What characteristics apply to DOT cylinders?

• A. They may be transported at fill capacity, have to be requalified, and they are filled by weight
• B. They may be transported at fill capacity only
• C. They are not requalified
• D. They are filled by volume

Answer: (A)

DOT cylinders are designed to safely contain propane under pressure. They are filled by weight, not by volume, so the exact amount of propane is known regardless of the cylinder’s size or temperature. They must undergo regular requalification (hydrostatic testing) to ensure the cylinder remains sound and safe to use. They are transported at fill capacity, which means up to about 80% of the cylinder’s water capacity to allow for liquid expansion. Because of these requirements—being filled by weight, requiring periodic requalification, and being transported at a capped fill level—the statement you chose correctly reflects how DOT cylinders are handled.