IEC 60079-0 Explained: General Requirements for Ex Equipment

Almost every explosion-protected product used in hazardous areas has one thing in common: it is built upon the requirements of IEC 60079-0.

Whether the equipment uses flameproof protection (Ex d), increased safety (Ex e), intrinsic safety (Ex i), pressurization (Ex p), encapsulation (Ex m), or protection by enclosure (Ex t), the manufacturer must first comply with the general requirements specified in IEC 60079-0.

Because of its broad applicability, IEC 60079-0 is often considered the foundation of the entire IEC 60079 series. Most protection concept standards reference this document and add only the additional requirements specific to their particular protection technique.

The standard establishes fundamental requirements for the design, construction, testing, marking, and documentation of equipment intended for use in explosive atmospheres. It also defines many of the terms and principles used throughout the explosion protection industry.

For engineers, inspectors, and certification professionals, understanding IEC 60079-0 is essential because many requirements encountered in daily practice—including temperature classes, equipment markings, ingress protection, and material considerations—originate directly from this standard.

This article explains what IEC 60079-0 is, why it is important, and the key requirements that every engineer working with explosion-protected equipment should understand.

Quick Answer

What Is IEC 60079-0?

IEC 60079-0 is the international standard titled Explosive Atmospheres – Part 0: Equipment – General Requirements.

The standard specifies the common requirements applicable to electrical equipment intended for use in explosive atmospheres. It does not define a particular protection concept by itself but instead establishes the baseline requirements that apply across multiple protection techniques.

For example, a flameproof enclosure certified to IEC 60079-1 must also comply with the applicable requirements of IEC 60079-0. The same principle applies to equipment certified under IEC 60079-7, IEC 60079-11, IEC 60079-18, and many other standards in the series.

In practical terms, IEC 60079-0 can be viewed as the common engineering framework upon which the other explosion protection standards are built.

Why Is IEC 60079-0 Important?

Without a common set of requirements, every protection concept standard would need to repeat the same basic provisions regarding construction, marking, testing, and documentation.

IEC 60079-0 eliminates this duplication by establishing a single set of fundamental requirements that can be referenced by multiple standards.

The standard helps ensure:

• Consistency across different protection concepts.
• Uniform marking and identification requirements.
• Standardized testing methodologies.
• Common definitions and terminology.
• Consistent construction requirements.
• Improved safety and reliability of Ex equipment.

Because of these benefits, IEC 60079-0 has become one of the most important standards in the entire explosion protection industry.

Which Equipment Uses IEC 60079-0?

The requirements of IEC 60079-0 apply to a wide range of explosion-protected equipment, including:

• Lighting fixtures.
• Junction boxes.
• Motors.
• Control stations.
• Instrumentation equipment.
• Control panels.
• Cable glands.
• Sensors and transmitters.
• Battery systems.
• Communication equipment.

In practice, almost every electrical product certified for use in explosive atmospheres relies on IEC 60079-0 as part of its certification basis.

Scope of IEC 60079-0

IEC 60079-0 establishes the general requirements applicable to electrical equipment intended for use in explosive atmospheres. However, the standard does not provide the complete requirements for a specific protection concept.

Instead, it works together with other standards within the IEC 60079 series.

For example:

Protection Concept	Applicable Standards
Flameproof Enclosure (Ex d)	IEC 60079-0 + IEC 60079-1
Pressurization (Ex p)	IEC 60079-0 + IEC 60079-2
Powder Filling (Ex q)	IEC 60079-0 + IEC 60079-5
Increased Safety (Ex e)	IEC 60079-0 + IEC 60079-7
Intrinsic Safety (Ex i)	IEC 60079-0 + IEC 60079-11
Encapsulation (Ex m)	IEC 60079-0 + IEC 60079-18
Protection by Enclosure (Ex t)	IEC 60079-0 + IEC 60079-31

This relationship explains why IEC 60079-0 is often referred to as the foundation of the entire IEC 60079 series.

