What does an empty box on a building indicate at the time of marking?

An empty box on a building during the marking process signifies normal stability at that moment. This marking system is used by fire departments and emergency responders to quickly communicate the condition of a structure to incoming units. When a building is marked with an empty box, it indicates that the structure is currently stable, which means that it does not pose an immediate risk to emergency personnel entering the site.

This type of system helps ensure safety by providing clear communication about the building's status, allowing for efficient assessment and response based on its condition. It is important as it guides firefighters in determining how to proceed with their operations, especially in emergency situations. Other markings suggest varying conditions, such as ongoing investigations, renovations that may impact safety, or indications of potential structural issues, but an empty box specifically reassures that there is no immediate concern regarding the building's stability at that time.