Observation style doors are becoming more common in Hospitals, Assisted Care and Schools as UV lights and other germ killing and purification devices are being specified inside the duct wall. In some applications, access to the duct interior is not necessary but a viewport would be. The 10 x 6 Viewport door has 2 layers of safety glass with a 4″ x 2-5/8″ viewport to allow someone to safely view inside the duct without having to remove the door.
Used strictly as a viewport for observation, not access.
