1. What Is Explosion Protection?

Explosion protection is the set of measures used to prevent explosions or limit their consequences when flammable substances can create an explosive atmosphere.

An explosive atmosphere can occur when air mixes with a flammable gas, vapor, mist or combustible dust in a concentration where ignition can result in combustion spreading through the mixture. Such conditions can occur in many industrial environments, including chemical plants, refineries, pharmaceutical production, food processing, grain handling and manufacturing facilities.

The basic principle is simple:

An explosion requires an explosive atmosphere and an ignition source. Explosion protection aims to prevent either one from causing an explosion.

1.1 How Can an Explosion Occur?

For an explosion to occur, three basic elements are generally required:

• A flammable substance – such as a gas, vapor, mist or combustible dust
• Oxygen – normally supplied by the surrounding air
• An ignition source – such as a spark, flame, hot surface, electrical arc or electrostatic discharge

This is often illustrated as the explosion triangle.

If one of these conditions is eliminated or controlled, an explosion can be prevented.

In industrial environments, however, eliminating the flammable substance or oxygen is often not practical. Explosion protection therefore frequently focuses on preventing ignition sources and ensuring that equipment cannot become an ignition source under the conditions in which it is intended to operate.

1.2 What Is an Explosive Atmosphere?

An explosive atmosphere is not simply an area where a flammable substance is present.

The substance must be capable of forming a mixture with air that can ignite and allow combustion to propagate. The concentration, physical state, temperature, pressure and other environmental conditions therefore matter.

Explosive atmospheres can be created by:

Gases and vapors

Examples include:

• Hydrogen
• Methane
• Propane
• Butane
• Solvent vapors
• Gasoline vapors

Mists

Flammable liquids can also form combustible mists, particularly when they are sprayed, leaked under pressure or otherwise finely dispersed.

Combustible dust

Many materials that are not normally considered hazardous can become an explosion risk when present as fine dust.

Examples include:

• Flour
• Sugar
• Wood dust
• Coal dust
• Certain plastics
• Metal dust

This is why explosion protection is relevant not only to the oil and chemical industries but also to sectors such as food processing, woodworking, pharmaceuticals and manufacturing.

1.3 Why Can Electrical Equipment Be an Ignition Source?

Electrical equipment can create several potential ignition sources.

Examples include:

• Electrical sparks
• Arcing contacts
• Hot surfaces
• Overheated components
• Fault currents
• Static electricity
• Electrical connections with insufficient protection

A product that is completely safe in a normal industrial environment may therefore become unsuitable when installed in an area where an explosive atmosphere can occur.

This is the fundamental reason why specific requirements exist for equipment intended for hazardous areas.

1.4 Explosion Protection Is Not Limited to Electrical Products

Explosion protection is often associated with electrical equipment, but the scope is broader.

Mechanical equipment can also create ignition sources through:

• Hot surfaces
• Friction
• Mechanical sparks
• Bearings
• Rotating components
• Electrostatic charging

For this reason, explosion-protection requirements can apply to both electrical and non-electrical equipment.

The European ATEX framework, for example, covers equipment and protective systems intended for use in potentially explosive atmospheres, as well as certain safety, controlling and regulating devices that contribute to the safe operation of such equipment.

1.5 The Goal of Explosion Protection

Explosion protection is therefore not simply about making a product “explosion-proof.”

The objective is to ensure that a product:

1. Does not create an unacceptable ignition source,
2. Remains safe under its specified operating conditions,
3. Is suitable for the hazardous environment in which it will be used, and
4. Provides the required level of protection for the classified area.

The applicable requirements depend on the product, the hazardous substance, the environment and the intended application.

This relationship between the product and its environment is fundamental to understanding ATEX and other explosion-protection frameworks.

The following chapters explain when an area is considered hazardous, which products can be affected, and how hazardous areas are classified.

2. When Is Explosion Protection Required?

Explosion protection is required whenever a potentially explosive atmosphere can occur and an ignition source could be present.

The decisive factor is therefore not simply whether a company works with flammable substances. What matters is whether those substances can form an explosive atmosphere under the actual operating conditions and whether equipment or other ignition sources are present in the affected area.

2.1 What Makes an Area Hazardous?

An area can become hazardous when a flammable substance can be released and mix with air in an explosive concentration.

This can happen during:

• Normal operation
• Filling and emptying processes
• Production and processing
• Storage
• Cleaning
• Maintenance
• Leakage or equipment failure

The likelihood and duration of an explosive atmosphere are important because the risk is not the same in every location.

For example, a tank containing a flammable liquid may create an explosive atmosphere inside the tank continuously or frequently, while a nearby production area may only be affected briefly in the event of a leak.

This is why hazardous areas are classified according to the probability and duration of an explosive atmosphere, rather than simply being designated as hazardous or non-hazardous.

2.2 Typical Industries

Explosion hazards can occur in many different industries.

Common examples include:

Oil & Gas

• Refineries
• Fuel storage
• Gas processing
• Filling stations
• Pipelines

Chemical Industry

• Chemical production
• Solvent handling
• Mixing and processing
• Storage facilities

Pharmaceutical Industry

• Solvent-based processes
• Powder handling
• Production and processing equipment

Food & Beverage

• Flour and grain processing
• Sugar production
• Food powders
• Feed production

Woodworking

• Wood processing
• Sawmills
• Furniture production
• Dust extraction systems

Manufacturing

• Metal processing
• Plastic processing
• Paint and coating processes
• Battery and energy-related applications

Mining

• Underground mining
• Coal mining
• Areas where methane or combustible dust can occur

The specific explosion hazard varies significantly between these applications. A gas explosion, for example, requires a different assessment from an explosion involving combustible dust.

2.3 Does Every Product in a Hazardous Facility Need Ex Protection?

No.

This is an important distinction.

The presence of an explosive atmosphere somewhere in a facility does not automatically mean that every product installed in the facility requires explosion protection.

The relevant question is:

Is the product intended to operate in an area where an explosive atmosphere can occur, and could the product itself become a source of ignition?

For example, equipment installed in a non-hazardous control room may not require Ex protection even if the control room is part of a facility that processes flammable materials.

Conversely, a relatively simple electrical device installed directly inside a classified hazardous area may require specific explosion-protection measures.

2.4 The Intended Installation Area Matters

The same product can therefore have different compliance requirements depending on where it is installed.

Consider an industrial sensor:

• Installed in a normal production area → standard industrial requirements may apply.
• Installed in Zone 2 → equipment suitable for Zone 2 may be required.
• Installed in Zone 1 → a higher level of protection may be required.
• Installed in Zone 0 → equipment intended for the highest level of protection may be required.

The product itself has not changed. The intended application has.

This is one of the most important principles when determining explosion-protection requirements.

2.5 Who Needs to Consider Explosion Protection?

Explosion protection can be relevant to several parties:

• Equipment manufacturers – when their products are intended for hazardous areas
• System integrators – when combining equipment into systems
• Plant operators – when identifying and managing hazardous areas
• Engineering companies – when designing installations
• Installers – when installing equipment in classified areas
• Importers and distributors – when placing relevant products on a market

Their responsibilities are not necessarily the same.

For manufacturers, the key question is whether the product falls within the applicable product requirements. Operators and plant designers, on the other hand, are responsible for assessing the workplace and determining where hazardous areas exist.

2.6 Explosion Protection Is Application-Dependent

Explosion protection therefore cannot be determined from the product name alone.

A manufacturer cannot simply state that a product is intended for “industrial use” and determine the applicable requirements from that information.

A proper assessment normally requires information about:

• Where the product will be installed
• What flammable substance may be present
• How often an explosive atmosphere can occur
• Whether the hazard involves gas, vapor, mist or dust
• What operating conditions apply
• What type of equipment is being used

These factors ultimately determine which protection concept, equipment category, certification or conformity-assessment route may be required.

This is why explosion protection should be considered during product definition and market-access planning, rather than only after a product has been designed and is ready for testing.

3. Which Products Require Explosion Protection?

Explosion protection requirements can apply to a wide range of products. The decisive factor is not the product category alone, but whether the product is intended for use in a hazardous area and whether it could create an ignition source.

This means that explosion protection can affect products that are normally considered standard electrical, electronic or mechanical equipment.

3.1 Electrical Equipment

Electrical equipment is one of the most common categories requiring explosion protection.

Examples include:

• Sensors
• Switches
• Relays
• Motors
• Generators
• Power supplies
• Control equipment
• Electrical cabinets
• Lighting equipment
• Measurement equipment
• Heating equipment

Potential ignition sources can include electrical arcs, sparks, hot surfaces, faulty connections or component failures.

The required protection therefore depends on the intended hazardous area and the specific characteristics of the equipment.

3.2 Electronic and Communication Equipment

Modern industrial equipment increasingly contains electronic components and communication interfaces.

Products that may require consideration include:

• Industrial computers
• HMIs
• Data acquisition equipment
• Network equipment
• Cameras
• Displays
• Communication devices
• Remote monitoring equipment

Wireless products can be particularly relevant because they may contain both electronic circuits and intentional RF transmitters.

A product does not become exempt from explosion-protection requirements simply because its primary function is communication or data processing.

3.3 Sensors and Measurement Equipment

Sensors are widely used in hazardous environments to monitor:

• Temperature
• Pressure
• Flow
• Level
• Gas concentration
• Position
• Speed
• Process parameters

Because sensors are often installed directly at the process, they may be located inside a classified hazardous area.

The required protection depends on the installation location, the substances present and the design of the sensor.

3.4 Motors, Pumps and Mechanical Equipment

Motors, pumps, fans and other rotating equipment can create ignition sources through:

• Hot surfaces
• Friction
• Mechanical sparks
• Bearings
• Electrical components
• Electrostatic effects

Explosion protection therefore also applies to equipment that combines electrical and mechanical functions.

For purely mechanical equipment, ignition-risk assessment is still important even when there are no electrical circuits.

3.5 Machinery and Non-Electrical Equipment

Explosion protection is not limited to products that contain electrical components.

Examples of potentially relevant non-electrical equipment include:

• Valves
• Pumps
• Gearboxes
• Conveyors
• Fans
• Mechanical mixers
• Couplings
• Braking systems
• Hand-operated equipment

Mechanical equipment can generate sufficient heat, friction or mechanical sparks to ignite an explosive atmosphere.

For this reason, European explosion-protection requirements also address non-electrical equipment. Standards such as ISO 80079-36 and ISO 80079-37 provide the basis for assessing and protecting non-electrical equipment intended for potentially explosive atmospheres.

3.6 Lighting and Heating Equipment

Lighting equipment installed in hazardous areas requires particular attention because it can contain:

• Electrical switching components
• Hot surfaces
• Internal arcs
• High-temperature components

Similarly, electrical heaters and other equipment designed to generate heat must be assessed carefully because surface temperature itself can become an ignition source.

The required temperature limits depend on the hazardous substance and the applicable equipment classification.

3.7 Wireless and RF Equipment

Wireless equipment deserves special attention because RF products can combine several potential ignition considerations.

Examples include:

• Wi-Fi devices
• Bluetooth equipment
• Cellular equipment
• RFID readers
• Wireless sensors
• Industrial wireless gateways
• Two-way radios
• RF identification and tracking systems

For such products, the assessment may need to consider both:

1. The electrical and thermal characteristics of the equipment, and
2. The RF energy generated by the transmitter.

The fact that a radio module is already certified for normal industrial use does not automatically mean that the complete product is suitable for a hazardous area.

This is particularly important for manufacturers integrating pre-certified wireless modules into an Ex product.

3.8 The Same Product Can Have Different Requirements

A product category alone does not determine whether explosion protection is required.

For example, an industrial temperature sensor could be:

• Installed outside a hazardous area → no Ex-specific product requirements may apply.
• Installed in Zone 2 → equipment suitable for Zone 2 may be required.
• Installed in Zone 1 → a different protection concept and higher protection level may be required.
• Installed in Zone 0 → equipment meeting the requirements for the highest applicable protection level may be necessary.

The same principle applies to cameras, motors, computers, lighting, sensors and other equipment.

3.9 What Determines the Requirements?

Before determining the applicable explosion-protection requirements, manufacturers generally need to know:

• Intended market
• Intended use
• Installation location
• Hazardous area classification
• Gas, vapor, mist or dust
• Properties of the hazardous substance
• Equipment type
• Electrical or non-electrical design
• Operating temperature
• Potential ignition sources
• Required protection concept

These parameters determine whether explosion protection is required and, if so, what level and type of protection must be provided.

The next chapter explains how hazardous areas are classified and why the classification is one of the most important inputs when determining the requirements for an Ex product.

4. Hazardous Area Classification

Hazardous area classification is one of the most important steps in determining which explosion-protection requirements apply to a product.

The basic principle is straightforward: the more likely an explosive atmosphere is to be present, and the longer it can remain present, the higher the level of protection required from equipment installed in that area.

