Packaged ice melt generally has a “works to” temperature written on the bag. While bulk salt doesn’t have a label, anyone in the industry knows that bulk rock salt will melt to, at best, +5°F. Do you need the same amount of salt per area to melt ice at +25°F that you would for +5°F? NO YOU DON’T. You could be literally throwing away thousands of dollars every season if you don’t adjust your application rates to the temperatures expected.
How much salt is required for a ground temp of 25°F to 30°F degrees? The Champaign, IL Public works says,” At a temperature range of +25°F to +30°F, application rates of 100 to 200 pounds per lane mile can provide adequate control. At temperatures of +20°F, a rate of 300-400 pounds of salt might be required for adequate control. ” A lane mile is 12 ft. wide ,There are 5280 ft. in a U.S mile, so this amounts to the equivalent of 63,360 sq. ft. (1.45 acres).
The most important data concerning rock salt application rates vs. temperature is a melter’s ‘melting capacity’ at differing temperatures. Molecular water is always present on the surface of ice and the amount of water increases at higher temperatures. Thus, at higher temperatures rock salt works faster and melts more ice with less brine(melted ice + salt) and will not work at temperatures that are too low to allow enough water on the ice surface to dissolve the rock salt.
|Temperature||Pounds of ice melted by 1 pound of salt|
While working to determine your own application rates, do track your results. Chloride Conscious offers data tracking sheets to help your record keeping for future comparisons. Get our tracking sheets here.
There are a few variables that you will want to consider when picking an application rate because adjustments . See the next chart for a base guide line.
Type of precipitation- Loose snow, Regular snow, Wet/Heavy Snow, Freezing Rain
Temperature Now and expected trends- Air temperature now and where it will be going (Morning = the temp will likely be rising throughout the day)
Pavement Temperature (If the pavement is very cold it will take much longer for warmer air temps to assist in the melting process)
Traffic Loads (High traffic will help spread the salt brine making more effective melting of lesser amounts of salt)
Pavement Types ( Up to 20% more salt should be applied to cement over asphalt due to thermodynamic properties)
For more information, read our article on application rates and adjustments HERE.