Fire Station Solar-Powered Flashing Beacons: A Hot Way to Stretch Your Budget by Joseph Wise As urban areas grow more congested,traffic issues surrounding fire stations havebecome more critical. The traditionalapproach to fire station safety has been toinstall static signs in advance of the stationand sometimes, pavement markings in frontof the facility. Unfortunately, drivers tend tobecome oblivious to static warning devices.

In the last 20 years, traffic agencies haveadvanced to using full-blown signalassemblies for fire stations, especially onarterials where high traffic volumes make itdifficult for emergency vehicles to enter thetraffic flow.

These traditional systems primarily consistof a control cabinet, two mast arm signalsand a pre-emption device. They areexpensive and time consuming to install asthey require hardwiring from the controllerto each of the signals. Their costs rangefrom $50,000 to $65,0000 per fire stationfor a set of signals. This creates a financialburden for any agency with limited funding.

An affordable and reliable option to thetraditional signal assembly for fire stationsis the solar-powered flasher with radio links.Solar-powered flashers eliminate the needto hardwire the signals to AC power or to acentral control point, where most of thecosts occur. Adding to their practicality andaffordability, solar electric module pricescontinue to decrease. LED lamps aregetting cheaper as well as more efficient,and license-free radio links continue toimprove both in cost and quality.

In recent years, manufacturers have fieldedsystems around the country which arespecifically targeted to these applicationsand have proven the affordability and

reliability of solar-powered fire stationflashers. As with any properly designedsolar-powered system, it's critical that theend user correctly define the load config-uration (quantity and size of lamps perpole); the number of hours per day ofanticipated use (duty cycle) and thegeographical area in which the equipmentis to be used. (See my article “WirelessTraffic Control Solutions” IMSA Journal -July/August 2002, pp 48 - 59.)

Presently, two types of systems areavailable for fire stations. The first, andmost basic, Type I, consists of one or twoamber beacons situated in advance of thestation. The Type II system is morecomplex: a combination of amber and redlamps placed in advance or immediately infront of the station.

Each system can be configured for remoteactivation three ways: from either a hand-held radio transmitter; a wall-mountedtransmitter assembly; or an optical detectorunit with a radio transmitter.

There are two types of timing controlalgorithms for the systems: distributed andcentralized. The timing logic in thedistributed system is located at each of theflasher units. In the centralized system, thetiming logic is located at the transmitterstation. The choice of distributed orcentralized timing is largely determined bythe type of activation source used in theproject.

Projects which require handheldtransmitters will have distributed timinglogic, as the transmitters generally transmitan activation signal and are incapable ofrunning timed sequences. Systems using a

Figure 1 - typical Type I firestation flasher with 2 LEDlamps

Figure 2 Type I fire station withconfirmation strobe beacon

fixed transmitter can be configured witheither a central or distributed timing logicset up, yet may benefit from use of centraltiming control logic since the position of thetransmitter and receiver remain fixed.

Type I controls can be fairly simple. Theelectronics package includes the solarcontrols, radio receiver and the timingcontrol logic for the distributed timingapproach. Timing control logic can be assimple as a time delay relay or, for a moreuser-friendly approach, a micro-logicmodule with an LCD user interface screen.With a logic module, the user can keeptrack of the number of activationcommands received by the unit; view theprogrammed run time; run control logic selftests; and depending on the radio, monitorfor loss of the transmitter.

Figure 1 shows a typical Type I fire stationflasher with two 8-inch amber LED lampsand distributed timing logic.

With centralized timing on a Type I systemthe logic control module is omitted as thecentral station's logic control handles timingfunctions and transmits a contact closuresignal to the radio receiver at the flasher.Figure 2 is a Type I with dual 12-inchlamps, distributed logic and a clearconfirmation strobe.

Since it involves both red and yellow lampswith specific sequences of operation, TypeII system controls are more complex. Thesystems are usually configured to provide aflashing yellow interval, followed by a solidyellow interval then finished with a flashingred interval. Type II systems are equippedwith both a radio and control logic sinceself-test functions are necessary for theseunits. Figure 3 is a Type II system mountedon a mast arm pole assembly configuredwith F signal heads and a clearconfirmation strobe lamp activated duringthe red flash interval.

Figure 3 - Type II system installed as a mastarm with type F signal heads

Figure 4 - Optical detector unitwith radio transmitter package

Both Type I and Type II systems can beequipped with optional confirmationstrobes. This is an effective way for the firetruck operator to observe that the lampshave been activated.

As I have mentioned, there are threechoices for activating the fire stationbeacon system. Handheld or wall mountradio transmitters are the most commonsince they are relatively inexpensive.However, since newer fire trucks areequipped with optical preemptiontransmitters, the optically-activated flashersare being used more frequently.

Both of the major manufacturers of opticallyactivated preemption systems offer DCsensor units which are well suited to theseapplications. These units do not need thecard cages or additional circuitry a fullpreemption detection package requires.

The typical output is an open collectoreasily interfaced to a radio or a logic controlmodule. Figure 4 illustrates an opticaldetector unit mounted at the end of a firestation driveway. Optical detectors canalso be integrated into certainconfigurations of the Type II system bymodifying the program's logic control andchanging the radio from a receiver to a

transmitter. The system in Figure 3 is partof a set of crossing signals with one unitconfigured as a master with an opticaldetector and the other as a slave.

How can these systems improve safety andstretch a tight budget? Without question,fire station flashers help reduce theincidence of accidents. They improveresponse times and alert motorists whenemergency vehicles are leaving the station.

Personnel at the fire station served by thesignals (as shown in Figure 3 ) indicatethey have reduced response time by asmuch as one minute. Furthermore the costof solar-powered systems is substantiallyless than my estimate of $50,000 to$65,000 for a set of traditional signals.

The agency which installed the signals inFigure 3 estimates the total cost—includingconstruction, solar equipment, andpoles—at approximately $32,000.

The agency which purchased the system inFigure 1 spent $9,900 for two Type IIflashers and an optical detector/transmitterunit at the station driveway. In many cases,these expenses would represent the cost oftrenching, boring, conduit work, and siteremediation. In addition to these benefits,these systems can be installed in muchless time than a traditional signal. There islittle maintenance and the systems remainoperational during power outages as theyhave their own batteries. I M S A

Reprinted with permissionIMSA JournalJuly / August 2003