Under which circumstance is it inappropriate to use exterior to interior streams?

Using exterior to interior streams is typically considered inappropriate when the location of the fire is unknown. In firefighting, it is crucial to identify the exact location of a fire before applying water. If the fire's location is uncertain, directing water from the outside into the structure could inadvertently push fire and smoke towards potential victims or firefighters inside, creating a more dangerous situation. Additionally, it may hamper the efforts of rescuing individuals, as you could unintentionally obscure their escape routes or create an environment that leads to increased visibility issues and greater heat release within the building.

In situations where multiple fire engines are available, it may allow a more coordinated approach to firefighting. If an interior escape route is blocked, firefighters must quickly assess the situation, and using exterior streams might provide an alternative method of intervention that could help clear the fire. Lastly, clear visibility generally allows for safer firefighting strategies, and firefighters can visually assess the fire’s location, which is contrary to the condition that renders exterior to interior streams inappropriate.