Hazardous area signalling
Hazardous areas are defined as areas where concentrations of flammable gases, vapours or dusts may occur, either constantly (Zones 0 and 20), under normal operating conditions (Zones 1 and 21) or unusually (Zones 2 and 22). A whole series of additional conditions relating to the temperature classification and the auto-ignition temperatures of the type of gas or dust to be found ensure that any equipment will not initiate an explosion or fire.
Hazardous areas are to be found in a very wide range of manufacturing industries, far beyond the obvious petrochemical plants. Food, pharmaceutical and cosmetics manufacturing all involve processing potentially explosive substances, while the problems of explosions in grain silos and sugar processing plants are very well documented.
There are two ways of ensuring that the alarm sounders or strobes do not initiate an explosion when operated in a hazardous area: by using explosion proof or intrinsically safe devices.
Simplistically, the input energy entering an intrinsically safe device is constrained so that any arcing or sparking within the unit cannot generate enough heat to start ignition.
The alternative approach, explosion proof, is to house the equipment in an enclosure that is sufficiently robust to prevent any internal explosion from reaching the outside. Clearly, explosion proof devices will, by their very nature, be bulkier, heavier and more robust than intrinsically safe ones, and are therefore more likely to be installed in external applications, particularly as they will be environmentally sealed to IP66 or IP67 in order to achieve the degree of protection required.
For Zones 2 and 22, ‘increased safety’ devices are required. E2S offers powerful and cost-effective ex sounders and ex beacons for these environments.
E2S Warning Signals, the world’s leading independent signalling manufacturer, offers an extensive range of alarm horn sounders, beacons, loudspeakers and call points for fire and gas warning systems in offshore and onshore hazardous area installations.
E2S offer a full range of signalling devices in different enclosure materials.
LM6 — marine grade aluminium (BEx and D2x product families)
The BEx family are available with a choice of 5J, 10J, 15J and 21J xenon beacons, and LED beacons with high power Cree LED array. Sounders are available in a choice of 117 dB(A) and 123 dB(A) with 32 tones and up to three stages. The BExS110 117 dB sounder is available with a choice of flare or radial horns. A combined sounder beacon with a choice of either 5J xenon or LED beacons and a range of loud speakers complete the range. All devices are approved by IECEx and ATEX for Zone 1, 2, 21 and 22 use.
The D2x family beacons are available with a high power Cree LED array and 5 and 10 Joule Xenon strobe beacons that offer exceptionally low inrush and operating currents to optimise cable selection and reduce power supply requirements. The range of sounders offer high output, up to 116 dB(A), remote stage selection with up to four stages and a choice of 64 tones. Sounders are available with a choice of LED or xenon beacons.
GRP — glass reinforced polyester (GNEx product family)
The GNEx family is approved by IECEx and ATEX for Zone 1, 2, 21 and 22 use. All the GNEx visual signals utilise a polycarbonate UV stable prismatic lens that is available in amber, blue, clear, green, magenta, red and yellow and are field-replaceable.
Sounders are available in a choice of 117 dB(A) and 123 dB(A) with 64 tones and up to four remotely selectable stages. The GNExS1 sounder is available with a choice of flare or radial horns. The range is completed with 15 W and 25 W loudspeakers.
316L stainless steel (STEx product family)
For extreme environments the STEx family offers the same features as the GENx range with the addition of either a sounder/beacon combination or 5J xenon or LED beacon, in a 316 stainless steel enclosure.
All families have ATEX and IECEx approvals as a minimum, and many products also carry marine and fire approvals which, together with Mechtric’s fast delivery times, expert technical support and 5-year warranty, means there is a solution for all applications.
The complete E2S range of hazardous area signals are available through the Australian distributor Mechtric: www.mechtric.com.au.
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