What color disk indicates that a fire system is fully out of service?

• A. Red
• B. Yellow
• C. White
• D. Green

Answer: (C)

The color disk that indicates a fire system is fully out of service is white. This color is used to clearly communicate that a fire protection system is non-operational and may not provide the necessary safety functions in the event of a fire. The use of white for this purpose helps to prevent confusion among staff and first responders who may need to rely on the fire protection systems for safety.

In contrast, other colors, such as red, are typically used for systems that are in alarm or indicate a problem that requires immediate attention, while yellow may denote a caution or warning status, and green generally signifies that a system is in good working order. Therefore, the use of white is crucial for quickly conveying the status of a fire system being completely out of service.