Air curtains consist of a fan and nozzle system which creates a jet of high-velocity air directed across a door opening, providing a protective air shield. The air shield minimizes the transfer of heat, moisture, dust, fumes and insects through the doorway. The air curtain fan adds kinetic energy to the air, providing resistance to the penetration of unwanted air or particles. This added kinetic energy in the discharge air also resists the penetration of outside air due to wind, as well as the invasion of insects. The air is provided at a critical velocity and volume flow as well as a discharge angle selected for its particular application. The air curtain enables traffic to flow unobstructed through door openings while maintaining distinct environments, thus resulting in energy savings.   Advantages of Air Curtains • Environmental separation for open doorways without the drawbacks of visibility-limiting solid barriers such as strip and impact doors; • Reduced risk of accidents as vehicles and people are able to move through doorways without obstructions to visibility or movement; • Provide excellent resistance to the penetration of outside winds; • Prevent the intrusion of insects, fumes and dust; • Reduce mechanical door maintenance costs; • More aesthetically appealing than plastic strip doors or high-speed doors.   Applications Air Curtains are used for a wide variety of applications from thermal barriers at shopping mall entrances, to fly and insect prevention at restaurant service doors, to factory freight doors for wind resistance and temperature separation.

Insect Control Sanitation maintenance applications require that air curtains prevent airborne insects from entering. For fly and insect control, the air curtain projects the high velocity air jet across the opening, deflecting and prohibiting the entrance of unsanitary insects, thereby maintaining sanitary conditions.   For applications such as fly and insect control which require maximum protection, it is common and accepted to use a more powerful air curtain in order to achieve the necessary level of protection.

Thermal Barriers When dividing spaces with temperature differences, the air curtain prevents the natural flow of air caused by differing temperatures. The difference between indoor and outdoor temperature creates an imbalance in density, and therefore a pressure variation which causes the infiltration of outside air.

Wind Resistance In many instances the infiltration of unconditioned air is driven by a combination of the temperature difference and the added problem of a prevailing wind at a door opening. Air curtains resist this infiltration of outside unconditioned air by blocking and deflecting the incoming wind. Wind resistance is achieved by using a well-designed air curtain with an appropriate velocity and volume of air, directed at the appropriate angle at the exterior doorway.   A factor often confused as a wind condition is negative pressure. Negative pressure is created when more air is exhausted from a building than is replaced through make-up air equipment. Air curtains are available that can remedy negative pressure conditions by delivering the appropriate amount of make-up air as well as functioning as a air curtain.

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Separation of Indoor Environments In many facilities there often exist manufacturing or production areas adjacent to either offices or other clean environments, such as shown in Figure 5. The production side may generate fumes, dust and heat which are undesirable in the adjacent areas. Air curtains are ideally suited for these applications, repelling the undesirables without restricting traffic. The air curtain is mounted on the clean side so as not to circulate the contaminants through the unit, as well as to prevent blowing the contaminants into the clean side.