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Building Manager Green Tip

January 2011

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Thoughtful Selection of Ice Melt Products

Since the 1940s, deicing chemicals have been implemented to create “bare pavement” during freezing weather. Fast-acting and effective deicing of roads, steps, walkways, and other travelled common areas mitigates the risk of injuries, but concerns have been raised regarding adverse environmental impacts to infrastructure and ecosystems.


Environmental Considerations and Tips


Consider Green Alternatives to Conventional Ice Melt Products
Calcium magnesium acetate (CMA) is one option for an effective, environmentally benign ice melt product. While CMA is significantly more expensive than conventional deicing products, it has the corrosive potential of tap water. When considering the increased initial costs of ‘greener’ alternatives such as CMA, one should consider the maintenance costs resulting from ice melt-induced corrosion of metallic infrastructure and automobiles, as well as damage to vegetation.

Avoid Rock Salt (Sodium Chloride)
Sodium chloride is the least expensive ice melt product, but it is corrosive to plants, concrete, asphalt and cars. Chlorides can also be harmful to pets by ingestion and absorption through the paws.

More is not Better
Most damage can be minimized by using ice melt in moderation, as most landscape damage occurs in the spring along grass edges that receive overspray and runoff. “Right-size” the application amount to conserve product and reduce the effects of soil and groundwater contamination. Following the suggested application concentrations and frequencies also helps prevent the product from being tracked into buildings. Some ice melt products have a dark blue color. Contrast between the dark ice melt and white ice and snow enhances the ability to determine the concentration of applied product. 

Science of Solutes


Ice melt compounds work because of a scientific phenomenon known as freezing point depression, which holds that the freezing point of a solution is always lower than the freezing point of the pure solvent. In the case of ice, water is the solvent. When the ice melt product, or solute, is applied to the ice, a solution is formed which includes molecules of water and dissolved components of the solute. If enough of the solute is added, the freezing point will be depressed to a point where the equilibrium state is disrupted and melting occurs.

Green Building Services provides consulting services to ensure that the design, construction and operation of Harvard's built environment has minimal environmental and human health impacts, maximizes occupant comfort and generates an awareness of sustainable design and building operations. To learn more about our work and services, visit http://green.harvard.edu/gbs.