Which approved method should be considered for transferring liquids to avoid static electricity hazards?

Electrically interconnected nozzles are an approved method for transferring liquids to mitigate static electricity hazards. This method helps ensure that any static charge generated during the transfer of liquids is dissipated safely. By interconnecting the nozzles electrically, static electricity can be prevented from accumulating, which in turn reduces the risk of sparks that could ignite flammable vapors present during the transfer process.

The other options, while they may have their own utility in liquid transfer, do not specifically address the challenges posed by static electricity. Hand pumps might be useful for manual transfer but do not inherently mitigate static build-up. Pneumatic systems introduce compressed air into the transfer process, which can also generate static but again does not provide a means to eliminate it effectively. Gravity-fed systems rely on the weight of the liquid, which doesn’t account for static charge accumulation during the fill or transfer process. Each of these alternatives has its benefits in specific contexts, but they do not provide the same level of protection against static electricity hazards as electrically interconnected nozzles.