Getting rid of The White Stuff: What to use and how to use it
Plowing and shoveling always have been major components of snow-removal operations, and, when combined with effective use of chemicals, they continue to be the most cost-effective snow removal techniques in many situations. Plowing and shoveling can remove large volumes of snow as long as the snow is fresh and has not bonded to the pavement. Early application of deicing chemicals prevents that bond from forming, allowing time for normal plowing and shoveling operations to remove the snow throughout the storm.
After a snow storm, chemicals can help clear pavements. Salt is the most commonly used deicing chemical and usually is effective. Alternative chemicals become more effective when temperatures drop below 15 F. Calcium chloride and magnesium chloride can be effectively used in temperatures well below zero. Because they are more costly than salt, calcium chloride or magnesium chloride often are blended with salt to create a mix that can be even more effective at lower temperatures.
Because salt must first be dissolved into a brine before it can melt ice, pre-wetting can provide a jumpstart. Wet salt also is less likely to bounce and roll off a paved surface.
The liquid — which can be dissolved salt, calcium/magnesium chloride or a chemical deicer called Ice Ban — is applied at eight to 10 gallons per ton of salt. Pre-wetting the salt as it is applied is the most effective application method, but that requires specialized tanks and on-board spray equipment. Salt also can be pre-wetted at the shop as it is loaded into the truck. Some managers even find it effective to pre-treat the salt pile.
Corrosion of reinforced steel in parking garages is a significant issue, and several special chemicals are available to minimize it. For example, calcium magnesium acetate has been available for many years and has been thoroughly tested by the Federal Highway Administration. Potassium acetate is effective in cold temperatures and also is non-corrosive. Corrosion-inhibiting additives also are available for liquid calcium chloride, magnesium chloride and Ice Ban.
Common fertilizer products such as urea and potassium chloride also have historically been used for deicing. However, tests indicate that those products are not effective deicers, especially when temperatures fall below 25 F. In addition, the runoff of those materials into surface waters may be undesirable in areas sensitive to nutrient-laden runoff.
Abrasives, such as sand, also are effective in snow-removal operations. When pavements reach temperatures at which salt is no longer effective, abrasives can help deal with slippery conditions. However, abrasives do not melt ice. Plowing and chemical applications will likely be required for final snow removal. Additionally, abrasives often require post-storm cleanup, which adds to the total job cost.
The most effective snow removal method for a particular area depends on many factors — terrain, amount of snow and/or ice, particular liability concerns, etc. Vendors can be an excellent source of information — especially when their information is used in conjunction with training sessions provided by universities and trade associations. Small-scale testing of various methods also is useful. Additionally, employees should have the opportunity for refresher training prior to activation of snow removal operations. Finally, upgrades in equipment and appropriate use of new chemicals can help grounds managers create the best and most cost-effective snow removal operation.
Don Walker is professor of engineering at the University of Wisconsin, Madison. This article was adapted from an article first published in Grounds Maintenance (www.grounds-mag.com). It is reprinted with permission.