ATEX zones:

guide to area classification, risks, and safety in explosive environments

In plants where flammable fluids (solvents, fuels, etc.) or combustible dusts are handled, the risk of explosion is a critical issue for safety and operational continuity.
ATEX regulations are the technical and regulatory reference for the correct design and management of ATEX zones.

Understanding what ATEX is, how zones are classified, and how to choose suitable equipment is essential for technical managers, HSE managers, and designers.

What does ATEX mean and why does it matter in industrial plants?

ATEX derives from the French ATmosphères EXplosibles and refers to the European directives that regulate the prevention of and protection against the risk of explosion in potentially explosive atmospheres.

An explosive atmosphere can form when combustible gases, vapors, mists, or dusts mix with air in certain concentrations and encounter a source of ignition, even a minimal one.

In work environments such as industrial plants (chemical, petrochemical, pharmaceutical, food, painting, fuel storage), ATEX directly impacts:

plant design
equipment selection
operating procedures
maintenance
staff training

ATEX zone classification: the starting point

ATEX zones are not all the same: the regulations distinguish between:

explosive atmospheres caused by gases and vapors
explosive atmospheres caused by combustible dusts

This is not a “theoretical” difference: it affects the design, choice of equipment, and operating procedures. A classification error can lead to unsuitable components, with impacts on safety, reliability, and compliance.

ATEX zones for gases and vapors

Typical during the handling, transfer, and storage of flammable liquids. Classification depends on the probability and duration of the presence of an explosive atmosphere:

Zone 0: explosive atmosphere present continuously or for long periods
Zone 1: explosive atmosphere likely during normal operating activities
Zone 2: explosive atmosphere unlikely, but possible only for short periods

This classification guides the choice of suitable components such as pumps, motors, electrical panels, and instrumentation used in potentially explosive atmospheres.

ATEX zones for dust

The risk posed by dust is often underestimated but can be high: even “unsuspected” materials can become explosive under certain operating conditions (e.g., food, mills, pharmaceuticals).

Zone 20: constant or prolonged presence of explosive atmosphere due to dust
Zone 21: probable presence during normal operations
Zone 22: rare and brief formation of explosive atmosphere

Correctly identifying the zone helps prevent ignition linked to dust accumulation or localized overheating, thus ensuring safety throughout the entire process.

ATEX certification: obligations and responsibilities

If ATEX zones are identified, it becomes necessary to adopt suitable solutions to ensure safety for those areas. Responsibility lies not only with the equipment manufacturer, but also with those who design, install, and operate the system.

For compliance, products must be accompanied by:

declaration of conformity (CE/ATEX) with ATEX certificate
user and safety manuals for hazardous areas
technical data sheets indicating class/category

Orderly document management is essential in the event of audits or inspections.

ATEX pumps and practical safety solutions

In ATEX environments, standard products are not suitable: solutions designed to minimize the risk of ignition are required. ATEX pumps are central to the transfer of flammable fluids, preventing sparks, overheating, and electrostatic charges.

Typical features: