Frequently Asked Questions (FAQ)
The noise surrounding the sale of ice melters seems to have reached an all-time high with more brands on the market than ever before. Complicating matters, some claims may be confusing. Many newer ice melters are actually only blends of one or more common deicers, sometimes with a few additives.
The pitch on the package might be "safe for vegetation", "less tracking", or "low-temperature effectiveness", but such claims offer require classification, if not a grain of salt. A blend's ice-melting capacity, for example, is always diminished by its weaker ingredients. The followings tips are designed to help through the noise and help educational and health care facility managers make the right choice.
Keeping the grounds safe for vehicles and pedestrians is a main concern when snow and ice accumulate. Use of deicing products is a common way to rid walks and roads from potentially dangerous ice.
There are hundreds of brand names for ice-melting products on the market. Not all ice melters are created equal, however, so they are not equally effective and safe to use. Take a close look at deicers before deciding which products are right for your site.
Don't be misled by advertising claims. Catchy names, colorful packaging and impressive statistics can lure you to buy ice melters that may not meet expectations.
Using ice melting compounds too clear snow and ice from walks, drives, and entries near public buildings is virtually a universal practice today. Facility maintenance personnel learned long ago that to achieve safe surfaces in the shortest time with the least total cost, ice melters are a necessity. Understandably, whenever a product category gains such widespread acceptance, the market attracts a host of suppliers looking to capture a share. As a result, there are more than 100 brands of ice melters available today. Unfortunately, many of these products are packaged with no mention of their chemical composition. Others carry labeling that specifies contents but make erroneous or misleading claims about the products' abilities. The result is considerable confusion about the benefits and limitations of such products.
There are a few elements and compounds used to melt ice. I will talk about the most popular ones. Of course rock salt is the most common. Probably the most cost effective too. Remember that de-icers, are for just that, de-icing. Don't try to use them to melt snow. It's a waste of material. Spread your de-icer after clearing the areas of snow. Apply after the threat of more snow is gone. Only if the property is in use, would I recommend de-icer application before the threat of more snow passes. Liability being the factor here. In the eyes of the law, the snowfall is an act of God. Once you start your clearing process, you can be held liable, for anyone slipping. You were contracted to remove snow (and/or ice).
Protect yourself, do a good job, and try not to leave any slippery areas. Keep your de-icing materials dry at all times. Large chunks may damage your spreader, and dry material spreads easier, and farther, with smaller spreaders. Most tailgate spreaders are designed to use #1 rock salt. This is sold in bags. The slide in salters, can use larger size chunks, since their conveyors and augers break up the chunks better. Some of the large slide in spreaders, even wet the salt with a brine solution. This helps the salt work better.
How Ice Melters Work
Generally, all ice melters work in the same way. They depress the freezing point of ice or snow and turn the mixture into a liquid or semi-liquid slush. Solid chemical salts bore through ice or snow and form a strong brine solution. This brine spreads under the ice or hard-packed snow and undercuts, breaking the bond to the surface. Once lose, the ice or snow is easily removed by mechanical means. Or, in many cases, users, apply the material in anticipation of ice or snow. This prevents the bond to the surface and melts the snow or ice as it comes in contact with the brine.
Fertilizer products work in much the same manner, though they do not form a brine. All are soluble in water and the resulting solution acts by depressing the freezing point of snow and ice.
Though common deicing materials work in the same way, they vary widely in performance. The determining factors are speed, quantity of material required, and duration of melting action. Environmental considerations are also important.
Another measure of ice melter effectiveness is the amount of material needed to accomplish the undercutting job. Perhaps the best way to compare materials is to look at the volume of ice they are able to melt pound-for-pound within normal temperature conditions over a reasonable time period. When reviewing materials based on amount, most users will choose calcium chloride first, followed by magnesium chloride and sodium chloride.
A final measure of performance for an ice melter is how long it will provide deicing action. Obviously, the longer the ice melter acts, the less often reapplication will be required. The natural state of the chemical has the greatest effect on how long an ice melter will last. Those which are naturally liquids - calcium chloride and magnesium chloride - continue as brines longer since they resist evaporation.
Beyond physical properties, the shape of ice melters is important. Research confirms that rounder particles have distinct performance advantages. Round particles contact a smaller surface area than flakes or irregularly shaped granules, so they're more effective a t boring vertically downward rather than horizontally. This results in faster penetration to the pavement and quicker disbondment.
