Which piece of equipment is commonly used to produce a master stream?

• A. Deck gun
• B. Fog nozzle
• C. Handline
• D. Sprinkler head

Answer: (A)

Master streams are large-volume water jets used to control big fires from a distance, requiring a powerful, distance-capable nozzle mounted on the apparatus. A deck gun fits this role perfectly: it’s a high-flow, fixed or semi-fixed water cannon mounted on the engine that the operator can aim and control from the pump panel or nearby, delivering a sustained, heavy stream over a long reach to knock down flames and protect exposures.

Fog nozzles can deliver versatile patterns and are great for interior work or ventilation, but they aren’t built for the sustained, high-volume master streams needed for exterior or long-range attacks. A handline is smaller in diameter and flow, intended for closer, interior, or targeted work. A sprinkler head is part of a building’s fixed suppression system, not a portable device used to produce a master stream from an apparatus.