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CDL · Loading and Unloading

When transporting cylinders of compressed gas, they should be:

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

Secured in an upright position (or as designed) with valves protected, and braced to prevent shifting

  1. A Secured in an upright position (or as designed) with valves protected, and braced to prevent shifting
  2. B Mixed freely with other cargo
  3. C Loose on the floor of the trailer to allow for movement
  4. D Stacked horizontally without restraint

Why this is the answer

Compressed gas cylinders must be transported as designed — usually upright with valve protectors in place — and securely braced to prevent rolling or shifting. A loose cylinder can become a missile if it falls and the valve breaks (the cylinder becomes propelled by escaping pressurized gas); this has caused serious injuries and damage. Cylinders also must not exceed safe temperature limits during transport, must not be exposed to direct flame, and must be loaded so the valve protector caps are in place. Stacking horizontally is allowed only for certain cylinders and only with proper bracing. Mixing cylinders of incompatible gases (oxidizers with flammables, for example) is prohibited.
Source: FMCSA CDL Manual 9.3.4 Compressed Gases

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About this topic: Loading and Unloading

Loading and unloading hazmat questions cover segregation of incompatible materials, securing the load, the no-smoking and engine-off rules, and the special handling for explosives, flammables, oxidizers and poisons. This is one of 10 Hazardous Materials questions on loading and unloading, each with a full explanation on a single study page.

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