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Considerations for Vehicle Wash Bays

By Jeff Oertel, Oertel Architects

Although automated wash systems are intended for cleaning vehicles, I have witnessed a curious public works visitor accidently walk into a system activation trigger, only to receive an unintended shower. While this is good for a laugh, interior vehicle wash bays can be one of the most important assets for a public works operation in a northern climate. When you consider the value of a fleet of plow trucks--collectively in the millions of dollars for an agency--regularly removing salt and dirt from a vehicle becomes very important.

To oversimplify, the main components of a wash bay include equipment, a sediment interceptor, building materials, and heat/ventilation.

Equipment. There are two distinct options for wash equipment: manual and automated systems. The best wash bays have both. A properly designed manual bay would include pressure washers along with higher volume fire hoses. Automated bays include systems designed and installed by specialized manufacturers.

An automated wash system includes a chemical tank, pumps, piping and sprayers with switches, gates, and other automated components. These systems typically cost between $150,000 and $200,000. Driers are optional, but are key components to the effectiveness of the operation if a vehicle exits the wash bay into the outdoors. On a cold day, a windshield can fog up in seconds and equipment can refreeze.

One of the most important locations for washing down a vehicle is from underneath the vehicle. Automated units include, as an option, under-carriage washes. When an automated bay is not affordable or wanted, it is still possible to provide an undercarriage wash.

Although there are many options, one low-tech option for providing an undercarriage wash would include a pipe that is drilled with numerous holes, continuous along the length of the pipe. The pipe would be half-buried into the concrete floor, or set into a recess, and connected to a water line with a shut-off valve located at an adjacent wall. The vehicles slowly pass over the pipe. Using this low-tech option takes a little practice and may require two people--an operator and someone controlling the water line.

Although automated systems are quite useful, they have limitations.

First, an automated system cannot effectively remove all salt, debris, and ice from a truck during more extreme weather conditions. Use of a fire hose may be necessary in order to knock off ice and reach areas of the units which are blocked from the sprayers, such as the area behind a wing.

Second, automated systems are designed and built for a primary piece of equipment, such as a plow truck. Results on buses, sweepers, and pickups will vary. The results for trucks with wings and plows will not be a good as they would be for trucks without attachments.

Third, a bay for an automated system needs to be quite a bit larger in size than a manual bay. It is our experience that a properly designed bay (with automated driers) needs to be approximately 110-feet in length by 26-feet in width, plus space for the equipment. The additional space needed for effective operation, versus a comparable manual bay, could add an additional $150,000 in construction cost. Include the automated system and the total cost would approach $300,000.

So why go with an automated system? Ease of use, time savings, and operator satisfaction. When weather conditions are not extreme, the time savings can be considerable. It can take an operator 20 to 40 minutes to wash down a vehicle manually. Including the rinse, wash, and automated drying, an automated system will take minutes. This translates to considerably less time involvement during a wash, and less time waiting for the wash bay to become available. With a large fleet of trucks, this can translate to hours of time saved or spent doing other things after an event.

One optional piece of equipment in a manual bay would be an elevated platform. Galvanized steel platforms, approximately 5-feet above the floor, include open platform grating and stairs. The elevated platform serves to provide better access to the top of the vehicle. It is our experience that a public works operation either likes or dislikes these features. A platform will add 5-feet in width to a bay as well as cost for the stairs and the additional building area.

Sediment interceptor. A sediment interceptor (sand pit) is not as critical as it has been in the past. Many public works operations have moved away from sand, using a straight salt or brine system instead. Still, a pit is a necessary component for the wash bay, especially to avoid gritty materials from passing through the oil-water separator.

A sand pit can be a cylindrical sump pit, a basic open box with a slanted surface (for scooping materials), or a large vault. If an agency has a vactor, the residue can be removed through a standard manhole. If not, removable heavy duty grating needs to be included at the floor level so that the sand material can be scooped out of the recess.

Building materials. Due to the corrosive nature of the wash environment, the materials used for walls, ceilings, and floors become important. Except in an existing retrofit situation, steel should be avoided for obvious reasons. Precast concrete has proven to be the best material choice for walls and ceilings. Regardless of the building materials, epoxy paint should be applied to all wall and ceiling surfaces. Ideally, the concrete floor would be sprayed with a clear bridge type coating, such as a modified siloxane.

Heat and ventilation. Heating the bay can be a dilemma, especially in a retrofit. Overhead radiant systems and forced air units will corrode over time. The most effective heating system is an in-floor radiant system, which has no exposed components and will more readily dry out the floor slab. Air exhaust units are typically an important feature; they should be located away from the over-spray.

The investment into an effective wash system can translate into better use of manpower, extend the value or use of the vehicles and maintain a more attractive fleet. Regardless of the system choices, this all starts with an operational policy to wash the fleet regularly while giving staff the tools to do so. And if you need a laugh, invite a neighboring public works department to see your new automated bay and ask them to look around.

If you have any questions regarding manual or automatic wash bays, please feel free to contact Jeff Oertel at joertel@oertelarchitects.com or (651) 696-5186, ext. 303.