Loading, Unloading, and Load Securement of Hazardous Materials
What the exam tests
This domain covers loading, unloading, segregation, and load securement for hazmat. The exam tests whether you can prevent shifting, keep incompatible materials apart, and control ignition and access during transfer.
Core rules
- Secure every package against movement. Use blocking, bracing, dunnage, and tiedowns. For general cargo, the aggregate working load limit of tiedowns must be at least 50% of the cargo weight, and tiedowns are spaced so cargo cannot shift.
- Keep shipping papers accessible and keep packages marked/labeled so they can be identified during loading.
- Do not load poisons or foodstuffs together when contamination is possible. Follow the §177.848 segregation table for incompatible classes; cyanides and acids, and oxidizers and flammable liquids, are classic examples.
- Set the parking brake, place the transmission in gear or park, and chock wheels before loading or unloading. Shut off the engine unless it is needed for the transfer operation. No smoking or open flame within 25 feet of a vehicle containing flammable liquid or gas.
- Cylinders must be upright, valve-protected, and secured. Do not drop or roll cylinders.
Worked example
You are securing ten 55-gallon drums, each weighing 400 lb. Total cargo weight is 4,000 lb. The aggregate working load limit of your tiedowns must be at least 2,000 lb. Use at least one tiedown for each 10 feet of cargo length, plus blocking at the front and rear. A single strap rated at 1,000 lb is not enough by itself; two properly rated tiedowns meet the 50% rule, but the drums still need bracing to prevent rolling.
Traps
Counting the strap's breaking strength instead of its working load limit; forgetting wheel chocks; leaving the engine running during a flammable liquid transfer; and loading incompatible materials because "they are both in drums."