Major Topics Covered by IEC 60079-0

Although the standard contains numerous technical requirements, the major topics can generally be grouped into several areas.

• Equipment construction requirements.
• Material requirements.
• Ingress protection requirements.
• Temperature classification requirements.
• Equipment marking requirements.
• Documentation requirements.
• Type testing requirements.
• Routine verification requirements.
• Mechanical strength requirements.
• Non-metallic enclosure requirements.

These requirements establish the minimum technical baseline that explosion-protected equipment must satisfy before the specific requirements of an individual protection concept are applied.

Construction Requirements

IEC 60079-0 contains general construction requirements intended to ensure that equipment remains safe during its intended operating life.

Examples include requirements related to:

• Mechanical strength.
• Resistance to environmental conditions.
• Protection against corrosion.
• Resistance to impact.
• Suitability of materials.
• Integrity of enclosure components.

These requirements are important because equipment operating in hazardous areas is often exposed to harsh industrial environments, including vibration, moisture, dust, chemicals, and elevated temperatures.

Ingress Protection Requirements

IEC 60079-0 also establishes minimum ingress protection requirements for certain types of equipment.

Ingress protection ratings help ensure that dust, moisture, and foreign objects do not compromise the explosion protection characteristics of the equipment.

Depending on the protection concept and intended application, equipment may require ratings such as:

• IP54
• IP55
• IP56
• IP65
• IP66
• IP67

The appropriate level of ingress protection depends on the equipment design and the specific protection concept being used.

Temperature Requirements

One of the most important principles in explosion protection is ensuring that equipment surfaces do not become hot enough to ignite the surrounding atmosphere.

IEC 60079-0 therefore establishes requirements related to:

• Maximum surface temperatures.
• Temperature classes.
• Ambient temperature limitations.
• Temperature testing procedures.

The standard supports the use of familiar temperature classifications such as T1, T2, T3, T4, T5, and T6, which are widely used throughout the explosion protection industry.

Marking Requirements

Many of the equipment markings commonly found on explosion-protected products originate directly from IEC 60079-0.

Typical marking requirements include:

• Manufacturer identification.
• Certificate number.
• Explosion protection marking.
• Equipment Group.
• Equipment Protection Level (EPL).
• Temperature class.
• Ambient temperature range.
• Special conditions for safe use where applicable.

Proper marking is essential because it allows users to determine whether equipment is suitable for a particular hazardous area application.

Material Requirements

The materials used in explosion-protected equipment can significantly influence safety and long-term reliability. IEC 60079-0 therefore establishes requirements for both metallic and non-metallic materials used in equipment construction.

The standard addresses issues such as:

• Resistance to corrosion.
• Resistance to ultraviolet radiation.
• Thermal stability.
• Mechanical strength.
• Resistance to chemicals and environmental exposure.
• Electrostatic charging characteristics.

Particular attention is given to non-metallic materials because excessive electrostatic charge accumulation can become an ignition source in hazardous areas.

Non-Metallic Enclosure Requirements

Many modern explosion-protected products incorporate plastic or composite materials. IEC 60079-0 includes specific requirements intended to ensure that these materials remain suitable for use in explosive atmospheres.

Examples of considerations include:

• Impact resistance.
• Resistance to environmental aging.
• Temperature stability.
• Electrostatic charge limitations.
• Resistance to ultraviolet exposure.

These requirements are particularly important for junction boxes, enclosures, control stations, and instrumentation products that use engineered polymers instead of metal housings.

Mechanical Strength and Impact Resistance

Equipment installed in industrial environments may be exposed to mechanical abuse, accidental impacts, and harsh operating conditions.

IEC 60079-0 therefore specifies various tests intended to verify that equipment can withstand normal service conditions without compromising explosion protection.

Depending on the equipment type, testing may include:

• Impact testing.
• Thermal endurance testing.
• Resistance to mechanical stress.
• Verification of enclosure integrity.
• Resistance to environmental conditions.

