In 2010, the Michigan Technological University’s Keweenaw Research Center analyzed and measured the effectiveness of the most widely used ice melt products in both laboratory and external field settings.Ice melt helps snow professionals work faster and safer, yet there are many unknowns when it comes to which specific ice melt products to use, when to use them and how much to apply. The reality is that most current melt research addresses application rates for highway use while it doesn't address rates for typical commercial snow removal sites such as parking lots or walkways. This lack of clear scientific data for commercial snow professionals has led to ineffective melting, over-application and unnecessary environmental runoff – not to mention lost profits and lost customers.
Recognizing the need to study ice melt application rates and to provide more definitive guidelines for commercial use, Morton Salt teamed up with the Michigan Technological University's Keweenaw Research Center in 2010 to analyze and measure the effectiveness of the most widely used ice melt products in both laboratory and external field settings.
Research overview During the 2010-11 winter season, indoor laboratory "cold room" tests were conducted according to the Strategic Highway Research Program (SHRP) H-205.1 protocol to validate safety and performance claims in a controlled setting while field tests were performed to validate melting performance in real-world conditions. Air and surface temperature, melter type and application rate were identified as primary performance variables. Because air temperature directly impacts surface temperature, it was used as a starting point, while commonly-used ice melters – sodium chloride (rock salt), anhydrous calcium chloride, calcium chloride/rock salt blend and magnesium chloride – were identified for trial.
Weather studies show that even in extreme climates, such as Minneapolis, the average temperature does not drop below 0F for extended periods of time. With that said, snow professionals are forced to work in extreme temperature and wind chill conditions at different times in the season, so the research team identified several surface temperature "groups" to represent a range of conditions.
- "Extreme Cold": less than 0F
- "Below Average": 0F to 10F
- "Average": 11F to 20F
- "Just Freezing": greater than 21F
High, medium and low ice melt application rates were selected based upon recommendations from a variety of reputable sources.
In the Lab Lab research bore the following results:
- At -5F, salt and calcium chloride/salt blends were not sufficient to melt significant amounts of ice; however, calcium chloride did produce some melting at this temperature.
- At 5F, calcium chloride melted faster; however, the melting action of the salt/calcium blend and salt caught up over time.
- At 15F, salt and salt/calcium blend resulted in the most melting over time (magnesium chloride demonstrates the least melting capacity despite hydrate levels).
- At 25F salt became the most effective melter and all melters – except magnesium chloride – performed fairly consistently.
Using a melter that doesn’t perform or using a more expensive melter than necessary ends up costing money and clients.
In the field Below 0F, only calcium chloride melted, and a minimum of 60lb./1,000 sq. ft. was necessary to create partial bare pavement. Mechanical snow removal was required to achieve bare pavement. From 0F to 10F a blend of salt and 10 percent calcium chloride performed better than pure calcium chloride. A minimum of 60lb./1,000 sq. ft. was needed to melt to bare pavement.From 11F to 20F a blend of salt and 10 percent calcium chloride performed as well as calcium chloride. A minimum of 60lb./1,000 sq. ft. for 30 minutes was needed to melt to bare pavement.
At or above 21F, the blend containing calcium melted comparably to straight calcium chloride and magnesium chloride, albeit a bit slower, whereas salt achieved similar results, but only at the highest application rate.
Guiding Application For Efficiency
To ensure the research would provide a solid basis for productivity and cost-efficiency, criteria for deicer selection and application rate took into consideration field melter usage practices, availability, price and melting range. Through this lens, the laboratory and field tests revealed a blend of salt and 10 percent calcium chloride is a cost-effective melting workhorse. This blend performed better than salt or calcium chloride in blow-average temperatures and was able to do so at lower application rates and lower costs.
Through a scientific approach to melting applications and solutions, snow fighters will be better-equipped to adopt more effective strategies for evaluating and addressing deicers to reduce environmental damage, increase safety and enhance profits.
Niles Hysell is director, ice melt product management at Morton Salt.