DIN EN ISO 5802:2011-10

DIN EN ISO 5802 "Industrial fans - Performance testing in situ" contains the German version of the standard which has been prepared by Technical Committee ISO/TC 117 "Fans" and been adopted as EN ISO 5802 by Technical Committee CEN/TC 156 "Ventilation for buildings". The national interests during the preparation were represented by the Technical Section General Ventilation of the Mechanical Engineering Standards Committee (NAM) at DIN. The standard specifies tests for determining performance characteristics of fans installed in an operational circuit when handling a monophase fluid. The method for performance testing in situ is dealt with separately from the tests using standardized airways (see DIN EN ISO 5801) in this independent document. A detailed description of the velocity area methods for all commonly encountered airway cross-sections is provided. This standard also contains annexes describing the selection of suitable measuring stations and instrument calibration. It should be recognized that the performance of a fan measured under site conditions will not necessarily be the same as that determined from tests using standardized airways. The reasons for such differences are not only due to the inherently lower accuracy of a site test, but also due to the so-called "system effect factor" or "installation effect", where the ducting connections at fan inlet and/or outlet modify its performance. The need for good connections cannot be understated. The standard specifies the use of "common parts" immediately adjoining the fans and ensures that air/gas is presented to the fan as a symmetrical velocity profile free from swirl and undue distortion. Only if these conditions are met, will the performance under site conditions equate with those measured in standardized airways. The standard specifies the positioning of velocity-area measuring points according to log-Tchebycheff or log-linear rules. Arithmetic spacing can lead to considerable error unless a very high number of point readings are taken. This standard does not cover the assessment of the additional uncertainty where the lengths of straight duct either side of the measuring station are less than those specified in Annex C. ISO 5168 and ISO 7194 contain methods from which it will be seen that where a significant radial component exists, uncertainties can considerably exceed the normally anticipated 4 % at 95 % confidence levels.