EZQ 20/4 E E Ex e - Maico fans

PLANNINGINSTRUCTIONSEZQ 20/4 E E Ex eFlash pointThe lowest temperature at which a spontaneously inflammable mixture of gas or vapour and air can occur above a liquid, under prescribednorm conditions.Device groupElectrical equipment for use in potentially explosive atmospheres is divided into 2 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.Device categoryElectrical equipment from device group II is then further sub-divided into three categories 1, 2 and 3, dependant on the level of danger.Limits of the explosion areaAn explosion can occur only if the concentration of the inflammable substance is between the upper and lower limits of the explosion range.Thus, for example, a potentially explosive atmosphere may develop inside a partially filled petrol tank, while a full petrol tank would pose noexplosion hazard.Primary explosion protection measuresThese prevent the occurrence and the spreading of an explosive atmosphere, e.g. ventilation, inertisation, concentration monitoring withswitch-off.Cross-ventilationSupply and exhaust air openings are made at opposite ends of the room that is to be ventilated. In this way, air flows across the room beforeit is extracted again.Secondary explosion protection measuresPreventing the effectiveness of ignition sources: Explosion protection of electrical and non-electrical equipment with ignition protectionmeasures.Temperature classPotentially 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.Tertiary explosion protection measuresMeasures that are taken to reduce the effect of an explosion to a non-dangerous level, e.g. through explosion-proof construction, release ofpressure or suppression of explosionDiluent ventilationBy distributing the combustible material through the air, concentration levels can be reduced such that they are below the lower explosionlevel. The lower explosion level and the upper explosion level are respectively the lowest and the highest concentration level values of acombustible material in a mixture of gasses, vapours, mist or dust, outside which it is no longer possible for flames to propagate themselvesindependently after an ignition source has been ignited (EN 1127-1).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 42