What is a critical consideration when using a master stream inside a building?

When utilizing a master stream inside a building, a crucial consideration is that it cannot be operated when firefighters are inside. This is primarily due to the significant volume of water and the force with which it is discharged from a master stream device. The high pressure and large water flow can create hazardous conditions, including the risk of injury from forceful water impacts, reduced visibility, and potential structural damage.

Operating a master stream in confined spaces can also displace heat and smoke, which can overwhelm firefighters and complicate rescue operations. Therefore, for the safety of all personnel, it is best practice to use a master stream from an exterior position when firefighters are inside the structure, ensuring that they are not exposed to potential dangers associated with such powerful firefighting tools.