Tanker · Center of Gravity, Surge, and Outage
You are told to load a tank with a dense liquid such as an acid. According to CDL manual guidance, what three things govern how much of it you can put in?
Explanation
The three governing factors are how much room the product will need as it warms en route, how heavy that product is, and the legal weight limits the vehicle has to stay inside. Density is what makes the second and third interact: a tank filled to the brim with a dense product can put the vehicle over legal weight well before the tank is physically full, so heavy liquids are routinely loaded only partway, which in turn leaves the driver with a partly filled tank and all the surge that goes with it. 49 CFR 383.119(i) makes operating practices and procedures not otherwise specified a required knowledge area, and 383.119(e) separately requires knowledge of how surge differs between liquids of varying product densities, but neither states a loading figure or a method, so the three factors above are the manual's. The wrong options all treat rated capacity as the only real constraint, or substitute scheduling and equipment details that do not bear on how much mass the vehicle may legally carry.
Source: 49 CFR 383.119(i)
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