An Introduction To ATEX Certification
ATEX is the name used to cover the European Directive for controlling equipment in explosive atmospheres. An explosive atmosphere is a mixture of dangerous substances with air, under atmospheric conditions, in the form of gases, vapours, mist or dust in which, after ignition has occurred, combustion spreads. It is necessary for all products exposed to a potentially hazardous environment to be ATEX certified. To prevent an explosion from occurring you must isolate one side of the fire triangle, methods such as excluding the fuel/oxygen or removing/limiting the heat and lastly stop the explosion from expanding and causing a larger explosion.
Figure 1. Fire triangle showing fire elements
ATEX covers Europe but with its alignment to IECEx is also gaining applications internationally after the Macondo disaster in the Gulf of Mexico. ATEX allows the free movement of Ex products across the European Union. Under ATEX Directive, Ex certification is a marking shown on products to prove that they have been tested to comply with the explosive atmosphere standards.
It is a requirement that where hazardous explosive atmospheres occur they must be classified into zones. Each zone is determined by its size and location and is dependent on the likelihood of an explosive atmosphere occurring and for how long. There are three zones of risk:
- Zone 0 ‘Gas vapour or mist present continually or for long periods of time’
- Zone 1 ‘Occasionally in normal operation’
- Zone 2 ‘Not likely in normal operation or not likely’
The higher the risk, the safer the equipment should be, therefore equipment used in Zone 0 should be designed to be safe even after two faults and Zone 1 should be safe for one fault.
All products that are ATEX certified must be marked with the CE mark, the ‘Ex’ mark and the equipment coding. For example, an AnTech Type CA Wellhead Outlet is certified as ‘Ex db T3 Gb’. ‘Ex’ meaning explosion proof, ‘db’ is the type of protection ‘Flameproof enclosure’, ‘T3’ Temperature class, meaning the surface of the equipment won’t exceed 200°C, ‘G’ suitable for atmospheres containing gas and ‘b’ must be safe after one fault. The Type CA outlets are also marked with an extended ambient temperature rating (60°C < Ta < +160°C), for more information on this see here: 'The Temperature Confusion Of The ATEX Marking Scheme Explained'. 'Ex d’ is marked on several AnTech Wellhead Outlets meaning that the equipment that may cause an explosion is contained within an enclosure which can withstand the force of an explosion and cools the venting gas preventing it spreading to the outside hazardous atmosphere.
AnTech Type XA is certified as ‘Ex e IIC T3 Gb’ ‘Ex’ meaning explosion proof, ‘e’ type of protection is increased safety, ‘II’ Equipment group is surface above ground industries, ‘C’ Most easily ignited (hydrogen or acetylene), ‘T3’ Temperature class, ‘G’ suitable for atmospheres containing gas and ‘b’ must be safe after one fault. ‘Ex e’ is typically marked on AnTech’ s Type X Wellhead Outlets meaning safety measures are applied to the installation to ensure increased security against the possibility of increasing temperatures and sparks from electrical equipment.
AnTech’s products are designed to a standard which are approved and tested by a third party notified body, involving the testing and approval of prototypes. Which leads to the next stage of certification: production quality. AnTech’s products are produced and tested precisely to the work instructions, including full traceability of the people who have carried out the manufacturing task and full traceability of the company's used suppliers. AnTech will have an annual audit to check ATEX products. For AnTech’s customers, the approval is in the declaration of conformance found in the QA packs distributed with its products, which includes third party certifications.
AnTech can offer various product options with different certifications to meet the customers’ requirements and welcome any questions regarding our Ex products and are happy to provide any education or clarification.
Author: Emily Blackman