In energy, petrochemical, and storage tank industries, safety is not a target, it is a non-negotiable requirement. Every equipment that enters a refinery, tank terminal or a petrochemical plant must operate without creating ignition risk. This requirement becomes significantly more critical when operations involve explosive atmospheres such as hydrocarbon vapors, flammable gases or volatile residues inside storage tanks.

At AIS Field, our mission is to bring digital technologies, mainly robotics, safely into these hazardous environments. With ATEX-certified, in-service inspection robots like our RUVI OilDiver, we enable clients to carry out inspection and asset integrity tasks without shutdown and decommissioning, without degassing and without exposing personnel to confined-space risks. This leads to significant cost savings for our customers.

To understand how and why this is possible, this article provides an overview of explosive atmospheres, ATEX certification, hazardous area classifications in refineries and storage tanks, and how AIS Field meets and exceeds these standards.

What is an explosive atmosphere?

An explosive atmosphere exists when a mixture of flammable substances (gas, vapor or dust) and air is present in conditions where a single ignition source can trigger a combustion event. In industrial facilities, especially refineries and petroleum storage tanks, these atmospheres can occur near fuel handling areas, inside or above storage tanks, during transfer operations, inside process units, around leakages, inside floating roof drain sumps etc. Explosiveness is describes by the ignition triangle:

1. Fuel (vapor, gas, dust)
2. Oxygen (air)
3. Ignition source (electrical spark, heat, static discharge, mechanical friction)

When all three are present, an ignition can occur. ATEX standards aim to eliminate at least one element these through rigorous design, testing and certification of all equipment operating in these conditions.

What is ATEX Certification and its Role?

ATEX derives its name from “ATmosphères EXplosibles”. ATEX, IECEx and NFPA/NEC standards form the global framework for ensuring equipment safety in explosive atmospheres. ATEX (EU) and IECEx (international) share nearly identical technical foundations, both based on IEC 60079, and they certify that equipment will not become an ignition source in areas with flammable gases, vapors or dust. ATEX is a legal requirement within the European Union, while IECEx is a voluntary but widely respected global conformity system used across many regions. In the United States, hazardous locations are regulated under NEC/CEC Class & Division standards. Although the frameworks differ in structure [Zones (ATEX/IECEx) vs. Classes & Divisions (NEC)] all three aim to classify hazardous areas and verify that equipment is engineered with explosion-proof and intrinsically safe protection methods. For companies operating internationally, understanding these systems is crucial, as each imposes rigorous design, testing, documentation and marking requirements to ensure safe operation of electrical and mechanical equipment in explosive atmospheres.

ATEX consists of two EU directives:

• ATEX 2014/34/EU (Equipment Directive) – Defines requirements for equipment used in explosive atmospheres
• ATEX 1999/92/EC (Workplace Directive) – Defines safety obligations for employers operating such workplaces

For a piece of equipment to be ATEX-certified, it must be engineered to prevent ignition through mechanisms such as:

• Flame or explosion proof enclosure (d-type): The enclosure withstands an internal explosion without rupturing.
• Increased safety (e-type): No arcs, sparks or dangerous temperatures allowed during normal operation.
• Intrinsic safety (i-type): Limits electrical energy and temperature so ignition cannot occur.
• Pressurization and purging (p-type): Positive pressure inside enclosure prevents entry of explosive gas, generally includes purging cycles with an inert gas before energizing.
• Encapsulation (m-type): Components are fully embedded in resin to prevent contact with explosive atmosphere.
• Oil immersion (o-type): Potential ignition parts are immersed in oil, preventing contact.
• Powder/sand filling (q-type): Components are surrounded by powder to prevent ignition.
• Non-sparking (n-type): Equipment designed to avoid arcs, sparks or hot surfaces under normal operation. Limited to Zone 2 only.
• Dust enclosure (t-type): For dust atmospheres, preventing dust ingress and limits surface temperatures.
• Non-electrical equipment protection (h-type): For mechanical equipment, including constructional safety, control of ignition sources and liquid immersion.

In robotics, implementing ATEX compliance becomes significantly more complex. Unlike static equipment, robotic systems move, use multiple motors and actuators, require sensor payloads, consume varying levels of electrical power, operate with dynamic loads, handle data acquisition, communication and real-time control.

Hazardous Area Classification: ATEX Zones Explained

ATEX divides hazardous areas into Zones based on the likelihood of an explosive atmosphere being present.

