BS EN 779:2002 pdf download – Particulate air filters for general ventilation — Determination of the filtration performance 5 Requirements The filter shall be designed or marked so as to prevent incorrect mounting. The filter shall be designed so that when correctly mounted in the ventilation duct, no leak occurs at the sealing edge. The complete filter (filter and frame) shall be made of material suitable to withstand normal usage and exposures to those temperatures, humidities and corrosive environments that are likely to be encountered. The complete filter shall be designed so that it will withstand mechanical constraints that are likely to be encoun- tered during normal use. Dust or fibres released from the filter media by air flow through the filter shall not consti- tute a hazard or nuisance for the people (or devices) exposed to filtered air. 6 Classification Filters are classified according to their efficiency (arrestance) under the following test conditions: the air flow shall be 0,944 m 3 /s (3 400 m 3 /h) if the manufacturer does not specify any rated air flow rate; 250 Pa maximum final pressure drop for Coarse (G) filters; 450 Pa maximum final pressure drop for Fine (F) filters. If the filters are tested at 0,944 m 3 /s and at maximum final pressure drops, they are classified according to Table 1 . For instance G3, F7. Filters tested at airflows and final pressure drops different from those above shall be classified according to Table 1 . The classification shall be qualified by test conditions in parentheses, e.g. G4 (0,7 m 3 /s, 200 Pa), F7 (1 ,25 m 3 /s). 7 Test rig and equipment 7.1 Test conditions Room air or outdoor air may be used as the test air source. Relative humidity shall be less than 75 %. The exhaust flow may be discharged outdoors, indoors or recirculated. Requirements of certain measuring equipment may impose limits on the temperature of the test air. Filtration of the exhaust flow is recommended when test aerosol and loading dust may be present. 7.2 Test rig The test rig (see Figure 1 ) consists of several square duct sections with 61 0 mm × 61 0 mm nominal inner dimen- sions except for the section where the filter is installed. This section has nominal inner dimensions between 61 6 mm and 622 mm. The length of this duct section shall be at...
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