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Safety OIL IMMERSION


BS EN 60079 Part 6 Electrical apparatus for potentially explosive atmospheres, Oil immersion ‘o’.


A method of protection where the electrical apparatus is made safe by oil immersion, in the sense that an explosive atmosphere above the oil or outside the enclosure will not be ignited. The oil presents a barrier between the explosive atmosphere and the electrical apparatus.


This design concept is reflected in the equipment marking by the symbol ‘Ex o’. Equipment designed to this concept is suitable for use in ‘Zone 1’ and ‘Zone 2’ classified hazardous areas.


POWDER/ SAND FILLING


BS EN 60079 Part 5 Electrical apparatus for potentially explosive atmospheres, Powder filling ‘q’.


A method of protection where the enclosure of the electrical apparatus is filled with a mass of granular material such that, if an arc occurs the arc will not be liable to ignite the external explosive atmosphere.


This design concept is reflected in the equipment marking by the symbol ‘Ex q’. Equipment designed to this concept is suitable for use in ‘Zone 1’ and ‘Zone 2’ classified hazardous areas.


ENCAPSULATION


BS EN 60079 Part 18 Electrical apparatus for explosive gas atmospheres, Construction, test and marking of type of protection encapsulation ‘m’ electrical apparatus.


A type of protection in which parts that could ignite an explosive atmosphere by either sparking or heating are enclosed in a compound in such a way that the explosive


Figure 4. Certificate Coding Example


Focus on ATEX


ic and incorporated into the Intrinsic Safety standard, EN 60079 Part 11


atmosphere cannot be ignited. The compound provides a barrier between the electrical apparatus and the explosive atmosphere.


BS EN 60079-18 gives the specific requirements for the construction, testing and marking of electrical apparatus, parts of electrical apparatus and Ex components with the type of protection encapsulation 'm'.


This part only applies for encapsulated electrical apparatus, encapsulated parts of electrical apparatus and encapsulated Ex components where the rated voltage does not exceed 10 kV with a relative tolerance of +10%.


This design concept is reflected in the equipment marking by the symbol ‘Ex ma or Ex mb, designated against equipment designed for use in ‘Zone 0’ and ‘Zone 1 classified hazardous areas respectively.


Electrical Equipment Marking


The electrical equipment that has been assessed and tested and, found to be in compliance with the relevant European Harmonised Standard is marked with the certification coding as described in the aforementioned standards.


CERTIFICATION CODING EXAMPLE Figure 5. Certificate Number Example


The equipment marking, assuming full compliance with the relevant standard/s is met, will also include the Hexagon Ex symbol, the affixing of this symbol enables the equipment to be sold and installed freely within Europe.


Figure 6. Hexagon Ex Symbol


From July 1st 2003 equipment manufactured for use in Hazardous Areas must be ATEX certified in order to carry the ‘CE Mark’. (CE marking is a declaration by the manufacturer that the product meets all the appropriate provisions of the relevant legislation implementing certain European Directives. CE marking gives companies easier access into the European market to sell their products without adaptation or rechecking. The initials "CE" do not stand for any specific words but are a declaration by the manufacturer that his product meets the requirements of the applicable European Directive(s).)


The implementation and use of mechanical or electrical product on the market in Europe after this date that is designed to be used in a potentially explosive dust or gas atmosphere will be subject to compliance with the ATEX Directive and will be mandatory by law.


The marking details will also include the certificate number issued by the certification body.


CERTIFICATE NUMBER EXAMPLE


World Class ATEX Compliant Manufacturer


JCE Group (UK) is a global organisation who specialise in the design and manufacture of high performance control systems for applications where both hazardous and non-hazardous conditions exist, compliant with the ATEX directive. From their key locations (Aberdeen and Plymouth, in Britain, and Singapore) they provide ATEX approved solutions to meet the needs of customers across a broad spectrum of industries. They have the capability to produce items, from simple junction boxes to complex control panels built to customer specifications, and deliver them anywhere in the world. JCE’s technicians are highly qualified and experienced in installation, inspection, commissioning and maintenance of all types of Ex and safe area equipment. They offer ongoing support along with completed certification packages to meet client requirements. For the alternative energy industry, the Group has a division called JCE Energy which has established itself in the design, manufacture, installation and maintenance of control systems for use with solar, tidal, wind, biochemical and other renewable energy sources. A key revolutionary product in their portfolio is the ATEX compliant Zone 1/Zone 2 Solar Power Pod. Its innovative design, featuring a battery pack and a control system gives a constant and maintenance free AC/DC power source.


Reader Reply Card No 28 Toxic Gas Detector Family Receives ATEX Approval


US manufacturer Detector Electronics Corporation (Det-Tronics) GT3000 Toxic Gas Detectors have received ATEX hazardous location and performance certification. In addition, GT3000 Toxic Gas Detectors are FM, CSA, CE, and IECEx certified and have earned the IP66 rating. Det-Tronics is part of UTC Fire & Security, a unit of United Technologies Corp.


The GT3000 family is a group of electrochemical fixed-point detectors that provide non-intrusive calibration, communication via 4-20mA with HART protocol, and the ability to swap sensors without de-classifying hazardous areas. A GT3000 detector consists of a transmitter (GTX) and a sensor module (GTS). The transmitter generates a 4-20mA output signal with HART that is proportional to the concentration of the target gas and corresponds directly to 0-100% full scale.


Currently, the GT3000 family includes sensors that detect these gases: hydrogen sulphide (H2S), oxygen (O2), carbon monoxide (CO), ammonia (NH3), chlorine (Cl2), and sulfur dioxide (SO2). More gases will be added soon.


FlexVu®


“Although GT3000 is approved as a stand-alone device,” says product development manager Mike Bragg, “many users choose to partner it with Det-Tronics’ Universal Display for quick device set up and easy access to sensor status.”


Det-Tronics is part of UTC Fire & Security, which provides fire safety and security solutions to more than one million customers worldwide. Headquartered in Connecticut, UTC Fire & Security is a business unit of United Technologies Corp.


Reader Reply Card No June/July 2010 29


Gas Measurements from ATEX Installations


Gas sampling and conditioning in hazardous areas can be extremely challenging for operators and providers of analytical measurement systems. In order to provide reliable and auditable systems there needs to be consideration not only of the process parameters and local environmental conditions but also of the hazardous area rating in which the equipment must be certified to in order to operate continuously. This includes the area rating for the process gas itself as well as the rating for the installation location.


M&C TechGroup offers a range of precertified components for all hazardous area zones and can take the uncertainty of hat to provide away from the operator and the system provider. Connection to a process can be achieved with a range of certified sample probes - both sampling and mounting can be achieved from and in zones 0, 1, 2, 20, 21, 22.


Transport and conditioning of sample gas can be provided through regulated, or self- regulated, heated sample lines and gas coolers, certified for specific zones. Further downstream gas conditioning and also full System Integration can be offered by M&C.


Reader Reply Card No 27


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