For gases and vapors, the internationally established classification uses Zones 0, 1 and 2. For combustible dust, the corresponding classification uses Zones 20, 21 and 22. IEC 60079-10-1 covers the classification of areas where explosive gas atmospheres may occur, while IEC 60079-10-2 addresses explosive dust atmospheres.

4.1 Gas and Vapor Zones

Zone 0

An area in which an explosive gas atmosphere is present continuously, for long periods or frequently.

Typical examples can include the inside of tanks, vessels or process equipment where flammable liquids or gases are present.

Zone 1

An area in which an explosive gas atmosphere is likely to occur occasionally during normal operation.

Examples can include areas around filling points, process equipment, valves or connections where the release of a flammable substance can occur during normal operation.

Zone 2

An area in which an explosive gas atmosphere is not likely to occur during normal operation, but, if it does occur, will exist only for a short period.

Examples can include areas surrounding equipment where an accidental leak could release a flammable gas or vapor.

The distinction between Zones 0, 1 and 2 is therefore primarily based on how likely the explosive atmosphere is to occur and how long it can persist.

4.2 Combustible Dust Zones

Dust hazards use a different numbering system:

Zone 20

An area in which an explosive dust atmosphere is present continuously, for long periods or frequently.

This can occur, for example, inside equipment where combustible dust is continuously present.

Zone 21

An area in which an explosive dust atmosphere is likely to occur occasionally during normal operation.

Examples can include areas where dust is routinely released during filling, emptying or processing.

Zone 22

An area in which an explosive dust atmosphere is not likely to occur during normal operation, but, if it does occur, will exist only for a short period.

Dust layers are also important because accumulated combustible dust can become a source for an explosive dust atmosphere. The current IEC 60079-10-2:2026 specifically addresses both explosive dust clouds and combustible dust layers when classifying areas.

4.3 Gas Zones vs. Dust Zones

The two classification systems should not be confused:

Hazard	Zone	Meaning
Gas / vapor	Zone 0	Explosive atmosphere continuously, frequently or for long periods
Gas / vapor	Zone 1	Likely to occur occasionally in normal operation
Gas / vapor	Zone 2	Not likely in normal operation; short duration if it occurs
Dust	Zone 20	Explosive dust atmosphere continuously, frequently or for long periods
Dust	Zone 21	Likely to occur occasionally in normal operation
Dust	Zone 22	Not likely in normal operation; short duration if it occurs

The numbers should therefore not be interpreted as a simple scale where Zone 2 is automatically “twice as safe” as Zone 1. They identify different hazardous-area classifications.

4.4 Why the Zone Matters for the Product

The zone classification directly affects the equipment that can be installed in the area.

For example, a product suitable for Zone 2 cannot simply be installed in Zone 1 because both areas involve gases or vapors.

The equipment must provide a protection level appropriate for the hazards of the intended installation area.

This is why a manufacturer needs to know the intended installation zone before determining the applicable explosion-protection requirements.

4.5 Gas and Dust Properties Also Matter

The zone alone is not sufficient to determine the complete product requirements.

For gases and vapors, additional characteristics can include:

• Gas group
• Ignition temperature
• Required temperature class
• Other properties relevant to ignition risk

For combustible dust, relevant characteristics can include:

• Dust group
• Ignition characteristics
• Layer ignition temperature
• Cloud ignition temperature
• Other material-specific properties

These characteristics influence the selection of suitable equipment and its protection concept.

4.6 The Hazardous Area Is Determined by the Installation, Not the Product

An important distinction is that the zone describes the environment, not the product.

The plant operator or responsible engineering organization determines the hazardous-area classification based on factors such as:

• The substances present
• Sources of release
• Release frequency
• Release duration
• Ventilation
• Operating conditions
• Process design

The equipment manufacturer then needs to ensure that the product is suitable for the intended classified area.

This creates a direct relationship:

Hazardous substance → Release conditions → Area classification → Equipment requirements

Understanding this relationship is essential before selecting an Ex product or determining its certification route.

4.7 Zones Are Only One Part of the Assessment

A zone classification does not, by itself, provide all the information needed to select equipment.

The final assessment may also need to consider:

• Gas or dust group
• Temperature class
• Equipment Protection Level (EPL)
• Type of protection
• Ambient temperature
• Electrical characteristics
• Mechanical characteristics
• Intended installation and operating conditions

The next chapter focuses on ATEX in Europe and explains how these hazardous-area classifications are translated into European equipment categories, conformity-assessment procedures and market-access requirements.

5. ATEX in Europe

In the European Union, explosion protection for products intended for potentially explosive atmospheres is primarily governed by Directive 2014/34/EU, commonly known as the ATEX Equipment Directive.

ATEX is not a single test or certification. It is a European regulatory framework that defines requirements for equipment and protective systems intended for use in potentially explosive atmospheres.

A separate ATEX directive, 1999/92/EC, addresses the protection of workers who may be exposed to explosive atmospheres in the workplace. The two directives therefore address different responsibilities.

5.1 ATEX 2014/34/EU – Equipment and Protective Systems

Directive 2014/34/EU applies to equipment and protective systems intended for use in potentially explosive atmospheres.

It covers:

• Electrical equipment
• Non-electrical equipment
• Protective systems
• Safety devices
• Controlling devices
• Regulating devices
• Components intended for incorporation into relevant equipment

The directive establishes the essential health and safety requirements that products must meet before they can be placed on the EU market for the intended application.

5.2 ATEX 1999/92/EC – Workplace Requirements

Directive 1999/92/EC has a different purpose.

It addresses the minimum requirements for improving the health and safety protection of workers potentially at risk from explosive atmospheres.

Among other things, it requires employers to assess explosion risks and classify areas where explosive atmospheres may occur.

This distinction is important:

ATEX 2014/34/EU primarily concerns the product. ATEX 1999/92/EC primarily concerns the workplace and its operation.

A manufacturer therefore cannot determine the complete ATEX requirements for a product without considering the intended installation environment.

5.3 Manufacturer Responsibilities

When a product falls within the scope of ATEX 2014/34/EU, the manufacturer is responsible for demonstrating that the product complies with the applicable requirements.

Depending on the equipment and category, this can involve:

• Identifying the applicable ATEX category
• Applying the relevant harmonized standards
• Performing the required technical assessment
• Carrying out or arranging the necessary testing
• Involving a Notified Body where required
• Preparing the technical documentation
• Preparing the EU Declaration of Conformity
• Applying the CE marking
• Applying the required explosion-protection marking

The exact conformity-assessment procedure depends on the equipment group and category.

5.4 Notified Bodies

For many ATEX products, conformity assessment cannot be completed solely by the manufacturer.

A Notified Body may need to assess the product, documentation or quality system depending on the applicable conformity-assessment procedure.

For higher-risk equipment categories, third-party involvement is generally required before the product can be placed on the EU market.

The manufacturer should therefore determine the applicable category and conformity-assessment route before testing and certification are planned.

5.5 CE Marking and EU Declaration of Conformity

ATEX products that fall within the applicable scope must meet the relevant conformity requirements before being placed on the EU market.

The manufacturer must prepare an EU Declaration of Conformity stating that the product complies with the applicable Union legislation.

The product must also bear the CE marking.

For ATEX products subject to notified-body involvement, the identification number of the relevant Notified Body is placed after the CE marking.

For example:

CE 0123

The number identifies the Notified Body involved in the applicable conformity-assessment procedure.

5.6 ATEX Categories

ATEX classifies equipment according to its intended level of protection.

For equipment in Group II, which covers equipment intended for use in areas other than mines, the main categories are:

• Category 1 – very high level of protection
• Category 2 – high level of protection
• Category 3 – normal level of protection

These categories are linked to the likelihood of an explosive atmosphere being present.

The relationship is broadly:

ATEX Category	Typical Gas Zone	Typical Dust Zone
Category 1	Zone 0	Zone 20
Category 2	Zone 1	Zone 21
Category 3	Zone 2	Zone 22

The exact suitability of a product must always be determined from its complete certification and marking rather than from the category alone.

5.7 Group I and Group II Equipment

ATEX also distinguishes between two main equipment groups:

Group I
Equipment intended for use in mines and parts of surface installations of mines where there is a risk of firedamp and/or combustible dust.

Group II
Equipment intended for use in other places where explosive atmospheres may occur, such as chemical plants, refineries, manufacturing facilities and other industrial environments.

For most manufacturers of conventional industrial electrical and electronic products, Group II is the relevant category.

5.8 ATEX Is Product-Specific

ATEX compliance is not simply a general approval for a company or product family.

The assessment is based on the specific product, its intended use, its protection concept and its intended hazardous environment.

Changes to a product can therefore affect its ATEX assessment.

Examples include:

• Changes to electronic components
• Changes to enclosure materials
• Changes to motors or other heat-generating components
• Changes to software or control functions where safety is affected
• Changes to operating temperature
• Changes to the protection concept
• Integration of a new wireless module

Manufacturers should therefore consider ATEX requirements early in the product-development process.

5.9 What ATEX Means for Market Access

For manufacturers selling products in Europe, ATEX can therefore become an additional regulatory layer on top of other applicable legislation.

For example, an electrical wireless device intended for a hazardous area may need to address:

• ATEX
• Radio requirements
• EMC requirements
• Electrical safety
• RoHS
• Other product-specific legislation

The exact combination depends on the product.

This is particularly important for complex products because ATEX does not replace the other regulatory requirements that may apply.

The next chapter explains how ATEX equipment categories, protection levels and markings are used to identify exactly where and under which conditions an Ex product can be used.

6. ATEX Marking, Equipment Protection Levels and Protection Types

ATEX products carry specific markings that provide information about where the equipment can be used and against which type of explosion hazard it is protected.

For manufacturers and users, understanding the marking is essential. An Ex marking is not simply a label indicating that a product is “explosion-proof.” It contains structured information about the equipment group, category, atmosphere, protection concept and other relevant characteristics.

6.1 Typical ATEX Marking

A typical ATEX marking may look like:

II 2G Ex db IIC T4 Gb

Each part provides specific information.

Marking	Meaning
II	Equipment Group II – non-mining applications
2	Equipment Category 2
G	Gas, vapor or mist
Ex	Explosion-protected equipment
db	Type of protection: flameproof enclosure
IIC	Gas Group IIC
T4	Temperature Class T4
Gb	Equipment Protection Level for gas atmospheres

The complete marking must be interpreted as a whole. Individual elements cannot normally be considered independently.

6.2 Equipment Protection Level (EPL)

The Equipment Protection Level (EPL) provides another way of expressing the level of protection provided by equipment.

For gas atmospheres, the main EPLs are:

• Ga – very high protection
• Gb – high protection
• Gc – enhanced protection

For dust atmospheres:

• Da – very high protection
• Db – high protection
• Dc – enhanced protection

There is also Ma and Mb for mining applications.

The EPL is linked to the hazardous area classification and the required level of protection.

For example:

Hazardous Area	Typical Minimum EPL
Zone 0	Ga
Zone 1	Gb
Zone 2	Gc
Zone 20	Da
Zone 21	Db
Zone 22	Dc

The actual suitability must always be determined from the complete equipment marking and certification.

6.3 Types of Explosion Protection

ATEX equipment can use different protection concepts depending on its design.

Common protection types include:

Ex d – Flameproof Enclosure

The enclosure is designed to withstand an internal explosion and prevent the flame from propagating to the surrounding explosive atmosphere.

This protection concept is commonly used for motors, switches, control equipment and other electrical equipment.

Ex e – Increased Safety

The equipment is designed so that under normal operation, and under specified abnormal conditions, the likelihood of sparks, arcs and excessive temperatures is minimized.

It is commonly used for components such as terminals, junction boxes and motors.

Ex i – Intrinsic Safety

Electrical circuits are designed so that the electrical and thermal energy available is limited to a level that cannot ignite the specified explosive atmosphere.

Intrinsic safety is particularly common for instrumentation, sensors and measurement circuits.

Ex p – Pressurization

A protective gas is used to maintain a pressure inside the enclosure that prevents the surrounding explosive atmosphere from entering.

This approach can be used for larger electrical or electronic equipment that would otherwise be difficult to protect using conventional methods.

Ex t – Protection by Enclosure

This protection concept is primarily used for equipment exposed to combustible dust.

The enclosure prevents dust from entering in a way that could create an ignition risk and controls the maximum surface temperature.

These are only some of the available protection concepts. The applicable protection type depends on the product design and intended application.

6.4 Gas Groups

For equipment intended for gas atmospheres, gases are divided into groups according to their ignition characteristics.

For Group II equipment, the main gas groups are:

• IIA
• IIB
• IIC

IIC represents the most demanding of these three groups.

A product certified for IIC can generally be used for applications covered by the less demanding IIA and IIB groups, provided all other requirements are also satisfied.

The reverse is not true: equipment certified only for IIA cannot automatically be used in an IIC atmosphere.

6.5 Temperature Classes

The temperature class defines the maximum surface temperature of equipment for gas applications.

