What is the water delivery device that flows a minimum of 350 gallons of water per minute called?

A water delivery device that flows a minimum of 350 gallons of water per minute is referred to as a master stream. Master streams are typically used in firefighting operations for their ability to deliver high volumes of water over greater distances or in situations where a substantial water application is required to control a fire quickly. They are often mounted on apparatus or positioned on the ground and are designed for use in large-scale incidents.

The capability to deliver such significant amounts of water is essential for effectively combating larger fires or when dealing with industrial or commercial structures. Master streams include devices such as portable monitors, aerial streams, or deck guns mounted on fire apparatus. Utilizing a master stream can rapidly suppress a fire, protect exposures, and improve overall firefighting effectiveness.

Other choices, while closely related to firefighting tactics, either do not meet the minimum flow requirement or pertain to different types of attack strategies. For example, a large handline typically flows less than 350 gallons per minute, and a two-and-a-half is a specific size of hose that typically flows between 250-300 gallons per minute. A combination attack line is designed for versatility but also does not reach the flow rates associated with master streams.