Most liquid chemicals (brines) for snow and ice control are based on one or more of the commonly used deicing chemicals, such as salt, calcium chloride and magnesium chloride. Others, like calcium magnesium acetate (CMA), potassium acetate and urea are of organic origin. A number of variations of these products are on the market, with often proprietary additives designed to reduce corrosion and/or enhance performance.
What is in the product you are buying, and what does each ingredient do in terms of price, performance and the environment? Look at the material safety data sheet (MSDS) to get an idea of the components. If the vendor or manufacturer does not provide a list of ingredients, that should be cause for concern.
Not every chemical is right for every application. Which option you choose will depend on the following:
As the table shows, the characteristics of each chemical are different, even though all are designed to change the freeze point of water. Most often, the selected brine will be used for both pre-wetting and direct application—often during the same storm event. Selecting the product that meets your needs in terms of price and performance is critical. Ask yourself, "What product will fill my needs at the lowest cost at least 90% of the time?" Use the answer as a guide to product selection. A hint: the exception(s) will often hinge on corrosion and/or cold-temperature performance.
Pavement surface temperature history is a primary criterion and should be used as a basis for decision. Expected low pavement temperature and level of service goals are key determiners for the best product(s) for your operations.
Corrosion, both surface (vehicles) and embedded reinforcing bar, can be considered as one of the factors in selecting a chemical. This is where the use of inhibitors that provide low-corrosion products or non-chloride chemicals should be evaluated. Corrosion issues are almost always a balancing act among initial purchase price, long-term purchase price and corrosion effects. The total cost of use can be higher—is the client willing to pay for that?
Environmental restrictions can significantly affect the selection of any product in some areas. However, it is often easier for a customer to require the use of a non-chloride environmentally preferred product than it is to pay for it. Here again, ask: "Which is less expensive in the long run?" and "How will it be mitigated under these circumstances if problems occur?" Use the answers to guide your product selection.
The bottom line is the economics. All of the noted concerns are parameters in the economic equation, resulting in the bottom line. Carefully consider the priorities given to purchase price over the total cost of use. In some cases, this may not be easy. Customer expectations vs. customer billing values based on their expectations are often miles apart.
Openly discussing customer requirements—and placing price tags on them—is the best way to proceed. Give them exactly what they asked for with pricing, and then present alternatives. Thoroughly discuss each option presented and let the customer decide. Document their choice and that options were fully discussed.