Types: Air curtains, also called air doors, are used in foodservice applications for environmental separation, temperature control or for combating insects. These units consist of a powerful fan that creates an invisible air barrier. Typically mounted over doorways, air curtains and doors pull in conditioned air, accelerate it and force it through an air curtain. Discharged air hits the floor and is directed outward and inward.
Recirculating air doors recirculate air from an establishment's interior to prevent the loss of heated and cooled air in order to maintain interior temperatures. Commercial establishments where doors are frequently opened, tend to be the primary users of these products.
Non-recirculating air doors simply separate the exterior from the interior of a cooler or other piece of equipment and prevent insects from entering the foodservice facility. The doors come in various sizes and can be used for drive-thru windows, coolers and loading docks. Air curtains can also work in conjunction with plastic strip doors or swinging plastic doors; oftentimes used at the entrances of walk-in coolers and freezers. Another option is to position air curtains on front-of-the-house reach-in coolers. These air curtains help keep food in the coolers at safe temperatures while maintaining the temperature of the surrounding area. When negative air pressure is strong, air curtains also can be used in conjunction with make-up air fans.
Capacities/Footprints: Air curtains, mounted above a door either on the interior or exterior, fit on doors ranging in size from 36" to 144" wide, and can now be custom-manufactured for doors up to 16' wide and 20' high.
Energy Source(s): Most air doors require between 115V and 480V to operate. Gas, electricity or steam can power the optional heating function most units feature. Air velocity ranges from 1,800 up to 5,100 ft. per minute. Single- and dual-speed models come with either remote or automatic switches.
Standard Features: Air doors are typically available in satin anodized-aluminum, bronze anodized-aluminum, stainless-steel, white-aluminum, powder-coated and custom- painted types. These units create an invisible air seal generated by high-efficiency, direct-driven centrifugal fans that compress air inside the unit and release it through a directional nozzle outlet with a pressure that's powerful enough to stop winds up to 25 mph. An air curtain used for repelling flying insects requires a higher velocity of air than one designed for environmental preservation.
New Features/Technology/Options: One manufacturer offers a controller that can be built in or used as a remote control to operate the air curtain. It offers start/stop capabilities, a thermostat and time-delay feature. For front-of-the-house applications, manufacturers now offer recessed air doors that house all of the internal components above the ceiling. Such units are designed for operations that pay particular attention to interior design.
Prime Functions: Air curtains help prevent the intrusion of flying insects, dust, fumes and other airborne contaminants, and they also help keep inside conditioned or heated air untainted by outside air. Air curtains also facilitate free-flowing traffic in facilities as well as unobstructed vision. In addition, some operators now use air curtains to separate smoking and non-smoking areas inside their facilities.
Key Kitchen Applications: Specialty units can surround large pieces of cooking equipment, such as conveyor ovens, to contain the units' heat, thereby making the kitchen environment more pleasant for staff.
Purchasing Guidelines: Air curtains and doors offer operational savings and can pay for themselves in as little as two years because they can help maintain heated or conditioned air temperatures. When installing an air curtain, operators should take into consideration its location in relation to staff and especially the front of the house. This is because different units have different noise outputs and air velocities. If operators plan to access a walk-in cooler frequently, they should consider adding an air curtain and strip door. Doing so prevents cooled air from escaping, which will lower energy costs and extend compressor life.
Maintenance Requirements: For best performance, regularly clean air curtains and plastic strip doors. Air-cleaning filters are available for many air curtains. These filters, which are often constructed of washable aluminum mesh and are hence reusable, offer the benefits of both improving air quality and reducing odors.
Food Safety & Sanitation Essentials: As food safety continues to pose widespread concerns, operators may use air doors and curtains to help reduce the risk of foodborne illness by preventing insects from entering a kitchen or dining area. The FDA also recommends the use of air doors specifically at loading docks and delivery doors to repel insects.