SAFETY
Standards for hazardous environments A
TEX is a mandatory standard across Europe for environments that contain explosive or
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potentially explosive conditions. The certification of equipment against the ATEX standard involves all stages of production from the first stages of construction to the actual installation and use of the equipment. The ATEX Standard consists of two parts: 1. Directive 99/92/EC: This is the ATEX Use Directive which focuses primarily on the health and safety of the worker in explosive or potentially explosive environments. It includes the selection, installation, inspection, and maintenance of the certified explosion proof equipment.
2. Directive 2014/34/EU: The ATEX Equipment Directive which focuses on the manufacture of the products, and the trade and sales of the explosion proof equipment.
IECEx stands for International Electro- Technical Commission Explosive. It is a voluntary standard used internationally for safe explosion-proof equipment that can be traded across countries with confidence. The IECEx standard reduces the need for re-testing and re-certification due to the fact that many countries operate under different standards. The IECEx certification is based on the IEC 60079-0 standard, which has no governmental body involvement. To obtain the certificate, equipment must go through an IECEx certified body for both the equipment and the manufacturing facility, with surveillance of the related work procedures. IECEx certification is accepted in countries such as Canada, Australia, Russia, China, South Africa, USA, and most of Europe. ATEX and IECEx have many similarities in terms of providing
ATEX or IECEx certified equipment is usually required in any environment that contains explosive, or potentially explosive conditions/atmosphere. Chiller manufacturer Petra takes a look at the differences between each standard.
assurance that everything from the manufacturing, installation, operation and maintenance of the equipment, complies with explosion proof requirements. The main difference between the two standards is the geographical location where the certifications are recognised and accepted.
While ATEX is a mandatory certification in Europe, IECEx is optional. On the other hand IECEx is accepted many countries around the world. Furthermore, an ATEX certificate can be based on an IECEx test report, but ATEX documentation may not support an IECEx certificate. Given the above, it is now common for products to have both certifications. For both standards, all equipment manufactured for use in potentially explosive atmospheres, whether this is gases, vapors and/or mists or combustible dust, must be suitably marked to indicate in which area of the potentially explosive atmosphere the equipment can be installed. Hazardous places are classified in terms of zones on the basis of the frequency and duration of the occurrence of an explosive atmosphere. According to the health and safety executive, gases, vapors and mists zone classifications are: ■ Zone 0 – A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapors or mist is present continuously or for long periods or frequently.
■ Zone 1 – A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapors or mist is likely to occur in normal operation occasionally.
■ Zone 2 – A place in which an explosive atmosphere consisting of a mixture with
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air of dangerous substances in the form of gas, vapors or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only.
For dusts the zone classifications are: ■ Zone 20 – A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently.
■ Zone 21 – A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally.
■ Zone 22 – A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only.
The marking on the equipment identifies in which zone the equipment can be safely installed and used. Historically, it has been acceptable to install equipment into specific zones based on the type of protection, and it was necessary to understand the protection concept to know in what zone the equipment being installed could be located. Marking of IECEx equipment is a requirement. It allows a user to choose appropriate equipment for a specific hazardous atmosphere. Typical marking of electrical equipment must include the manufacturer’s name, the model number, serial number, ratings and the following Ex-marking at a minimum: ■ Type of protection (d, ia, e, p, nA, etc.).
■ Group for which equipment is approved (IIA, IIB, IIC, etc.).
■ Temperature code or maximum surface temperature (T1,T2,...T6).
■ Equipment Protection Levels (Ga,Gb, Gc, etc.).
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