Photos by Chris Martin
Last month we looked at the functions of the of the engine company with respect to master stream operations. This month we are going to look at different uses of ground deluge systems or ground master streams. The primary job function of an engine company is to suppress fire. This is accomplished by using different size hoses and delivering water from the source to the fire.
Ground deluges or master streams are one way for an engine company to deliver water at high flow rates with effective results. When going into a defensive operation or position, these weapons of mass destruction will be an asset for the fire department. It will also allow for operations to take place at a safe distance due to the reach of the streams.
Just like with an elevated master stream, the options are there for either a straight tip (photo 1) or a combination nozzle (photo 2). Each one will provide sustainable reach for safe fireground operations. Depending on water supply issues, pump capacity, and length and size of supply hose being used, the choice for either tip will vary based upon these factors. Smooth bore tips will require half the pressure at the tip when compared with that of an automatic combination nozzle. This is a great advantage for pump capacity and long hoselay situations. If exposure protection is desired for a building, a fire truck, or even fire personnel, then a combination nozzle tip will be best; a fog pattern can be used, as in photo 2.
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Most ground deluge systems are designed so that a lone firefighter can set it up. Once the system has been set up, it can be manned by a single member, as well. This is to ensure the safety of the system with respect to the end user. It if needs to be shut down right away, then the operator can do so. Newer ground monitors will have a built-in safety function that will allow the monitor to be left unmanned if need be. In such cases, when there is any movement detected, the nozzle will point straight up, driving the monitor into the ground with the opposing force. This will prevent the monitor from moving but still flowing water at the same time.
There are two choices for the diameter of the supply hose for these systems: 4-inch (100 mm) large diameter hose or 2 ½-inch (65 mm) supply hose. If large diameter supply hose is being used, it will be a single-inlet type of system, as opposed to two 2 ½-inch (65 mm) supply hoses required for the smaller size.
Regardless of the size of hose, there is a standard way to set up the ground deluge or master stream so that it will not move away on us while flowing water. In photo 3, you can see how we are going set up a standard system. The supply hose is looped around the front of the device with a minimum 10 feet (3 m) radius. The device is secured to the hose by a piece of webbing, hose strap, or chain that ties the device into the hose. The idea with this setup is that when the hose is charged with water, it will become the anchor system for the device. In photo 3, you can see how a two-hose system would look like set up and anchored to the hose.
Some of the newer ground monitors are designed to only have one 2 ½-inch (65 mm) supply line. This is designed for ease of use and set up. One firefighter can easily grab the preconnected monitor (see photo 4), advance it to where they need it, and set it up with the device not having to be anchored to the hose. The difference here is that the supply hose needs to be at least in a straight line behind the monitor for about six to 10 feet. This ensures that the monitor will work effectively as it has been designed to.
No matter what type of fire apparatus responding to an incident, this type of water delivery can be accomplished. With an elevated master stream, it requires an aerial device or a truck-mounted master stream. Not every fire apparatus will have this, but a ground master stream can be carried and used by any type of fire apparatus.
Another application for the ground monitor is to use it for interior offensive operations. In photo 5 you can see how we can take a small or regular-sized ground monitor and set it up for interior water flow. Why use it in this fashion? Because it will allow us to deliver a vast amount of water with long reach capabilities, allowing us to achieve knockdown in a large building or a long hallway. In photo 6, you will see how the same ground monitor can be advanced inside the structure to accomplish an interior attack. This advancement can be accomplished with a two-person attack team with one firefighter controlling the monitor by shutting it down fully or halfway to move it forward. The other firefighter can help move the hoseline supplying it. Once in position, the monitor can be fully opened again.
Another good use for the ground monitor is if there is a need to advance a smaller hoseline off it. The ground monitor acts like a gate valve where we can attach a gated wye supply one or two handlines, then open the monitor up to supply the gated wye (see photo 7). The advantage here is a large supply line already in place that can easily supply a smaller set of handlines. A good application for this feature is with garden apartments or buildings with long setbacks, requiring a leader line to be used. The ground monitor can act as both negating the need to load a separate leader line on the back of the engine.
With the safety features built in with some of the ground monitors, it is important to note the limitations of the ground monitor. If the monitor shuts off completely when movement is detected, there is no water flowing to your handlines. If the ground monitor’s safety feature is to aim the nozzle straight up but still flow water, then the handlines attached will still be flowing water.
Do not overlook the ground monitor when large water delivery is needed. Pull the ground deluge out from the truck storage compartment and practice setting it up and flowing water.
MORE MARK VAN DER FEYST
Firefighting Basics: Master Streams, Part 1
Back to The Basics: Elevated Master Streams