Gas/Vapor Zones (G):

• Zone 0: Explosive atmosphere is continuously present or present for long periods
• Zone 1: Likely to occur during normal operation
• Zone 2: Not likely during normal operation, or only for short durations

Dust Zones (D):

• Zone 20: Continuous presence of combustible dust
• Zone 21: Likely presence during normal operation
• Zone 22: Unlikely but possible presence, only for short duration

For hydrocarbon industries, gas zones are most relevant. Equipment that operates inside or near these zones must comply with specific ATEX categories. Zone 0 is category 1 (very high protection), Zone 1 is category 2 (high protection) and Zone 2 is Category 3 (normal protection. The closer to the source of hydrocarbons, the stricter the certification.

ATEX Zones in Refineries and Storage Tanks

Refineries contain a wide range of units and assets with high risk of vapor release. Common ATEX-classified areas include process units, crude distillation, vacuum distillation, hydrocracker, reformers, FCC units, alkylation units etc. These units often include Zone 1 classifications due to continuous or frequent hydrocarbon vapor presence. For example in tank farm areas: storage tank perimeters, floating roof seals, vents, breathing systems and drain sumps often include Zone 0/1 classifications. Understanding these classifications is essential for planning inspections, robotic deployment and maintenance work.

Storage tanks hold large volumes of crude oil, naphtha, gasoline, diesel, jet fuel and other flammable liquids. They present unique hazardous area conditions. Inside the tank, above liquid level is continuous vapor presence and it is classified as Zone 0. Manhole areas are typically classified as Zone 1 and roof and shell areas are generally Zone 2. These may slightly change depending on the tank and terminal design.

Given these classifications, any robot entering a storage tank (i.e. submerged in product) must be certified. This is exactly where RUVI OilDiver stands out.

AIS Field’s ATEX Capabilities

At AIS Field, with over 20 years experience working in refinery and explosive environments, and 10 years of experience in designing ATEX-compliant systems, we specialize in designing inspection robots that operate safely inside explosive or high-risk environments. Our engineering approach integrates a combination of protection systems. These capabilities allow us to develop and use robots suitable for in-service refinery and above ground storage tank operations, something only a few companies globally can deliver.

RUVI OilDiver is our flagship in-service tank floor inspection robot, designed for fuel and chemical storage tanks. RUVI OilDiver is ATEX Zone 0 certified, fully capable of operating in storage tank environments mentioned above.

The products we inspected with RUVI OilDiver so far:

• Gasoline (with and without high benzene)
• Methanol
• Naphtha (both heavy and regular)
• Kerosene
• Jet fuel
• Diesel
• Lubricants

For new petrochemical or chemical products, we perform submergence tests in our workshop to ensure compatibility. For example, RUVI OilDiver system can be used in Xylene storage tanks.

Thanks to this approach, our clients receive safer inspections, shorter downtimes, reduced gas freeing and degassing activities and better compliance with API 653, API 575, EEMUA 159 and EEMUA 247 standards.

Contact us if you would like to see our certifications and to get more information about our engineering approach.

Why ATEX Matters for In-service Robotic Inspection

• Robotic inspection drastically reduces the need for human entry into hazardous zones.
• Avoiding conventional maintenance and shutdown can save millions per tank.
• In-service robots operate without disrupting operations.
• Regulatory compliance is key, for many industrial facilities ATEX certification is a must.
• From the perspective of environmental responsibility: by applying ATEX certified systems, unnecessary hydrocarbon emissions also prevented.

AIS Field ATEX certified RUVI OilDiver system helps facilities achieve all of these outcomes simultaneously.

AIS Field: Leading the Future of ATEX-Safe Robotics

As energy infrastructure becomes more complex, the demand for safer, more reliable robotic inspection will only increase. Explosive atmospheres and ATEX classification are not just regulatory topics, they directly shape how industrial facilities manage risk. As robotics becomes the new standard for in-service and confined-space inspections, the ability to safely operate within ATEX zones becomes a major differentiator.

As AIS Field, we have built our systems around this requirement. Through engineering, strict safety principles and real-world deployment experience, our robots offer unmatched capability in hazardous environments. RUVI OilDiver and our broader family of robotic inspection tools enable refineries and tank terminals to turn the most challenging inspection tasks into safe, predictable and non-intrusive operations. If your facility is seeking safer, faster, and ATEX-compatible inspection solutions, AIS Field is here to support you, with proven systems trusted across multiple continents.