We see fire engines all the time, but have you ever stopped to think about all of the things that these machines do? Fire engines are amazing pieces of equipment that allow firefighters to perform their jobs and get to fire scenes quickly. The important thing to know about a fire engine is that it is a combination of a personnel carrier, tool box and water tanker. All three components are essential to fighting fires.
Pump It Up
The primary function of any pumper/tanker fire engine is to carry water in a water tank or suck water in from an outside source, such as a fire hydrant, drop tank, swimming pool or lake. tank is inside the vehicle, it holds 1,000 gallons (3,785 liters) of water and it runs down the center in the rear of the truck. A drop tank is like a big aboveground pool that can hold about 2,000 gallons of water. A 6-inch diameter, hard suction line is used to suck water out of the drop tank or other exterior water source. Water stored in the engine's tank or sucked through an outside source is then discharged through water lines, or hoses. These lines are connected at points around the truck. We'll look at all the different lines later.The large black pipes on the side of the engine are the hard suction lines. The walls of these pipes are rigid so that the suction of the pump does not collapse them. The heart of the pump/tanker is the impeller water pump. You control the hoses using the truck's pump panel on top of the fire engine. The pump panel is a series of levers and switches that controls how much water is flowing and which lines are being discharged. When arriving at a fire scene, the driver will jump out and climb to the top of the truck to begin pump operation. An indicator -- a series of red lights on the pump panel -- lets the operator know how much water is left in the tank. The first thing the pump operator is going to do is make sure that the valve between the tank and pump is open. An electric switch on the right side of the pump will open that valve, and ensure that water is flowing into the pump. Next, the operator will check to see which lines have been pulled off the fire engine by the firefighters, and the operator will discharge those lines. "Discharge" means that water is allowed to flow out of the pump and into the hose. The lines are color-coded to make it easy for the operator to know which lines to discharge. The color of the line corresponds to a plate below each lever on the pump panel. Most of the discharging is controlled by a built-in electronic device, called a mastermind. It automatically controls the pump, and runs the pressure up or down. It also has a built-in relief valve, so that if one person suddenly cuts off a line, the pressure from that line doesn't automatically get fed into another line. This truck also has a foam system, and carries about 20 gallons (76 L) of foam. The foam tank is embedded in the main water tank. Pumper/tankers carry different types of foam. This particular truck carries Class A foam, which can be used to saturate materials inside a structure to keep those materials from re-igniting. Class B foam is used to fight car fires and other fires where flammable liquids might be present. In the next section, you'll learn more about the various hoses on the fire engine.
Hose It Down
There are many types of hoses on the fire engine, and each has its own specific role in putting out a blaze. Hoses, also called lines, will put out different amounts of water depending on the hose length, diameter and the amount of pressure in the pump. When responding to a house fire, the firefighters will immediately pull off the crosslay hoses. These lines are located directly below the pump panel. They lay out in the open and are light, so they are easy to get off the fire engine for attacking a fire. Crosslays are 200 feet (61 m) long, have a diameter of 1.5 inches and can gush water at 95 gallons (360 L) per minute. For smaller fires, such as small wood fires or chimney fires, the small booster line is adequate. A booster line is the smallest hose on the truck and has a diameter of about 1 inch. Located directly above the pump panel is the deluge gun, also called a deck gun or master stream. Just by looking at it, you know why this water cannon carries those names. The deluge gun is used to put a lot of water on large fires. It can put out in excess of 1,000 gallons per minute. "If we get a big fire, like a house fire that we can't control with handlines, we can darken it down with that," Doug Mchose, of the Bayleaf Volunteer Fire Department, said. "We can use that on it for a couple of minutes to knock it down to where we can get in there." The truck also has at least three lines called preconnects. These lines are preconnected to the truck in order to save time at the fire scene. There's one preconnect on the driver's side, one on the back and one on the captain's side of the truck. These lines are between 1.5 and 2.5 inches in diameter, and can put out 250 gallons (946 liters) per minute. A 5-inch-diameter hose is stored on top of the truck. There is a total of 1,000 feet (305 m) of this line, but it is stored in 100-foot sections. This is the line that the firefighters will hook up to fire hydrants. There's also another 2.5-inch line stored on top of the truck. In one of the compartments on the captain's side of the truck, there are extra sections of hose. There are two extra sections of the 5-inch hose: a 25-foot and a 50-foot section. These two sections are called curb jumpers, because they typically lay on the curb. These sections give firefighters just a little bit more line to connect to a fire hydrant without having to get another 100-foot section down.
you can catch me later at[email protected]