Which type of information is crucial during the first phase of size-up according to NFA standards?

During the first phase of size-up, pre-incident plans are essential as they provide critical information about the building or location being responded to. These plans include details such as building layout, occupancy types, potential hazards, access points, and operational procedures that have been established prior to the incident. This information helps fire officers quickly assess the situation and make informed decisions about resource allocation, strategy, and tactics during the response.

By understanding the specific characteristics of the environment they're dealing with, firefighters can enhance their situational awareness and improve their safety and the effectiveness of their response. Pre-incident plans serve as a vital reference that can significantly influence the outcome of an incident, making them paramount during the initial assessment phase of size-up.