These requirements help ensure that explosion-protected equipment maintains its protective characteristics throughout its expected service life.

Documentation Requirements

IEC 60079-0 also establishes important documentation requirements that support the safe use of explosion-protected equipment.

Manufacturers are generally required to provide information such as:

• Equipment identification details.
• Installation instructions.
• Operating limitations.
• Special conditions for safe use.
• Ambient temperature limitations.
• Maintenance recommendations.

Proper documentation is essential because users often rely on these instructions to determine whether equipment is suitable for a particular hazardous area application.

Type Testing Requirements

Before explosion-protected equipment can be certified, it must undergo testing to demonstrate compliance with the applicable standards.

IEC 60079-0 establishes many of the fundamental testing requirements used throughout the certification process.

Depending on the equipment type, testing may include:

• Temperature testing.
• Impact testing.
• Ingress protection testing.
• Thermal endurance testing.
• Resistance to environmental conditions.
• Verification of construction requirements.

Additional testing requirements are then imposed by the applicable protection concept standard, such as IEC 60079-1 for Ex d equipment or IEC 60079-7 for Ex e equipment.

Relationship Between IEC 60079-0 and Equipment Markings

One of the most visible contributions of IEC 60079-0 is the standardized equipment marking system used throughout the explosion protection industry.

Markings such as the example below originate largely from the requirements of IEC 60079-0:

Ex eb mb IIC Gb
Ex tb IIIC Db IP66
Ex ia IIC T4 Ga

These markings provide critical information regarding:

• The protection concept.
• The gas or dust group.
• The Equipment Protection Level (EPL).
• The temperature classification.
• The intended application.

Without standardized markings, selecting suitable equipment for hazardous areas would become significantly more difficult and increase the likelihood of application errors.

Advantages of IEC 60079-0

IEC 60079-0 plays a fundamental role in the explosion protection industry because it establishes a common technical framework that can be applied across numerous protection concepts and equipment types.

Without a general requirements standard, each protection concept standard would need to duplicate many common requirements, resulting in inconsistencies and unnecessary complexity.

Key advantages of IEC 60079-0 include:

• Provides a common technical foundation for Ex equipment.
• Promotes consistency across different protection concepts.
• Standardizes equipment markings and identification.
• Establishes uniform testing requirements.
• Improves equipment reliability and safety.
• Facilitates international certification and market acceptance.
• Supports harmonization between IECEx and national standards.
• Provides a common engineering language for the explosion protection industry.

Because of these benefits, IEC 60079-0 has become one of the most widely referenced standards in hazardous area engineering.

Limitations of IEC 60079-0

Although IEC 60079-0 is extremely important, it should not be viewed as a standalone standard for equipment certification.

The document provides only the general requirements and does not contain the detailed technical requirements for specific protection concepts.

Some limitations include:

• Does not define the requirements for a specific protection concept.
• Cannot be used alone to certify most Ex equipment.
• Must be used together with additional IEC 60079 standards.
• Requires engineering knowledge to interpret correctly.
• Is periodically revised and requires continuous updates.

For example, an Ex d junction box cannot be evaluated using IEC 60079-0 alone because the specific requirements of IEC 60079-1 must also be applied.

How IEC 60079-0 Works With Other Standards

IEC 60079-0 can be visualized as the foundation upon which other protection concept standards are built.

Foundation Standard	Additional Standard	Result
IEC 60079-0	IEC 60079-1	Ex d Equipment
IEC 60079-0	IEC 60079-2	Ex p Equipment
IEC 60079-0	IEC 60079-7	Ex e Equipment
IEC 60079-0	IEC 60079-11	Ex i Equipment
IEC 60079-0	IEC 60079-18	Ex m Equipment
IEC 60079-0	IEC 60079-31	Ex t Equipment

This layered approach allows the IEC 60079 series to remain organized and avoids repeating common requirements across multiple standards.

