With regard to air flow control in a commercial kitchen, attention must be given to the layout of exhaust ducts. The direction of flow needs to be from high clean areas to low clean areas. An independent exhaust system for toilets is necessary if possible. Given that commercial kitchens must constantly deal with moisture, cooking odors, and grease, effective ventilation is indispensable. Economical air circulation prevents grease from being deposited throughout the kitchen, which decreases the risk of fire. As a result, the comfort of the kitchen staff will be optimized. In addition, kitchen planners need to consider whether the air is to be intentionally pushed in or out of the facility. A building’s dimensions, the method utilized to regulate airflow, the direction of airflow, and the internal air quality determines the amount of air needed. The difference between the internal and external temperature of a building plays a major role on the airflow rate.