What's Most Important
Steps, walkways and other common areas that are the responsibility of the site manager require rapid cleanup to help maintain a safe environment. That's priority one. An effective, fast acting deicer naturally makes ice and snow removal easier which, in turn, saves time and reduces maintenance.
That's consistent with the opinions of more than 2,000 of the biggest buyers of deicers as captured in an independent nationwide survey. The following indicates how often they rated each factor "most important".
- Works Fast (44%)
- Won't Harm Concrete (21%)
- Works at Low Temperatures (13%)
- Non-Tracking (13%)
- Safe for Plants (8%)
In short, an ice melter should work fast under all conditions and not create any new problems while it is working.
The major considerations for choosing ice melters are:
- melting temperature
- product formulation
- application method
- types and uses of pavement to be cleared
- nearby vegetation and water
- interior floor surfaces
Don't forget, however, to also look at product availability in quantities both large and small, lead-time necessary for delivery, and container size and type for safe and efficient storage, handling and disposal.
Finally, take time to speak with a knowledgeable sales representative to discuss specific site needs and determine the most effective, safe and economical products.
Did you know that 95% of chemical ice melters on the market are made from one or more of these five basic ingredients: sodium chloride, otherwise know as rock salt; potassium chloride and urea, which are fertilizers; and magnesium chloride , calcium chloride, sodium acetate, and calcium magnesium acetate, which are hygroscopic chemicals?
By knowing the properties of each raw material, you can decide more accurately which products will be most effective for your situation.
Although there are many dozen brands of ice melter, the list of materials in common use is much shorter.
Of the materials listed, rock salt and calcium chloride are most extensively used in applications around commercial, industrial, and institutional facilities. Rock salt, calcium chloride, potassium chloride, and magnesium chloride are naturally occurring salts.
Here is a list of common ice melting products:
- Sodium Chloride (rock salt)
- Calcium Chloride
- Potassium Chloride
- Magnesium Chloride
- Sodium Acetate
- Calcium Magnesium Acetate
- Ammonium Nitrate
- Ammonium Sulfate
- Various blends
Ammonium based ice-melting products like ammonium nitrate and ammonium sulfate are fertilizers. They are not recommended for use as ice melters, as they have been found to chemically attack and damage concrete.
Sodium acetate, calcium magnesium acetate (CMA) and potassium acetate -- are environmentally friendly, biodegradable and less corrosive.
Sodium acetate and CMA is a dry formulation used as an ice melter on bridges, parking decks and airport runways. It does not attack rebar in reinforced concrete and is biodegradable, creating no problems in runoff water. It changes ice and snow into an oatmeal texture. This is not desirable for sidewalks, and it also may be cost-prohibitive, as it costs four to five times more than calcium chloride.
Gives some improvement in traction. A downfall is it gets tracked all over the buildings, if it's applied on sidewalks. Working at a high school doing maintenance, I got to see how well it worked outside, and how it destroyed the shine on the hallway floors.
Sometimes it's the lesser of the evils, as far as concrete stairs, and walks go. The building occupants will have to wipe their feet. De icers will dull the shine on a tile floor fast too. This is a common complaint from customers, and building superintendents.
A small drawback, when a slip and fall lawsuit is a possibility, if nothing is done to improve traction on walkways, steps, and parking areas. Remember that when everything melts, it will have to be cleaned up. If you do the grounds maintenance too, you are in effect, creating work for yourself come Spring.
This is a traction material. It is used for the running surface, of some high school tracks. Possibly available at mason yards, and quarries. Provides a great improvement in traction. This is the grit, in many salt/grit mixtures. I'm talking about the type that was used to make cinder blocks years ago. There are a few other types of cinders. Coal ash cinders, and furnace cinders. Coal cinders weigh about 40 pounds per cubic foot. About 1080 pounds per cubic yard. Furnace cinders on the other hand, weigh about 57 pounds per cubic foot, about 1539 pounds, per cubic yard. As far as I know, they are only sold in bulk. Utility companies around here use a sand/grit to backfill around power and gas lines. A coarse dark gray sand. It's most likely dust created by a rock-crushing machine. All the rocks crushed are sold in different grades, and combinations. Remember, when you apply a salt/grit mix, that when everything melts, it will have to be cleaned up. If you do the grounds maintenance too, you are in effect, creating work for yourself.
