This report describes the fan design philosophy currently used in China. It has been written for the general process engineer and does not require any previous knowledge about fans. It is also intended for use by the purchaser of AFBC fans, so he can better understand the fan performance and control limitations. This will assist the purchaser in writing more meaningful specifications to the fan supplier, and to get a better appreciation for the installation, operation and maintenance requirements. For an insight in the US design philosophy, the reader is referred to one of the many publications supported by EPRI (Electric Power Research Institute) on the Design and Specification Guidelines for Large Draft Fans and Systems.