TETRA network coverage in hazardous areas

24 September 2010

To avoid life-threatening disasters emergency communication is an extremely important aspect of life. Sufficient coverage is needed in order to allow the emergency communication to work perfectly. As far as European and Asian countries are concerned, TETRA, a digital trunked mobile radio standard, is the leading technology to assure the communication of government agencies, emergency services, rail transportation staff, transport services and the military.

TETRA network coverage in hazardous areas

To avoid life-threatening disasters emergency communication is an extremely important aspect of life. Sufficient coverage is needed in order to allow the emergency communication to work perfectly. As far as European and Asian countries are concerned, TETRA, a digital trunked mobile radio standard, is the leading technology to assure the communication of government agencies, emergency services, rail transportation staff, transport services and the military.

Usually the TETRA base station signal covers almost 100% of open areas. However, sometimes the signal level from base station is too weak or does not exist at all so full functionality between the base station and TETRA mobile radio user cannot be ensured. In these cases the important communication is at risk and inadequate coverage can cause critical and life-threatening situations. To enhance this TETRA network coverage various TETRA repeaters are offered.

However, there are areas that have specific requirements. Hazardous areas, e.g. oil refineries and chemical factories, require equipment that is secure in explosive atmospheres, where different substances such as flammable gases, mists, vapours or combustible dusts are present. In hazardous areas the enhancement of TETRA coverage is often even more critical because an explosion can cause significant damage, serious injuries and loss of life. Preventing the release of dangerous substances, which can create explosive atmospheres, and preventing sources of ignition are two widely used ways of reducing the risk. Using the correct equipment is a major part of this.

For hazardous areas it is typical that large metal constructions, such as oil tanks, block the TETRA signal creating areas where coverage is either very weak or does not exist at all. In hazardous environments, there are specific safe areas which are areas free from explosive gases. In these safe areas a regular indoor repeater can be installed to enhance the TETRA network coverage. However, in many cases the coverage is needed in a location far away from the safe area. To enhance the TETRA coverage in these cases a new safe area or an ATEX certified TETRA repeater must be acquired.

In most cases the use of ATEX certified TETRA repeater is by far the simplest, most logical and cost-effective way to solve this problem than building a whole new safe area. The designing of an ATEX certified repeater is more demanding than the designing of a normal TETRA repeater because the safety standards in hazardous environments are extremely high. The repeaters for these hazardous areas must conform to the ATEX directive. At the moment there is believed to be only one manufacturer in the world providing ATEX certified repeaters for hazardous areas – the Finnish Creowave Oy.

The Creowave ATEX certified TETRA repeater is designed to be a reliable, robust and easy-to-install device for Zone 1 which can be configured on site or remotely through Creowave Repeater Manager Software.