Which of the following is a requirement for tanks larger than 10 gallons?

For tanks larger than 10 gallons, a critical requirement is that they must be placed away from fire sources. This regulation is in place to ensure safety and minimize the risk of fire hazards. Larger tanks often contain substantial amounts of volatile materials, and if they are positioned close to potential ignition sources, such as open flames or heat-generating equipment, the risk of combustion and subsequent accidents significantly increases. Maintaining a safe distance from such sources is crucial in preventing fires and protecting both the facility and personnel involved in the operation.

The other options may encompass general safety practices but do not address the specific requirement pertinent to tanks of this size within the mechanical code. For instance, while warning signs can be important for safety awareness, they do not constitute a mandatory installation requirement for the tanks themselves. Similarly, while keeping tanks filled may be beneficial for certain operations, it contradicts practical considerations for tank operation and maintenance. The focus on fire safety and distance is paramount for larger tanks, making the correct response the most relevant to regulatory compliance.