IEC 60079-0 Explosive Atmosphere Hazardous Location Testing

For any engineer involved in designing or specifying equipment for hazardous locations, IEC 60079-0 is the single most important standard to understand. Think of it as the foundational “umbrella” document for all Explosion Protected (Ex) equipment testing. It specifies the general requirements for the construction, testing, and marking of any electrical and non-electrical equipment intended for use in explosive atmospheres.

This standard is used in conjunction with one or more specific protection method standards. For example, to certify a product, you must meet all the applicable requirements of IEC 60079-0 plus the requirements of the specific standard, such as:

• IEC 60079-7: Increased Safety (‘Ex e’)
• IEC 60079-11: Intrinsic Safety (‘Ex i’)
• IEC 60079-31: Dust Ignition (‘Ex t’)

This standard provides the core technical basis for the world’s two main certification schemes:

• IECEx (the international system)
• ATEX (the mandatory directive for the European Union, 2014/34/EU)

North America’s HazLoc system of Classes and Divisions, like UL or CSA standards, is increasingly aligning with the IEC 60079 series.

Why is IEC 60079-0 Compliance Testing Important?

Compliance with IEC 60079-0 is the core of ensuring safety in environments where a single spark could be catastrophic. The importance of IEC 60079 testing is threefold.

Safety & Risk Mitigation

The primary goal is to prevent ignition. Explosive atmospheres can be ignited by three main sources:

1. Hot Surfaces: A component or enclosure surface gets hotter than the auto-ignition temperature of the surrounding gas or dust.
2. Sparks: An electrical spark from a switch, a static discharge from a plastic enclosure, or a mechanical spark from friction or impact.
3. Component Failure: A fault condition that compromises a protection method.

IEC 60079-0 compliance testing rigorously verifies that the equipment’s design, materials, and construction. The goal is to prevent these ignition sources under both normal and fault conditions.

Market Access (ATEX & IECEx)

Compliance is non-negotiable for legal market access in most of the world.

• ATEX: To place your product on the market in the 27 member states of the European Union, you must have an ATEX certificate (EU-Type Examination Certificate) issued by a Notified Body. This proves compliance with the relevant standards.
• IECEx: The IECEx scheme provides an international Certificate of Conformity (CoC) that is accepted in many countries (like Australia, New Zealand, Singapore, and others). This scheme also simplifies the process of obtaining national certifications in many more (like Brazil or South Africa).

Prerequisite for All Other Protection

You cannot achieve Intrinsic Safety certification or Flameproof enclosure certification without first meeting the general requirements of IEC 60079-0.

This standard covers the fundamental robustness of the product. It doesn’t make sense to test the complex energy-limiting circuits of ‘Ex i’ if the plastic enclosure will crack when dropped or build up a static spark.

Scope of IEC 60079-0: What Equipment & Concepts are Covered?

The scope of IEC 60079-0 is extremely broad. It applies to all electrical and non-electrical Ex equipment. In addition, it applies to Ex Components. Ex Components include terminal block or enclosure that is certified to be integrated into a larger Ex product.

The standard organizes equipment and concepts into three key areas:

Equipment Groups

This defines where the equipment is intended to be used.

• Group I: Equipment for underground mining, specifically where hazards from methane (firedamp) and combustible coal dust are present.
• Group II: Equipment for surface industries with explosive gas atmospheres (e.g., chemical plants, refineries, paint shops). This is further subdivided by gas type: IIA (e.g., propane), IIB (e.g., ethylene), and IIC (e.g., hydrogen, acetylene).
• Group III: Equipment for surface industries with explosive dust atmospheres (e.g., food processing, grain silos, woodworking, metal powder facilities). This is subdivided by dust type: IIIA (combustible flyings), IIIB (non-conductive dust), and IIIC (conductive dust).

Ex Marking

IEC 60079-0 defines the grammar for the mandatory Ex marking string. This string is the end-user’s guide to the equipment’s certification. A typical marking might look like: Ex db IIB T4 Gb.

This standard dictates the format, content, and order, including the overall protection concept, the Gas/Dust Group (IIB), the Temperature Class (T4), and the EPL (Gb).

The Certification Process: From Test Report to Market

Understanding the tests is half the battle; navigating the certification pathway is the other.

1. Select a Test Lab: The manufacturer must choose an accredited laboratory. For IECEx, this is an IECEx Test Lab (ExTL). For ATEX, it’s an ATEX Notified Body. Often, one lab holds both accreditations.
2. Submit for Testing: The manufacturer provides the lab with the technical documentation file, drawings, and several product samples (some for destructive testing).
3. Receive the Test Report: After (and if) the product passes all tests, the lab issues a comprehensive IEC 60079-0 test report. For the IECEx scheme, this is officially known as an IECEx Test Report (ExTR). This report details every test performed and its result.
4. Achieve Certification: The test report is the evidence, not the certificate.
   • IECEx: The ExTR and technical file are submitted to an IECEx Certification Body (ExCB) (which may be the same organization as the test lab). The ExCB reviews the file and issues the final IECEx CoC (Certificate of Conformity), which is published online for public verification.
   • ATEX: The ExTR and file are reviewed by an ATEX Notified Body, which then issues an EU-Type Examination Certificate. This certificate, along with a manufacturer’s Declaration of Conformity, allows the CE and Ex marks to be applied.
5. Enable Production (QMS Audit): A product certificate is not enough. The manufacturing facility must also be audited to ensure it has a quality management system (QMS) capable of consistently producing the product exactly as it was tested.

Navigating the IEC 60079-0 Latest Edition

Standards are living documents. The IEC 60079-0 latest edition (currently IEC 60079-0:2017, Edition 7.0) introduced several key technical updates that engineers must be aware of, especially when updating existing product portfolios.

For example, Edition 7.0 introduced:

• Stricter requirements for non-metallic layers on metal enclosures. This includes things like paint, powder coating, and labels, which now have defined thickness and surface area limits to control electrostatic risks.
• Clarified test procedures for electrostatic testing of portable equipment and devices with small plastic parts.

Staying current with the latest edition is essential, as certification bodies will require compliance with it for all new products and significant updates to existing ones.

Start Your Ex Certification Project

Navigating the complexities of IEC 60079-0 testing and the broader ATEX/IECEx certification landscape can be daunting. A simple design choice, like the material of an enclosure or the type of cable gland used, can be the difference between a smooth certification process and a costly, time-consuming failure.

Ready to ensure your equipment is safe and compliant? Get a quote for IEC 60079-0 testing and full ATEX/IECEx certification to start your project with confidence.