This column is a component of VFIS' "Operation Safe Arrival" initiative, aimed at heightening safety awareness and reducing the frequency and severity of accidents involving emergency vehicles.
Winter is here and when the temperatures fall below the freezing mark, there are a number of special hazards that can present themselves to emergency service organizations. This article will focus on some of these hazards and prevention methods to insure safe operation of fire apparatus.
Take a moment to review the following topics. By acting on them, you can help insure the only thing that freezes this winter is your local ice skating pond and the only thing that falls is the temperature.
Tire condition is always important; but for winter operations it's critical. The two main areas of concern are proper inflation and tread depth. Over- and under-inflation can both cause problems with traction and steering control. Over-inflation can actually reduce the amount of surface area that comes in contact with the road. During long trips (and in warm weather) it can also contribute to blowouts due to overheating.
Under-inflation is a particular winter hazard. In the summer, tire pressure naturally expands several PSI due to heat buildup from contact with road surfaces than can exceed 125 degrees F. However, with colder ambient temperatures in the winter, this natural expansion will not take place leaving the tire under-inflated. This can cause over-flexing of the sidewalls, which can lead to blowouts through physical contact with the road surface. Under-inflation may also make it difficult to install snow chains because of the improper configuration of the tire.
Another critical area of tire condition is tread depth. Inadequate tread depth may greatly reduce moisture displacement and cause insufficient traction on snow or slush covered roadways. Obviously, loss of traction will affect speed and directional control, as well as braking efficiency.
Air brake systems on apparatus need special attention during cold weather operation. Compressed air usually has some water in it. This moisture, which is produced in the compression process, is bad for the air brake system. In cold weather, it can freeze and cause brake failure.
You should routinely drain the water, which tends to collect at the bottom of the air tank, completely to prevent ice from forming in the brake lines. Each air tank is equipped with a drain valve located on the bottom of the tank. There are two general types of systems: manual and automatic. The manual systems can be maintained by simply opening the quarter-turn valve on the bottom of the air tank and draining the moisture.
Some brake systems are equipped with automatic drain systems; however they may also be equipped for manual draining. Automatic systems may be available with electric heating devices. These help prevent freeze-up of the automatic drain in cold weather, but even when so quipped, they should be tested and maintained to insure proper operation.
If we have to explain to you what snow chains are, then there is a real good chance you are not going to need them. However, if you know what they are, and your organization owns a set (or two or six), then there are a few things you need to take care of before you have to use them.
First, visually examine the chains' cross links and replace any that are worn or damaged. Also look for any attachment hooks ("S" hooks) that are spread and re-secure them. Before the threat of snow is present, place the chains on the apparatus to test the fit. Tire wear since the last fitting may cause the chains to be too loose. Tire replacement may make them too tight. Adjust the chains for the proper fit and mark them for proper wheel placement for when they are needed (i.e. "Engine 1, right rear"). As previously mentioned, make certain that the tires are properly inflated to insure safe operation and proper fit of the snow chains. Pre-fitting the chains will also provide you with an opportunity to train personnel on the safe and proper methods of installation.