The commonly used classes are:

Temperature Class	Maximum Surface Temperature
T1	450 °C
T2	300 °C
T3	200 °C
T4	135 °C
T5	100 °C
T6	85 °C

The equipment’s maximum surface temperature must remain below the ignition temperature relevant to the hazardous substance.

A T6 product therefore has a lower maximum surface temperature than a T4 product.

Temperature class is particularly important for equipment containing heating elements, power electronics, motors or other components that can become hot during operation.

6.6 Dust Marking

Dust-protected equipment uses a different marking structure.

A typical marking could be:

II 2D Ex tb IIIC T135°C Db

Here:

• II = Equipment Group II
• 2D = Category 2 for dust
• Ex tb = Protection by enclosure
• IIIC = Dust Group IIIC
• T135°C = Maximum surface temperature
• Db = Equipment Protection Level

Dust equipment therefore does not use the gas temperature classes T1–T6 in the same way. Instead, the maximum surface temperature is normally stated directly.

6.7 Why the Marking Matters for Manufacturers

The ATEX marking is the result of the product’s technical assessment.

It determines whether the equipment is suitable for the intended application and provides users with the information required to select the correct equipment for a hazardous area.

For manufacturers, this means that the marking should not be selected simply because a particular category or protection type appears desirable.

The marking must accurately reflect:

• The equipment design
• The protection concept
• The certified configuration
• The applicable gas or dust group
• The temperature limitations
• The permitted hazardous area
• The applicable EPL

Incorrect marking can result in a product being unsuitable for its intended installation even if the underlying product appears technically functional.

6.8 ATEX Certification Is More Than a Test Report

For many products, ATEX conformity involves considerably more than simply performing an electrical or environmental test.

Depending on the equipment category and conformity-assessment procedure, the process can involve:

• Product design assessment
• Ignition-risk assessment
• Applicable standards
• Laboratory testing
• Technical documentation
• Quality-system requirements
• Notified Body assessment
• EU Declaration of Conformity
• Product marking

The exact process depends on the equipment category and protection concept.

For manufacturers, determining the correct route before testing begins is therefore critical.

The next chapter looks at the European standards used for ATEX and explosion-protected equipment, including the IEC 60079 series and standards for non-electrical equipment.

7. European Standards for Explosion Protection

ATEX defines the legal requirements for products placed on the EU market, but it does not itself provide all the detailed technical requirements for designing and testing Ex equipment.

For this purpose, manufacturers rely heavily on the IEC 60079 series and related standards. In Europe, many of these standards are adopted as EN IEC 60079 standards and can be used to demonstrate conformity with the essential requirements of the ATEX Directive when the relevant edition is harmonized under the applicable EU framework.

The standards are therefore an important bridge between the legal requirements of ATEX and the actual technical design and testing of a product.

7.1 IEC 60079 – The Core Ex Standard Series

The IEC 60079 series is the central international family of standards for equipment used in explosive atmospheres. The series covers equipment design, different types of protection, area classification, installation, inspection and maintenance.

The series contains many individual parts. Manufacturers normally use only the parts relevant to their particular product and protection concept.

Some of the most important standards are:

Standard	Main purpose
IEC 60079-0	General requirements for Ex equipment
IEC 60079-1	Flameproof enclosure “d”
IEC 60079-2	Pressurized enclosure “p”
IEC 60079-5	Powder filling “q”
IEC 60079-6	Liquid immersion “o”
IEC 60079-7	Increased safety “e”
IEC 60079-10-1	Classification of areas – explosive gas atmospheres
IEC 60079-10-2	Classification of areas – combustible dust atmospheres
IEC 60079-11	Intrinsic safety “i”
IEC 60079-14	Electrical installations – design, selection and installation
IEC 60079-17	Inspection and maintenance
IEC 60079-18	Encapsulation “m”
IEC 60079-26	Equipment with Equipment Protection Level (EPL) Ga
IEC 60079-28	Protection of equipment and transmission systems using optical radiation
IEC 60079-29	Gas detection and measurement equipment
IEC 60079-31	Protection by enclosure “t” for dust

The IEC series continues well beyond these parts. The applicable standards depend on the product and its intended protection concept.

IEC has published a new IEC 60079-0:2026, which replaces the 2017 edition and provides updated general requirements for construction, testing and marking of Ex equipment and components. (IEC Webstore)

7.2 EN IEC 60079 in Europe

For European products, manufacturers will commonly encounter standards designated as EN IEC 60079.

These are European adoptions of the corresponding IEC standards, sometimes with European modifications or additional requirements.

However, an important distinction must be made:

Having an IEC or EN IEC standard available does not automatically mean that the standard is harmonized under the ATEX Directive.

For demonstrating conformity with EU legislation, manufacturers need to consider the applicable harmonized standards and their current status.

This is particularly important when a new edition of an IEC standard has been published. The newest international edition is not automatically the edition that should be used for an ATEX conformity assessment.

7.3 Standards for Non-Electrical Equipment

Explosion protection also applies to equipment without electrical components.

For non-electrical Ex equipment, two particularly important standards are:

• ISO 80079-36 – Basic method and requirements for non-electrical equipment
• ISO 80079-37 – Non-electrical types of protection, including constructional safety “c”, control of ignition sources “b” and liquid immersion “k”

ISO 80079-36 provides the basic methodology and requirements for the design, construction, testing and marking of non-electrical Ex equipment that has its own potential ignition sources. (ISO)

ISO 80079-37 specifies requirements for the corresponding non-electrical protection concepts c, b and k. (ISO)

Both standards are currently undergoing revision, so manufacturers should verify the applicable edition and regulatory status before using them for a conformity assessment. (ISO)

7.4 Standards Depend on the Protection Concept

There is therefore no single “ATEX standard” that applies to every product.

The applicable standards depend on the product design.

For example:

• A product using flameproof enclosure → IEC 60079-1
• A product using intrinsic safety → IEC 60079-11
• A product using increased safety → IEC 60079-7
• A product using encapsulation → IEC 60079-18
• A dust-protected product using an enclosure → IEC 60079-31
• A non-electrical product → ISO 80079-36/-37, depending on the design

In practice, a product may also need to comply with IEC 60079-0 together with one or more specific protection standards.

7.5 Installation Standards Are Different from Product Standards

Another important distinction is between product standards and installation standards.

For example, IEC 60079-14 deals primarily with the design, selection and installation of electrical installations in hazardous areas.

It is therefore highly relevant to the safe use of Ex equipment, but it is not itself the product certification standard for every Ex device.

Similarly, IEC 60079-17 addresses inspection and maintenance of electrical installations in hazardous areas.

Manufacturers should therefore distinguish between:

Product design → Product standards → Conformity assessment

and

Installation → Installation standards → Safe use in the facility

This prevents installation requirements from being confused with the requirements for placing an Ex product on the market.

7.6 Choosing the Correct Standards

For a manufacturer, the standards selection should therefore follow the product and its intended application rather than simply using the complete IEC 60079 series.

A typical assessment can be structured as:

Product → Hazardous atmosphere → Zone → Required EPL/category → Protection concept → Applicable standards → Testing and conformity assessment

This approach helps avoid unnecessary testing while ensuring that all relevant ignition risks are addressed.

The next chapter looks at North America, where explosion protection follows a fundamentally different regulatory and certification approach from the European ATEX system.

8. Explosion Protection in North America: USA and Canada

For manufacturers planning to sell Ex products in the United States or Canada, one point is important from the outset:

The North American system is not simply the US or Canadian version of ATEX.

The fundamental objective is the same — preventing equipment from igniting an explosive atmosphere — but hazardous-area classification, regulations, certification and marking differ significantly from the European ATEX system.

8.1 USA – Hazardous Locations

In the United States, hazardous locations have traditionally been classified using the Class/Division system.

The main classes are:

• Class I – flammable gases and vapors
• Class II – combustible dust
• Class III – ignitable fibers and flyings

For Class I and Class II, the Division system is used:

• Division 1 – a hazardous atmosphere may exist under normal operating conditions or occur frequently
• Division 2 – a hazardous atmosphere is not normally present but may occur under abnormal conditions

The US regulations also recognize the international Zone system for Class I locations, using Zones 0, 1 and 2.

This means that two classification systems can be encountered in the United States:

System	Typical classification
Class/Division	Class I Div. 1 / Div. 2
Class/Zone	Class I Zone 0 / Zone 1 / Zone 2

This distinction is important because product requirements can depend on which classification system and which specific hazardous location the equipment is intended for.

8.2 The Three US Hazardous-Location Classes

Class I – Gases and Vapors

Class I covers locations where flammable gases or vapors may be present.

Typical examples include:

• Refineries
• Tank farms
• Fuel stations
• Chemical plants
• Paint and coating facilities
• Areas containing flammable solvents

Class II – Combustible Dust

Class II covers locations where combustible dust can create a fire or explosion hazard.

Examples include:

• Grain processing
• Food processing
• Plastics manufacturing
• Wood processing
• Metal processing
• Facilities handling aluminum or magnesium dust

Class III – Fibers and Flyings

Class III covers locations where easily ignitable fibers or flyings may be present.

This can be relevant, for example, in certain areas of:

• Textile manufacturing
• Wood processing
• Paper processing

The US classification system therefore explicitly distinguishes between these three types of hazards.

8.3 Division 1 and Division 2

For Class I and Class II, the distinction between Division 1 and Division 2 is particularly important.

Division 1 generally means that a hazardous concentration may exist under normal operating conditions or occur relatively frequently.

Division 2 means that the hazardous material is normally contained within closed systems and would only be released in the event of a leak, malfunction or other abnormal operating condition.

Equipment approved for Class I, Division 1 may, under the applicable conditions, also be suitable for a corresponding Class I, Division 2 application. The reverse is not automatically true.

8.4 USA – NEC and OSHA

The technical requirements for electrical equipment and installations in hazardous locations are closely connected to the National Electrical Code (NEC), NFPA 70.

OSHA requires electrical equipment and installations in classified locations to be suitable for the specific hazard. The NEC provides the corresponding technical requirements.

For manufacturers, the basic logic is therefore:

Hazardous Location → Class/Division or Zone → Permitted protection method → Appropriate product certification

The product approval must match the intended installation.

8.5 Typical US Protection Concepts

Depending on the classification, different protection concepts may be used.

Examples include:

• Explosionproof
• Intrinsically Safe
• Nonincendive
• Dust-Ignitionproof
• Dust-Tight
• Purged and Pressurized
• Hermetically Sealed

The permitted protection method depends on the specific hazardous location and the product design.

8.6 UL and Other US Certifications

The US system is also different from the European CE approach.

There is no general “UL certification for ATEX.” Instead, a product is evaluated against the applicable US standards for its intended application and certified by an appropriately recognized certification body.

Important US standards for hazardous-location equipment can include:

Standard	Application
UL 1203	Explosion-Proof and Dust-Ignition-Proof Electrical Equipment
UL 913	Intrinsically Safe Apparatus and Associated Apparatus
UL 121201	Nonincendive Electrical Equipment for certain Hazardous Locations
UL 60079-0	General requirements for Ex equipment
UL 60079-11	Intrinsic Safety “i”
UL 60079-15	Protection type “n”
UL 60079-18	Encapsulation “m”
UL 60079-25	Intrinsically Safe Electrical Systems
UL 60079-26	Equipment for Class I, Zone 0
UL 60079-28	Protection using optical radiation
UL 60079-31	Protection by enclosure “t” for dust

The applicable standard depends on the product and its intended protection concept.

UL 1203 and UL 913 are therefore not simply “the two US Ex standards.” They cover specific types of equipment and protection concepts. Products assessed under the Zone system may instead use standards from the UL 60079 series.

8.7 Canada – Canadian Electrical Code

Canada has a similar but separate regulatory system.

A central basis is the Canadian Electrical Code (CE Code), CSA C22.1. For hazardous locations, it includes requirements in Section 18 and Appendix J.

Canada also uses both:

• The Class/Division system
• The Zone system

For manufacturers, this means that a US certification does not automatically replace Canadian certification.

8.8 CSA and Canadian Certification

CSA standards and Canadian certification bodies play an important role in the Canadian market.

Depending on the product, standards from the CSA C22.2 series or Canadian-adopted IEC standards may apply.

Examples include:

• CSA C22.2 No. 30 – Explosion-Proof Equipment
• CSA C22.2 No. 213 – Nonincendive Electrical Equipment
• Relevant CSA/IEC 60079 standards for different Ex protection concepts

Again, the correct standard depends on the product, protection concept and intended hazardous location.

8.9 USA and Canada Are Not Simply “UL/CSA”

A common mistake is to reduce the North American market to:

“UL for the USA and CSA for Canada.”

In reality, the process should start with determining:

Which hazardous location?

→ Class I / II / III
→ Division or Zone
→ Gas, dust or fiber hazard
→ Required protection concept
→ Applicable product standard
→ Required certification body
→ Required marking

Only then can the appropriate certification route be determined.

