By Craig Weeks
Visually, the emergency warning lights that were once incandescent light bulbs with noisy spinning rotating assemblies or flashing sealed-beam lamps drawing up to 100 amps or more on a single vehicle have been replaced with the light emitting diode (LED), which is actually not a bulb at all and draws less than half the amps for the same number of light positions with more visible light output. But just like fine fashion, old styles seem to come full circle in the fire service as manufacturers reintroduce the beacon and even rotating light bar styling with modern LED technology. And, flash patterns can be easily adjusted—even altered on scene—through smart phone apps. But, take caution, especially with commercial vehicles, when introducing flashers, such as with headlights, into the chassis electrical system because they can play havoc with the chassis PCM (PCMs described in Part 1).
Audibly, the old school power-draining mechanical siren is still a traditional favorite, including mine. Besides the sound of a real fire truck, the mechanical sound waves tend to penetrate vehicles and wrap around structures better than most modern electronic sirens. But, technology has improved the electronic siren output, including some that now actually vibrate the pavement to get the attention of even the most distracted driver or best sealed passenger compartment.
Inside the cargo compartments, LED strip lighting—either rigid or flexible and operated by magnetic switches that are more reliable and less sensitive to moisture and dirt than mechanical plunger switches—illumination is so powerful that I pity the helicopter pilot wearing night vision goggles while trying to land on an adjacent helipad.
In the cab, most of the nondriving functions and apparatus monitoring are controlled by touchscreen displays instead of switches. Engine and chassis gauges provide real time information directly from the ECM and PCM. Calibration is done through computer software, and we are providing some of this information to the officer as well by daisy chaining to additional instruments. Automated vehicle location (AVL) uses GPS technology to provide a vehicle’s location to dispatch the closest unit rather than the district apparatus to improve response times. And, all of this information is also available in real time to managers by satellite and cellular signals to a desktop computer via the Internet.
Vehicle data recorders (VDRs) provide a recorded document of driving habits and activity before, during, and immediately after a significant event. I believe that the fire service will also adopt in-cab audio and video recording in the very near future. Why not? Law enforcement does. Is this all to reduce liability or for “Big Brother” to watch? That’s for you to decide, but I always tell our personnel, “If you are asked how fast you were going when involved in an accident, they are only asking to see if you are going to lie because they already know the answer.” This information is also discoverable in the event of a lawsuit.
Safety features include enough air bags to nearly encapsulate the occupants in the event of an impact, and electronic stability control (ESC) will take over throttle and braking if the PCM senses the vehicle is making an unsafe maneuver. Passenger seats, once little more than two pieces of plywood attached to a frame with foam padding, now emulate those in the cockpit of a fighter jet wrapping around the occupant with seven-way adjustability.
This article describes a highly technically equipped fire apparatus but does not limit the potential nor does it promote any necessity of specifying your apparatus in such a manner. Except for the chassis and powertrain computerized technology, most other aspects are optional. I personally prefer a “hard-wired system” because it is less expensive and simpler to diagnose on the side of the road and you aren’t going to let the magic smoke out of an expensive computer module by using a test light. However, it is cumbersome and takes up more space. Electronic controllers and servos are very accurate when programmed and working properly but are very sensitive to environmental conditions and can hide and misdirect the actual cause of a problem.
Most importantly, when developing new apparatus specifications, all technology needs to be taken into consideration when it comes to the electrical system. Technology does not like low voltage or voltage spikes. What would have been an insignificant voltage drop previously, even a dirty ground, may cause significant problems. I always use a dedicated battery bank isolated from the engine starting batteries to maintain critical electronic components. I believe there is a good balance between high tech and traditional technology when it comes to fire apparatus specifications, but that point of balance does have variables that depend on department-specific operations. The question is: have you found the balance?
CRAIG WEEKS is division chief/fleet manager for the Los Angeles County (CA) Fire Department and president of Specialty Fleet Consulting.