CDL Hazardous Materials Endorsement (HME)Loading and Unloading Hazardous MaterialsMedium
A driver is transporting a portable tank containing a hazardous material. What is the minimum aggregate working load limit (WLL) for the tiedown assemblies used to secure this tank on a flatbed trailer?
- AAt least 1 1/8 times the gross weight of the tank and its contents.
- BEqual to the gross weight of the tank and its contents.
- CAt least 1/4 times the gross weight of the tank and its contents.
- DAt least 1/2 times the gross weight of the tank and its contents.
Show answer & explanationAnswer & explanation
Correct answer: D. At least 1/2 times the gross weight of the tank and its contents.
According to federal regulations (49 CFR 177.834), the aggregate working load limit of all tiedowns used to secure a portable tank must be at least 1 1/2 times the gross weight of the tank and its contents. This ensures sufficient strength to withstand forces during transport.
Why the other options are wrong
- A. This value (1.125 times) is incorrect; the regulation specifies 1.5 times.
- B. Simply equaling the gross weight is insufficient for dynamic forces during transport.
- C. This value is too low and does not meet the regulatory requirement for securement.
Portable Tank Tiedown WLL
The minimum combined working load limit required for all tiedowns used to secure a portable tank, ensuring it can withstand forces encountered during transportation.
- Must be at least 1.5 times the gross weight.
- Applies to portable tanks of hazardous materials.
- Ensures adequate securement against dynamic forces.
Memory trick: One and a half times the weight, keeps the tank from taking flight.