What does a 'red tag' signify in boiler operations?

A 'red tag' in boiler operations signifies that equipment is inoperable or unsafe to operate. This tagging system is a crucial safety measure used by operators and maintenance personnel to quickly identify equipment that has been deemed hazardous, allowing them to take appropriate action before attempting to use or repair the equipment.

The presence of a red tag alerts workers to the risks associated with the equipment, ensuring that necessary repairs or inspections are conducted before it is returned to service. This helps prevent accidents and ensures compliance with safety regulations.

Other options like a maintenance reminder, an indication to increase temperature, or a warning about low water pressure do not accurately reflect the critical nature of the red tag system, which is explicitly about the operational status and safety of the equipment.