本文件规定了通用风机圆形和矩形法兰的尺寸以及风机尺寸名称。它不适用于横流风扇或用于单个家庭或类似应用的风扇设备。 对于圆形法兰，它提供了三种不同的法兰系列:一种用于轻型外壳厚度，另一种用于中型风扇，第三种用于海船或重工业中使用的重型风扇。 为了不过度限制风扇设计，只规定了中径、孔数和孔径。法兰厚度以及内外法兰直径可在良好工程实践的范围内自由选择。

This document 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, can be chosen freely within the limits of good engineering practice.