8.10 Europe vs. North America

The fundamental systems can be summarized as follows:

Europe	USA / Canada
ATEX 2014/34/EU	National/regional regulations and electrical codes
Zone 0 / 1 / 2	Class I Division 1 / 2 or Zone 0 / 1 / 2
Zone 20 / 21 / 22	Class II Division 1 / 2
ATEX Categories	Hazardous-location classifications
EPL Ga / Gb / Gc	Different markings and protection concepts depending on the system
EN IEC 60079	UL / CSA / ANSI / IEC-based standards
CE + Ex marking	Product certification/listing and applicable marking
EU Declaration of Conformity	Certification by an appropriately recognized body, depending on the application

The systems have the same fundamental objective, but they are not automatically interchangeable.

An ATEX certificate therefore does not automatically mean that a product can be installed in the USA or Canada. Likewise, a North American hazardous-location certification does not automatically establish ATEX compliance for Europe.

The next chapter examines IECEx and its role as an international certification system alongside the European and North American approaches.

9. IECEx – International Certification for Ex Equipment

IECEx is an international certification system for equipment intended for use in explosive atmospheres. It is based primarily on the IEC 60079 series and related international standards.

Unlike ATEX, IECEx is not an EU directive or law. It is a voluntary international certification system that can support market access in countries that recognize or use IECEx-based certification.

9.1 What is IECEx?

The IECEx System is operated by the International Electrotechnical Commission (IEC) and provides a common framework for evaluating and certifying Ex equipment.

The objective is to reduce the need for completely different technical evaluations in every country by using internationally agreed standards and certification procedures.

IECEx certification can cover:

• Electrical Ex equipment
• Non-electrical Ex equipment
• Ex components
• Equipment protection systems
• Service facilities
• Personnel competence

For manufacturers, the most relevant part is generally the IECEx Certified Equipment Scheme.

9.2 IECEx and ATEX

IECEx and ATEX are closely related but are not the same system.

The main difference is:

ATEX	IECEx
European legal framework	International certification system
Required for products within the applicable ATEX scope placed on the EU market	Generally voluntary, depending on the target market
Based on EU legislation and applicable harmonized standards	Based primarily on IEC standards
CE + Ex marking	IECEx certification and IECEx marking
EU Declaration of Conformity	IECEx Certificate of Conformity

The technical requirements can be very similar because both systems rely heavily on the IEC 60079 family of standards.

However, an IECEx certificate does not automatically replace ATEX compliance when a product is placed on the EU market.

9.3 IECEx Certificate of Conformity

The central document for certified equipment is the IECEx Certificate of Conformity (CoC).

It identifies important characteristics of the certified equipment, including:

• Manufacturer
• Product type
• Applicable standards
• Protection concept
• Ex marking
• Equipment Protection Level
• Certificate conditions
• Approved product configuration

The certificate is issued by an IECEx-approved Certification Body (ExCB) based on the required assessment and testing.

The associated testing is performed by an IECEx-approved Ex Testing Laboratory (ExTL).

9.4 IECEx Scheme and Quality Assessment

IECEx certification is not limited to testing the physical product.

Depending on the certification route, the manufacturer’s production arrangements and quality system are also assessed.

This is particularly important because Ex certification depends on the manufacturer continuing to produce the product in accordance with the certified design.

The IECEx system therefore includes mechanisms for:

• Product testing
• Technical documentation assessment
• Quality-system assessment
• Ongoing surveillance

This helps ensure that certified products remain consistent with the configuration that was originally assessed.

9.5 Where IECEx Is Relevant

IECEx is particularly useful for manufacturers targeting multiple international markets.

Countries and regions may recognize IECEx certification directly, use it as part of their national approval process, or base their national requirements on IEC standards.

This can make IECEx an efficient starting point for products intended for global deployment.

However:

IECEx recognition is country-specific.

A manufacturer should therefore always verify the actual national requirements before assuming that an IECEx certificate alone is sufficient for market access.

9.6 IECEx Does Not Eliminate National Requirements

Even when a country recognizes IECEx certification, additional requirements may still apply.

These can include:

• National registration
• Local certification
• Import requirements
• Local representative requirements
• National electrical codes
• Installation requirements
• Additional documentation
• Language requirements

IECEx should therefore be viewed as a global certification framework, not as a universal replacement for every national approval.

9.7 Why IECEx Matters for Manufacturers

For a manufacturer developing an Ex product for several markets, the combination of IECEx + national requirements can provide a more structured international certification strategy.

Instead of developing completely different technical solutions for Europe, Asia, the Middle East and other markets, manufacturers can often use a common IEC-based technical foundation and then address the additional national requirements where necessary.

This is particularly valuable for products such as:

• Industrial sensors
• Instrumentation
• Wireless devices
• Motors
• Control equipment
• Lighting
• Process equipment
• Industrial automation products

The next chapter examines how Ex certification is actually carried out, from the initial product assessment through testing, documentation, certification and marking.

10. The Ex Certification Process – From Product Assessment to Approval

Ex certification does not start with laboratory testing. The most important step is first to assess the product and its intended use.

Only once it is clear which hazardous areas the product is intended for and which protection concept is used can the applicable standards, tests and conformity assessment procedure be determined.

A typical process can be summarized as:

Product definition → Ignition hazard assessment → Classification → Protection concept → Standards → Testing → Conformity assessment → Documentation → Certification → Marking

10.1 Step 1 – Product and Intended Use

First, the product and its intended application must be defined.

Relevant characteristics may include:

• Electrical or non-electrical product
• Power supply
• Power consumption
• Operating temperatures
• Potential heat sources
• Moving components
• Electronic circuits
• Enclosure design
• Materials used
• Intended environment

The intended operating conditions are also critical.

A product designed for a non-hazardous industrial environment may not require Ex protection. The same product may require an Ex assessment if it is intended for use in a hazardous area.

10.2 Step 2 – Identify Potential Ignition Sources

The next step is to determine whether the product itself can represent a potential ignition source.

Potential ignition sources can include:

• Hot surfaces
• Electrical sparks
• Arcs
• Electrostatic discharges
• Mechanical sparks
• Friction
• Hot gases
• Electrical or thermal energy
• Mechanical movement

This assessment is particularly important for non-electrical equipment, where mechanical components can also create potential ignition sources.

The objective is to identify all relevant ignition sources and prevent them from igniting an explosive atmosphere through appropriate protection measures.

10.3 Step 3 – Determine the Intended Zone and Protection Level

The manufacturer then determines the hazardous area for which the product is intended.

For example:

• Zone 0 → very high level of protection
• Zone 1 → high level of protection
• Zone 2 → enhanced level of protection

For dust atmospheres:

• Zone 20
• Zone 21
• Zone 22

This determines, among other things, the required Equipment Protection Level (EPL) and corresponding ATEX category.

The zone classification is not simply selected by the manufacturer. It is based on the intended installation and the likelihood of an explosive atmosphere being present.

10.4 Step 4 – Select the Protection Concept

Based on the product design and required protection level, an appropriate protection concept is selected.

Depending on the product, this may include:

• Ex d – Flameproof enclosure
• Ex e – Increased safety
• Ex i – Intrinsic safety
• Ex m – Encapsulation
• Ex p – Pressurized enclosure
• Ex t – Protection by enclosure
• Ex c – Constructional safety for non-electrical equipment

A product may also combine several protection concepts.

The choice of protection concept is a technical design decision and determines which standards and tests will subsequently apply.

10.5 Step 5 – Determine the Applicable Standards

Only at this stage can the relevant standards be properly identified.

Depending on the product, these may include:

• IEC/EN IEC 60079-0 – General requirements
• IEC/EN IEC 60079-1 – Ex d
• IEC/EN IEC 60079-7 – Ex e
• IEC/EN IEC 60079-11 – Ex i
• IEC/EN IEC 60079-18 – Ex m
• IEC/EN IEC 60079-31 – Ex t
• ISO 80079-36/-37 – Non-electrical Ex equipment

The actual standards depend on the product and its protection concept.

10.6 Step 6 – Technical Assessment and Testing

The product is then assessed against the requirements of the applicable standards.

Depending on the product, testing may include:

• Temperature tests
• Pressure tests
• Impact and drop tests
• IP protection
• Insulation and dielectric-strength tests
• Creepage and clearance requirements
• Ignition protection tests
• Material tests
• Electrostatic tests
• Mechanical tests
• Fault-condition testing

Not every product requires all of these tests.

The test program is derived from the specific characteristics of the product and the selected protection concept.

10.7 Step 7 – Conformity Assessment Procedure

At the same time, the required conformity assessment procedure must be established.

For ATEX, this depends particularly on:

• Equipment group
• Equipment category
• Product type
• Protection concept

For certain ATEX categories, a Notified Body is required, while for other products the manufacturer may be able to perform the conformity assessment under the applicable procedure.

For higher protection categories, involvement of a Notified Body is typically mandatory.

10.8 Step 8 – Technical Documentation

The technical documentation must demonstrate that the product meets the applicable requirements.

Depending on the product, this can include:

• Product description
• Engineering drawings
• Circuit diagrams
• Bills of materials
• Component information
• Calculations
• Risk or ignition hazard assessment
• Test reports
• Standards list
• Operating instructions
• Marking information
• Certificates for relevant components

The documentation is not only important for the initial certification. It also provides the basis for assessing future product changes.

10.9 Step 9 – Certification

Where an external certification body is required, it evaluates the relevant documentation and technical results.

Depending on the certification system, this may result in documents such as:

• EU-Type Examination Certificate under ATEX
• IECEx Certificate of Conformity
• North American Hazardous Location certification

Following successful assessment, the product can be certified and marked accordingly.

10.10 Step 10 – Marking and Market Access

The required markings must then be applied to the product.

For a European ATEX product, for example, this may include:

CE marking + Ex marking + other required product information

IECEx and North American certifications have their own specific marking requirements.

The marking must correspond to the actual certified product configuration.

10.11 Changes After Certification

An Ex-certified product cannot subsequently be modified without considering the impact on the certification.

Changes to, for example:

• Enclosure
• Electronics
• Components
• Materials
• Thermal characteristics
• Software
• Power supply
• Radio modules

may affect the original assessment.

Before making a product change, it should therefore be determined whether the change is certification-relevant.

Depending on the change, a technical reassessment, certificate amendment or additional testing may be required.

10.12 The Key Principle for Manufacturers

The most important principle is:

Do not test first and determine the required certification afterward.

The correct sequence is:

Product → Application → Explosion hazard → Zone → Protection concept → Standards → Conformity assessment → Testing → Certification

An incorrect assessment at the beginning can result in testing against the wrong standards or a product that ultimately cannot be certified for the intended application.

For complex products involving radio, electronics, sensors or multiple integrated functions, Ex requirements should therefore be considered early in the product development process.

11. Ex Compliance for Products with Electronics, Wireless and Other Functions

Many modern products are no longer purely mechanical or purely electrical. They may combine electronics, sensors, wireless communication, batteries, displays, motors or other functions in a single product.

For these products, Ex compliance can become significantly more complex because every potential ignition source must be considered within the complete product.

11.1 Electronics Can Become an Ignition Source

Electronic components can create potential ignition sources through:

• Sparks or arcs
• Hot surfaces
• Switching components
• Fault conditions
• Stored electrical energy
• Short circuits
• Overheating
• Component failures

This does not mean that every electronic component requires its own Ex certification. The relevant question is whether the component contributes to an ignition hazard within the complete equipment.

11.2 Wireless Products

Wireless products require particular attention because they combine several potential sources of energy.

A wireless Ex product may contain:

• RF transmitter
• Antenna
• Power amplifier
• Battery
• Charging circuit
• Processor
• Display
• Sensors
• Connectors

The RF output itself may need to be considered as a potential ignition source, while the electronics and battery can introduce additional electrical and thermal hazards.

For this reason, a standard radio certification such as FCC, ISED or RED compliance does not automatically demonstrate Ex compliance.

These are separate regulatory questions:

Radio compliance

→ Does the radio transmitter comply with the applicable spectrum, EMC and radio requirements?

Ex compliance

→ Can the complete product safely operate in the specified explosive atmosphere without creating an ignition source?

A product may therefore need to satisfy both sets of requirements.

11.3 Batteries

Batteries are particularly important in Ex products.

Potential hazards include:

• Surface temperature
• Short circuits
• Internal faults
• Overcharging
• Thermal runaway
• Sparks during connection or disconnection
• Stored electrical energy

The battery, battery pack and charging system therefore need to be considered as part of the overall ignition hazard assessment.

A commercially available battery with general safety certification is not automatically suitable for an Ex product.

The complete combination of battery, electronics, enclosure and protection concept must be evaluated.

11.4 Displays, Connectors and User Interfaces

Components that appear harmless in a conventional product can become relevant in an Ex environment.

Examples include:

• Displays
• Buttons
• Switches
• USB ports
• Charging connectors
• LEDs
• External terminals
• Mechanical interfaces

Depending on their construction, these components may introduce electrical, thermal or electrostatic ignition hazards.

