By Don Sjolin
Originally published in International Fire Fighter Magazine
From a general perspective, monitors can be categorized into two broad application uses. The first category is fixed mounted monitors, usually made of brass or stainless steel, for use in industrial fire protection systems in such locations as oil and chemical processing facilities. The second, main category of monitors is for use with fire apparatus. These are constructed of lighter weight materials, normally aluminum alloys to aid in reducing overall vehicle weight.
Within this general vehicle category, we can further divide monitors into five subgroups depending on intended use:
- Aerial devices
- Top mounted Deck Guns
- Bumper/Turret mounted
- Hybrid type
Here are the top considerations when buying new monitors.
Weight considerations are extremely important for monitors that are mounted at the end of aerial devices. They are used for pre-piped telescoping waterways with typical flow rates of 1000 GPM (3,785 LPM) to 2000 GPM (7,570 LPM). Basically, these monitors are used as the master stream device, flowing water rather than foam, in a defensive fire operation. Pump requirements to provide adequate pressure at the end of a long aerial are demanding, therefore the internal efficiency or friction loss of the monitor should be carefully considered. Because of monitor location at the end of the ladder or basket, multiple electronic control capability, from both the ladder and from the base of the pedestal on the vehicle, is very commonly accomplished by hard wire electric cabling or radio frequency wireless. Multiple travel stops and the ability to stow to a preset position are other common features of aerial monitors.
The second, sub-group of monitors are deck guns. Employed for quick knockdown or as a master stream in defensive roles, the typical flow rates of these monitors are from 500 GPM (1,892 LPM) to 2000 GPM (7,570 LPM). Both water and foam capabilities are needed with foam being supplied by an internal vehicle proportioning system or through a foam educting nozzle. A popular component to a deck gun is an extension device to provide a means to extend the height of the gun above top of vehicle obstructions. While traditionally hand extended, electronic extenders are now available that raise the gun at the push of a button.
Bumper or turret monitors are identified by the fact that they are typically operated from within the vehicle, often by the vehicle's driver. These monitors are normally electric controlled by either joysticks or toggle switches with a manual override. The bumper units are in fact mounted on the bumper of the vehicles with typical flows of 15 GPM (56LPM) to 500 GPM (1,892 LPM). Applications for these monitors vary significantly and include such areas as forestry/wild land. For a very specialized application, ARFF (Aircraft Rescue and Fire Fighting) vehicles utilize turret mounted monitors, some with hydraulic controls systems.
Increasingly gaining in number of units deployed, portable monitors allow high flows in areas not accessible to the apparatus deck gun. Lightweight offensive units are used for initial rapid attack, thus, issues such as weight and speed of set-up are of utmost importance. Many times, these monitors are pre-connected to hose lines for quick deployment. Lightweight monitors can even be utilized in interior attacks. Since these units are ground positioned, a wide footprint is essential to provide stability and safety on uneven surfaces. Typical flow rates are in the range of 500 GPM. Larger portable monitors take on more of a defensive role, handling exposure control with higher flow rates up to 1250 GPM.
The last sub-group is a hybrid of the deck gun and portable monitor. This versatile device functions as a deck gun that can be detached and deployed also as a portable ground monitor. These can be either manual, electronic or radio frequency wireless. Flow rates vary from 350 GPM (1,325 LPM) to 1250 GPM (4,731 LPM).
Control options are greater than ever and should be considered not merely a matter of personal preference but integral to a department's operational goals for efficiency and safety.
Most are familiar with manual control; however options and considerations still exist. The most important of which is assuring ergonomic and safe operating conditions. The inherent placement of a monitor atop an apparatus creates the potential for pinch points as wells as falls. The two most common manual monitor control configurations are 1) tiller and 2) geared hand wheel. Tiller control allows the monitor to be positioned very quickly but compared to hand wheel control can require greater operating force. Hand wheel controls generally remain stationary at the back of the monitor letting the operator remain in place as the stream is directed while tiller control requires the operator to move with the monitor.
These offer a significant advantage in regards to safety. Typically the control point for an electrically operated monitor is at the pump panel. Employing electric control, the firefighter is not required to climb atop the apparatus to operate the monitor. The United States' National Fire Protection Association, in its guidelines for apparatus construction, recommends the use of remotely operated monitors "without the need for a person to climb to the top of the apparatus". Electric control also allows control from multiple locations around or on the apparatus. Multiple control points are most often specified for aerials driven by the need to provide monitor control in the bucket as well as at the pump panel. The actual operator interface for an electric monitor can vary from simple toggle switches to an integrated multi-function joystick. During specification, consideration should be given to the size of monitor required as well as control locations to assure the vehicle's electrical power and wiring provisions can accommodate the monitor.
Hydraulic and Pneumatic Controls
These offer largely the same benefits as electric control and were really the earliest options fitted. With the ever increasing flexibility of electric controls, hydraulics and pneumatics offer little to justify their cost and demanding maintenance.
As with nearly everything else, fire monitors are now also available with wireless control. Wireless control essentially provides all the advantages of an electric monitor while further allowing the operator to be positioned away from the apparatus altogether. Freed from his position at the apparatus, a firefighter can better site the monitor stream, remain in a safer less congested area, and perform other fire ground tasks. Because they typically utilize more advance controls, wireless monitors often also provide features such as automatic stow, programmable stops, multiple travel speeds, and programmable oscillation. While the wireless technology required in firefighting monitors might not be considered leading edge by consumer electronic standards, the application to firefighting can be challenging.
Apparatus specifications should demand that the wireless system has been properly design and configured for use in firefighting. In many applications wireless control can actually be an economic decision. In the case of aerials, where multiple control points and long cable runs can drive up the cost of a traditional hardwired electrical control system, wireless monitors are often lest costly overall.
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