A "+" sign on a cylinder indicates it qualifies for what percentage overfill?

The presence of a "+" sign on a cylinder indicates that it is qualified for a 10% overfill. This marking is significant because it allows for additional liquid storage beyond the nominal capacity of the cylinder. The 10% allowance takes into account the expansion of fuel or the potential for slight overfilling during normal operation, ensuring safety and compliance with regulations.

Understanding the marking systems and their implications is crucial for ensuring safe handling and storage of fuel. This knowledge helps prevent overfilling that could lead to spills or leaks, which are hazardous and can result in environmental damage or fire risks. Regulatory compliance requires an accurate interpretation of these markings for safe operational practices in maintaining fuel-oil piping and storage systems.