Figure 11 exhaust ( source: googleimage.com

Natural Ventilation: An adequate supply of clean air must be provided and maintained within a commercial kitchen using gas. The simplest form of ventilation is natural, involving the use of windows, vents and skylights. These should allow sufficient airflow to maintain a healthy working environment. All vents should be screened to prevent flies and be rodent proof. If no replacement air by natural or mechanical means, the ventilation will suck the air from the restaurant drawing in the warm air / cool air from the restaurant increasing the running cost. Replacement air provides the airflow required by exhaust systems. If replacement air doesn’t come into the room, then the exhaust hood may not capture and contain airborne cooking waste due to the reduced airflow. This could allow cooking odours and waste air to escape into the dining area. If there is no replacement air in kitchen, when using gas appliances, lack of replacement air can cause the gas burners to go out because of lack of oxygen. Considerable care should be taken where doorways and windows are used for natural ventilation that fumes, dirt and rodents from surrounding premises are not drawn into the kitchen. Make up Air distribution: Air that is removed from the kitchen through an exhaust hood must be replaced with an equal volume of makeup air Following ways: • DIFFUSERS • INTEGRATED HOOD PLENUM

Figure 11 exhaust ( source: googleimage.com )