Most people think of airplanes when they hear “de-icing.” That’s not the whole story, though. De-icing airplane wings is one thing, de-icing walkways and roads is something else.
Then there is anti-icing.
What is the difference between De-icing and Anti-icing in ice management?
De-icing is the application of ice-control materials to walkways and roads to melt existing snow and ice.
Anti-icing is the application of melting products to walkways or roads before it snows. Anti-icing helps
prevent snow and ice from sticking to the pavement in the first place. Sort of a preventive measure.
Managing an anti-icing program can create safe winter conditions before people go slipping and sliding on their way from the parking lot to the office building. Not having to wait for the snow to melt saves a lot of money on health insurance costs. Fewer broken ankles.
Anti-icing may be a more cost-effective alternative to de-icing. Managers cannot rely on one method for de-icing and anti-icing because each chemical and storm is different.
The most common de-icer is sodium chloride. The problem with it is that below 23 degrees, salt begins to lose its effectiveness. Pretty soon it stops working altogether and snow and ice begin to build up again. Back to slipping and sliding.
The other problem with salt is that in a big storm in the Chicago area can deplete resources quickly.
An alternative, of course, is mixing in some sand and salt for deicing. Sand is effective in improving traction, but it reduces the amount of salt workers can apply to an area which makes the salt less effective and the clean-up is a mess.
An icemelter, calcium chloride (CaCl), works down to about minus-20 degrees. It is an exothermic salt. That means it releases heat as it melts the ice.
Calcium chloride melts ice faster than other common de-icers, but it can attract moisture from the air causing the pavement to stay wet. If the temperature stays below freezing and moisture refreezes, it gets very icy again. If the ice expands, you have a damaged surface.
Wet-dry and freeze-thaw cycles lead to “spalling”, which is flaking or chipping. Calcium chloride also can be corrosive to metal surfaces and cost more.
An alternative is magnesium chloride which is similar to calcium chloride and similar in cost. It is also exothermic and will absorb moisture. This makes it fast-acting when mixed with sand or salt. It’s efficient when spread directly on pavement before a storm in keeping the snow from sticking. It’s also more effective when the temperatures dip down to minus-20 degrees and more effective than sodium chloride, but less effective than calcium chloride.
Which to choose
The art and science of snow melting materials is a conundrum. How the chemicals and options in terms of ways to maximize the effectiveness of anti-icing and de-icing is essential for the success of snow and ice removal.
The goal is always to keep people safe and remains the top priority for managers. As well, the environmental impact of snow and ice operations is also on the list of issues managers must understand and consider.
When considering a company to manage your snow and ice removal, please contact us to discuss your needs.