When should the sprinkler system be shut down according to procedure?

The correct choice emphasizes the importance of following established protocols during an emergency response situation. Sprinkler systems are critical for controlling or suppressing fire in a building, and their operation is typically essential for maintaining the safety of occupants and firefighters alike.

Shutting down the sprinkler system should occur only when it is deemed necessary by the incident commander, who is responsible for the overall strategy and safety of operations on the scene. This directive ensures that the decision to disable the system is made with full consideration of the fire's status, the building's conditions, and potential hazards that may arise. The incident commander has the experience and situational awareness to ascertain when it is appropriate to turn off the sprinkler system, which could be required for reasons such as needing to access a specific area or ensuring firefighter safety.

In contrast, shutting down the system during the fire attack or immediately upon arrival could compromise safety by allowing the fire to grow unchecked, while shutting it down before leaving the scene could inadvertently lead to a resurgence of the fire if, for example, smoldering materials are present. Thus, the emphasis on following the command structure is crucial to maintaining control during an emergency response.