The design must therefore consider not only the internal electronics but also how the user interacts with the product.

11.5 Antennas and RF Energy

For wireless products, the antenna and RF output require specific consideration.

The assessment can involve:

• Transmit power
• Frequency
• Antenna type
• Antenna gain
• RF energy
• Distance to other conductive parts
• Surface temperature
• Fault conditions

The relevant assessment depends on the protection concept and applicable Ex standards.

This is especially important for products using technologies such as:

• Bluetooth
• Wi-Fi
• LoRa
• Cellular
• RFID
• UWB
• Proprietary industrial radio

The fact that a radio module is already certified for use in ordinary environments does not mean that it is automatically suitable for an Ex product.

11.6 Pre-Certified Components

Manufacturers sometimes use components that already have an Ex certificate.

This can significantly simplify product development, but it does not automatically transfer the component’s certification to the complete product.

The manufacturer must determine:

• Under which conditions the component is certified
• Which protection concept it uses
• Its permitted electrical parameters
• Its temperature range
• Its installation requirements
• Whether it can be used within the intended Ex equipment
• Whether the combination affects the overall certification

A certified Ex component therefore remains a component within the final product assessment.

11.7 Software and Firmware

Software normally does not constitute an ignition source by itself, but it can influence safety-relevant functions.

For example, software may control:

• Power limitation
• Temperature monitoring
• Battery charging
• Shutdown functions
• Motor control
• Fault detection

Where such functions are relied upon as part of the protection concept, their behavior under normal operation and foreseeable faults may need to be considered.

The importance of software therefore depends on how the product’s protection concept is implemented.

11.8 Combined Regulatory Requirements

A modern Ex product may therefore require several separate compliance assessments.

For example, a wireless industrial sensor intended for Europe could potentially involve:

ATEX

→ Explosion protection

RED

→ Radio equipment requirements

EMC

→ Electromagnetic compatibility

RoHS

→ Restriction of hazardous substances

Battery requirements

→ Where applicable

The exact combination depends on the product.

The important point is that Ex compliance does not replace the other regulatory requirements.

11.9 Why Early Scoping Is Important

For complex products, Ex requirements should be considered during the design phase rather than after the product has already been finalized.

A late Ex assessment can reveal issues such as:

• Insufficient creepage or clearance
• Excessive surface temperature
• Unsuitable enclosure
• Incorrect component selection
• Inadequate battery protection
• RF energy concerns
• Insufficient protection against electrostatic discharge
• Components that cannot be used in the intended Ex configuration

Correcting these issues after the design is complete can result in significant redesign, testing and certification costs.

A structured Ex scoping assessment at the beginning of the project can therefore reduce both technical and certification risks.

12. Understanding ATEX Marking

ATEX marking contains considerably more information than just the Ex symbol. It indicates the type of explosive atmosphere for which the equipment is intended and the level of protection provided.

For manufacturers, marking is therefore not merely a formal requirement. It must correspond to the actual product configuration that has been assessed and certified.

12.1 The Ex Symbol

The familiar symbol for explosion protection is:

Ex

It indicates that the product has been designed for use in an explosive atmosphere according to the relevant protection concept.

However, the symbol alone does not indicate where the product may be used.

The additional marking elements provide this information.

12.2 An Example of ATEX Marking

A typical marking could be:

II 2G Ex db IIC T4 Gb

Each element has a specific meaning:

Marking	Meaning
II	Equipment Group II – use outside mining
2G	Category 2 for gas atmospheres
Ex	Explosion protection
db	Protection type “d” with protection level “b”
IIC	Gas group IIC
T4	Temperature class T4
Gb	Equipment Protection Level

The marking must therefore be considered as a complete set of information. Individual elements cannot be interpreted independently.

12.3 Equipment Groups I and II

The ATEX framework essentially distinguishes between two equipment groups.

Equipment Group I

This group covers equipment intended for use in underground parts of mines and parts of surface installations of such mines that may be endangered by firedamp and/or combustible dust.

Equipment Group II

This group covers equipment intended for all other explosive atmospheres, for example:

• Chemical plants
• Refineries
• Manufacturing facilities
• Tank storage facilities
• Food-processing facilities

Most industrial Ex products outside mining therefore belong to Equipment Group II.

12.4 Equipment Categories

Within Equipment Group II, categories indicate the required level of protection.

For gas and vapor atmospheres, the relevant categories are:

• 1G
• 2G
• 3G

For dust atmospheres:

• 1D
• 2D
• 3D

In simplified terms:

Category	Gas	Dust	Typical application
1G / 1D	Very high protection	Very high protection	Zone 0 / 20
2G / 2D	High protection	High protection	Zone 1 / 21
3G / 3D	Enhanced protection	Enhanced protection	Zone 2 / 22

The category is therefore linked to the intended zone.

12.5 Gas or Dust – G and D

The letters indicate the type of explosive atmosphere for which the equipment is intended:

• G = Gas
• D = Dust

Equipment marked 2G is therefore intended for applicable gas or vapor atmospheres.

Equipment marked 2D is intended for applicable dust atmospheres.

Equipment can also be designed for both applications and carry corresponding markings for both.

12.6 Protection Type

The protection type follows the Ex symbol.

Examples include:

• Ex d → Flameproof enclosure
• Ex e → Increased safety
• Ex i → Intrinsic safety
• Ex m → Encapsulation
• Ex p → Pressurized enclosure
• Ex t → Protection by enclosure

This indicates how the equipment prevents a potential ignition source from igniting the explosive atmosphere.

12.7 Gas and Dust Groups

For gases, the gas group is also specified.

Typical groups are:

• IIA
• IIB
• IIC

IIC represents the most demanding of these three gas groups.

For dust, the following groups may apply:

• IIIA – combustible flyings
• IIIB – non-conductive combustible dust
• IIIC – conductive combustible dust

The grouping is important because different substances have different ignition and explosion characteristics.

12.8 Temperature Classes

For gas applications, a temperature class may also be specified:

Temperature class	Maximum surface temperature
T1	450 °C
T2	300 °C
T3	200 °C
T4	135 °C
T5	100 °C
T6	85 °C

The maximum surface temperature of the equipment must remain below the applicable ignition temperature of the substance.

The lower the temperature class, the lower the permitted maximum surface temperature.

For dust applications, maximum surface temperatures are specified differently and must take into account factors such as dust clouds and dust layers.

12.9 Equipment Protection Level – EPL

In addition to the ATEX category, the Equipment Protection Level (EPL) is commonly specified.

Typical EPLs for gas atmospheres are:

• Ga
• Gb
• Gc

For dust:

• Da
• Db
• Dc

The EPL describes the protection level of the equipment and is directly related to the intended hazardous area.

For example:

Ga → Zone 0

Gb → Zone 1

Gc → Zone 2

For dust:

Da → Zone 20

Db → Zone 21

Dc → Zone 22

EPL and ATEX category are related, but they are not identical. They originate from different classification systems and can appear together on the same product.

12.10 Why the Marking Matters

The marking allows operators and installers to determine whether a particular product is suitable for the intended hazardous area.

The following elements must be compatible:

Zone → Gas/Dust → Group → Temperature → EPL/Category → Protection type

For example, a product may be suitable for Zone 2 but still be unsuitable for a particular application because of its gas group or temperature class.

The assessment should therefore not stop at:

“Is the product ATEX certified?”

The more important question is:

“Is this specific marked product suitable for this exact hazardous-area application?”

This is why Ex marking is a central part of the technical assessment and safe use of Ex equipment.

13. Ex Components, Assemblies and Combined Equipment

Ex compliance becomes more complex when a product is not a single standalone device but a combination of components, modules or several pieces of equipment.

This is common in modern industrial products, where manufacturers integrate:

• Certified Ex components
• Radio modules
• Sensors
• Power supplies
• Batteries
• Displays
• Control electronics
• Connectors
• Motors
• Valves
• Mechanical components

A key principle is:

The certification of individual components does not automatically certify the complete assembly.

13.1 Ex Components vs. Complete Equipment

An Ex component is designed to be incorporated into other Ex equipment and is generally not intended to be used independently in the same way as complete certified equipment.

A component may have its own certificate and defined conditions of use.

When incorporated into a final product, the manufacturer must verify that:

• The component is used within its certified parameters
• Its installation conditions are respected
• The combination does not invalidate the protection concept
• The complete assembly meets the applicable requirements

The final product may therefore require its own conformity assessment or certification.

13.2 Combining Different Ex Protection Concepts

A product can contain several different protection concepts.

For example, a device could contain:

• An intrinsically safe sensor circuit
• An Ex e terminal compartment
• An Ex d enclosure
• An encapsulated power supply

The individual protection concepts must work together as part of the complete design.

The interfaces between them are particularly important.

Examples include:

• Electrical connections
• Cable entries
• Mechanical interfaces
• Thermal interfaces
• Pressure boundaries
• Grounding
• Isolation

A component that is compliant on its own may therefore still create a problem when integrated into a different configuration.

13.3 Cable Glands, Connectors and Other Accessories

Accessories can also be part of the Ex assessment.

Examples include:

• Cable glands
• Plugs
• Connectors
• Terminal blocks
• Switches
• Enclosure windows
• Breathers and drains

These components may have their own Ex certification and specified installation conditions.

The manufacturer must ensure that the selected accessories are compatible with:

• The enclosure
• The protection concept
• The cable type
• The temperature range
• The gas or dust group
• The intended zone

Incorrect selection of an otherwise certified accessory can compromise the protection of the complete product.

13.4 Assemblies and Systems

Some products are delivered as complete assemblies or systems rather than individual devices.

Examples include:

• Control panels
• Pump systems
• Sensor assemblies
• Motor systems
• Automated production equipment
• Battery-powered systems

In such cases, the assessment may need to consider the interaction between the individual components.

For example, integrating an Ex-certified motor into a larger machine does not automatically make the entire machine an Ex-certified assembly.

The manufacturer must determine which parts fall within the Ex assessment and which regulatory requirements apply to the complete product.

13.5 Combined Equipment with Non-Ex Components

Not every component inside an Ex product necessarily needs to be independently Ex-certified.

A non-Ex component may sometimes be used inside an Ex-protected assembly if the overall design prevents it from becoming an ignition source and the applicable requirements are fulfilled.

This depends entirely on the protection concept and the relevant standards.

The important question is therefore not simply:

“Is every component Ex-certified?”

but rather:

“Does the complete product provide the required level of explosion protection?”

13.6 Product Changes and Component Substitution

Component substitution is particularly important for certified Ex products.

Replacing a component with an apparently equivalent alternative can affect:

• Electrical parameters
• Temperature
• Creepage and clearance
• Mechanical strength
• Material properties
• IP protection
• Flame paths
• Intrinsic safety parameters
• RF characteristics

Even if the replacement component has its own Ex certification, the change may require a reassessment of the final product.

Manufacturers should therefore establish a formal change-control process for certified Ex products.

13.7 The Importance of the Certified Configuration

An Ex certificate applies to a defined product configuration.

This can include specific:

• Components
• Materials
• Dimensions
• Enclosures
• Electrical parameters
• Temperature ranges
• Accessories
• Installation conditions

The manufacturer cannot assume that every future product variant remains covered by the original certification.

Where a product family contains several variants, the certification documentation must clearly define which configurations are covered.

13.8 What Manufacturers Should Check

Before integrating a component into an Ex product, manufacturers should verify at least:

1. Is the component suitable for the intended protection concept?
2. Are its certified parameters compatible with the final design?
3. Are its installation conditions fulfilled?
4. Does the integration affect temperature, energy or mechanical protection?
5. Does the final configuration remain within the scope of the existing certification?
6. Is additional testing or certification required?

This is especially important for products that combine electronics, wireless modules, batteries and mechanical components.

The next chapter looks at the most important Ex standards, with a focus on the standards manufacturers are most likely to encounter in Europe, the USA and Canada.

14. The Most Important Ex Standards – Europe, USA and Canada

Explosion protection is covered by a large number of standards. Manufacturers do not normally need to apply the entire Ex standards library. The relevant standards depend on the product, the protection concept, the hazardous area and the target market.

The IEC 60079 series forms the central international standards framework for electrical equipment used in explosive atmospheres. IECEx itself lists IEC 60079 and related ISO standards as the basis for its certification system. (IECEx)

For manufacturers, the following standards are particularly important.

14.1 IEC 60079 – The International Core

The IEC 60079 series is the most important international standards family for Ex equipment.

