How to calculate the pipe size and fan size of the kitchen duct exhaust is as follows:

First, calculate the required exhaust volume according to the specification. Generally according to the stove head and hood projected area to calculate the exhaust volume. According to the stove, generally 2500~3000m?/h a stove calculation; according to the fume hood projected area, according to the 0.5~0.8m/s projected surface wind speed calculation. Calculate the larger of the exhaust air volume is the design exhaust air volume.

Secondly, to determine the location of the fan installation, to determine the specifications of the air duct and so on. According to the layout of the kitchen and space conditions, choose the appropriate fan installation location, generally should be as close as possible to the exhaust port, reduce the length of the duct and the number of elbows. At the same time, to determine the direction and specifications of the duct, generally should try to use a larger diameter, shorter length, fewer elbows round duct to reduce wind resistance and noise.

Finally, calculate the duct resistance. According to the length of the duct, diameter, elbows, valves and other factors, calculate the total resistance of the duct. From the above calculated air volume as the selection of fan air volume parameters, duct resistance * 1.1 as the static pressure of the fan parameters, check the fan sample to select the appropriate fan.