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Understanding salt brine

By:
  • Dale Keep
- Posted: October 17, 2016
I often hear statements about how salt brine doesn’t work and how real salt (crystals) does. Since salt applied as a solid must first become a brine to bring about the melting of ice, such a comment reveals an incomplete grasp of the actual process that allows salt to function as a deicer.

I believe the confusion arises from two key sources: inadequate planning and preparation regarding salt brine application and unrealistic expectations concerning the degree of deicing available from it. Either or both may lead to inadequate applications and results, which may short circuit a company’s efforts to add a proven strategy to their ice management toolbox.

Adequate planning and preparation
A common obstacle to adequate planning and preparation for successful salt brine use is insufficient attention to details. Regularly tracking frequently changing weather to assure that planned actions match the latest forecast and established goals is critical to success. Applying these details is a key component of determining the amount of salt brine required for an effective application.

Critical to the successful use of any product or tool is a basic understanding of its inherent limitations, how to use it and how to assess its effectiveness. It appears that too often salt brine and other liquid deicers are used without much thought, either to an established goal, or to whether they are being utilized correctly for the current conditions and/or contract terms. The need for keeping an eye on possible winter storms is obvious. Less obvious, perhaps, is the need to know the variables affecting the ability of salt and salt brine to perform as a deicer and how to respond.

Key variables in deicing

Application rates, for example, must be known and tracked in terms of gallons per acre, per square yard or any other unit of measure that works for you. Whatever system is employed, application rates, conditions at the time of the application, and weather occurring between the time of application and the time of evaluation must be accurate and considered to correctly assess results. Bear in mind that deicers will do what they are supposed to every time and unfavorable results are not because they perform inconsistently.

Quality control of the brine
Also significant to this process is quality control of the brine utilized. Salt brine is best when used at 23.3% concentration. Using it at even a perceived slightly lesser concentration can greatly reduce performance. For example, at 30°F (-1°C), applying a 20% brine rather than 23.3% incurs about a 15% reduction in performance, with colder temperatures worsening results. Know what you are making and applying and be consistent in product quality control and use. Most automated and manual brine making systems produce quality brine when the brine making process is approached correctly for that system. Note that additives to the brine will change the mixture’s overall concentration value, and this has to be known and considered when additives are utilized. Nevertheless, quality control is easy once established, and when done frequently pays big dividends.

Establishing realistic expectations

Once these variables have been taken into account, it becomes possible to establish realistic expectations for actions taken. Too often the liquid application has delivered the results it should have, but results are considered a failure due to lack of reasonable expectations resulting in an unfair evaluation of results achieved. Remarkably, a deicer user will often, when applying salt as a solid, just reapply, say nothing and move on when the initial application didn’t go as expected. However, if the application was a liquid, then the liquid is blamed for the shortfall between expectations and results. Remember, salt is salt, and the solid must form a liquid to melt anything. Therefore, the steps described earlier must be considered for the successful use of both solid and liquid deicers.

Brine as an anti-icer

Basically, excluding pre-wetting of solids and follow-up applications, for the purpose of this article there are only two times to use a liquid such as salt brine as an anti-icer:

1. Bare surface. When the goal is to maintain a “bare surface” or mostly bare surface throughout the storm as much as possible, with easy removal of minimal snow accumulations when the storm is over.

2. After the storm
. When the expected winter storm is to be of such severity and duration there is no way you can stay ahead of it and accumulations are inevitable. These applications are made knowing the surface will not remain snow free because of it. The benefits of this application are received when the storm is over.

Since these two scenarios differ markedly, the next section describes ways to ascertain if either is appropriate for the conditions you need to manage. Then a walk-through of each scenario offers details for establishing a process to follow in either instance.

Goals and steps to achieve them
When using liquids, it is critical to have a process to consider for goal setting before making any deicer application, and to consistently follow it. First of all, what are the current conditions and Level of Service (LOS) requirements for this property? What is the precipitation type(s), intensity and duration of the forecasted storm event? Next, ask yourself, “Can I stay ahead of this storm event and maintain bare or mostly bare surfaces?” 

If yes: Your goal is Scenario #1
With a yes answer, the goal is a “bare surface” as much as possible during the storm event or very quickly when the event is over. With this goal, apply liquid deicer as an anti-icer as near to the start of the event as possible while still allowing you time to cover other sites with the equipment you have available. Plow and reapply deicer as necessary during the storm event.

Keep in mind with this “bare surface” scenario, that even if you apply 110% of the salt brine required to melt the expected snow as it falls, the melting rate of the brine applied can be surpassed by snowfall rate. When this happens you will see some snow accumulations on the property but it will not bond to the pavement. At such times, plowing may be beneficial if the accumulation is enough to warrant it, circumstances allow it and/or the contract terms permit it.

If no: Your goal is Scenario #2
With a no answer, the goal must be “after the storm,” meaning the benefits of the application will be realized during cleanup. With this goal the purpose of the liquid deicer application is to weaken the bond between the surface and the heavy snowfall expected. With this plan, apply enough liquid deicer as an anti-icer ahead of the storm event to give good coverage in terms of the appearance of the property after the application. Less is best here as long as you have good coverage as assessed visually. Increasing the application rate will not change the final results. A larger application rate will increase the time before the snow starts to accumulate, but it also increases costs and the conditions at the end of the storm will be the same.

With this “after the storm” scenario there will be snow accumulation. Ideally, plowing will be taking place during the storm event to minimize accumulations present when the storm ends. But whether plowing is accomplished during, after the storm or both, its completion needs to be followed by a reapplication of deicer. This application is used to penetrate through existing snow and ice to travel to the surface below and spread out. The purpose is to enhance the performance of the original anti-icing application, either by melting any snow and ice remaining from plowing, or by breaking the already weak bond providing easy removal by plowing. For post-plowing, a liquid application may be all that is required. If not, then pre-wet solids would be my next application of choice.

During this re-application, remember you have chemical under the snow and you will not need 100% of the salt normally required to deice this property. Without knowing a number of details, I cannot even approximate how much less deicer to use, but the overall rate required should be less than if you had not anti-iced at all. With training and prolonged practice, results from this application can be substantial and deliver the bare surface desired quickly.

Invest in quality training
The use of liquid deicers is, in my opinion, essential for effective and efficient snow and ice control operations. Although this article is generally focused on the use of liquids, the approach described applies to all forms of deicers. A better than average understanding of how a product works, including its limitations, and how to use it during those limitations, allows one to set reasonable goals, determine correct application rates and establish realistic expectations for actions taken. However, this process does require more than “just go do it.” This is a perfect example where investing in quality training specific to conditions and your needs will pay for itself very quickly.
State of the Industry insights
  • Liquids on board: 36%. Percentage of survey respondents who reported using liquids in their ice management toolbox.
  • Liquid applications: Of those respondents who are using liquids, here’s how (respondents could choose all that apply):
    • Applied liquids directly to pavement pre-storm 57%
    • Applied liquids directly to pavement post-storm 35%
    • Pre-wet the stockpile 32%
    • Pre-wet solids at the spinner 29%
    • Made our own brine 26%
  • Ice best practices: 53%. Respondents who provide training for ice management best practices. The salt supply shortfall a few years back jumpstarted the discussion on how to more effectively use salt (including the use of liquids). Learn more about how you can help SIMA work toward established application rate best practices at www.sima.org/sustainablesalt.
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Dale Keep owns Ice & Snow Technologies, a training and consulting company based in Walla Walla, WA. Email him at snowbusiness@grandviewmedia.com.
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