Which factor indicates the deployment of a master stream during firefighting efforts?

The deployment of a master stream during firefighting efforts is primarily indicated by the fire size. In situations where a fire is large and beyond the capabilities of standard handlines, firefighters will opt for a master stream, which delivers a high volume of water to effectively combat significant fire conditions. This tactic is especially important in suburban environments where structures may be close together, and the risk of fire spread increases with larger fire sizes.

The decision to utilize a master stream is also influenced by the ability to reach the fire effectively and the need to quickly reduce the intensity of the flames to protect not only the structure being attacked but also surrounding exposures. In many cases, the sheer volume of the fire dictates the need for more aggressive tactics, such as using master streams, to ensure the safety of both firefighters and civilians in the area.