(a) D.O.T. United States Department of Transportation, which has jurisdiction over compressed gas cylinders and cartridges.

(b) Dry Chemical Closed Recovery System. A system that is constructed in a manner that prevents the introduction of foreign material into the agent being recovered. It shall also have a means of visually inspecting the recovered agent for contaminants and is closed to prevent the loss of agent to the atmosphere.

(c) Dry Powder. Solid materials in powder or granular form designed to extinguish Class D combustible metal fires by crusting, smothering, or heat transferring means.

(d) Dry Chemical. Various mixtures of finely divided solid particles additionally supplemented with special treatments to provide resistance to packing, moisture absorption (caking), and proper flow characteristics. These agents are designed for extinguishment of Class “A” and “B” fires. They are nonconductors and approved for use on energized Class C fire situations.