A dual heating system, for example a heat pump and a fossil fuel furnace.
Dual level drain
An item that will permit drainage at two different levels.
Dual listing
Listing where a real estate broker represents both the buyer and seller, creating two principals.
Dual motion sander
Dual motion sanders give users the ability to choose between straight-line strokes and orbital motion for finish sanding or stock removal.
Dual voltage
Dual voltage allows a power tool to convert from standard 120 volts to 240 volts for cooler motor operation under heavier loads.
Dual-duct system
A central plant heating , ventilation and air conditioning (HVAC ) system that produces conditioned air at two temperatures and humidity levels. The air is then supplied through two independent duct systems to the points of usage where mixing occurs.
Dual-paned (double-glazed)
Two panes of glass or other transparent material, separated by a space.
Duckbill pliers
Pliers with jaw ends that are tapered to a horizontal flat wedge.
Duckboard
Board that is placed over a muddy area to provide firm walking surface.
Duct
A pipe or closed conduit made of sheet metal, fiberglass board, or other suitable material used for conducting air to and from an air handling unit. A passageway made of sheet metal or other suitable material used for conveying air or other gas at relatively low pressures.
