"Catering Building Design Code" (JGJ 64-89) on the ventilation of the kitchen operating room made clear: (1) 65% of the calculated exhaust air volume through the exhaust hood to the outdoors, and 35% by the room's full ventilation; (2) exhaust hood mouth suction velocity should not generally be less than 0.5 m / s, the speed of the exhaust ducts should not be less than 10 m / s; (3) the heat processing room to make up for the volume of wind It is appropriate for the exhaust air volume of about 70%, the negative pressure value of the room should not be greater than 5 Pa. However, some projects of the kitchen is not equipped with exhaust hood, only a few sets of exhaust fans on the outside wall; some of the exhaust hood is set up, but the hood mouth suction velocity is far less than 0.5 m/s, the selected exhaust fan air volume is insufficient. Most of the projects have not set up a comprehensive ventilation device, also did not take into account the supplementary air device, it is difficult to ensure that the indoor health environment requirements and negative pressure value requirements.