Key standards include:

Standard	Main subject
IEC 60079-0	General requirements for Ex equipment
IEC 60079-1	Flameproof enclosures – Ex d
IEC 60079-2	Pressurized enclosures – Ex p
IEC 60079-7	Increased safety – Ex e
IEC 60079-10-1	Classification of areas – explosive gas atmospheres
IEC 60079-10-2	Classification of areas – explosive dust atmospheres
IEC 60079-11	Intrinsic safety – Ex i
IEC 60079-14	Design, selection and installation of electrical installations
IEC 60079-17	Inspection and maintenance
IEC 60079-18	Encapsulation – Ex m
IEC 60079-25	Intrinsically safe electrical systems
IEC 60079-26	Equipment with EPL Ga
IEC 60079-28	Protection using optical radiation
IEC 60079-29-0/-1/-2	Gas detection equipment
IEC 60079-31	Protection by enclosure – Ex t

The series also contains standards covering electrostatic hazards, trace heating, repair, special protection and other specialized applications. (IECEx)

The current IEC series continues to evolve. For example, IEC 60079-0:2026 was published in June 2026 and replaces the previous edition of IEC 60079-0. (IEC Webstore)

14.2 Europe – EN IEC 60079 and ATEX

In Europe, the IEC standards are adopted as European standards, typically appearing as EN IEC 60079-….

They provide the technical basis for demonstrating conformity with the applicable ATEX requirements.

However, manufacturers should distinguish between:

ATEX Directive 2014/34/EU

→ the legal framework for products

and

EN IEC 60079 series

→ the technical standards used to demonstrate compliance.

The European Commission maintains the current references of harmonized standards for ATEX and regularly updates the list published in the Official Journal of the European Union. (IMIES)

This distinction is important because using an IEC or EN standard does not by itself constitute ATEX certification. The applicable conformity assessment procedure must also be followed.

14.3 Non-Electrical Equipment – ISO 80079

Not all Ex equipment is electrical.

For mechanical equipment, two particularly important standards are:

• ISO 80079-36 – Basic method and requirements
• ISO 80079-37 – Non-electrical types of protection

ISO 80079-37 covers protection concepts including:

• Ex h / constructional safety
• Ex h / control of ignition sources
• Ex h / liquid immersion

These standards are particularly relevant for products such as pumps, gearboxes, mechanical drives, fans and other equipment where mechanical ignition sources must be controlled. (IECEx)

14.4 USA – NEC and UL Standards

The United States uses a different regulatory structure from Europe.

Hazardous locations are classified under the National Electrical Code (NFPA 70) using systems such as:

• Class I – Flammable gases and vapors
• Class II – Combustible dust
• Class III – Ignitable fibers and flyings

The traditional US system also uses:

• Division 1 / Division 2
• Gas and dust Groups

The US also supports the Zone classification system for certain applications.

For product certification, standards such as the following may be relevant:

• UL 1203 – Explosionproof and Dust-Ignitionproof Electrical Equipment
• UL 60079 series – US adoption of IEC 60079 standards
• Other product-specific UL standards depending on the equipment

UL 1203, for example, covers explosionproof and dust-ignitionproof electrical equipment for hazardous locations, including Class I and Class II locations and certain Zone applications. (Shop UL Standards)

Therefore, a manufacturer targeting the US must determine not only the technical Ex requirements but also which US classification and certification route applies to the specific product and installation.

14.5 Canada – CSA and Canadian Standards

Canada uses a similar but separate regulatory framework.

Important standards include the CSA C22.2 No. 60079 series, which adopts IEC 60079 standards with Canadian deviations where applicable.

Examples include:

• CSA C22.2 No. 60079-0 – General requirements
• CSA C22.2 No. 60079-1 – Flameproof enclosures
• CSA C22.2 No. 60079-11 – Intrinsic safety
• CSA C22.2 No. 60079-15 – Type of protection “n”

Canadian standards may use the same IEC technical foundation as the US and international systems, but national deviations and certification requirements can differ. (ccn-scc.ca)

14.6 Europe vs. USA/Canada – The Main Difference

The fundamental technical principles are increasingly aligned internationally, but the classification and certification systems are not identical.

A simplified comparison:

Europe	USA	Canada
ATEX	NEC / hazardous locations	Canadian Electrical Code
EN IEC 60079	UL / ANSI standards	CSA / CSA C22.2 standards
Zones 0, 1, 2 / 20, 21, 22	Class/Division and Zones	Class/Division and Zones
ATEX categories	Classifications / protection methods	Classifications / protection methods
CE + Ex marking	US certification marking	Canadian certification marking

IEC 60079 therefore provides a common technical foundation, but a manufacturer cannot assume that an IECEx certificate or European ATEX certification automatically provides access to the US or Canadian market.

14.7 Which Standards Does a Manufacturer Actually Need?

The answer depends on the product.

A manufacturer should not begin with a long list of standards and try to test against all of them.

Instead, the assessment should follow:

Product → Intended hazardous area → Gas or dust → Required protection level → Protection concept → Applicable standards → Certification route

For example:

Wireless sensor for Zone 1

may require a completely different combination of standards from:

Mechanical pump for Zone 2

or:

Control panel for Class I, Division 1.

This is why Ex compliance should be scoped before testing.

The objective is not to identify every Ex standard that exists, but to identify the smallest correct set of standards and certification requirements for the specific product and target markets.

15. ATEX in Europe – Directive, Categories and Conformity Assessment

In the European Union, explosion protection for products is primarily governed by ATEX Directive 2014/34/EU.

ATEX defines the requirements for equipment and protective systems intended for use in potentially explosive atmospheres and establishes the conformity assessment framework manufacturers must follow before placing covered products on the EU market.

15.1 ATEX 2014/34/EU

The ATEX Product Directive applies to:

• Electrical equipment
• Non-electrical equipment
• Protective systems
• Safety devices
• Control devices
• Regulation devices
• Components intended for incorporation into Ex equipment

The directive applies where these products are intended for use in potentially explosive atmospheres.

It is important to distinguish the ATEX Product Directive from the requirements placed on workplaces and installations. The product directive addresses the equipment placed on the market, while workplace and installation requirements determine how hazardous areas are classified and how equipment is used.

15.2 Equipment Groups

ATEX divides equipment into two main groups.

Group I

Equipment intended for use in underground parts of mines and certain surface installations of mines.

Group II

Equipment intended for use in other potentially explosive atmospheres.

Most industrial Ex products outside mining therefore fall under Group II.

15.3 Equipment Categories

For Group II equipment, ATEX uses equipment categories that correspond to the required level of protection.

For gas atmospheres:

• 1G
• 2G
• 3G

For dust atmospheres:

• 1D
• 2D
• 3D

In general:

Category	Typical zone
1G	Zone 0
2G	Zone 1
3G	Zone 2
1D	Zone 20
2D	Zone 21
3D	Zone 22

The relationship is important, but the category alone is not sufficient to determine whether a product is suitable. Gas or dust group, temperature limits, EPL and other product-specific requirements must also be considered.

15.4 When Is a Notified Body Required?

One of the most important questions for manufacturers is whether an external Notified Body must be involved.

The answer depends on the equipment group, category and applicable conformity assessment procedure.

For higher-risk categories, such as Category 1 and Category 2 equipment, third-party conformity assessment is generally required.

For certain Category 3 products, the manufacturer can use a conformity assessment procedure based on internal production control, without the same type of mandatory Notified Body involvement.

The exact procedure must be determined from the specific product and ATEX category.

15.5 EU-Type Examination

For applicable products, the Notified Body performs an assessment of the product design and technical documentation.

Where required, this results in an:

EU-Type Examination Certificate

This certificate demonstrates that the examined product type meets the applicable requirements under the relevant conformity assessment procedure.

The certificate applies to a defined product configuration and should therefore not be treated as a general approval covering unlimited future variants.

15.6 Quality Assurance and Production

ATEX conformity assessment is not limited to testing a single sample.

Depending on the selected procedure, the manufacturer may also need to demonstrate that production consistently remains in accordance with the certified or assessed design.

This can involve:

• Quality management
• Production controls
• Inspection
• Testing
• Documentation
• Control of changes
• Traceability

This is particularly important where a Notified Body is involved in production-related conformity assessment.

15.7 Technical Documentation

The manufacturer must maintain technical documentation demonstrating conformity.

Depending on the product, this can include:

• Product description
• Drawings
• Circuit diagrams
• Component specifications
• Risk assessment
• Ignition hazard assessment
• Applied standards
• Calculations
• Test results
• Certificates for relevant components
• Manufacturing information
• Instructions
• Marking information

The documentation must provide sufficient evidence that the product meets the applicable ATEX requirements.

15.8 EU Declaration of Conformity

After the applicable conformity assessment has been successfully completed, the manufacturer prepares an EU Declaration of Conformity.

By issuing the declaration, the manufacturer formally takes responsibility for the product’s conformity with the applicable EU legislation.

The CE marking can then be applied where required.

For Ex equipment, the marking is accompanied by the relevant Ex marking and other required information.

15.9 ATEX Certification Is Not the Same as CE Certification

A common misunderstanding is that ATEX certification and CE marking are two completely separate approvals.

ATEX is one of the EU product legislation frameworks that can require CE marking.

A product may also be subject to other EU legislation depending on its characteristics, such as:

• Radio Equipment Directive (RED)
• EMC Directive
• Low Voltage Directive, where applicable
• Machinery legislation
• RoHS
• Pressure Equipment Directive, where applicable

The manufacturer must therefore determine all applicable EU legislation, not only ATEX.

For a wireless Ex product, for example, ATEX and RED may both be relevant.

15.10 The ATEX Assessment in Practice

For a manufacturer, the practical sequence is therefore:

Product definition

↓

Intended hazardous area

↓

Gas / dust and substance characteristics

↓

Equipment group and category

↓

Protection concept

↓

Applicable harmonized standards

↓

Conformity assessment procedure

↓

Testing and technical assessment

↓

Notified Body involvement, where required

↓

Technical documentation

↓

EU Declaration of Conformity

↓

CE + Ex marking

This is the core European route for placing ATEX-covered equipment on the EU market.

The next chapter looks at IECEx, which is particularly important when manufacturers want a more internationally recognized Ex certification route beyond the EU.

16. IECEx – International Ex Certification

While ATEX is the key regulatory framework for Ex products in the European Union, IECEx provides an internationally recognized certification system based primarily on the IEC 60079 standards.

IECEx is particularly relevant for manufacturers who want to sell Ex products in multiple international markets.

16.1 What Is IECEx?

IECEx is the IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres.

It provides a common certification framework based on internationally recognized IEC standards.

Unlike ATEX, IECEx is not an EU directive or law.

Instead:

ATEX → European legal framework

IECEx → International certification system

IECEx certification can therefore support market access in countries that recognize or accept IECEx certificates, although local regulatory requirements may still apply.

16.2 What Can Be Certified?

The IECEx system covers a wide range of Ex-related products and services, including:

• Electrical equipment
• Non-electrical equipment
• Ex components
• Protective systems
• Equipment for gas atmospheres
• Equipment for dust atmospheres

The certification is based on the applicable IEC standards, particularly the IEC 60079 series and related standards.

16.3 IECEx Certificate of Conformity

The most relevant certification for manufacturers is the:

IECEx Certificate of Conformity (CoC)

The certificate confirms that the specified product has been assessed against the applicable IECEx standards and that the defined production requirements are fulfilled.

The certificate is tied to a specific product and defined configuration.

Manufacturers therefore need to control changes carefully.

16.4 IECEx vs. ATEX

ATEX and IECEx use many of the same technical standards, but they serve different purposes.

ATEX	IECEx
EU legal framework	International certification system
Required for products within its scope placed on the EU market	Used to support international market access
Based on EU legislation	Based primarily on IEC standards
Uses EU conformity assessment procedures	Uses IECEx certification procedures
CE + Ex marking	IECEx certification / Ex marking
Notified Body where required	IECEx Certification Body

A product can therefore have both ATEX and IECEx certification.

This is often useful for manufacturers targeting Europe as well as international markets.

16.5 IECEx Certification Bodies

IECEx certification is performed by approved IECEx Certification Bodies (ExCBs).

Testing is carried out by recognized IECEx Testing Laboratories (ExTLs).

The certification process can therefore involve:

Manufacturer

↓

Testing Laboratory / ExTL

↓

Certification Body / ExCB

↓

IECEx Certificate of Conformity

The exact process depends on the product and certification scheme.

16.6 Quality Assessment

IECEx does not only evaluate the product design.

The production system is also important.

For applicable certification schemes, the manufacturer must demonstrate that the products manufactured in series remain consistent with the certified design.

This is addressed through an IECEx Quality Assessment Report (QAR) and associated quality requirements.

This makes IECEx particularly relevant for manufacturers producing Ex equipment in series.

16.7 IECEx and Global Market Access

One of the major advantages of IECEx is its international recognition.

Countries and regulatory systems may:

• Accept IECEx certificates directly
• Use IECEx as part of their national certification process
• Allow IECEx reports to support local certification
• Require additional national requirements

The exact situation depends on the target country.

Therefore:

IECEx simplifies international Ex certification, but it does not automatically replace every national approval.

A manufacturer selling the same product in Europe, the USA, Canada, Australia or other markets must still check the specific requirements of each market.

16.8 IECEx for Product Development

IECEx can also be valuable during product development.

Designing a product around the relevant IEC 60079 requirements can provide a strong international technical foundation.

