Zone Two ATEX Fans Designed to Equipment Category 3G

Zone 2 ATEX fans designed to the exacting standards required for category 3G are suitable for gas environments where there is a rare or abnormal chance of an explosion occurring. Our Zone two classified range of metal, stainless steel and polypropylene fans are available from our enhanced ATEX certified portfolio, all of which are designed and constructed for use in potentially explosive atmospheres. In this article we cover some of the protection requirements that ensure a fan is suitable for zone two, category 3 applications.

• Gc, Dc – enhanced protection; the equipment remains safe in normal operation, and may have extra protection to minimize ignition risk in fault situations (a fault may cause equipment to shut down) In zone two equipment, enhanced protection is required to ensure that the fan component and motor, remain safe during normal operation. In most occasions, in zone 2 equipment, a fault may cause the equipment to shut down. Conversely, zone one equipment could handle one single fault in normal operation and still remain safe for operation.

Motors characterised as “Increased Safety” Ex ec, are used on industrial zone 2 explosion proof fans. The previous motor protection rating Ex Na (non-sparking) has now being superseded by the Ex ec motor classification to signify increased safety for use in zone two. This is the lowest and most normal level of Ex protection also known as reduced risk protection. The design of these ex ec motors aims to prevent an internal malfunction from creating sparks in normal operation and therefore is not capable of causing an explosive atmosphere to ignite. The construction ensures reliable prevention of unacceptably high temperatures and sparks or electrical arcs that could act as ignition sources in hazardous areas. It also aims to prevent excessive heating and offers a safer design against the risks of sparks during starting.

When we talk about zones, we refer to the external and internal environment the equipment is located. This could be the external air, or the internal carried air respectively. For accurate hazardous area classifications, qualified ATEX consultants are contracted to undertake a full assessment of the area to determine the internal and external zones. This may differ, or it could be the same across both areas. If the presence of the potentially explosive gas is only noted during a rare or abnormal occurrence, then the area will be noted a zone 2. In terms of possible zones in ATEX hazardous area classifications, zone 0 represents the highest risk, zone 1 a potential risk and zone 2 a rare/abnormal risk. Each zone requires specific equipment protection.

As mentioned above, each classified zone requires a specific equipment protection. We refer to this as the EPL. In zone two ATEX applications, the equipment protection level required is “c”. Our zone two gas fans offer protection to Gc level. This means that the equipment remains safe in normal operation but as stated previously, the fan may shut down when a fault occurs to prevent ignition. The equipment protection level is the last part you see on ATEX equipment labelling. This indicates one of three standard protection levels that are based on the risk of the equipment being a source of ignition in a hazardous area. In ATEX coding, G stands for gas and D stands for Dust.

• Ga, Da – very high protection; the equipment remains safe in normal operation, even in rare fault situations (two faults at once)

• Gb, Db – high protection; the equipment remains safe in normal operation (single fault)

• Gc, Dc – enhanced protection; the equipment remains safe in normal operation, and may have extra protection to minimize ignition risk in fault situations (a fault may cause equipment to shut down) Equipment intended for use in gas zone two will be classified in the ATEX category II 3G. A high level of protection is ensured. In addition to the equipment category, the fan itself should be ATEX compliant.

We’ve already discussed the protection ratings of the electrical parts; the motor to Ex ec, but it’s important to note the ATEX characteristics and labelling in accordance with the directive of other make up components. ATEX certified fan constructions should be marked Ex h to show a high level of protection of the non-electrical parts that make up the entire fan assembly.

Axair's ATEX fans are designed and constructed in accordance with all EU and UK ATEX Directives to Ex h high protection standards. Most of the time, when we discuss ATEX fans, we’re referring to our metal constructed components, but quite often the application also requires a different material that can handle corrosive and explosive fumes.

Stainless steel fans will obviously handle both of these aspects but where shorter lead times and a more transportable option is required, our polypropylene corrosion resistant fans are the ideal solution. All of EX-fans are labelled clearly to show the gas and dust zone that each can operate in. Please check the ATEX labelling carefully before processing your order.

For more information on Zone Two ATEX Fans Designed to Equipment Category 3G talk to Axair Fans UK Ltd