Why Engineers Should Understand IEC 60079-0

Even engineers who do not work directly in product design frequently encounter requirements that originate from IEC 60079-0.

Examples include:

• Reading equipment markings.
• Understanding temperature classifications.
• Selecting suitable equipment for hazardous areas.
• Reviewing equipment certificates.
• Evaluating ambient temperature limitations.
• Understanding ingress protection requirements.
• Interpreting special conditions for safe use.

A basic understanding of IEC 60079-0 can therefore help engineers avoid equipment selection mistakes and improve communication with manufacturers, certification bodies, and inspection personnel.

Common Misunderstandings About IEC 60079-0

IEC 60079-0 Is a Protection Concept Standard

No. IEC 60079-0 establishes the general requirements applicable to explosion-protected equipment. It does not define a specific protection concept.

Equipment Can Be Certified Only to IEC 60079-0

In most cases, no. Equipment usually requires compliance with IEC 60079-0 together with one or more additional standards that define the applicable protection concept.

IEC 60079-0 Applies Only to Manufacturers

Incorrect. The standard is frequently referenced by manufacturers, certification bodies, EPC contractors, inspectors, maintenance personnel, and end users.

IEC 60079-0 Covers Installation and Maintenance Requirements

No. Installation and maintenance requirements are covered by other standards within the IEC 60079 series, such as IEC 60079-14 and IEC 60079-17.

IEC 60079-0 Is Relevant Only During Certification

No. The requirements of IEC 60079-0 continue to influence equipment selection, installation, inspection, and maintenance activities throughout the entire lifecycle of explosion-protected equipment.

Frequently Asked Questions (FAQ)

What is IEC 60079-0?

IEC 60079-0 is the general requirements standard within the IEC 60079 series that establishes the fundamental design, construction, testing, marking, and documentation requirements for explosion-protected equipment used in explosive atmospheres.

Is IEC 60079-0 a protection concept standard?

No. IEC 60079-0 does not define a specific protection concept such as Ex d, Ex e, or Ex i. Instead, it provides the common requirements that apply across multiple protection concepts.

Can equipment be certified only to IEC 60079-0?

In most cases, no. Equipment is typically certified to IEC 60079-0 together with one or more additional standards that specify the applicable protection concept requirements.

Why is IEC 60079-0 important?

IEC 60079-0 provides a consistent technical foundation for explosion-protected equipment and establishes common requirements for construction, marking, testing, and documentation across the entire IEC 60079 series.

Which equipment uses IEC 60079-0?

Almost all electrical equipment intended for use in explosive atmospheres relies on IEC 60079-0, including lighting fixtures, junction boxes, motors, control stations, instrumentation equipment, and communication devices.

Does IEC 60079-0 cover installation and maintenance?

No. Installation and maintenance requirements are covered by other standards within the IEC 60079 series, particularly IEC 60079-14 and IEC 60079-17.

Conclusion

IEC 60079-0 is arguably the most important standard in the entire IEC 60079 series because it establishes the common engineering foundation for explosion-protected equipment.

The standard defines the general requirements for construction, testing, marking, and documentation that apply across numerous protection concepts, helping to ensure consistency, reliability, and safety throughout the explosion protection industry.

Although IEC 60079-0 does not provide the specific requirements for individual protection concepts, it forms the baseline upon which standards such as IEC 60079-1, IEC 60079-7, IEC 60079-11, and IEC 60079-31 are built.

For engineers, inspectors, certification professionals, and end users, understanding IEC 60079-0 is essential because many of the requirements encountered in everyday hazardous area applications originate directly from this foundational standard.

Technical Review

References

• IEC 60079-0 – Explosive Atmospheres – Part 0: Equipment – General Requirements.
• IEC 60079 Series – Explosive Atmospheres.
• IECEx System – International Certification System for Equipment Used in Explosive Atmospheres.
• International Electrotechnical Commission (IEC).
• EN IEC 60079-0 – Explosive Atmospheres – Equipment – General Requirements.