For a manufacturer targeting several markets, a practical strategy can therefore be:

Design to IEC 60079

↓

IECEx assessment

↓

ATEX conformity for Europe

↓

Additional national requirements where required

This can reduce duplicated engineering and testing compared with developing a completely different Ex design for every market.

16.9 When Should a Manufacturer Consider IECEx?

IECEx becomes particularly attractive when:

• The product is intended for several international markets
• Customers specifically request IECEx certification
• The product is intended for global industrial applications
• The manufacturer wants a recognized international Ex certification
• The same product will be sold in Europe and other IECEx-oriented markets

For a product intended only for the EU, ATEX may be sufficient.

For a product intended for global markets, IECEx should normally be considered during the initial compliance strategy.

The next chapter covers the US and Canadian Ex certification systems, including UL, FM, CSA and the Class/Division and Zone systems.

17. Ex Certification in the USA and Canada – UL, FM and CSA

For manufacturers targeting the North American market, European ATEX or IECEx certification is generally not sufficient on its own. The USA and Canada have their own regulatory requirements, hazardous-location classification systems and certification routes.

At the same time, the technical foundations are increasingly aligned with the international IEC 60079 framework.

17.1 USA – Hazardous Locations

In the USA, explosive atmospheres are generally addressed as Hazardous (Classified) Locations.

The central installation standard is:

NFPA 70 – National Electrical Code (NEC)

The NEC uses Class/Division and Class/Zone systems to classify hazardous locations.

Class System

The three basic classes are:

Class	Hazard
Class I	Flammable gases and vapors
Class II	Combustible dust
Class III	Ignitable fibers and flyings

The traditional system further distinguishes between:

• Division 1
• Division 2

In simplified terms:

Division 1 → the hazard exists under normal operating conditions or may frequently occur.

Division 2 → the hazard is not normally present and generally results from abnormal conditions such as leaks or equipment failures.

17.2 The Zone System in the USA

The NEC also permits a Zone classification system, which is more closely aligned with the international IEC approach.

For gas atmospheres:

• Zone 0
• Zone 1
• Zone 2

For dust atmospheres:

• Zone 20
• Zone 21
• Zone 22

This makes it easier to apply internationally developed Ex protection concepts.

However, the use of the Zone system does not mean that ATEX or IECEx certification automatically provides US market access.

US requirements for equipment marking, protection methods, gas and dust groups, temperature classes and certification still apply.

17.3 UL – Underwriters Laboratories

UL is one of the most important certification organizations for the US market.

Depending on the product and protection concept, different UL standards may apply.

One particularly important standard is:

UL 1203 – Explosion-Proof and Dust-Ignition-Proof Electrical Equipment for Use in Hazardous (Classified) Locations

There is also the UL 60079 series, which is based on the corresponding IEC 60079 standards.

Additional product-specific UL standards may apply depending on the equipment.

Therefore:

There is no single “UL Ex standard” that applies to every product.

The applicable standard depends on the product, protection concept and intended hazardous location.

17.4 FM Approvals

Another major US certification organization is FM Approvals.

FM certifies electrical and other equipment for hazardous locations.

FM uses both Division- and Zone-based protection concepts.

Examples of relevant FM standards include:

• FM 3600 – Electrical Equipment for Use in Hazardous (Classified) Locations
• FM 3615 – Explosionproof Electrical Equipment
• FM 3611 – Nonincendive Electrical Equipment

Additional FM standards may apply depending on the product and protection concept.

For manufacturers, UL and FM are therefore two important but distinct certification routes in the US.

17.5 Canada – Canadian Electrical Code

Canada has its own regulatory framework.

The central installation standard is:

CSA C22.1 – Canadian Electrical Code (CE Code)

For hazardous locations, particularly important requirements are found in:

• Section 18
• Appendix J

Canada also uses both:

• Class / Division
• Zone classification

The technical requirements are strongly aligned with international IEC standards, although Canadian requirements and deviations must still be considered.

17.6 CSA – Canadian Standards Association

CSA is one of the most important certification organizations in Canada.

For Ex equipment, the CSA C22.2 No. 60079 series is particularly important.

Examples include:

• CSA C22.2 No. 60079-0 – General requirements
• CSA C22.2 No. 60079-1 – Flameproof enclosures
• CSA C22.2 No. 60079-11 – Intrinsic safety

Depending on the product, additional product-specific CSA standards may also apply.

17.7 Combined US and Canadian Certification

For manufacturers, it can be particularly useful that certification for the USA and Canada can sometimes be combined.

A product may, for example, carry both UL and C-UL markings when it has been evaluated against the applicable US and Canadian requirements.

However, this does not mean that one generic certification automatically covers both countries. The applicable national requirements must be assessed as part of the certification process.

17.8 ATEX / IECEx vs. UL / FM / CSA

For manufacturers, the overall structure can be summarized as follows:

Market	Typical regulatory / technical framework
EU	ATEX 2014/34/EU + EN IEC 60079
International	IECEx + IEC 60079
USA	NEC + UL / FM / ANSI/ISA
Canada	Canadian Electrical Code + CSA

IEC 60079 therefore provides an important common technical foundation across several markets.

Nevertheless, national requirements and certification routes must be assessed separately.

17.9 What Does This Mean for Manufacturers?

Manufacturers should define their target markets before finalizing the Ex product design.

For example:

EU only

→ ATEX

EU + international IECEx markets

→ ATEX + IECEx

USA

→ US hazardous-location requirements + appropriate UL or FM certification

Canada

→ Canadian requirements + appropriate CSA certification

USA + Canada

→ Evaluate a combined North American certification strategy

Making this decision early is important because the requirements can affect:

• Product design
• Components
• Enclosure construction
• Protection concept
• Marking
• Testing
• Certification costs

For products intended from the beginning for Europe, the USA and Canada, an international Ex strategy can significantly reduce duplicated engineering and testing effort.

18. Ex Marking – How to Read Ex Product Markings

Ex marking provides essential information about where and under which conditions an Ex product may be used.

For manufacturers, installers and users, the marking is one of the quickest ways to determine whether a product is suitable for a particular hazardous area.

A typical European Ex marking can look like:

II 2G Ex db IIC T4 Gb

This short code contains a large amount of information about the intended application and protection level.

18.1 The ATEX Marking Structure

A typical ATEX product may carry several markings, for example:

CE 0123
II 2G Ex db IIC T4 Gb

The individual elements have different meanings.

CE

The CE marking indicates conformity with the applicable EU legislation.

For ATEX products, the CE marking is part of the overall EU conformity assessment.

0123

The four-digit number identifies the Notified Body involved in the applicable conformity assessment or production-related assessment.

The number is therefore not a product model number.

II

This identifies the ATEX equipment group.

• I → Mining
• II → Other industries

Most industrial Ex products therefore carry Group II.

2G

This identifies the ATEX equipment category and atmosphere.

• 2 → Equipment Category 2
• G → Gas

The corresponding dust designation would use D, for example:

2D

18.2 The Ex Protection Marking

The following part describes the technical protection concept:

Ex db IIC T4 Gb

Each element provides additional information.

Ex

Indicates equipment designed according to the applicable explosion protection requirements.

db

Identifies the protection concept.

Ex d refers to flameproof enclosure.

The additional letter b relates to the protection level within the relevant protection concept.

Other examples include:

• Ex eb → Increased safety
• Ex ia / ib / ic → Intrinsic safety
• Ex p → Pressurized enclosure
• Ex mb → Encapsulation
• Ex t → Protection by enclosure for dust

The exact marking depends on the protection concept used.

18.3 Gas and Dust Groups

The marking can also identify the group of hazardous substances for which the equipment is suitable.

For gases, common designations are:

• IIA
• IIB
• IIC

IIC represents the most demanding of these gas groups.

A product marked IIC can generally be used for applications covered by the less demanding IIA and IIB groups, provided all other requirements are also satisfied.

For dust, different group designations are used, such as:

• IIIA
• IIIB
• IIIC

Here, IIIC represents conductive dust.

18.4 Temperature Classes

For gas atmospheres, the marking can include a temperature class:

• T1
• T2
• T3
• T4
• T5
• T6

The temperature class defines the maximum surface temperature of the equipment under the relevant specified conditions.

The maximum surface temperature becomes lower from T1 to T6.

For example:

Temperature class	Maximum surface temperature
T1	450 °C
T2	300 °C
T3	200 °C
T4	135 °C
T5	100 °C
T6	85 °C

The temperature class must be compatible with the ignition characteristics of the hazardous substance present in the installation.

18.5 Equipment Protection Level – EPL

Modern Ex markings may also include an Equipment Protection Level (EPL).

Examples are:

• Ga
• Gb
• Gc
• Da
• Db
• Dc

For gas atmospheres:

EPL	General protection level
Ga	Very high
Gb	High
Gc	Enhanced

For dust:

EPL	General protection level
Da	Very high
Db	High
Dc	Enhanced

The EPL provides a direct indication of the equipment’s protection level and is closely related to the intended hazardous area.

18.6 Reading the Complete Example

Consider:

II 2G Ex db IIC T4 Gb

This can be interpreted as:

• II → Equipment Group II
• 2G → Category 2, gas atmosphere
• Ex → Explosion-protected equipment
• db → Flameproof enclosure with the specified protection level
• IIC → Gas Group IIC
• T4 → Maximum surface temperature of 135 °C
• Gb → High Equipment Protection Level

The marking therefore provides a compact summary of the product’s intended Ex application.

18.7 Marking Is Not the Same as Certification

An important point for manufacturers is that the marking should not be considered in isolation.

The complete certification documentation may contain additional information and restrictions, such as:

• Special conditions of use
• Permitted ambient temperature
• Specific installation requirements
• Approved cable glands
• Electrical parameters
• Mechanical restrictions
• Battery requirements
• Restrictions on component replacement

Therefore:

The Ex marking provides a quick summary, but the certificate and technical documentation define the complete conditions of use.

This becomes particularly important for complex products, product variants and equipment incorporating certified Ex components.

18.8 North American Markings

The US and Canadian systems use different marking conventions.

A North American product may, for example, be marked according to:

Class I, Division 1, Groups C and D

or using a Zone-based designation.

The marking can contain information about:

• Class
• Division or Zone
• Gas or dust group
• Temperature class
• Protection method
• Certification organization

The exact marking depends on the certification standard and the applicable hazardous-location classification.

For this reason, manufacturers targeting multiple markets should not simply copy an ATEX marking onto a North American product.

18.9 Why Ex Marking Matters for Market Access

The marking is not merely an administrative label.

It directly communicates whether the product is suitable for a particular hazardous location.

A product can have an apparently valid Ex certificate but still be unsuitable for a specific installation if, for example:

• The zone is different
• The gas group is different
• The temperature requirements are different
• The ambient temperature is outside the certified range
• The installation conditions are not fulfilled

For manufacturers, the Ex marking should therefore be treated as the final condensed representation of the certified product configuration and its permitted application.

The next chapter looks at Ex testing and explains what is actually tested when a product is assessed for explosion protection.

19. Explosion Protection Testing – What Is Actually Tested?

Ex testing is fundamentally different from a typical EMC or electrical safety test.

The purpose is not simply to verify that the product functions correctly. The objective is to demonstrate that the equipment does not become an ignition source under the conditions for which it is intended.

The exact tests depend on the product, the protection concept, the gas or dust atmosphere, the temperature class and the applicable standards.

19.1 What Is the Testing Trying to Prove?

An Ex assessment typically addresses potential ignition sources such as:

• Electrical sparks
• Hot surfaces
• Arcing
• Static electricity
• Mechanical sparks
• Friction
• Compression
• Flames
• Electrical or mechanical faults

The fundamental question is:

Can the product ignite the surrounding explosive atmosphere under the specified operating and fault conditions?

The answer must be demonstrated for the particular protection concept used.

19.2 Typical Test Areas

Depending on the product, Ex testing can include:

Electrical Tests

These can verify parameters such as:

• Voltage
• Current
• Power
• Capacitance
• Inductance
• Creepage and clearance distances
• Electrical isolation

For intrinsically safe equipment, these parameters are particularly important because the protection concept relies on limiting electrical and thermal energy.

Temperature Tests

The product may be operated under specified conditions to determine its maximum surface temperature.

This is particularly important for determining the applicable temperature class or maximum surface temperature for dust applications.

For example:

T4 → maximum surface temperature 135 °C

The measured temperature must remain within the applicable limits under the specified operating and fault conditions.

19.3 Flameproof Enclosure Testing – Ex d

For equipment using Ex d flameproof enclosure protection, the enclosure itself is a critical part of the protection system.

Testing can include:

• Internal pressure testing
• Flame transmission testing
• Enclosure strength
• Joints and flamepaths
• Threaded connections
• Impact resistance
• Temperature-related requirements

The purpose is to demonstrate that an internal explosion does not ignite the surrounding atmosphere and that the enclosure can withstand the resulting pressure.

The geometry and dimensions of flamepaths are therefore critical.

