Reference guide

ATEX Regulations: Everything you need to know

The most comprehensive guide to ATEX regulations in Spain. European directives, zone classification, equipment marking, temperature classes and selection criteria.

What are ATEX regulations

The ATEX regulations (from the French ATmospheres EXplosibles) form the European regulatory framework that establishes safety requirements for equipment and protective systems intended for use in potentially explosive atmospheres. These regulations are mandatory throughout the European Union and directly affect sectors such as oil and gas, chemicals, pharmaceuticals, food, mining and wastewater treatment.

The term ATEX covers two fundamental European directives that regulate both equipment manufacturing and working conditions in environments with explosion risk. Understanding these directives is essential for any company operating in industrial environments where explosive atmospheres may form.

The two ATEX directives

ATEX 114

Directive 2014/34/EU (ATEX 114)

Equipment and protective systems

This directive regulates the design, manufacture and marketing of equipment and protective systems intended for use in potentially explosive atmospheres. It applies to manufacturers and distributors of ATEX equipment. It replaced the former Directive 94/9/EC from 20 April 2016. It establishes essential health and safety requirements, conformity assessment procedures and obligations for economic operators.

ATEX 153

Directive 1999/92/EC (ATEX 153)

Worker protection

This directive establishes minimum provisions for improving the health and safety protection of workers potentially at risk from explosive atmospheres. It requires employers to classify risk zones, prepare an explosion protection document (EPD), select appropriate equipment and train workers.

ATEX zone classification

Zone classification is fundamental for determining what type of equipment can be used in each area. Zones are classified according to the frequency and duration of explosive atmosphere presence.

Gas and vapour zones (Flammable gases)

Zone 0

Maximum risk

Explosive atmosphere present continuously, for long periods or frequently. Example: inside fuel storage tanks, chemical reactors.

Zone 1

High risk

Explosive atmosphere likely to occur periodically during normal operation. Example: vicinity of loading/unloading points, pumping areas, zones around valves and flanges.

Zone 2

Moderate risk

Explosive atmosphere unlikely during normal operation and, if it occurs, only for a brief period. Example: areas adjacent to Zone 1, areas with forced ventilation, chemical storage rooms.

Dust zones (Combustible dust)

Zone 20

Maximum risk

Combustible dust cloud present continuously, for long periods or frequently. Example: inside silos, cyclones, bag filters, pneumatic conveying systems.

Zone 21

High risk

Combustible dust cloud likely to occur periodically during normal operation. Example: loading/unloading points of silos, vicinity of grinding and sieving equipment.

Zone 22

Moderate risk

Combustible dust cloud unlikely during normal operation and, if it occurs, only for a brief period. Example: vicinity of silo openings, areas where dust settles.

Equipment groups and categories

ATEX equipment is classified into groups and categories according to the intended environment and the level of protection provided.

Group I - Mining

Equipment intended for underground work in mines and their surface installations at risk from firedamp and/or combustible dust.

Category M1: Very high level of protection. Operates even with explosive atmosphere present.
Category M2: High level of protection. Disconnected when explosive atmosphere is detected.

Group II - Surface industry

Equipment intended for use in other environments at risk from explosive atmospheres of gas, vapour or mist.

Category 1: Very high level of protection. For Zone 0 (gas) / Zone 20 (dust). Two independent means of protection.
Category 2: High level of protection. For Zone 1 (gas) / Zone 21 (dust). Safe operation with normal disturbances.
Category 3: Normal level of protection. For Zone 2 (gas) / Zone 22 (dust). Safe operation under normal conditions.

Group III - Dust

Equipment for environments with explosive atmospheres of combustible dust. Same categories as Group II but specifically for dust.

ATEX equipment marking

ATEX marking identifies the safe conditions of use for equipment. Understanding each symbol is crucial for selecting the correct equipment.

Marking example

Ex II 2G Ex d IIB T4 Gb

Indicates equipment certified for explosive atmospheres

Equipment group (I = mines, II = surface industry)

Category 2 for Gas (G) - suitable for Zone 1

Protection types

Ex d

Flameproof enclosure: Contains the internal explosion without propagation to the exterior. Robust steel or aluminium housings.

Ex e

Increased safety: Additional measures to prevent arcs, sparks or excessive temperatures. No spark-generating parts.

Ex ia

Intrinsic safety (level a): Limits electrical energy to levels incapable of causing ignition. Highest level, suitable for Zone 0.

Ex ib

Intrinsic safety (level b): Similar to Ex ia but with a lower safety factor. Suitable for Zone 1.

Ex p

Pressurisation: Maintains positive pressure of inert gas to prevent entry of explosive atmosphere.

Ex n

Non-incendive: Does not generate arcs or sparks capable of causing ignition under normal conditions. Zone 2 only.

