Setting up master streams around the perimeter of a burning building is dangerous. Firefighters using ground or aerial master streams are in danger from collapses, explosions, falling overhead power lines and blasts of radiated heat from a burning structure. Large-caliber master streams have saved many firefighters’ lives and prevented the destruction of millions of dollars in property. However, if not used properly, master streams can be deadly.
A fire department master stream is a ground-based or aerial stream with a fog or straight-stream pattern capable of delivering more than 300 gpm to a fire. Handheld nozzles delivering this amount of water volume and pressure are too difficult to control and direct by firefighters, so mechanical, electrical or hydraulic assists are required. Fog streams with a delivery rate of more than 300 gpm and solid-stream nozzles of 1½ inches or more in diameter are considered master stream nozzles.
There are two types of master streams: ground and aerial. Ground-based master streams include deck guns mounted permanently on top of apparatus and portable deluge nozzles that can be operated from atop an apparatus or at ground level. Aerial master stream are nozzles mounted on top of aerial ladders, snorkels and aerial platforms.
Platform Vs. Ladder
In 1962, the FDNY bought its first aerial platform. The chief chose a telescopic-boom aerial platform instead of the articulating-boom aerial platform made famous by the Chicago Fire Department in the 1950s. The telescopic boom extended outward, with the thinner tube sections sliding out from the wider sections. The FDNY chose the telescopic boom because of the city’s narrow streets and overhead wires. New York City called this aerial platform a “tower ladder” and firefighters referred to the enclosed platform at the tip as a “bucket,” or basket.
The aerial platform was one of the great firefighting apparatus improvements of the 20th century, improving aerial rescue and master-stream effectiveness. Unlike an aerial ladder, the aerial platform allows the rescue of several people trapped at different windows during a fire. The firefighter in the bucket uses the controls to move the boom from window to window accumulating victims into the bucket and then like an elevator safely lowering them to the street. The aerial ladder cannot be moved from window to window with firefighters and people on the tip. The aerial ladder does not have a set of controls at the tip which allow precision placement at upper reaches of a burning building. With the aerial platform, there is no need to negotiate terrified people step-by-step down the thin ladder rungs of an aerial ladder.
The other important feature of the aerial platform is the aerial master stream nozzle in the bucket and its ease of operation. The aerial platform has a permanent waterway inside the telescopic boom. Unlike a master stream used from an aerial ladder, there is no need to stretch and tie a hose on the ladder, and then attach a clamped portable nozzle at the tip and then hope there is no problem with the halyard ropes from the nozzle to the turntable tangling up and preventing up-and-down stream direction. With the aerial platform, you need only to stretch a large-diameter hoseline into the aerial platform inlet and you have a powerful aerial master stream. This nozzle can be controlled safely by a firefighter securely belted and standing upright in the bucket. A close-up, pinpoint approach to the fire by the firefighter in the bucket and the aerial platform’s maneuverability make this master stream much more effective. With the aerial platform, the switch from offensive to defensive firefighting is accomplished easily.