CDL Hazardous Materials Endorsement (HME)Bulk Tanks and Other ContainersMedium
A cargo tank motor vehicle is transporting a non-pressure liquid hazardous material. The cargo tank is equipped with an internal self-closing stop valve. Federal regulations require that this valve must be designed to close automatically when activated by specific types of systems. Which of the following is NOT a federally mandated system for automatic closure of an internal stop valve on a cargo tank carrying non-pressure liquid hazardous materials?
- AExcess flow system
- BManual system (at the valve)
- CThermal activation system
- DRemote control system
Show answer & explanationAnswer & explanation
Correct answer: B. Manual system (at the valve)
While a manual system is present, the question asks for a federally mandated system for AUTOMATIC closure. Manual activation directly at the valve is not an automatic closure system, but rather a direct operator intervention.
Why the other options are wrong
- A. Excess flow systems are mandated to automatically close if there is a break in the line or excessive flow rate.
- C. Thermal activation is a mandated automatic closure system, often triggered by fire.
- D. Remote control systems are mandated for automatic or emergency closure from a distance.
Cargo Tank Internal Valve Automatic Closure
Internal self-closing stop valves on cargo tanks carrying non-pressure liquid hazardous materials must be designed to close automatically via thermal, remote control, or excess flow systems.
- Mandated for non-pressure liquid hazmat.
- Protects against spills during incidents.
- Thermal, remote, and excess flow are key systems.
Memory trick: TRaCE your steps to safety: Thermal, Remote, Excess.