Expert Advice on Green Buildings

Ice Melt for LEED Buildings: What Is a Safe Green Deicer?

 
Question:

Mitch asks: What ice melt chemical or product do you recommend for LEED certified buildings?

Answer:

Hi Mitch, thanks for your question on environmentally friendly de-icing products.

There isn't really one product that will tackle this issue, but hopefully this information will help you make a good decision as to which product will work for your particular situation.

Types of De-icers: Rock Salt

Most chemical de-icers work by melting the snow and ice and forming brine. This brine breaks the bond between the pavement and the ice due to the brine’s lower freezing point.

The most common de-icing agent used is sodium chloride, more commonly referred to as ‘rock salt’. Rock salt has been used for decades because its inexpensive and abundant, and more importantly – it works.

However, there are some environmental issues with salt, such as corrosion to concrete and metals and potential groundwater contamination. It can also be hazardous to many types of vegetation.

According to a study by Iowa State University, there are five chemicals that are commonly used as de-icers. These are sodium chloride (rock salt), calcium chloride (CaCl2), potassium chloride (KCl), urea, and calcium magnesium acetate (CMA). Rock Salt is effective to about 25 degrees F, and CaCl2 and KCl are more effective at lower temperatures.

All of the ‘chlorides’ are types of salts that work well, but they have the aforementioned environmental issues. Also, these types of salts tend to leave residues when tracked indoors.

Green Products for De-icing

A more environmentally friendly de-icer would be a product that would be some kind of combination of these five chemicals, along with a mixture of sand for grit and traction. Trying to limit the environmental impacts of salt while still having an effective de-icing product is quite a challenge, but there are some products that have managed to come up with an effective mixture.

However, beware of the products claiming to be ‘organic’. Read the small print, because that product could simply be rock salt.

There are also strategies that you can use with these de-icing chemicals to minimize their environmental impact. Try not to spread the agent excessively – only use the minimum amount necessary to break up the snow and ice. Then, use your shovel or plow to do the rest of the job. This will limit how much salt is actually introduced into the environment.

Also, there are physical barriers that you can put over your vegetation to keep the salt away from them.

Snow Melting Systems: Hydronic or Electric Heating

An alternative method to using chemicals for de-icing around your building would be to install some kind of hydronic or electric heating system in the pavement.
This could be something as simple as some hot water pipes in the pavement that would prevent the snow and ice from forming.

This is a more expensive and energy-intensive method, but it would have less of a direct environmental impact.

I hope this information helps! Good luck this winter.

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Expert Advice and Comments
dpratt's picture

Thanks for your comments Rob,

Thanks for your comments Rob, all very good points. I agree, heated pavements do have a carbon footprint and energy usage to consider and weigh versus the environmental benefits of not using a chemical de-icer. This is a good example where no decision will be perfect, and you may just have to select the better of two evils, whichever that may be for you.

David M. Pratt, P.E., CEM, LEED AP
Energy Management Consultant
MWH Americas, Inc.