When cleaning a tank without dikes, how far must an air compressor be positioned upwind?

Positioning an air compressor at least 50 feet from the tank when cleaning a tank without dikes is critical for safety reasons. This distance helps minimize the risk of ignition of flammable vapors that may be present in the area surrounding the tank. While cleaning, volatile substances may be released, and having the compressor too close can potentially create a spark or heat source that could ignite any vapors.

The 50-foot guideline is established based on safety protocols that account for the potential concentration of vapors and the operational hazards associated with the cleaning process. By maintaining this safe distance, the chance of any incidents or accidents occurring is substantially reduced, promoting a safer working environment.

The other options do not provide the same level of safety assurance. For example, placing the compressor just 20 feet from the manhole might be insufficient to avoid risks associated with flammable vapors. The options regarding being just inside or outside the dike also do not apply in this case, as they are relevant only where dikes are in place to contain spills and do not ensure the safe distance needed for an air compressor. Thus, the requirement to position the air compressor at least 50 feet away is vital for compliance with safety regulations during tank cleaning operations.