Thursday 7 November 2013

Explosion-proof heaters meet latest IEC/EN 60079 safety standard

Intertec has requalified a broad range of its explosion-proof heaters and controllers, and at the same time has formally validated their suitability for use in extremely cold environments. This development is likely to be of particular interest to designers of instrumentation systems requiring safety certification for hazardous areas, such as onshore and offshore oil and gas exploration/recovery projects in the Arctic polar region.

All Intertec ATEX and IECEx heaters and controllers are now certified as complying with the latest editions of the relevant parts of the IEC/EN 60079 safety standard for electrical equipment in explosive atmospheres. The materials, construction and performance of these products have been thoroughly tested by an independent third-party certification agency and verified against the most up-to-date criteria that is available.

All Intertec explosion-proof heaters comply
with the latest IEC/EN 60079 safety standard
& are certified for use down to -60 C ambien
Representative samples of every ATEX and IECEx heater and controller currently manufactured by Intertec were tested under the auspices of Germany’s national metrology institute, the Physikalisch-Technische Bundesanstalt (PTB), which is a Notified Body for ATEX and IECEx conformity assessment. To help address the growing demand for explosion-proof environmental protection equipment suitable for use in very cold climates, Intertec requested that the tests should include verification of performance at an ambient temperature of minus 60 degrees Celsius – far lower than many competitive products on the market. All submitted products passed the tests and the PTB updated the certificates accordingly.

In Europe, ATEX approval is mandatory for all electrical equipment used in hazardous areas, while many countries around the world accept IECEx test reports as the basis for their own national safety certificates. When seeking safety approvals for a complete instrumentation system, designers benefit from the presumption of conformity to IEC/EN 60079 held by ATEX and IECEx approved devices, which do not in themselves require further safety assessment. However, as part of the harmonisation process, many safety standards now carry an expiry date, known as the ‘Date of cessation of presumption of conformity of superseded standard’. After this date, to obtain a safety certificate based on the latest standards, designers must ensure that all devices in the system – including ATEX and IECEx approved components – have been certified to the same revision of the standards.

Customers can specify Intertec’s ATEX and IECEx compliant heaters and controllers secure in the knowledge that they benefit from the presumption of conformity to IEC/EN 60079 conferred by the tests, and that the products have been tested to the latest version of the standard – and are also now certified for operation at ambient temperatures as low as -60 C. Existing customers can obtain copies of the updated compliance certificates from Intertec.

Intertec’s range of explosion-proof heaters includes a wide variety of ATEX and IECEx compliant models, with individual power ratings from 25 to 600 watts and a choice of temperature classes. There are different models to cover the principal application areas of freeze protection, condensation protection and temperature maintenance, with a choice of convection or conduction heaters in each category. Special profile heaters are available for bringing liquid or gas samples in pipes or cylinders up to operational temperature, together with a heat tracing cable and controller to protect exposed measuring lines against freezing.

There is also a series of explosion-proof smart heaters for temperature maintenance that use a patented redundant control method of limiting their surface temperature to ensure safety, which are supplied complete with a precision digital controller. The digital controller is an all-solid-state design with no mechanical switching contacts; it features fully encapsulated electronics and an intrinsically safe external sensor for directly monitoring the temperature of equipment such as gas analyzers.

Most of Intertec’s explosion-proof heaters and controllers are also available in versions that comply with country-specific safety standards, including the latest editions of the National Electrical Code (NEC) standard used in the USA, and the Canadian Electrical Code (CEC) standard. The company is currently obtaining supplements to the relevant national standards of various Asian countries, including China, Korea and India, prior to any necessary third-party compliance testing.

Intertec produces an exceptionally wide range of environmental protection enclosures, cabinets and shelters, many of which are available in explosion-proof versions. These can either be ordered at the same time as the heaters, or as separate items. Another approach that is popular with many instrumentation engineers and project managers is to use Intertec’s turnkey enclosure assembly service - SAFE LINK. This enables designers to configure a complete system, including the enclosure, heater and controller, and instrumentation if required, using a free software design tool. Once the design is finalised, Intertec will manufacture and assemble the system, and deliver it to the installation site.

Intertec has nearly 50 years’ experience of producing high-reliability, cost-effective field instrumentation protection solutions for use in hazardous environments such as explosive atmospheres. Some of the first products that the company manufactured when it was founded in 1965 were enclosures and heaters for pressure regulation and temperature monitoring instruments at a large oil refinery in southern Germany; these remained fully operational until they were decommissioned recently after more than 40 years of service!

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