This International Standard specifies the dimensions of the circular and rectangular flanges of
general-purpose fans, as well as the fan size designations. It is not applicable to cross-flow fans or to fan
appliances used for individual household or similar applications.
For circular flanges, it provides for three different flange series: one for light-duty casing thicknesses, another
for medium-duty fans and the third for heavy-duty fans as used on sea-going vessels or in heavy industry.
In order not to restrict fan design unduly, only the pitch diameter, hole numbers and hole diameters are
specified. Flange thickness, as well as internal and external flange diameters, may be chosen freely within the
limits of good engineering practice.
BS EN ISO 13351:2009 Referenced Document
ISO 13349 Fans - Vocabulary and definitions of categories*, 2010-07-01 Update
ISO 3 Preferred numbers; Series of preferred numbers