ATEX Zone Classification for Fuel Storage Areas: A Practical Guide

ATEX zone classification is a legal requirement in the European Union and a safety requirement recognised globally for any area where flammable vapours, gases, or mists may be present. For fuel storage and dispensing facilities, correct zone classification determines which electrical and mechanical equipment may be installed — and getting it wrong creates both legal liability and serious safety risk.

This guide covers the practical application of ATEX zone classification to fuel storage tanks, dispensing areas, and associated pipework.

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What Is ATEX?

ATEX refers to two European Directives governing explosive atmospheres:

• ATEX 114 (Directive 2014/34/EU) — covers equipment and protective systems for use in potentially explosive atmospheres
• ATEX 153 (Directive 1999/92/EC) — covers minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres

The practical output of ATEX 153 is the requirement to produce a hazardous area classification drawing for any facility where flammable materials are handled, stored, or processed.

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Zone Definitions

ATEX classifies hazardous areas into zones based on the frequency and duration of the presence of an explosive atmosphere:

Zone	Definition	Frequency
Zone 0	Explosive atmosphere present continuously or for long periods	>1,000 hours/year
Zone 1	Explosive atmosphere likely to occur in normal operation	10–1,000 hours/year
Zone 2	Explosive atmosphere not likely in normal operation, but may occur briefly	<10 hours/year

For dust (rather than gas/vapour), the equivalent zones are 20, 21 and 22. Diesel fuel produces vapour, so gas zones (0, 1, 2) apply.

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Typical Zone Classification for Diesel Fuel Storage

Diesel has a relatively high flash point (typically 55–66°C for EN 590 diesel), which means it does not produce an explosive vapour at ambient temperatures under normal conditions. However, ATEX classification must still account for elevated temperatures, fuel mists from leaks, and the vapour space above liquid fuel.

Above-Ground Storage Tank (AST)

• Zone 0: Inside the tank (vapour space above liquid level)
• Zone 1: Within 1.5 m of any vent opening, fill point, inspection hatch or level gauge opening
• Zone 2: 1.5–3.0 m radius around Zone 1 boundaries; within the bunded containment area at grade level

Underground Storage Tank (UST)

• Zone 0: Inside the tank
• Zone 1: Inside the manhole/access chamber above the tank; within 0.5 m of manhole openings
• Zone 2: 1.0 m radius around manhole and vent pipe openings

Dispensing Area (Pump Island)

• Zone 1: Within 0.5 m of dispenser nozzle and hose connections; within the dispenser cabinet enclosure
• Zone 2: Up to 3.0–4.0 m radius from the dispenser; under the canopy at vehicle refuelling height

Reference standard: IP Model Code of Safe Practice Part 15 (Area Classification for Petroleum Installations) and EN 60079-10-1 (Classification of areas — explosive gas atmospheres).

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ATEX Equipment Categories

Equipment selected for installation in hazardous zones must be certified to the appropriate ATEX category:

Zone	Required Equipment Category	Protection Level
Zone 0	Category 1G	Very high — two independent means of protection
Zone 1	Category 2G	High — effective in normal and abnormal operation
Zone 2	Category 3G	Normal — effective in normal operation

The “G” suffix denotes gas/vapour atmospheres. Equipment for Zone 0 (Category 1G) is rare and expensive; well-designed systems minimise Zone 0 areas to the interior of sealed tanks.

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ATEX Marking on Equipment

ATEX-certified equipment carries a standardised marking that identifies its suitability. A typical marking looks like:

II 2G Ex db IIB T4 Gb

Reading this marking:

• II — Equipment group (II = surface industry, not mining)
• 2G — Category 2, gas atmosphere
• Ex — Explosion protection marking
• db — Protection concept (d = flameproof enclosure, b = control of ignition sources)
• IIB — Gas group (IIA = propane, IIB = ethylene/diesel vapour, IIC = hydrogen)
• T4 — Temperature class (maximum surface temperature 135°C)
• Gb — Equipment protection level (Gb = suitable for Zone 1)

For diesel fuel dispensing and transfer equipment, Group IIA or IIB, Temperature Class T3 or T4 is the typical specification.

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Who Must Produce the Zone Classification?

Under ATEX 153, the employer / site operator is responsible for producing and maintaining the hazardous area classification. In practice, this is typically performed by a qualified process safety engineer or the equipment supplier as part of the project documentation package.

The zone classification drawing must be:

• Prepared before installation of any electrical equipment
• Reviewed and updated when the facility changes
• Made available to all contractors working on site
• Included in the facility’s safety file

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Neftgen ATEX-Certified Fuel Systems

All Neftgen fuel transfer pumps, control panels, level instruments and electrical components supplied for Zone 1 and Zone 2 applications carry ATEX certification to the appropriate category and gas group. Project documentation includes hazardous area classification drawings and ATEX equipment schedules as standard.

Related resources:

• ATEX Self-Priming Fuel Pump
• Mobile Fuel Stations — ATEX Certified
• Generator Day Tank Systems

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