Changing a housing, thread, joint or enclosure material can potentially affect the certification.

19.4 Intrinsic Safety Testing – Ex i

For intrinsically safe equipment, the approach is fundamentally different.

The design must limit electrical and thermal energy so that ignition cannot occur even under defined fault conditions.

Testing and assessment can therefore involve:

• Maximum voltage
• Maximum current
• Power
• Stored energy
• Capacitance
• Inductance
• Transformer characteristics
• Semiconductor failures
• Component faults
• Spark ignition tests

The assessment can be particularly complex because the product may need to remain safe not only during normal operation but also under specified fault conditions.

19.5 Mechanical and Non-Electrical Equipment

Ex testing is not limited to electrical products.

For non-electrical equipment, the assessment can address potential mechanical ignition sources such as:

• Friction
• Impact
• Hot bearings
• Mechanical seals
• Moving components
• Static electricity
• Hot surfaces

The manufacturer may therefore need to perform an ignition hazard assessment in addition to physical testing.

This is particularly relevant for equipment such as:

• Pumps
• Gearboxes
• Fans
• Valves
• Mechanical drives
• Agitators

19.6 Dust Protection Testing

Dust presents different risks from gases.

For equipment intended for dusty hazardous areas, testing can include:

• Enclosure protection
• Dust ingress
• Surface temperature
• Thermal behavior
• Pressure or vacuum effects
• Mechanical integrity

For equipment using enclosure protection such as Ex t, the enclosure must prevent the hazardous dust from reaching potential ignition sources inside the equipment.

The required protection depends on the applicable dust group and EPL.

19.7 Environmental and Mechanical Tests

Depending on the product and certification standard, additional tests may include:

• Impact tests
• Drop tests
• Temperature cycling
• Humidity
• Corrosion
• UV exposure
• Ingress protection
• Vibration
• Cable entry tests
• Material compatibility

These tests are important because the Ex protection must remain effective throughout the specified environmental conditions.

An enclosure that provides adequate protection in laboratory conditions is not sufficient if the protection can be compromised by vibration, corrosion, temperature changes or mechanical damage during actual use.

19.8 Component Assessment

Many Ex products contain components that are already certified.

Examples include:

• Cable glands
• Connectors
• Switches
• Relays
• Batteries
• Terminals
• Enclosures
• Sensors

However, an existing component certificate does not automatically mean that the complete product is certified.

The component must be suitable for the intended application and used within the conditions specified by its certificate.

The complete product must still be assessed as a system.

19.9 Testing Under Fault Conditions

One of the most important differences from conventional product testing is the consideration of defined faults.

Depending on the protection concept, the assessment may consider failures such as:

• Short circuits
• Open circuits
• Component failures
• Loss of cooling
• Increased voltage
• Mechanical blockage
• Loss of protective functions

The applicable standards define which faults must be considered.

The objective is to demonstrate that the specified protection level is maintained under the required conditions.

19.10 Testing Is Only One Part of Ex Certification

A successful test result does not by itself create an Ex-certified product.

The overall assessment can include:

Product design

↓

Ignition hazard assessment

↓

Standards analysis

↓

Laboratory testing

↓

Technical documentation review

↓

Production / quality assessment

↓

Certification

This is why Ex compliance should not be treated as simply a laboratory testing exercise.

A product can pass individual tests and still require design changes, additional documentation or a different certification route before it can legally be placed on the market.

19.11 Why Changes Can Trigger Reassessment

Ex protection is often highly dependent on the detailed product design.

Changes that may appear minor can therefore be significant, for example:

• Changing enclosure material
• Changing wall thickness
• Changing a connector
• Replacing a battery
• Changing a PCB
• Changing component values
• Changing cable glands
• Changing seals
• Increasing operating temperature
• Changing the power supply

Before implementing such changes, the manufacturer should determine whether they affect the certified configuration.

In some cases, the certificate or assessment must be updated before the modified product can continue to be marketed as Ex-certified.

For Ex products, testing validates a specific safety concept and configuration — not simply a product name.

20. Documentation, Certificates and Product Changes

For Ex products, compliance does not end when testing has been successfully completed. Technical documentation, certificates, production control and change management are essential parts of maintaining Ex compliance.

In practice, problems often arise when components are replaced, suppliers are changed or technical characteristics are modified without assessing the impact on the Ex certification.

20.1 What Documentation Is Required?

The exact documentation depends on the product, target market and certification procedure.

Typical documentation includes:

• Technical documentation
• Risk or ignition hazard assessment
• Applicable standards
• Test reports
• Certificates
• Drawings and schematics
• Bills of materials
• Specifications of critical components
• Operating and installation instructions
• Product marking information
• Declaration of Conformity

For ATEX products, the EU Declaration of Conformity is particularly important.

For IECEx products, the IECEx Certificate of Conformity is a key document.

For the USA and Canada, appropriate certification documents from organizations such as UL, FM or CSA may be required.

20.2 The Certificate Defines the Certified Scope

An Ex certificate should not simply be considered a general product approval.

It defines a specific certified product type and may specify:

• Model designation
• Product variants
• Protection concept
• Electrical parameters
• Temperature range
• Approved components
• Enclosure
• Cable glands
• Special conditions of use

The product must therefore not automatically be used or modified outside these defined conditions.

20.3 Special Conditions of Use

Ex certificates can contain Special Conditions of Use.

These are commonly identified by an “X” suffix.

Such conditions may specify requirements relating to:

• Installation
• Grounding
• Cable glands
• Ambient temperature
• Mechanical stress
• Electrostatic properties
• Maintenance
• Assembly

These conditions must be considered during installation and reflected in the relevant product documentation.

20.4 Components with Their Own Certificates

An Ex product may contain numerous individually certified components.

For example:

Ex enclosure + Ex connector + Ex cable gland + Ex switch + Ex sensor

Existing component certificates can simplify the integration process.

However, they do not replace assessment of the complete product.

The manufacturer must establish that the components:

1. Are suitable for the intended application,
2. Are used within their certified parameters,
3. Are correctly integrated, and
4. Do not compromise the Ex protection of the complete assembly.

20.5 Product Changes

Every technical change to an Ex product should be assessed for its potential impact on certification.

Changes that may be particularly relevant include:

• Enclosures
• Materials
• Seals
• PCBs
• Batteries
• Connectors
• Cable glands
• Motors
• Sensors
• Electrical parameters
• Safety-relevant software functions
• Maximum operating temperatures

Not every change automatically requires recertification.

The key question is whether the change affects a property relevant to explosion protection.

20.6 Change Control

Manufacturers should therefore establish a defined change-control process.

A practical approach is:

Technical change

↓

Assessment of Ex relevance

↓

Review of certificate

↓

Review of applicable standards

↓

Decision: no further action / documentation update / additional testing / certificate amendment

↓

Approval of change

This prevents apparently minor engineering changes from unintentionally affecting the validity of the Ex assessment.

20.7 Changes to Standards

Changes to the underlying standards must also be monitored.

This is particularly relevant when:

• A new edition of an IEC 60079 standard is published,
• European harmonized standards are revised,
• Certification bodies introduce updated requirements,
• National requirements change.

An existing certificate does not automatically become invalid simply because a new edition of a standard has been published.

However, the manufacturer must determine whether a transition period, reassessment or update is required.

20.8 Production Changes

The product design is not the only area that matters.

Changes in production can also affect Ex compliance, for example:

• Changing a supplier
• Changing a material
• Modifying a manufacturing process
• Changing a subcontractor
• Moving production to another facility
• Changing inspection or test procedures

For certified Ex products, manufacturers must ensure that series production continues to correspond to the certified design.

20.9 Record Keeping and Traceability

Manufacturers must retain the required evidence for the applicable retention periods.

The documentation should make it possible to determine:

• Which product version was assessed?
• Which standards were applied?
• Which components were used?
• Which tests were performed?
• Which certificate applies to which version?
• Which changes were subsequently made?
• Which changes were approved?

Effective version and certificate management is therefore an important part of Ex compliance.

20.10 The Common Problem: Certificate Exists, but the Product Has Changed

A common practical scenario is:

Product certified → Certificate archived → Product subsequently modified.

For example, a battery is replaced, an enclosure material is changed or a component is sourced from a different supplier.

The product may continue to carry the original Ex marking even though the modification has never been assessed.

This creates a significant compliance risk.

An Ex certificate is not a blanket approval for future product variants.

Every relevant modification should therefore be reviewed against the certification documentation and applicable requirements.

20.11 Documentation as Part of the Product Strategy

For manufacturers, Ex compliance should not begin shortly before certification.

During product development, manufacturers should already determine:

• Which markets will be covered?
• Which Ex protection concept will be used?
• Which standards apply?
• Which components need certification?
• Which tests will be required?
• Which certification body should be used?
• Which documentation must be created?
• How will future changes be controlled?

This turns Ex compliance into a controlled product lifecycle process, rather than a one-time certification exercise at the end of development.

21. Practical Compliance Strategy for Manufacturers

For manufacturers, explosion protection is easiest to manage when the requirements are considered from the beginning of product development, rather than only shortly before certification.

A practical strategy can be reduced to a few key steps.

21.1 Step 1 – Define the Target Markets

First, determine where the product will be sold and used.

For example:

• European Union
• USA
• Canada
• International IECEx markets

This decision determines which legal requirements, standards and certification routes may apply.

21.2 Step 2 – Define the Intended Use and Environment

The next step is to define exactly how and where the product is intended to be used.

Important questions include:

• Will the product be used in a hazardous area?
• Gas, vapor, mist or dust?
• Which zone or classification?
• Which substances may be present?
• What ambient temperatures are expected?
• What operating conditions apply?

Without this information, the required level of Ex protection cannot be reliably determined.

21.3 Step 3 – Identify Potential Ignition Sources

All potential ignition sources associated with the product should then be assessed.

These may include:

• Electrical sparks
• Arcing
• Hot surfaces
• Electrostatic discharges
• Mechanical friction
• Mechanically generated sparks
• Overheating
• Stored electrical energy

For non-electrical equipment, the ignition hazard assessment is particularly important.

21.4 Step 4 – Select the Protection Concept

Based on the identified ignition hazards, the appropriate protection concept is selected.

Depending on the product, this may include:

• Ex d – Flameproof Enclosure
• Ex e – Increased Safety
• Ex i – Intrinsic Safety
• Ex p – Pressurized Enclosure
• Ex m – Encapsulation
• Ex t – Protection by Enclosure

The protection concept must be appropriate for the application, hazardous area classification and characteristics of the explosive atmosphere.

21.5 Step 5 – Determine the Standards and Certification Route

Only then should the manufacturer determine the applicable standards and conformity assessment or certification procedure.

For example:

EU

→ ATEX 2014/34/EU
→ Relevant EN IEC 60079 standards
→ Notified Body where required

International

→ IECEx
→ IEC 60079

USA

→ NEC / applicable US standards
→ For example UL or FM

Canada

→ Canadian Electrical Code
→ Applicable CSA standards

The selection should always be based on the specific product and application.

21.6 Step 6 – Define the Certification Strategy Early

Manufacturers should decide early whether they need, for example:

ATEX

or

ATEX + IECEx

or

ATEX + IECEx + North America

This can have a significant impact on the product design.

An enclosure, cable gland or component that is suitable for one market may need to meet additional requirements for another.

21.7 Step 7 – Testing and Certification

Once the design, protection concept and certification strategy have been established, the actual testing and certification process can begin.

Depending on the product, the assessment may cover:

• Design
• Materials
• Electrical parameters
• Temperature behavior
• Mechanical properties
• Protection concept
• Fault conditions
• Marking
• Documentation

21.8 Step 8 – Control Product Changes

Certification does not mean that compliance work is finished. It continues throughout the product lifecycle.

Every relevant product change should be assessed to determine whether it affects the Ex certification.

This may include:

• New components
• New suppliers
• Enclosure changes
• PCB changes
• Power supply changes
• New batteries
• Changes to operating temperature
• Changes to software or safety-relevant functions

A structured change-control process prevents certified products from gradually deviating from the design that was originally assessed.

21.9 A Practical Workflow

For manufacturers, the complete process can be summarized as:

Target Markets

↓

Intended Use

↓

Hazardous Area Classification

↓

Ignition Hazard Assessment

↓

Protection Concept

↓

Applicable Standards

↓

Testing & Certification

↓

Marking & Documentation

↓

Production Control

↓

Change Management

This workflow helps ensure that Ex requirements are correctly determined before product development and laboratory testing.

21.10 The Key Takeaway

Explosion protection is not a single test and it is not a single certificate.

It is a combination of:

Product + Environment + Protection Concept + Standards + Certification + Ongoing Control

For manufacturers, this means:

The best Ex compliance strategy does not start in the test laboratory. It starts with defining the product and its target markets.

Making these decisions early can help avoid unnecessary design changes, additional testing and certification costs while ensuring that the product is genuinely suitable for its intended markets and hazardous-area applications.