Air curtain
Also known as: PVC strip curtain, strip curtain
Short definitionA measure that keeps inside and outside air from mixing while the door is open. It is either a strong air stream blown down from above the door or clear PVC strips covering the opening.
At an open door cold air escapes at the bottom and warm air enters at the top; the load rises, and moisture and ice build up inside. An air curtain blows a wall of air downward from a fan unit above the door and cuts this exchange by 60–80%. A PVC strip curtain is simpler and cheaper: overlapping strips part as you pass and then close.
The choice depends on traffic and temperature. A 0 °C room opened more than 50 times a day gets at least a strip curtain. In a distribution store with forklifts an air curtain or a high-speed door is considered, because forklifts wear the strips out. In a freezer room the low-temperature strip grade rated to −25 °C is used; the standard grade hardens and cracks. The most effective solution is to build an anteroom in front of the door.