Field Testing

Field testing of the portable vehicle washer was completed in 2002 and 2003. Our original prototype (slightly different from the unit described previously) was used during the field testing. The final design addressed problems observed during field testing.

Cathedral Fire

From August 6 through 9, 2002, the prototype vehicle washer was set up and operated during demobilization of the Cathedral Fire camp near Darby, MT. The vehicle washer was set up on a level spot at the Deer Creek trailhead in the Bitterroot National Forest about 1½ miles from the fire camp.

The location's one drawback was that vehicles could not drive through the washing station. Instead, they had to drive forward onto the mat and back out. This presented problems when other vehicles were lined up and the vehicles being washed did not have enough room to turn around and leave.

A total of 74 vehicles were washed. The vehicles included cars, pickup trucks, sport-utility vehicles, hotshot crew vehicles, fire engines, and a school bus. All the used water ran down to one corner of the mat where it was pumped into the settling tanks. The wash water supply tank had to be refilled three times (about 175 gallons per refill).

The washing system did an excellent job. Washing a standard pickup truck, sport-utility vehicle, or car took about 2 to 3 minutes. Hotshot crew vehicles, fire engines, or tankers took about a minute or so longer.

The MTDC underbody washer did an excellent job, as evidenced by the amount of dirt on the mat and dirty (but filtered) water that was being used to wash the vehicles. The vehicles appeared clean after drying and were mud free. After the washer was returned to MTDC, the settling tanks had a lot of sediment in the bottom and were difficult to drain. Tanks should be partially drained daily to remove sediment, preferably early in the morning after the sediment has settled overnight.

The filters used on the last day of testing were kept for analysis. About 40 vehicles were washed that day. The filters were backflushed with water to remove all the particulate, seeds, and debris that had collected on them. This material was sent to the Montana State Seed Testing Laboratory in the Department of Plant Sciences at Montana State University in Bozeman, MT.

The laboratory's results indicated that the following seeds were collected in the 20-micron filter:

• Bluebunch wheatgrass (Pseudoroegneria spicata)
• Bluegrass (Poa spp.)
• Crested wheatgrass (Agropyron spp.)
• Orchardgrass (Dactylis glomerata)
• Reed canarygrass (Phalaris arundicacea)
• Sedge (Carex athrostachya)

No seeds were found in the 5-micron filter.

Mineral-Primm Fire

The portable vehicle washer was set up and used at the Mineral-Primm Fire camp (Lolo National Forest) at Potomac, MT, from August 19 to August 31, 2003 (figure 15). The Mineral-Primm Fire was a Type I fire. Vehicles that were washed ranged from small cars to excavators/harvesters and dozers loaded on lowboy trailers (figure 16). Most of the vehicles were pickup trucks and fire engines.

Figure 15—The vehicle washer set up for operation at the Mineral-
Primm Fire camp near Potomac, MT.

Figure 16—The vehicle washer cleaned many pieces of large equipment
used to construct fire line at the Mineral-Primm Fire near Potomac, MT.

The washer was set up in a field on a fairly level ground. This location provided enough space for vehicles to line up to drive onto the mat and plenty of room for water tenders to refill the tanks.

The Mineral-Primm Fire was a good test for the vehicle washer. It performed well during the first week of testing. The volume of vehicles was fairly low, under 20 vehicles a day, and operators had plenty of time to clean the vehicles and keep the mat, tanks, and filters clean.

After the first week, excessive mud became a problem. The roads from the camp to the firelines were being heavily watered to keep dust down. Vehicles were returning with plenty of mud, many with more than 4 inches of mud in the wheel wells, mud flaps, bumpers, and underbody.

This mud caused several problems. One problem was with the filters. They clogged very quickly, which required replacing them after nearly every other vehicle.

The large quantities of mud also caused problems with the mat. Because the washer was set up on a field, the mat had many dips. Sand and dirt collected in the dips. Removing the dirt from the mat proved difficult after much of the water had been removed.

Finally, the fine silt from the mud wore out the high-pressure bypass valve quickly. The valve had to be replaced twice.

One pass over the underbody washer did not remove all the mud under the heavily muddied vehicles. Operators had to spend more time with the wands to clean under the vehicles.

We also had problems with the sump pump used on the mat. The pump was difficult to prime and was clogging repeatedly. A larger sump pump used later in the test worked better, but it too was difficult to prime.