Apparatus Mounted Master Streams

Almost every engine company has an apparatus mounted master stream device.  Call it a deck gun, deluge set, wagon pipe, pipe, monitor, etc, its operating on the same principle, to deliver large volumes of water for large fires.  With these devices come a few points that aren’t often considered and are also overlooked and some common operational errors.

Design/Limitations/Flow.
There are two common types of master stream devices on most of today’s engines, the removable deluge set, that can be attached to a base for portable use and the fixed mount electrically controlled monitor.  There are also some models of fixed pipes that are manually controlled.  Removable deluge sets are typically rated for a maximum flow of 1250 GPM, whereas the fixed electric and manually operated models may be capable of operating up to 2000 GPM.  Why?  Simply a matter of safety for the most part.  Devices that are used in the portable mode are faced with even lower operating limitations, because the nozzle reaction (backpressure) can subject the device to tipping over or sliding along the ground from the high forces.  The portable deluge sets may be limited to between 800 and 1000 GPM, depending on the type of base that is used.  As with any equipment, check the manufacturers warning labels and operational guides.

Tips for the devices can be a hot topic for debate; I'll stay away from that battle at the moment and simply point out the options.  Removable deluge sets can be purchased with smooth bore tips and/or fog tips.  There are some very common tip options from the major manufacturers.

Smooth bore tips come in the stacked arrangement, with four typical discharge orifices.  1 3/8" is the top, or smallest tip.  It delivers about 500 GPM, next is the 1 1/2" tip for about 600 GPM, the 1 3/4" tip for about 800 GPM and the 2" tip for about 1000 GPM.  Some departments opt for a single smooth bore tip; however, this limits your ability to flow more or less water based on the needs for the situation.  There are triple stacked tip sets on the market as well, usually having some varying tip options.  There are stacked tips where the largest base orifice is only 1 1/2", and using these tips on a device that’s rated for 1250 GPM will limit your flow to about 600 GPM, or half its capability.  Be aware when purchasing tips.  A stream shaper pipe is critical for a crisp and well focused smooth bore stream.  The longer models, which are about 12-18" in length will provide a better stream than the shorter ones.

Fog nozzles come in three basic types, selectable gallonage, fixed gallonage and automatic.  There are low pressure automatic and fixed gallonage models as well.   Whatever tip you choose, it’s always best to have smooth bore and fog tips available.  Whichever tips you do not keep on the gun, are best mounted next to or near it, so changing over isn’t a hassle.

Mounting configurations
Most of these devices are mounted over the pump house, midship on the engine.  Top mount pump panels offer ease of access to operate the devices, whereas side mount panels make it harder to access them.  It is probably for this reason that many of today’s side mount pump panel engines are showing up with electrically controlled master stream devices.  The location of the device, how it is mounted and other apparatus features will determine the useful range of stream movement.  Whenever possible, it’s best to design the device so that it can project a stream 360 degrees at about zero degrees elevation.  This ensures more stream "scrub" area, and allows for the stream to reach first floor level windows in more instances.  Raised cab roofs and telescopic floodlight heads often interfere with nozzle or stream rotation and elevation.  Apparatus with large booster tanks and hose beds may hide the device in their shadow, reducing their effective e use to two very small areas off of either side of the apparatus, and reducing use over the front and rear to angles in the vicinity of 45 degrees or more.  To accomplish this range of motion, telescopic pipes or articulating devices are available.  Such devices are Akron’s "Hi-Riser" deluge set, which has a hinging waterway, which allows the gun to operate at a higher range.  There are also electric telescopic pipes such as TFT's "Extend-A-Gun" or Elkharts "Extender".  Other extending pipes can be attached as necessary such as "The Pipe" by Elkhart, and the "Upper Deck" by Akron.  However you accomplish getting the gun up high enough, it’s clear, there are definite advantages.

Operating the Devices
When operating apparatus mounted master streams, it’s important to remember a few things;

• Water supply from tank water is limited by two factors, the size of the tank and the size of the tank to pump piping.  Knowing what size tip you are flowing from will give you an idea how much water you will be able to flow from your booster tank.  In addition, the piping that supplies water to the pump is a critical piece of the success of the operation of the gun when operating from the booster tank.  It’s fair to say you can expect 400-500 GPM from a single 3" tank to pump pipe/valve and 800 to 1000 GPM from a 4" tank to pump valve, but you must test and verify the flow to be sure.
• Abide by all manufacturers recommendations
• The devices are typically not limited in their operating range when mounted to the apparatus.  This is important because the stop pin that prevents the removable devices from being lowered past about 30 degrees when in the portable mode must be pulled to operate at lower elevations when truck mounted.  This pin is often an unknown device to many firefighters, which can be evidenced by the number of master streams you see cascading over burning buildings, while the fire burns merrily under the rain shower of the passing stream.
• Use a tip size appropriate for the fire, using the smallest smooth bore tip is often a common mistake.  Use the largest possible tip for the best fire knockdown potential.
• Placing an inline gate valve at the base of the stream shaper will allow you better control of the stream when performing blitz-attacks.  The driver can charge the waterway and then ascend the apparatus and open the gate and direct the stream.  This saves precious water from errantly being thrown onto the ground or over the building, and affords better aim and water usage.  The inline valve should not be closed all the way, but left a turn or so cracked, to reduce the chance that water hammer when charging the riser does not cause damage.
• Master streams from ground level lose effectiveness past the third or fourth floor level, depending on the distance the rig is from the building.  It is often a good idea to divert the water to the more effective aerial streams when they are available for such situations.
• Knowing the scrub area of your stream is important when you are spotting your rig for known master stream operations.  You should consider this factor, but not cause havoc for additional companies that are coming in, by stopping in a spot just so you can use your wagon pipe.  In some cases, a company may elect to dump their tank water through the pipe and then spot in a different location once the tank is exhausted.  Be flexible and think ahead to the impact this decision makes.

The summary of my little article is simply to point out that this device is often overlooked to its potential flexibility and versatility, and there are often some key errors made when they are placed into operation.  Like any other tool, train, train, train.

Apparatus Mounted, removable deluge set on a side mount pump panel. Notice how floodlights can obstruct the tip.

Another example of a device mounted above the pump panel, on a side mount pump. Notice how this device is boxed in on several sides. The tip is lowered to the pin stop point as well. In this position, the effectiveness of this device is minimal.

Pulling the pin and rotating this "Hi-Riser" device now allows it to operate clear of the body obstructions. The elevation stop pin has not been pulled, so this is as low as the gun will operate unless the pin is pulled.

On the "Hi-Riser" device, this is the pin that you pull to rotate the device to its elevated position.

At its elevated position, this device can project its stream at less than zero degrees throughout its complete 360 degree rotation. The elevation stop pin must pe pulled to lower the stream angle

This is the elevation stop pin on the device, that must be pulled to operate it at low elevations when mounted on the apparatus

This raised cab roof will impede lower elevation nozzle scrub area. An extension pipe would solve the issue easily.

This is the elevation stop pin on al older device. Be familiar with the pin/limiting mechanism on your devices

Fog nozzle stored at point of use

"Quad Stack" smooth bore tips. 1 3/8", 1 1/2", 1 3/4" and 2" orifices

A gate valve at the base of the stream shaper pipe

The portable base for this device is limited to about 800 GPM. It is stored on top of the rig, to free up space in compartments, because this device is typically not used often

This is the approximate stream elevation you can expect if you do not pull the stop pin on the device. This stream will overshoot the roof of most 2 story dwellings if the rig is within any resonable distance

 Stay Safe!