Backdraft dampers are used in situations where air can only be permitted to flow in one direction. The most familiar example would be an exhaust duct where air needs to flow out of a building, but external air can’t be permitted to flow back into the same duct. Generally, backdraft dampers remain in a default closed position and are counterbalanced so that they only open when there is enough air pressure to force them open. However, backdraft dampers may be designed to open manually or by a motor, depending on the application.
Some industrial situations, such as factories, chemical plants or refineries, require dampers with added strength. In response, heavy duty dampers have been developed. These heavier dampers are generally fabricated from heavier gauge sheet metal for additional rigidity. In addition, as industrial settings may be more corrosive, heavy duty dampers may be fabricated from stainless steel – or offer some sort of coating, such as paint, powder coat or galvanization – for additional corrosion resistance.
Some industrial applications have unique requirements that standard, off-the-shelf dampers aren’t equipped to handle, and modifying them to work is either highly expensive or simply not a viable option. In response, some sheet metal fabricators have stepped in to manufacture custom dampers with special features, such as unusual dimensions or built-in motors for automation.