View Full Version : at what temp does salt stop melting
12-15-2010, 08:02 AM
i would like to know at what temp does regular rock salt stop working...and if you add some snow melt..ie the expensive stuff with the salt will that help any advice would be appreciated.
12-15-2010, 08:15 AM
around 5 degrees or less it wont melt worth a **** unless you mix in some mag, calcium etc. that will instantly start melting the snow and once some traffic drives on it it will trigger the salt and it will start melting....had to do that here yesterday and melt off a stubborn lot
12-15-2010, 09:20 AM
Check out www.saltinstitute.org There's some good info on the site.
"Sodium chloride melts ice at temperatures down to its eutectic point of –6° F (-21° C). The important variable is not the air temperature in this case, but the pavement temperature. Depending on whether the storm occurs early in the season or at the end of a particularly cold period, the pavement may be warmer or colder than the air, but even in the dead of winter, pavements are more often warmer than the air. Most snowstorms occur when the air temperature is between 20° F (-7° C) and 32° F (0° C), the temperature range where salt is very effective." (from www.saltinstitute.org)
Check out the SNOWFIGHTER'S HANDBOOK on the website. Some very good info.
12-22-2010, 08:47 AM
thanks for the info. i will check that out
12-22-2010, 08:12 PM
Sodium chloride is less effective as the temperature goes lower. In fact, you can go to Morton Salt's website and they even tell you that their product is five times less effective at 20 F than it is at 30 F.
That's why you may want to consider either using treated sodium or mixing another product with it.
12-23-2010, 12:21 AM
The rule of thumb I've given to customers for years is to plan on using a treated product or cutting some CaCl in with their NaCl when the ambient temps get much below 10°. Not because the rock salt will stop working, but more for the refreeze concern. Once the salt melts the snow, ambient temperature becomes an important factor, because it will freeze that nice melted snow into a nice shiny sheet of ice real quick if it's just NaCl brine.
And, taking a page from the heavy snow/mountain areas--if it's going to be so cold during a storm that everything will just ice over as soon as it's cleared (EXCEEDINGLY rare, as snow doesn't tend to fall much in those temps) then don't scrape it to the pavement at all. In fact, leave as much snow on the ground as you realistically can, because the snow layer will actually insulate the ground somewhat from the ambient temps, making it easier to actually get to the pavement when the temps subside. More often than not, you can plow it up and salt it with very good results.
The downside is you may be faced with a larger plowing effort, some hard pack or even iced areas where there is vehicular traffic, but again--the ice won't form if the snow never melts, and without traffic, the friction heat won't be present.. My logic here is based largely in liability--better to have snow on the ground than a huge sheet of perfect ice. And no, not everyone has agreed with this logic--but our attorney likes it, go figure.
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