Commonly asked questions about ice melters
The TRUTH about LEED Certified Ice Melt
Icemelters: What you should know
Some people find the world of de-icers, ice melters, anti-icers, or basic ice removal compounds somewhat confusing especially with all the claims various manufacturers make regarding these products. This article helps the reader navigate through that maze of confusion. These are the commonly asked questions about icemelters.
Anything used to melt the ice is considered to be a deicer or icemelter. It does not matter what the material composition is or what format it comes in. It can be in variety of solid formats, such as:, granular, flakes, pellets, pearls, powder or even in a liquid format. Many people assume that the word “icemelter” means that it is somehow eco-friendly. This simply is not the case. Rock salt is an icemelter.
An anti-icer is any product that can be applied to a surface before a storm to help prevent ice build-up from occurring. It typically does not eliminate ice build-up, but rather just delays it enough that clearing equipment can be brought out to remove the slush accumulation. Anti-icers come in granular or liquid formats.
Snow and ice storms generally occur between -18o and 0o Celsius (0o and +32o F). This is when ice melters will effectively melt ice and snow. When the weather gets too cold, such as below -30°C (-22°F) an icemelter becomes impractical and will not work. In this really cold weather one typically requires a traction aid - a grit substance to prevent slips and falls. At this temperature, ice typically does not form, as the falling snow will stay in its crystallized format, and will simply build-up in the form of compact snow. When the weather warms up, then melting and refreezing will occur to form ice build-ups.
Icemelters help to remove ice by breaking it down – first into smaller chunks, and finally into a liquid. Icemelters should not be confused with snow removal. Icemelters or deicers are designed to melt and break down the ice accumulations not the snow accumulations. In situations where there is ice and snow build up, it is best to remove the snow, using mechanical means such as shovels or snow blowers, and then use an ice melter to break down the ice into slush.
There are many different chemicals that can go into making up a deicer, however, only a few base compounds are used, due to price and availability. They are:
Some icemelters are simply variations of these basic types, blended with a non-icemelting additive for marketing reasons. Many products sold today are merely re-packaged commodities of rock salt, natural or artificially coloured.
Icemelters (or de-icers) are available in pellets, granules, flakes, pearls, powder and liquid, with granules being the most effective. Flaked forms are best avoided for two reasons: they do not penetrate as deep as granules, and therefore do not liquefy beneath the surface of the ice, nor do they apply well in windy conditions. Pellets, pearls and powder pose a similar problem: they blow away in stormy weather.
None. According the two leading concrete authorities, the American Concrete Institute (ACI), and the Portland Cement Association (PCA), NO icemelter should be used on newly poured concrete, as concrete requires a certain length of time to cure. This amount of time can vary depending on the type of concrete. It is best not to use icemelter on new or unsealed concrete less than 12 months old, exposed aggregate, brick, or pre-cast steps. Applying ice melter to damaged, cracked or chipped concrete may result in further damage due to the thaw and re-freeze cycles. For further information on concrete, here is a great article on the basics, “Icemelters & Concrete”.
Some icemelters containing ammonium nitrate or ammonium sulphate additives will rapidly disintegrate concrete and therefore should not be used. Discolouring, however, is primarily caused by calcium chloride. How? Calcium Chloride accelerates the hydration process, but has a retarding effect of the hydration of the ferrite compound in Portland cement. This ferrite phase normally becomes lighter with hydration, however, in the presence of calcium chloride, the unhydrated ferrite phase remains dark.
Concrete scaling (or flaking) is the loss of surface mortar. This is a primarily physical action caused by the hydraulic pressure that occurs when water freezes within the concrete, as opposed to a chemically corrosive action. For this reason, it is necessary to extend the freeze/thaw cycle as long as possible. Calcium chloride ice melters have the shortest freeze/thaw cycle.
Spalling is a surface defect that is deeper than scaling. Spalls tend to occur over corroded reinforcing steel due to the present of chloride ions.
