EZQ 20/4 E E Ex e - Maico fans

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PLANNINGINSTRUCTIONSEZQ 20/4 E E Ex ePotentially explosive substances can be classified into temperature classes by their ignition temperatures. The maximum surfacetemperature of a piece of equipment (the motor in the case of fans) must always be below the ignition temperature of the explosiveatmosphere in which it is used.T Z - Ignition temperatureEquipment that falls into a higher temperature class, e.g. T4, may also be used for applications in which a lower temperature class isrequired e.g. T2 or T3.Example: An electric motor with a surface temperature of 175°C may be used only in the potentially explosive atmosphere of temperatureclasses T1, T2 and T3.The following table assigns a range of flammable gases to a temperature class and explosion group.Key parameters of a potentially explosive atmosphereA potentially explosive atmosphere is characterised by:■ The potentially explosive substance it contains■ The concentration of that substance■ The flash point and ignition temperature■ The temperature classThese parameters must be known in order to be able to assess the risk of explosion and the corresponding explosion protection measures.Key parameters of electrical operating equipment and systems in the area subject toexplosion hazardsDevice groups and device categoriesElectrical equipment for use in potentially explosive atmospheres is divided into 2 device groups:■ Group I: Electrical operating equipment used underground where there is a risk of firedamp (not included in the MAICO product range).■ Group II: Electrical equipment in all other areas subject to explosion hazards. These are then further sub-divided into three categories 1, 2and 3, dependant on the level of danger.Version: 17.12.2013 - MAICO VENTILATOREN, www.maico-fans.com - We are not responsible for mistakes or printing errors and retain theright to make technical modifications without giving prior noticePage 14
PLANNINGINSTRUCTIONSEZQ 20/4 E E Ex eEquipment from Device group II are given a letter, which identifies the state of the atmosphere:■ G - for areas in which explosive gas-, vapour- or mist-air mixtures are present. These are applications where MAICO fans can be used.■ D - for areas in which dust mixed with air can cause the build up of an explosive atmosphere. These are not applications where MAICOfans can be used.ZoneAggregation state of the combustiblematerialFrequency with which a potentiallyexplosive atmosphere occurs0 Gas, vapour, mist Constantly, for long periods or frequently1 Gas, vapour, mist Occasionally2 Gas, vapour, mist Seldom and for short periods20 Dust Constantly, for long periods or frequently21 Dust Occasionally22 Dust Seldom and for short periodsClassification of zonesAreas subject to explosion hazards are classified into zones according to the frequency with which potentially explosive atmospheres occur.A differentiation is also made between gas/vapour and dust according to the aggregate status of the inflammable substance.Version: 17.12.2013 - MAICO VENTILATOREN, www.maico-fans.com - We are not responsible for mistakes or printing errors and retain theright to make technical modifications without giving prior noticePage 15
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EZQ 20/4 E E Ex e - Maico fans

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