A master stream is basically defined as a heavy-caliber stream delivered through a master stream water delivery appliance. A master stream is used when flows surpass 350 gallons per minutes (gpm), becoming too difficult to be delivered from a handline operation because of nozzle reaction. The master stream, which is high in flow and usually a straight stream, is produced with a smooth bore tip or some type of combination nozzle.
RELATED FIREFIGHTER TRAINING
HIGH-PRESSURE MASTER STREAM OPERATIONS USING SMOOTH BORE TIPS
The purpose of high-pressure smooth bore tip operations used in conjunction with a master stream is to provide the required gpm to extinguish the fire problem with a high-velocity stream that improves the reach and penetration capabilities of the firefighting stream while still maintaining efficient stream performance.
Maximum allowed inlet pressure to the master stream appliance. The three master stream appliance most commonly used for the municipal fire service are Task Force Tips, Akron Brass, and Elkhart Brass. Listed below are the specs for each of the three brands of these appliances in the fixed mode.
Task Force Tips, 200 psi inlet pressure–1,250 gpm, 631 nr; 2,000 gpm, 1010 nrAkron Brass 200 psi inlet pressure–1,250 gpm, 631 nr; 2,000 gpm, 1,010 nrElkhart Brass, 200 psi inlet pressure–1,250 gpm, 631 nr; 2,000 gpm, 1,010 nr
2. Maximum allowed flow for the master stream appliance.
3. Maximum allowed nozzle reaction for the master stream appliance. This is based on a 100 psi combination nozzle at the rated flow of the appliance. For example, a 1,250 gpm master stream appliance using a 100 psi combination nozzle flowing 1,250 gpm has a nozzle reaction of 631 pounds.
5. Stream angle capabilities for the appliance/apparatus combination.
- Running out of water;
- Running out of throttle;
- Running out of revolutions per minute.
- The stream’s accomplishing its goal;
- Opposed by other rules set by the department
- Opposed by orders from the company officer.
(2) This deck gun is using a 1¼-inch smooth bore tip flowing 623 gpm at 180 psi np.
Working a brush fire from a fixed master stream appliance is a heck of a lot easier than pulling hose. When possible, a fixed master stream can make very large sweeps in burn areas with the above mentioned high-pressure stream operations. In fact, the 1⅛-inch tip application will more than likely be the tip of choice for this operation.
Paul Shapiro is director of Fire Flow Technology. He is a nationally recognized instructor on large-flow water delivery. He is also a retired engineer from the City of Las Vegas (NV) Fire Department. He has authored numerous articles for fire trade magazines. He has been in the fire service since 1981 and is author of Layin’ the Big Lines and produced the first in a series of videos on large-flow water delivery. He is available to answer questions; he can be reached at (702) 293-5150 or Layinline @aol.com.