment they are required to advise the ExCB”—and the ExCB will determine if an up-issue of the certificate is required. Any design modification to a Dofun valve that affects its explosion protection characteristics must trigger a re-evaluation.

Dofun’s Quality Infrastructure: The Foundation for Compliance

Whether pursuing ATEX, IECEx, or other regional certifications, the foundation is a robust quality management system. Dofun’s credentials in this regard are well-established:

ISO 9001 Quality Management System: Ensures consistent quality across all valve production
ISO 14001 Environmental Management: Aligns with our core value of “Environmental Friendliness”
OHSAS 18001 Occupational Safety & Health: Protects our workforce in demanding manufacturing environments
EU CE Certification: Demonstrates compliance with European health, safety, and environmental protection requirements
Russian EAC Certification: Enables market access across Eurasian Economic Union countries
Special Equipment TS Certification: Required for pressure equipment in the Chinese market
30+ Invention Patents: Reflects our “Technology Leadership” core value

Our facility—more than 30 acres with over 10,000 square meters of workshop space—houses “several globally advanced valve production lines and testing platforms”. This infrastructure provides the manufacturing consistency and testing rigor that certification bodies evaluate during their audits.

Industry-Specific Implications

Energy & Chemicals

In “extreme operating conditions involving low temperature, high pressure, and strong corrosion”, Dofun valves ensure continuous and safe operation. A client confirms: “In our low-temperature, high-pressure core unit, Dofun’s products have been operating stably for over three years. Their exceptional reliability has completely eliminated our concerns about unplanned downtime.” For such installations in the EU, ATEX compliance is mandatory; for global operations, IECEx provides the recognized standard.

Defense & Security

“Specialized valves with exceptional performance and absolute reliability under extreme conditions” demand rigorous certification alignment. Dofun collaborates with defense clients to meet project-specific compliance requirements.

Heavy Industry & Resources

Mining and metallurgy present “heavy-load and high-wear challenges”. A client notes: “The solution provided by Dofun, with its remarkable durability, has significantly reduced our maintenance frequency and spare parts costs.” In mining environments with potentially explosive dust atmospheres (Zone 20/21/22), appropriate dust-protection certification is essential.

Public Welfare & Health

Food and pharmaceutical applications require “precision valves that meet stringent hygiene standards”. A client states: “Dofun’s sanitary-grade valves not only fully comply with GMP standards, but their excellent polishing craftsmanship gives us full confidence in every audit.” While hygienic areas may not always be classified as explosive, adjacent utility areas (boiler rooms, ammonia refrigeration plants) often are.

Thermal Control & Refrigeration

As “a core component in the refrigeration field”, Dofun valves achieve “exceptional precision” in “precise temperature control and energy efficiency management”. Ammonia (R717) refrigeration systems—widely used in industrial cold chain—operate with a flammable, toxic refrigerant, making explosion protection considerations relevant, particularly in machinery rooms classified as Zone 1 or Zone 2.

The Verdict: ATEX, IECEx, or Both?

For engineering teams specifying Dofun valves, the decision framework is straightforward:

If your project is in the EU/EEA → ATEX compliance (CE marking) is legally required. Confirm the specific Dofun valve model and its actuator/accessory configuration carry valid ATEX certification.

If your project is outside the EU, particularly in international EPC contracts → IECEx certification provides the globally recognized standard. Verify the IECEx CoC number on the IECEx On-Line Certification System.

If your project spans multiple regions → Pursue both. The shared IEC 60079 technical foundation means that “testing under ATEX… satisfies all requirements of the relevant IEC Standard(s)” can be transferred to IECEx format, streamlining the process.

If your application is purely mechanical (e.g., Dofun Manual Operation Valve with handwheel only) → Evaluate whether non-electrical equipment provisions apply. Even so, document the risk assessment and material compatibility.

Engaging Dofun for Hazardous Area Projects

Dofun’s commitment to “Quality as Foundation” and “User as Priority” means we partner with engineering teams to navigate the certification landscape:

Application engineering support: Our team reviews your zone classification, gas/dust group, and temperature class requirements
Product configuration: Through the DOFUN-CTP modular platform, we configure valves with appropriately certified actuators and accessories
Documentation: We provide available compliance documentation (CE, EAC, ISO, TS) and guide ATEX/IECEx-specific inquiries
Global compliance: With products “exported to 100+ countries and regions” and “overseas markets accounting for about 30%” of our business, we understand diverse regulatory environments

As our founding vision states: “The true meaning of Dofun is not just to achieve what we want in our hearts, but to finely carve every Dofun product into a metal artwork.” In hazardous area applications, this craftsmanship means engineering every valve—from the NANO-treated stem to the six-level sealing structure to the modular actuator interface—to perform safely and reliably within the applicable explosion protection framework.

Conclusion: Certification as a Language of Trust

ATEX and IECEx are not competitors—they are complementary frameworks serving different regulatory purposes. ATEX is the law of the European Union; IECEx is the global language of explosion protection certification. Both rest on the same technical foundation (IEC 60079 series), both use identical Ex marking codes (Ex d, Ex i, Ex e, etc.), and both demand rigorous testing and quality assurance.

For engineers specifying Dofun valves in hazardous areas, the path forward is clear:

Identify your market → EU requires ATEX; global projects benefit from IECEx
Classify your zone → Determine 0/1/2 (gas) or 20/21/22 (dust) requirements
Assess your valve assembly → Evaluate all electrical components (actuators, solenoids, transmitters)
Verify certification status → Confirm with Dofun’s engineering team for your specific model and configuration
Document compliance → Maintain certificates, declarations, and technical files

Dofun’s four core values frame our approach to hazardous area applications:

Quality as Foundation: Our ISO 9001-certified quality system underpins every valve
User as Priority: We partner with engineers to navigate complex compliance requirements
Technology Leadership: 30+ invention patents drive innovations like NANO treatment and six-level sealing
Environmental Friendliness: Our sustainable practices extend to safe, leak-free operation in hazardous environments

With more than 30 invention patents, a 30+ acre Liaocheng facility, products exported to 100+ countries, and a modular platform that enables tailored compliance solutions, Dofun stands ready to support your hazardous area valve specifications—whether they require ATEX for European installations, IECEx for global projects, or both.

Engage Dofun’s application engineering team to discuss your specific hazardous area requirements. Whether you are designing an ammonia refrigeration system in the EU, specifying valves for a petrochemical plant in the Middle East, equipping a mining operation in Australia, or configuring a defense application where absolute reliability is non-negotiable, our engineers will guide you through the ATEX and IECEx landscape—ensuring your Dofun valves deliver the safety, compliance, and performance your project demands.

💡 Dofun’s Certification Commitment: We don’t treat explosion protection as a checkbox—we treat it as a core engineering discipline. By understanding the nuanced differences between ATEX and IECEx, and by engineering our valves to meet the highest standards of both frameworks, Dofun enables engineers worldwide to specify with confidence. This is how we carve every valve into a metal artwork worthy of your most demanding hazardous area application.