In an air conditioned room with a horizontal diffuser, when air drops occur, what is this type of throw called?

• A. L-Throw
• B. V-Throw
• C. Straight drop
• D. D-Throw

Answer: (D)

Air distribution throw types describe how supply air travels from a diffuser into the room. When air from a horizontal diffuser has a downward trajectory, it is called a drop throw, or D-throw. This name comes from the air dropping toward the floor as it loses momentum and mixes with room air, rather than staying at a constant horizontal level. This downward pattern is typical for horizontal diffusers that promote mixing by letting some air descend before spreading. In contrast, L-throw describes air that hugs a wall and then descends, and V-throw describes a V-shaped path toward the opposite wall, while a straight downward path is not the usual behavior for many horizontal diffusers. So, the downward, dropping pattern is best described as a D-throw.