What are ATEX valves? Hawk answers

Safety, in industrial settings, is a top priority, especially in those environments where the presence of flammable substances can create potentially explosive contexts. To operate with total peace of mind, it is, therefore, essential that machinery and components be designed and certified to rigorous standards, and among these, ATEX valves play a key role.

But what exactly is meant by ATEX? And why are these valves so important in certain industries?

The ATEX directive: classification and requirements

The term ATEX comes from European Directive 2014/34/EU (formerly 94/9/EC), which covers equipment and protective systems intended for use in potentially explosive environments. Its purpose is to guarantee the free movement of such products within the European Union while ensuring a high level of safety for workers exposed to explosion hazards. Specifically, an explosive atmosphere occurs when a mixture of air and flammable substances (in the form of gases, vapors, mists or dusts) is present in such a concentration that an ignition source (spark, heat, flame, electrostatic discharge) can cause an explosion.

The ATEX directive classifies equipment into groups and categories according to the level of risk and the type of explosive atmosphere in which it may operate. Hazardous areas are divided into zones, depending on the likelihood and duration of the presence of an explosive atmosphere:

Zones for gases, vapors and mists:

• Zone 0: an area where an explosive atmosphere is constantly present, for long periods, or frequently;
• Zone 1: an area where an explosive atmosphere is likely to form occasionally under normal operating conditions;
• Zone 2: an area where an explosive atmosphere is not likely to form under normal operating conditions or, if it does form, persists only for a short period.

Combustible dust zones:

• Zone 20: an area in which an explosive atmosphere in the form of a combustible dust cloud is present continuously, for long periods, or frequently;
• Zone 21: an area in which an explosive atmosphere in the form of a combustible dust cloud is likely to form occasionally under normal operating conditions;
• Zone 22: an area in which an explosive atmosphere in the form of a combustible dust cloud is not likely to form under normal operating conditions or, if it does form, persists only for a short period.

ATEX equipment, in turn, is classified into groups and categories:

• Group I: equipment for underground mines and their surface parts subject to the danger of firedamp and/or combustible dust;
• Group II: equipment for all other areas (factories, plants) where there is a danger of explosive atmospheres.

Within Group II, equipment is further divided into categories (1, 2, 3) based on the level of protection; Category 1 offers the highest level of security.

The ATEX marking on a component, such as a valve, indicates that it has been designed, tested and certified to operate safely in a specific explosive atmosphere, minimizing ignition hazards from sparks, high surface temperatures or electrostatic discharge.

Where can ATEX valves be used? 

ATEX valves are essential in any environment where the combination of flammable substances and oxygen can create an explosive mixture. Their application extends to many high-risk industrial sectors, ensuring the safety of plants and personnel. The main sectors of use include:

• Oil and gas sector: the best-known area for the application of ATEX regulations. Certified valves are essential at every stage, from extraction to transport, from refining to the storage of hydrocarbons. Drilling rigs, refineries, fuel depots, and gas pipelines require valves that can operate safely with flammable gases, vapors, and liquids. Valves control the flow of crude oil, natural gas, gasoline, diesel, and other derivatives, where a single spark or hot spot can have catastrophic consequences.
• Chemical and pharmaceutical industries: these sectors use and produce a wide range of flammable substances, solvents, reagents, and powders. ATEX valves are used in mixing, reaction, transfer, and packaging processes to prevent explosions caused by the presence of organic vapors or fine dust.
• Food and beverage industry: although it may seem less risky, this sector can also have environments at risk of explosion, particularly in the presence of combustible dusts such as flour, sugar, cereals, or cocoa. ATEX valves are used in pneumatic conveying systems, silos, and processing operations where the formation of dust clouds can be dangerous.
• Wood and paper industry: Wood and paper processing produces large quantities of combustible dust, such as sawdust and cellulose fibers. Certified valves are required in extraction systems, storage silos, and transport systems.
• Power plants: In power plants that use finely pulverized solid fuels, the risk of dust explosions is significant; consequently, ATEX valves are essential in fuel supply and ash management systems.
• Wastewater treatment: Some wastewater treatment processes can generate flammable gases (e.g., methane from anaerobic digestion). Valves in these areas must be ATEX certified.

In all these contexts, choosing valves that do not comply with the ATEX directive or are not suitable for the specific risk zone constitutes a serious violation of safety regulations and may expose users to unacceptable dangers.

ATEX valve: operation and technical considerations

The operating principle of an ATEX valve is very similar to that of a standard valve; what makes it “ATEX” is its construction and compliance with specific requirements aimed at eliminating or minimizing potential sources of ignition. These requirements include:

• Surface temperature control: all external and internal components that could come into contact with the explosive atmosphere must operate below the ignition temperature of the gas or dust present, which may require materials with high heat dissipation or specific operating limits;
• Spark prevention: design measures are implemented to prevent the formation of sparks due to friction, impact, or the accumulation of electrostatic charges;
• Overpressure protection: In valves that handle fluids, preventing breakage due to overpressure is essential, as a leak of flammable fluid can create an explosive atmosphere. Relief or safety valves, in particular, are designed to release pressure in a controlled and safe manner.
• Construction materials: materials compatible with the fluid and the external environment are chosen, resistant to corrosion and wear, which do not generate electrostatic charges;
• Flame-proof or explosion-proof design: for valves installed in higher risk areas, the design may include containers capable of withstanding an internal explosion and preventing it from spreading outside (Ex d).

The choice of a specific ATEX valve depends not only on its function, but also on the ATEX zone in which it will be installed, the group of gases or dusts present, and the maximum permissible temperature class.

Hawk's ATEX valves for the oil industry

Well aware of the importance of safety and regulatory compliance in high-risk environments, particularly in the oil industry, Hawk Pumps includes ATEX-certified accessories and components in its catalog, specifically designed to work in synergy with its pumping systems in contexts where potentially explosive atmospheres are a constant reality.

Among the leading solutions are, for example, the VBA 80/280 ATEX control valve - ATEX II 2GD TX bypass control valve, an essential component for controlling flow and pressure within high-pressure systems, whose ATEX II 2GD TX certification makes it suitable for use in areas with gas, vapors (Category 2G), and combustible dust (Category 2D), where the formation of an explosive atmosphere is occasionally likely, and the VS 80/400 ATEX safety relief valve - ATEX II 2GD TX relief valve, an indispensable protective device in any high-pressure system operating in hazardous environments. The latter is also ATEX II 2GD TX certified, ensuring safe operation in explosive gas and dust atmospheres; its main function is to release excess pressure from the system, protecting the pump and pipes from damage due to overpressure.

Choosing Hawk Pumps ATEX valves means relying on components that not only offer the performance and reliability typical of the brand, but are also designed and certified to operate in complete safety in the most critical environments. Their integration into high-pressure systems ensures that the entire plant complies with the highest safety standards imposed by the ATEX directive.

For more information on the complete range of ATEX-certified accessories and to find the solution best suited to the specific needs of your plant in the oil industry or other hazardous areas, please contact us: our team of experts is at your disposal for advice and personalized technical support.