A renovation can temporarily remove the protection a building normally depends on. Sprinkler piping may be isolated, alarms may be under service, or portions of a fire detection system may be unavailable while crews work nearby.
That gap becomes more serious when workers are cutting steel, using torches, welding, grinding, or applying heat during roofing work.
A locked gate and warning signs do not provide active observation. A written fire watch plan assigns trained personnel to watch exposed areas, identify smoke or sparks early, report unsafe conditions, and start the required response without assuming that the impaired system will protect the site.