Which device is used to determine when a tank has been adequately filled?

• A. collar
• B. fixed maximum liquid level gauge
• C. hose end valve
• D. DOT special permits

Answer: (B)

Determining when a propane tank is adequately filled depends on having a reliable indication of the maximum safe liquid level. The fixed maximum liquid level gauge is built to show exactly when the tank has reached that limit, so the operator stops filling at the right point and avoids overfilling or venting. A collar is just protective hardware around the top of the tank neck and doesn’t provide level information. A hose end valve controls flow at the end of the fill hose but doesn’t indicate fill level by itself. DOT special permits are regulatory approvals, not a device used to measure fill level. So, the fixed maximum liquid level gauge is the correct device because it directly signals the proper fill limit.