The Incident Command System defines seven types of engines. Departments need to understand how to match each type to the appropriate job when fighting wildland fires.
The ICS engine designations are designed to give incident commanders a better idea of what resources are available to them at large-scale wildland fires. Under this system, rather than saying “we’re bringing a brush truck,” departments should say, for example, “we’re bringing a Type-6 engine.” That tells the commander that the unit has a small pump and tank, very little hose and a minimum crew of two. Such an engine would be better suited to patrol, limited attack in light fuels and mop-up operations, rather than structural protection or direct attack in heavy fuels.
Here is a quick summary of the various ISC engine types with recommendations on how they might be best used by individual departments when operating in their own jurisdictions. The newest designations use Arabic numerals (for example, Type 3), but older designations used Roman numerals (for example, Type III).
Type 7. These small units usually have pumps with minimum ratings of 10 gpm at 100 psi, tanks with 50- to 200-gallon capacities, 200 feet of 1-inch hose and a crew of two. Skid-mount pump and tank units with single booster reels are common. They are used for mop-up and patrol duties, as well as control of fires in light fuels where burning conditions prevent rapid spread. A crew of one is common when operating within their local area.
Type 6. These popular brush trucks have pumps with minimum ratings of 30 gpm at 100 psi, 150- to 400-gallon tanks, 300 feet of 1½-inch hose plus 300 feet of 1-inch hose and a crew of two. Their primary function is mobile attack of fires in light fuels, but they also can be used for stationary attack, mop-up and patrol duties. A crew of three allows more extensive operations.
Type 5. These units are characterized by tanks of 400 to 750 gallons for operations in areas where water sources are scarce. They have pumps with minimum ratings of 50 gpm at 100 psi, but otherwise carry the same amount of hose and crew as Type-6 engines. They are used for direct attack and line control in light to moderate fuels.
Type 4. These big units are identical to Type-5 engines, except they carry 750 gallons or more of water. Certain state and federal departments use them for direct attack in large wildland areas. They are big and heavy, so medium-duty or heavy-duty chassis are common. Proper tank baffling and low centers of gravity are important for stability.
Type 3. The California Department of Forestry made these units popular, and the design is now used by many other departments. The minimum specs include pumps with ratings of 150 gpm at 250 psi, 500-gallon or larger tanks, 500 feet of 1½-inch hose plus 500 feet of 1-inch hose and a crew of two. The higher pump pressure ratings are designed for use with long hoselays in steep terrain. In actual practice, these engines spend a lot of time performing structure protection duties, so they generally have 500-gpm pumps, more hose, short ground ladders and crews of three to five.
Type 2. This is classified as a structure pumper, rather than a wildland pumper. It has a pump with a minimum rating of 250 gpm or more at 150 psi, a 400-gallon or larger tank, a larger load of structure hose, 48 feet of ground ladders and a crew of three. These engines are best used for structure suppression and protection where pressurized hydrants are available.
Type 1. This is a full structure pumper. The principal upgrades from Type 2 engines are that the Type 1 has more 2-1/2-inchch hose, a 500 gpm or larger monitor and a minimum crew of four. Type 1 engines are best positioned on level, paved roads where pressurized hydrants are available. Unless they are specifically designed with short wheelbases and good ground clearances, they should not be assigned to areas where they have to negotiate narrow roads and driveways or operate off paved surfaces.
Matching Ford Chassis Designations to Tank Size
The Ford F-Series is a popular chassis for many Type 5-7 wildland pumpers. To avoid overloading the chassis, always match the total weight of the pump, tank, water, equipment and personnel to the available payload figure.
As a rough rule-of-thumb to determine the maximum tank size, match the first digit of the Ford model designation with the tank size in hundreds of gallons. For example, the Ford F-250 chassis usually can handle a 200-gallon water tank — match the “2” in the 250 designation to the 200-gallon tank. The F-350 can handle a 300-gallon tank, the F-450 can handle a 400-gallon tank and the F-550 can handle a 500-gallon tank. This rule works for apparatus with low-sided bodies, a minimum of equipment and one- or two-person crews. Apparatus with larger bodies, more equipment, or four-door cabs to carry more personnel should round down at least 100 gallons in tank size for each model.
When in doubt, contact your local Ford truck distributor for assistance in matching the proper chassis to your expected payload.