The average resistance of horizontal duct is about 10~12Pa/m (including straight pipe, reducer, tee, etc.), and the average resistance of vertical duct is about 15~18Pa/m. For example, the length of horizontal duct from the farthest suction outlet to the exhaust fan is 30 meters (about 300Pa).

Calculation of friction resistance along the path:

λ=0.0125+0.0011/D.

=0.0125+0.0011/0.564

=0.0144

R=(λ/D)*(ν^2*γ/2).

By the stove, generally 2500~3000m?/h a stove calculation; by the fume hood projected area, according to the projected surface wind speed of 0.5~0.8m/s calculation. Calculate the larger of the exhaust air volume is the design of the exhaust air volume you want.

Expanded information:

The Center for Disease Control and Prevention of the Chinese Ministry of Health tested the smoke conductor to improve the effectiveness of the oil compressor up to 3-4 times. Smoke conduction into the Chinese family kitchen time is not long, the current family kitchen smoke most of the work by the range hood to complete. Although the range hood can eliminate most of the smoke in the kitchen, but it is unable to completely solve the cooking smoke produced by the entire kitchen pollution.

Cooking fumes contain many harmful substances including aromatic amines and carcinogens such as N-PAHS. From the survey found that long-term exposure to high heat kitchen fumes, oil, gas and combustion exhaust, people's immune function, cardiopulmonary function will be much lower, leading to many diseases.

Baidu Encyclopedia - Kitchen Fumes