To mitigate the risk of static discharge while mixing fuel and water, how much liquid should ideally be removed from a tank?

To mitigate the risk of static discharge while mixing fuel and water, the recommendation is to remove at least 1 meter of liquid from the top of the tank. This practice is important because it reduces the amount of static electricity that can be generated during the mixing process.

When two liquids with differing properties are mixed, particularly those that do not easily blend, static charges can build up. Sufficiently removing liquid from the tank helps create a safer environment by minimizing the volume of the more volatile liquid, in this case, fuel, and reducing the potential for a dangerous static discharge.

While the other options suggest varying amounts of liquid removal, 1 meter has been determined to be a sufficiently effective practice to lessen the risk of static electricity generation while still allowing for effective mixing of water and fuel. Any lesser amount may not adequately reduce the risk associated with static discharge, while more than 1 meter might be unnecessary for minimizing the risk in most practical situations. This balance ensures both safety and operational efficiency in tank management during such processes.