What is the second major consideration during size-up of a building?

The second major consideration during the size-up of a building is use and occupancy. Understanding the use and occupancy of a building is essential for firefighters as it informs them about the type of activities that occur within the structure and the potential hazards present. Different classifications of buildings have varying levels of risk associated with them based on what takes place inside.

For example, a residential structure may have different hazards compared to an industrial facility or a school. Knowing the occupancy type helps firefighters assess the likely presence of occupants, the materials stored or present in the building, and potential hazards that might affect rescue operations or necessitate specific firefighting tactics. Recognizing these factors allows for more effective planning and prioritization during emergency response, influencing decisions such as where to establish command, how to approach the fire, and what resources to deploy.

While building height, fire load, and presence of occupants are also significant considerations, understanding the specific use and occupancy is paramount as it directly impacts the safety of both occupants and responders alike.