① Determine the type of ventilation fan based on different purposes. For example, when conveying dust-laden gases, select a dust-extraction ventilation fan; when handling corrosive materials or gases, choose a corrosion-resistant ventilation fan; for flammable or explosive materials or gases, use an explosion-proof ventilation fan; and for clean air conveyance, general ventilation and air exchange fans can be selected.

② Select the type of ventilation fan based on the required air volume and air pressure, and determine the fan model. When determining the fan model, account for potential air leakage in the dust removal system, calculation errors in system pressure loss. Typically, the air volume safety factor is 1.1 for general supply and exhaust systems, 1.1 to 1.15 for dust removal systems, and 1.15 for pneumatic conveying systems. The air pressure safety factor is 1.1 to 1.15 for general supply and exhaust systems, 1.15 to 1.2 for dust removal systems, and 1.2 for pneumatic conveying systems.

The performance parameters or curves on the fan sample are obtained under standard conditions with atmospheric pressure of 101.325 kPa, air temperature of 20°C, relative humidity of 50%, and air density of 1.2 kg/m³. When these conditions change, the fans performance will be altered.

④ To facilitate the connection and installation of the fan with the system piping, the appropriate fan inlet and outlet directions and drive method should be selected. Additionally, a fan with lower noise levels should be chosen.