CDL Hazardous Materials Endorsement (HME)Loading and Unloading Hazardous MaterialsHard
A driver is preparing to load a cargo tank with a Class 3 (Flammable Liquid). According to regulations, what is the maximum permissible speed at which the liquid can flow into the tank during the initial filling stage?
- A1 foot per second
- B3 feet per second
- C8 feet per second
- D5 feet per second
Show answer & explanationAnswer & explanation
Correct answer: B. 3 feet per second
To prevent static electricity buildup, which can be an ignition source, the initial filling rate for Class 3 (Flammable Liquids) into a cargo tank must not exceed 3 feet per second until the fill pipe opening is submerged. Once submerged, the flow rate can be increased.
Why the other options are wrong
- A. This is too slow and not the specified regulatory limit.
- C. This is significantly too fast for the initial filling stage and presents a high risk of ignition due to static discharge.
- D. This is too fast for the initial filling stage and could generate excessive static electricity.
Flammable Liquid Initial Filling Rate
The initial filling rate for flammable liquids into a cargo tank must not exceed 3 feet per second until the fill pipe opening is submerged to prevent static electricity buildup.
- Static electricity can be generated by liquid flow.
- Flammable liquids produce ignitable vapors.
- A slow initial fill rate minimizes static discharge risk.
Memory trick: Slow 'pour' for 'flammable' liquids, 'three' feet is the 'rule'.