Also called "Turf-Face Builder" This is clay that has been baked, and then crushed into granules. Has a texture like kitty litter. Provides a great increase in traction. It is extremely absorbent. It is used to improve compacted soil. It is also used on some baseball diamonds, to help them dry out faster after a rain. It can be used to dry areas that had puddles, after the water is broomed off. It builds up in the clay, and helps it dry much faster. It is often used when planting to break up compacted soil, and helps hold moisture in the root zone. A bonus when using this is it can be swept or blown onto grass areas in the Spring, and it will help improve the soil. Any that you have left in the Spring, can be spread on lawns. Aerating first will help it get into the soil. Don't leave it in piles. Spread it out evenly. It will help the soil breath better, absorb moisture better too. If it's on the surface, it will wick moisture away. Better if raked into the surface, like after running a thatcher over a lawn.
This should provide you with a good overall view of the different materials that are commonly used for de-icing, and traction. Use what works best for your accounts, based on the accounts requirements.
Keep in mind that ice melters do not melt ice in their solid form. The solid must first penetrate the pavement and dissolve into a brine. The lower freeze point of the brine breaks the bond between the ice and the sidewalk.
Calcium Chloride melts faster than most other common ice melters for several reasons. Unlike rock salt, calcium chloride absorbs moisture from its surroundings and actually release heat as it changes from a solid to a liquid. So it forms a potent brine faster.
At 15 degrees Fahrenheit, calcium chloride pellets melt about twice the volume of snow in 20 minutes as rock salt. In addition, calcium chloride pellets also penetrate ice faster than other deicers, and the difference is even more dramatic at colder temperatures.
In order for an ice melter to be effective, it must go into solution quickly. It is the solution which penetrates the ice or snow to provide the undercutting, not the solid material. There are basic differences in how quickly different compounds turn into a deicing brine at low temperatures. Calcium chloride and magnesium chloride are liquids in their natural states and have an affinity for returning to a liquid. Plus, when solid forms of these compounds come into contact with water, they release heat. In practice, once calcium chloride and magnesium chloride touch ice or snow, they immediately pick up water to form a strong brine, emit heat to give added deicing effect, create more water, and form more brine. This process is repeated over and over.
Sodium Chloride and potassium chloride are both solids in their natural state. When they come into contact with moisture, they also will go into solution to form a strong brine. But, in doing so, they must absorb heat from the environment. Urea, ammonium nitrate, and ammonium sulfate also go into a solution (though not a brine) when they contact moisture, but also must absorb heat before the solution can be formed.
Most deicers do not chemically attack properly placed and cured concrete. Rather, damage to improperly constructed concrete is actually the result of the expansion pressure caused by the repeated freezing of trapped water. As the number of freeze/thaw cycles increases, it can contribute to damage. Independent testing of commonly used deicers has shown that calcium chloride is the least harmful to concrete (excluding Sodium Acetate and Calcium Magnesium Acetate) after 500 freeze/thaw cycles. Incidentally, liquid calcium chloride is widely used in concrete to decrease the set time of concrete in the winter.
To minimize the impact on concrete, ice and snow should always be removed promptly and any excess deicer brushed away after sidewalks have been cleared.
According to the Concrete Institute, damage to concrete is primarily the result of freeze/thaw cycle on poor quality concrete. The chemicals sodium chloride and calcium chloride have very little effect on concrete. Ice melters, however, do increase the number of freeze/thaw cycles in a given season.
Ice melters also can damage concrete containing rebar. When chlorides in the brine seep into the concrete and come in contact with the rebar, corrosion begins, resulting in concrete cracking and spalling. For this reason, chlorides are not recommended for use on concrete containing rebar or around steel structures.
Some ice melters contain corrosion inhibitors, but these products have not always proven effective. These products do not act on the chloride ion in salt, but instead, work by pacifying the rebar. In a laboratory test, a bare metal strip is placed in a solution of ice melter with corrosion inhibitor and water. No corrosion occurs because the pacifying agent moves freely in the water and coats the metal. In the real world, the pacifying agent does not move freely; instead, it becomes tied up in the concrete and is not likely to reach the rebar.
Many are concerned with deicers' effects on concrete. Among the materials under review, only ammonium sulfate and ammonium nitrate will chemically attack concrete. The others do not chemically attack concrete, but can affect the freezing point of water. When the freezing point of water is depressed, the number of freeze-thaw cycles the water goes through can increase. And the expansion of freezing water (hydraulic pressure) can exceed the strength limits of the concrete. Spalling can be the result, but this is greatly minimized in good quality air-entrained concrete.