The type of concrete best at resisting these two effects is concrete where properly spaced air voids are present. Air-entrained concrete has an excellent resistance to surface scaling and mortar flaking due to freezing and thawing.
Beside the fact that calcium chloride causes damage to concrete by having a very short thaw/freeze cycle, and causes discolouration of concrete, Calcium Chloride inherently attracts moisture – is hygroscopic – and therefore has a limited shelf life. Further, Calcium chloride leaves behind an oily residue, which is easily tracked into buildings, soiling and damaging carpets and floorings and presenting a serious slip/fall hazard. Perhaps most frighteningly, it is harmful to the environment – damaging plant life, soil and the water system. Also, people must be very careful when using calcium chloride as it caustic and will burn skin causing an irritation. It should not be used around pets as it will burn their paws and irriatate their noses.
Rock salt has an enormously negative effect on the environment as it is toxic to vegetation and damaging to soil. The general impact of salt on grass, crops or vegetation is to impair or reduce growth. It does this by promoting high pH values which cause micronutrient deficiencies. Rock salt or sodium chloride is not only harmful to plant life but also the very soil that sustains life. Salt content in soils disperses both the clay particles and organic matter. This breakdown in the soil's aggregate structure reduces its permeability to air and water. As a result, root proliferation and penetration throughout the soil is impaired. Also, when these soils dry, they become hard and cloddy with a tendency to form heavy surface crusts. For more information on the effects of salt on plant life, here is a great article, “How Salt Damages Trees”
The shelf life of a bag of icemelter will depend on the basic components that make up the deicer being stored. Many icemelters that are stored in a dry location will generally have a shelf life of 3 – 5 years. However, it should be noted that some icemelter components such as calcium chloride or magnesium chloride are very hydroscopic, and attract moisture easily. These components have a much shorter shelf, such as around 1 – 2 years maximum. Storing these type of products in a humidity controlled warehouse is highly recommended.
When exposed to moisture, or excessive humidity, calcium chloride will soak up this moisture and solidify. A bag of calcium chloride will become solid like a brick and even when broken up cannot be used. Magnesium chloride, when exposed to these same conditions, breaks down to a slimy liquid, making the product very messy and completely un-useable. Extreme care should be taken with these two products.
Potassium based icemelters, seem to store well and are not as susceptible to high moisture conditions.
Icemelter tracking into buildings causes many problems including safety issues and excessive maintenance costs. Icemelter tracks into buildings in two ways: by being picked up on people’s shoes when the product is still in its solid format, and by being picked up on people’s shoes in its dissolved state. Rock salt (sodium chloride) leaves behind a white residue when tracked into buildings. Calcium chloride, leaves behind an oily type residue that is much more costly and dangerous. This oily residue soils carpets requiring excessive cleaning or replacement. If the entry way to a building is a smooth surface flooring, such as tile, linoleum, hardwood, or polished concrete, this residue will cause a serious slip hazard and must be continually cleaned up, increasing a building owner’s maintenance costs.
Experience has shown potassium based icemelters, do not track in a residue when in its dissolved states and many school boards are specifying such products on their bids because of this reason.
It is almost impossible to prevent the solid formatted ice melter from being picked up on people’s shoes and carried into buildings. The line of defence against this, however, is to have a very good quality mat at the entrance of the buildings.
Icemelters are best spread by using some mechanical means such as a spreader. Using a spreader guarantees even consistent distribution. While deicers can be spread manually using a scoop or by hand, it is not recommended. Spreaders are available in all sizes, from small hand held varieties to large dump truck attachments. XYNYTH Manufacturing Copr. (www.xynyth.com) makes a very durable mid-sized spreader that holds 75 lbs of icemelter and is great for doing large walkways or parking lots.
Many users of ice melters like to have their product coloured to make it easier for the person doing the spreading and to help over use of the product. Coloured deicers can easily be seen by people, assuring them that it is safe to walk on the ice.