Safety in the Plant
Calibration in hazardous environments
Heikki Laurila outlines the benefits of using intrinsically safe calibrators in environments where explosions can occur.
A
hazardous environment is an area that contains elements that may cause an explosion: source of ignition, a flammable substance and oxygen. Intrinsic safety (IS) is a protection
technique for safely operating electronic equipment in explosive environments. The idea behind intrinsic safety is to make sure that the available electrical and thermal energy in a system is always low enough that ignition of the hazardous atmosphere cannot occur.
Intrinsically safe calibrators are safe for employees, as they can be safely used in environments where the risk of an explosion exists. In addition, intrinsically safe calibrators are the only technique permitted for Zone 0 environments (explosive gas and air mixture is continuously present or present for a long time). Multifunctional intrinsically safe calibrators provide
the functionality and performance of regular industrial calibration devices, but in a safe way. They can be used for calibration of pressure, temperature and electrical signals. A documenting intrinsically safe calibrator, such as the Beamex MC5- IS, provides additional efficiency improvements with its seamless communication with calibration software. This eliminates the need of manual recording of calibration data and improves the quality and productivity of the entire calibration process. Intrinsically safe calibrators are different
Fig. 1. Beamex MC5- IS, provides seamless communication with calibration software.
An intrinsically safe calibrator is therefore designed to be incapable of causing ignition in the surrounding environment with flammable materials, such as gases, mists, vapours or combustible dust. Intrinsically safe calibrators are also often referred to being ‘Ex calibrators’, ‘calibrators for Ex Areas’, or ‘IS calibrators’. An Ex Area also refers to an explosive environment and an Ex calibrator is a device designed for use in the type of environment in question. Many industries require intrinsically safe calibration equipment. Intrinsically safe calibrators are designed for potentially explosive environments, such as oil refineries, rigs and processing plants, gas pipelines and distribution centres, petrochemical and chemical plants, as well as pharmaceutical plants. Basically, any potentially explosive industrial environment can benefit from using intrinsically safe calibrators.
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from other industrial calibrators in both design and technical features. In view of safety, there are also some guidelines and constraints for how to use them in hazardous areas. Every intrinsically safe calibrator is delivered with a product safety note, which should be read carefully before using the device. The differences in design and technical features were made with one purpose in
mind - to ensure that the device is safe to use and is unable to cause an ignition. The surface of the device is made of conductive material. The battery of an intrinsically safe calibrator is usually slower to charge and it discharges quicker. Many times intrinsically safe equipment operate only with dry batteries, but the Beamex intrinsically safe calibrators operate with chargeable batteries. When charging the battery, it must be done in a non-Ex area. External pressure modules can be used with IS-calibrators, but they must also be intrinsically safe. There are also usually small differences with electrical ranges compared to regular industrial calibrators (eg, maximum is lower). ■
For more information ✔ at
www.engineerlive.com/epe
Heikki Laurila is Product Manager at Beamex Oy Ab, Pietarsaari, Finland.
www.beamex.com
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