Final answer:
In fire protection systems, Out of Service (OOS) systems should be identified by placing signs at strategic points like fire department connections, system control valves, and the fire command center to ensure safety during an emergency.
Step-by-step explanation:
The question pertains to the identification of Out of Service (OOS) systems within the context of firefighting and fire protection systems. In fire protection systems, Out of Service (OOS) systems should be identified by placing signs at strategic points like fire department connections, system control valves, and the fire command center to ensure safety during an emergency.
OOS systems shall be identified by placing signs at fire department connections, system control valves, and the fire command center. These signs are critical for the safety of both firefighters and the building's occupants, as they quickly communicate which components of the fire protection system are not operational. This enables firefighters to make informed decisions during an emergency response.