The goal of using direct liquid application (DLA) to combat snow and ice on roadways is to get the right amount of the right material, in the right place, at the right time. A variety of factors should influence the equipment selection process.
Several different types of deicers can be used. In the best case, a deicer prevents a bond from forming between the snow and ice and the road surface. Even when it's impossible to prevent bonding altogether, the sooner the bond can be eliminated the easier snow removal will be.
Typical weather patterns in an area will affect DLA use and the kind of equipment needed. In areas where winter weather tends toward ice storms or black ice forming on pavements, an anti-icing strategy can be effective. Crews spread deicers ahead of the storm, and the chemicals prevent ice from forming. In such areas, distribution equipment dedicated strictly to liquid application makes sense.
In heavy snow areas like the upper Midwest and New England, on the other hand, liquid deicers are seldom able to keep roads clear by themselves. There, liquid deicing chemicals are used to reduce the bond between ice and pavement and to make plowing easier. These chemcials also are used to pre-wet and enhance the effectiveness of granular deicing salts. Here, you may be better off choosing equipment that can accommodate both liquid and granular forms.
Another important factor in selecting deicing equipment is the quantity of material to be applied. How many lane miles are involved and what application rate will be used? For anti-icing and deicing, application rates typically range from 30 to 50 gallons/lane mile, but can be lower or higher. Chemical suppliers can help calculate the safe and effective application rate for the type of deicer you plan to use. Answering these questions will help you determine the overall capacity your equipment will need to handle.
Also consider the types of roads to be treated. Are there mostly one- and two lane residential streets, larger arterial roads, divided highways, or some combination of all these? Is the area more urban or rural in character? These factors will affect how the trucks can be routed efficiently and at what speeds they should be able to travel.
The faster a DLA vehicle can travel, the sooner roads can be cleared. Trucks that operate close to the speed of other traffic also present less of a safety hazard than slower vehicles. Even DLA equipment designed to treat multiple lanes at a time can be designed to move faster than conventional salt spreading equipment. Operators, however, have to factor in the movement of liquid within the tank when stopping or changing direction. Higher speeds intensify these liquid surge effects and can be a safety concern.
Once you have a sense of how much liquid deicer to apply per event and the optimal tank capacity for efficient runs, you can determine what type of vehicles you need. DLA tanks range in capacity from 100 to 5,000 gallons, so suitable trucks can range from pickups to semis. Make sure that the vehicle's load rating is sufficient not only for the tank capacity, but also for the plows or other equipment it may need to handle. Weight should be distributed evenly to balance the load and ensure the lowest possible center of gravity.
Consider what type of equipment is already in your fleet and how DLA fits in your overall strategy. Will you be using liquid deicer only before a storm or throughout the storm event? If only prior to a storm event, you'll either need a piece of dedicated deicing equipment or one that will allow a quick changeover to granular spreaders. One good option is an independent trailer system that can be detached when you want to change applications from liquid to granular material. If you plan to use liquid deicer throughout the storm event, then you'll want onboard storage for both liquid and granular materials.
Some DLAequipment can serve other purposes when not being used to combat storms. Smaller trucks and tanks can be used to spray vegetation during the off season. Higher capacity systems can be used for street flushing or dust control, as well as for hauling deicing liquids over longer distances. The type of power unit that drives the equipment, such as a gasoline engine or an onboard hydraulic system, and its operating controls will affect its suitability for multipurpose use throughout the year.
Eric Holland, manufacturing manager with Force America Inc. and its subsidiary VariTech Industries Inc., is based in Burnsville, Minn.