Where flow control is not required but positive shut off is mandatory, guillotines are the most logical choice. Round or rectangular, their blade is completely withdrawn from the duct in its open position. Used when human access is essential during system shutdown for cleaning or repair.

"Zero leakage" features can be provided to assure safety, accomplished by pressurizing the peripheral sealing cavity with clean air.

When considering the use of guillotine dampers, sufficient space should be provided above the duct to accommodate for the overall size of the equipment.

"Slide Gates" are similar to guillotine characteristics but for specific horizontal applications. For use in Surge Bin or Hopper Discharge systems and outlets.