ANTI-ICING AND PRE-WETTING WITH LIQUIDS
In the past decade, the economy of using liquids has been studied by public agencies, the private sector, academia and other assorted winter maintenance groups. The conclusion is that liquid chemicals, when used correctly and with planning, provide a highly cost effective and efficient way to manage snow and ice in many conditions and ways.
Anti-icing
Anti-icing involves pre-treating a road before the freezing weather or storm arrives with the goal of limiting or preventing the buildup of ice. Applying ice melting chemicals before a storm hits is more effective at melting ice than applying an ice-melting material after a storm hits and a layer of ice has already formed because the chemicals prevent the snow from bonding to the pavement. As a result, snow can be removed with a shovel, blower or plow much easier and a lot faster. Snow and ice management professionals can decrease the time and cost of their operations by anti-icing.
Benefits of Anti-icing:
Less material used
* The chemical action of liquids reduces, or eliminates, the bond between the snow and ice and the pavement. This allows for quicker cleanup after the storm, thus saving labor and equipment time.
* Better control of use by allowing precise application patterns (putting the chemical where it is needed)
* Better on pavement retention. It has been proven that there is a significant reduction in the lose of liquid chemicals due to traffic and wind action. It will stay where you put it and where it will do the most good.
Less time spent
* Faster application speeds with liquid chemicals is possible. This clearly translates to dollars saved.
* Initial application can be done prior to the start of precipitation, allowing crews to apply at optimum times, often during slow traffic periods, thus reducing application time.
* Higher retention of the liquid chemical often leads to fewer reapplications, which means less total application time and less chemical used.
Less traffic impact
* The use of liquid chemicals as an anti-icer prior to or at the start of precipitation provides a wet surface longer at the start of the storm event, even without reapplications or plowing.
* The residual action of the liquid chemical application provides a means of obtaining the targeted level of service goals quickly at storm’s end.
Less environmental impact
* water quality. The reduction of the total chlorides released into the environment during a storm event is of significant importance. Be it an environmental agency monitoring water quality, damaged flora or your customer with concerns, reducing the amount of environmental loading is beneficial.
* corrosion. The reduction of overall chemical use, including chlorides, can be a significant factor in reduction corrosion. Reducing corrosion can benefit vehicles, equipment, parking decks and other structures such as fences, signs, guardrails, or most any mental object.
* vegetation. The reduction in chloride release can have significant positive effects on adjacent plantings. Reduced chemical use normally results in fewer plant fatalities in the spring. This reduces replacement costs, if required.
De-icing
De-icing methods generally involves spreading dry or liquid chemicals to speed the melting process of snow pack or ice that has already formed on the pavement. When sodium chloride (salt) comes in contact with moisture, it dissolves and generates heat. When temperatures drop below freezing there is no moisture on the road, and salt alone is ineffective. The use of dry solid chemicals in conjunction with a liquid de-icer will speed the melting process of the snow and ice pack. This method is called Pre-wetting.
Pre-wetting
Pre-Wetting is the process of spraying salt with a solution of liquid chemical before spreading the salt on the roadway. Pre-wetting the salt helps it work more effectively as a de-icing agent because it provides extra moisture to quicken the melting process and will begin dissolving snow pack and ice faster than dry material alone.
Benefits of Pre-wetting:
* When used on dry roads, materials adhere to roadway better instead of bouncing off or being swept off by traffic.
* Less materials are needed since less materials leave the roadway during spreading.
* Pre-wetted materials begin dissolving snow pack and ice faster than dry materials.
* The faster the snow and ice melt, the faster it can be plowed up which means less time spent on a job.
* Faster melting and clean-up means better service to the public.
* Corrosion of equipment is minimized by spraying the liquid salt at the spinner .
Anti-Icing Helps Michigan Contractor Cut Costs, Expand Sales
by Gregg Wartgow
Created: February 24, 2011
Michigan contractor cuts salt usage by 50%, and adds a new revenue stream in the process.
With salt prices skyrocketing and clients looking to control costs, some snow and ice management contractors are pre-wetting their granular deicers with a brine solution before spreading them. Using the same equipment, many are also trying the anti-icing approach, spraying brine onto pavement before a snow event.
Jim Berns, founder and president of Berns Landscaping Services in Warren, MI, is one such contractor. “I’d been looking to get into liquids for quite some time, mainly to add anti-icing services to my offering,” Berns relates. “When salt prices starting going through the roof, I knew I needed to do something soon to also reduce my materials cost.”
Last year Berns complemented his SnowEx V-Maxx spreader with an AccuSpray system (same manufacturer). Through separate controls right in the truck cab, the AccuSpray system allows operators to spray brine onto granular deicing materials such as rock salt before they hit the spreader’s spinner, hence the term “pre-wetting.” Then, for anti-icing procedures, a separate set of fan nozzles allows operators to spray brine directly onto the pavement.
Berns uses a brine solution comprised mainly of calcium chloride, along with small percentages of potassium chloride, magnesium chloride and sodium chloride.
“We have a large brine supplier in the area we buy our product from,” Berns relates. “I’ve learned that there are a multitude of suppliers who carry brine, but the recipes vary greatly. The thing I like about our supplier is that we’re given an MSDS sheet, which is very helpful when dealing with the commercial market. I can verify that what we’re using is a quality product that is less harmful to the environment.”
Berns stores his brine in a 6,500-gallon tank at his facility. As a general rule, the tank is completely refilled once it’s depleted to a level of roughly 1,000 gallons. “That way we know we should always have enough of a supply to handle any storm that comes our way,” Berns says.
The science behind pre-wetting
After the brine is sprayed onto the granular material, it is more likely to cling to the target surface, rather than bouncing or blowing away. This helps minimize material waste and achieve a consistent application on roadways and parking lots.
“I’m not putting too much salt down and getting a white parking lot,” Berns points out. However, he says the biggest benefit has been the significantly lower material costs. In fact, by pre-wetting, Berns reduced his salt usage by 50% last season.
Additionally, pre-wetting produces quick results in cold conditions. To work, deicing materials need to attract sufficient moisture from the environment. When temperatures drop below freezing, there is little moisture available for salt to initiate melting. Pre-wetting the salt ensures that enough moisture is present to facilitate the process, and the results are noticeable.
“When I look at my lots after we put down a pre-wetted salt, it can be 15º F and my lots are wet,” Berns relates. “I look at competitors who are just using salt, and their lots still have snow cover and slush.”
