What is a master stream and when is it typically used?

• A. A small decorative stream
• B. A stream used for interior attack only
• C. A stream used to wash down fire trucks
• D. A large-diameter, high-volume stream used for large fires or when distance/standing off is required

Answer: (D)

A master stream is a large-diameter, high-volume water stream designed to deliver a heavy flow from a distance. It’s used on large fires or when you need to stay back from the flames because of safety or exposure concerns. With equipment like deck guns or portable monitors, these streams can apply water quickly over a wide area, knocking down flames and cooling the fire environment to protect exposed areas and give ground crews room to operate. This makes it the go-to option when interior handlines alone aren’t practical due to the fire’s size, location, or the need to maintain distance. It’s not about decorative effects, interior-only attack, or washing down apparatus.