Ex o

Oil immersion: Electrical parts submerged in oil that prevents contact with explosive atmosphere.

Ex q

Powder filling: Enclosure filled with granular material (quartz sand) that prevents flame propagation.

Temperature classes

The temperature class indicates the maximum surface temperature of the equipment. It must be lower than the auto-ignition temperature of the gas or dust present in the installation.

T1: 450 degrees C

Hydrogen, methane, acetone, ethanol, ammonia

T2: 300 degrees C

Butane, ethylene, acetaldehyde

T3: 200 degrees C

Petrol, kerosene, hydrogen sulphide

T4: 135 degrees C

Acetaldehyde, diethyl ether

T5: 100 degrees C

Few industrial gases

T6: 85 degrees C

Carbon disulphide

The lower the T class number, the higher the maximum permitted temperature. T6 is the most restrictive class (85 degrees C), while T1 is the least restrictive (450 degrees C).

IP protection ratings in ATEX equipment

The IP (Ingress Protection) code defines the equipment's protection level against the entry of solid objects and liquids. In ATEX environments, an adequate IP rating is essential.

First digit: Protection against solids

IP 5x: Protected against dust (limited entry, not harmful)
IP 6x: Completely dust-tight

Second digit: Protection against liquids

IP x4: Protected against splashing water
IP x5: Protected against water jets
IP x6: Protected against powerful water jets
IP x7: Protected against temporary immersion
IP x8: Protected against prolonged immersion

For industrial ATEX environments, we recommend equipment with a minimum of IP65 (dust-tight and protected against water jets). The models we offer at Zona ATEX meet IP67 or IP68.

How to choose the right ATEX equipment

Selecting the right equipment requires a systematic analysis of the working environment.

Classify the zone

Determine whether your work area is Zone 0, 1, 2, 20, 21 or 22 based on the probability and duration of the explosive atmosphere.

Identify the substance

Determine the gas group (IIA, IIB or IIC) or the type of combustible dust present in the installation.

Auto-ignition temperature

Check the auto-ignition temperature of the substance and select equipment with a lower temperature class.

Select the category

Zone 0/20 requires Category 1; Zone 1/21 requires Category 2; Zone 2/22 requires Category 3.

Verify the IP rating

Ensure the equipment has an IP rating suitable for the environment (dust, humidity, washdown).

Functionality

Evaluate required functions: camera, scanner, PTT, 4G/5G connectivity, battery life.

Our team of consultants can help you select the right equipment. Contact us for a personalised assessment.

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Frequently asked questions about ATEX regulations

What does ATEX mean?

ATEX is the abbreviation for ATmospheres EXplosibles, the French term for explosive atmospheres. It refers to the European directives that regulate equipment and working conditions in environments where explosive mixtures of gas, vapour, mist or dust with air may form.

Is it mandatory to use ATEX equipment in classified zones?

Yes. Directive 1999/92/EC requires employers to use equipment that complies with the requirements of Directive 2014/34/EU in all areas classified as ATEX. Non-compliance can result in severe penalties and imply criminal liability in the event of an accident.

What is the difference between Zone 1 and Zone 2?

In Zone 1, the explosive atmosphere is likely during normal operation (it forms periodically). In Zone 2, the explosive atmosphere is unlikely and, if it occurs, is of short duration. This means equipment for Zone 1 (Category 2) requires a higher level of protection than Zone 2 equipment (Category 3).

Can I use Zone 1 equipment in Zone 2?

Yes. Equipment certified for Zone 1 (Category 2) offers a higher level of protection and can be used in Zone 2 without restriction. However, Zone 2 equipment CANNOT be used in Zone 1.

What is intrinsic safety (Ex i)?

Intrinsic safety is a type of protection that limits the electrical energy of the circuit to such low levels that it cannot ignite the explosive atmosphere. It is the only type of protection permitted in Zone 0 (level Ex ia). The devices we rent at Zona ATEX incorporate intrinsically safe circuits.

How often must ATEX equipment be recertified?

ATEX equipment must be maintained according to the manufacturer's instructions. There is no fixed recertification period, but periodic inspections are mandatory under IEC 60079-17. Repairs must be carried out by authorised workshops to maintain certification validity.

What ATEX regulations apply in Spain?

In Spain, the European ATEX directives transposed into national legislation apply: Royal Decree 144/2016 (ATEX 114 equipment) and Royal Decree 681/2003 (ATEX 153 worker protection), as well as the Regulations for electrical installations in explosive atmospheres (REBT ITC-BT-29).

Can Zona ATEX advise me on zone classification?

Yes. Our ATEX consultancy service includes assessment of your facilities, zone classification and recommendation of appropriate equipment. Contact us for a no-obligation consultation.

Need certified ATEX equipment?

Our team of experts advises you on regulations and helps you select the right equipment for your installation. Request a no-obligation quote.

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