Strip curtains consist of overlapping strips of flexible plastic material that hang by gravity. They are used most commonly with loading vehicles, such as forklift trucks. Lighter versions are available for use by people. The strips are usually transparent, which is a valuable safety feature. Figure 1 shows how strip curtains work. The main advantage of strip curtains is their low cost to install and to repair. The transparency of the plastic allows vehicles to approach the curtain safely and to drive through the strips without stopping. The curtain material is so light and supple that it does not pose a safety hazard when someone blasts through the door. Strip curtains can be annoying in applications where people, rather than vehicles, push through the door. The transparent plastic cannot be reinforced, so the strips must be fairly heavy to survive. The plastic strips drag against exposed skin, which is especially unpleasant if the strips are stiff and cold. Also, the strips become soiled, so strip curtains are not appropriate for people wearing formal clothing. For this reason, don’t use strip curtains as personnel doors except in rugged environments. Strip curtains can be made in any width. All you need is a structural element or a suspended bar from which the strips can be hung. Strip curtains can also be fairly tall. However, long strips tend to twist, allowing more air leakage. The transparent plastic is not crystal clear, and it becomes less clear with wear and soiling. To aid in guiding vehicles through the proper part of a strip curtain, you can install one or more colored strips among the transparent strips.