An air door, also called an air curtain, employs a controlled stream of air aimed across an opening to create an air seal. This seal separates different environments, while allowing a smooth, unhindered flow of traffic and unobstructed vision through the opening. Because air doors/air curtains help to contain heated or air conditioned air, they provide sizeable energy savings and personal comfort when applied in industrial or commercial settings. Air curtains can also be used to stop the infiltration of flying insects.
There are two major types of air curtains: recirculating and non-recirculating.
Recirculating air curtains, which are mainly used in supermarkets and store entrances, emit air from a discharge grille on one side of the door opening, collect it through a receiving grille on the opposite side, and return it through ductwork to the discharge grille. The non-obtrusive wide stream of low velocity air created by recirculating air doors is more desirable for separating environments. View diagram >
Non-recirculating air curtains are more widely used than the recirculating type because they are easier and less costly to install and have lower maintenance costs. View diagram >
The first U.S. patent for air doors was issued in 1904 to Theophilus Van Kannel. However, the first recorded air door installation was not made until some 12 years later. Air doors became increasingly popular in Europe throughout the late 1940’s and 1950’s. In 1956, Erling Berner brought the most advanced European air curtain technology to the United States and formed Berner Industries, the foundation of today’s Berner International Corporation. The first Berner air curtains were sold in the United States in 1960 for use on cold storage doorways. Since then, Berner International has developed and designed air door curtains for every conceivable need.