| | | Explosion proof according to ATEX100 a For operation in or to move potentially hazardous atmospheres or substances, explosion proof fans are supplied with motors approved to ATEX 100 a or VDMA 24169. They offer protection class 'e' ll (increased safety) or 'd' (flame proof) to EN 50019. The Eurpean Building Regulation approval to 94/9 EG confirms that the design fullfills VDE 0170/0171 and EN 50014/50019 and are enclosed with each unit. The reaction time tE (cut off time) is stated on the certificate of the motors and must be observed when selecting the motor protection device (circuit breaker) which must conform to VDE 0165. The temperature class of each fan is stated on the individual catalogue page; please see motor rating plate for correct data. The material combinations used in fans conform to the recommendations given in VDMA 24169 Part 1. All relevant regulation must be followed when making electrical connection. Explosion proof motors (protection 'e' increased safety) do not have thermal contacts. Helios's rectangular explosion proof fans (type KD...Ex) are fitted with PTC thermistors (positive temperature coefficient). Speed control is permited with these models if connected to a Helios MSA motor protection unit. Models for non standard voltages, frequencies and flameproof models to Ex d are available on request. Zone definition © The explosion proof zones are defined in the explosion proof regulations. If in doubt or for special applications, the local authorities should be consulted. Different zones (see figure ©) have been allocated to take into account the different degrees of likelyhood in which concentrations of flammable gas or vapour may arise in an installation. It consideres how frequent and for how long the hazardous atmosphere exists on each occasion. HELIOS explosion proof fans can be installed in zones 1 and 2. Types of protection For fan motors and terminal blocks protection to class 'e' (increased safety) is the standard, sometimes also class 'd'. | | Temperature classes and explosions groups © The EC-recommendations show two groups of apparatus: Group l: electrical apparatus for mines susceptible to firedamp. Group ll: electrical apparatus for places with a potentially explosive atmosphere, other than mines susceptible to firedamp. For electrical apparatus belonging to group ll there is a further division into explosion- and temperature classes. For EXe models 'increased safety' the degree of danger is defined by the temperature class where as for EX d models the explosion group ll A, ll B, II C is required in addition. The degree of danger increases from explosion group ll A to ll C. If an apparatus is suitable for group ll C it can automatically be used for the other two groups. An addtional way to categorise gases or steams is accoring to their ignition temperature ©. This is the temperature at which an ignition may occur e.g. through a hot motor surface. The maximum surface temperature of an electrical appliance must always be lower than the ignition temperature of the substance used. The gases are devided into 6 different temperature classes (T1 - T6) with a decreasing ignition temperature for higher classes. The gas will be put into the lowest class where its ignition temperature is still higher than the one of the temperature class. Apparatus with a higher temperature class can also be used for substances classified with a lower class. (e. g. T2 or T3). Installation According to the regulations for explosion proof apparatus a protection guard must be fitted to prevent items falling into the unit if installed vertically. The (cooling) air flow must not be affected by this. | | © Data for flammable materials for use with electrical equipment | | |
| | | * Extract from "Selection, Installation and maintenance of electrical apparatus for use In potentially explosive atmospheres' BS 5345 : Part 1 : 1989 (1)Also explosion group II B + CS2, (2) Also explosion group II B + H2, (3) Also explosion group II B + C2H2 -•For this substance an explosion group has not yet been determined | |
| | | | | | | | | | | | | | Flammable substances | Zones to IEC 60079-10 | Description | Permitted apparatus | Product-group | Product- category | | | | Gases, vapour, fog | Zone 0 | Zone in which an explosive atmosphere is continuously present, or present for long periods. | Intrinsically-safe apparatus or systems, special protection (specifically certified for use in Zone 0). | II | 1G | | | | | Zone 1 | Zone in which an explosive atmosphere is likely to occur in normal operation. | Any explosion protection suitable for Zone 0 and 'd' flammable enclosure, 'ib' intrinsically-safe apparatus 'e' increased safety, 's' special protection and 'p' | II | 1G or 2G | | | | | Zone 2 | Zone in which an explosive atmosphere is not likely to occur in normal operation, and if it occurs it will exist only for a short time. | Any explosion protection suitable for Zones 0 and 1 and 'n' type of protection, 'o' oil-immersion, 'q' sand filling | II | 3G, 2G or 1G | | | | Dust | Zone 20 | Zone in which an explosive atmosphere is continuously present, or present for long periods. | Intrinsically-safe apparatus or systems, special protection (specifically certified for use in Zone 20). | II | 1D | | | | | Zone 21 | Zone in which an explosive atmosphere is likely to occur for a short period due to the presence of dust in the atmosphere. | Any explosion protection suitable for Zone 0 and 'd' flammable enclosure, 'e' increased safety, with a minimum protection to IP 54. | II | 2D or 1D | | | | | | | | | | | | | |