Hazmat · Loading, Unloading, and Bulk Packaging

You are loading a Class 3 flammable liquid into a cargo tank motor vehicle. What does federal regulation say about the engine while that is going on?

1.It may not be running during loading or unloading, with two exceptions the rule states itself: the engine may run where it is being used to operate a pump, and a diesel engine may be left running where the ambient atmospheric temperature is at or below -12 C (10 F)Correct answer

2.It must be shut off with no exception whatever, so a cargo tank that needs engine power to drive its own transfer pump has to be loaded and unloaded by a stationary pump at the terminal rack instead of by its own equipment

3.It may idle freely throughout the transfer, because the bonding and grounding connection that the same section separately requires already neutralizes any static charge capable of igniting the vapor sitting above the liquid

4.It may run only while the vehicle is standing on the private property of either the shipper or the consignee, and has to be shut off for any transfer that is made at a public fueling facility or at a roadside stop

Explanation

A Class 3 material may not be loaded into or onto, or unloaded from, a cargo tank motor vehicle while the engine is running, unless the engine is to be used to operate a pump; and a diesel engine may be left running during loading and unloading of a Class 3 material if the ambient atmospheric temperature is at or below -12 C (10 F). Both exceptions are in the rule's own text rather than read into it, and they are narrow in different ways: the pump exception turns on what the engine is doing, while the diesel exception turns on the engine type and the outside temperature together. A running engine near a flammable liquid transfer is an ignition source sitting next to a vapor space, which is why the default runs the other way. The wrong options each misstate the exceptions, denying that any exist, treating the section's separate bonding and grounding requirement as a substitute for the engine rule, or inventing a property-line test the section does not use.

Source: 49 CFR 177.837(a)

Drill Loading, Unloading, and Bulk Packaging questions

You are loading a Class 3 flammable liquid into a cargo tank motor vehicle. What does federal regulation say about the engine while that is going on?

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