Judicious use of deicers will minimize concrete damage. Prompt removal of slush and residual deicer from concrete surfaces will further minimize the chance for damage.
Calcium chloride can be effective in cold-weather conditions down to minus 25 degrees Fahrenheit. In comparison, rock salt is effective down to 22 degrees Fahrenheit. Urea is effective to 15 degrees Fahrenheit and potassium chloride effective to 12 degrees Fahrenheit. Sodium Acetate and Calcium Magnesium Acetate are effective to 5 degrees Fahrenheit.
Recent reports from highway departments indicate the calcium chloride and sodium acetate can shield against frost and ice formation for several days following application. A highway superintendent described it as an almost shield-like effect.
The first measure of an ice melter's effectiveness is the range of temperatures in which it can provide deicing action (in a reasonable time period). The "practical" lowest temperature limits for these materials is defined as effective within 15-20 minutes of application and is listed next to the material. When reviewing deicing materials on the basis of their effectiveness at practical temperatures, they rank as follows:
- Calcium Chloride (-25o F)
- Magnesium Chloride (5o F)
- Sodium Acetate (5o F)
- Calcium Magnesium Acetate (5o F)
- Potassium Chloride (12o F)
- Urea (15o F)
- Sodium Chloride (20-22o F)
- Various Blends (usually 20-22o F)
"Scientifically proven to melt at temperatures to -5 degrees". This may be true, but this is a laboratory measurement taken in a controlled environment, not a practical ice melting temperature. In a laboratory, a liquid with a 10% concentration of salt will freeze at 20 degrees, a 20% solution will freeze at 2 degrees, a 23% solution will freeze at -5 degrees, and a 26% solution will freeze at -28 degrees. It's not likely that you will create an exact 23 percent concentration of salt out on the sidewalks.
The practical ice melting temperature is one at which visible ice melting occurs within 15 minutes of application. Temperatures given previously were the practical melting temperatures.
Most deicers dry to a white powdery residue. Magnesium chloride and calcium chloride leave a clear brine solution. Regardless of the deicer, again, prevention is the best approach. Walk-off mats are one of the simplest yet most effective ways to cut down on tracking. Studies show that at least four feet of mat is needed with six to ten feet for higher traffic areas.
Many ice melters claim to be non-tracking. If they melt ice and snow, they create slush, and it tracks into facilities, no matter what. Look for an ice melter that is easy to clean up. Calcium Chloride is the hardest to clean when it is tracked on carpets. Using floor mats also will help lessen the problem.
Of the materials under review, the only materials which have the potential for leaving a solid residue on internal flooring are those that naturally occur as a solid.
All common deicers have the potential to harm vegetation. The best way to protect trees, shrubs and grass is not to use too much.
Deicers are not intended to melt every bit of precipitation and should always be used sparingly. For Calcium chloride, it usually takes only two to four ounces per square yard to effective undercut bonded ice and snow.
Keep in mind, excess snow can damage bushes, too – another reason why treated areas should always be shoveled away from sensitive vegetation. Prior to planting new areas, select trees, shrubs and grass that are less sensitive to deicing salts.
Most ice melters state they will not harm vegetation when used according to label directions. This can be misleading because there are too many variables in the amount of ice melter used. How much snow and ice must be removed? How many times per year will ice melter be applied? Where does the melted snow and ice go?
Here are the results of a study of common deicing chemicals on turf.
- Sodium chloride generally is recommended for use at a rate of 1/2 cup to 1 cup per square yard. Damage to turf occurred with two to three applications and in one application if over applied.
- Salt also can kill the roots of plants, not just burn foliage. Sodium Chloride should not be used in area where melted runoff water will come in contact with sensitive plant material. Also, salt continues to build up in the soil, resulting permanent damage.
- Fertilizers often are assumed safe for turf because they are fertilizer. The rates for fertilizers used as ice melters, however, are much higher than the rates for feeding. Damage could occur is over applied.
The study also showed that blends of salt and fertilizer also caused damage to vegetation.
Considerable emphasis has been placed on the environmental impact of ice melters and many studies have been conducted. Virtually all of these studies have concluded that, given the alternative of hazardous conditions, the benefits of ice melters far outweigh their potential disadvantages. However, these concerns should be addressed.
All materials under review have the potential to damage plant life. However, in the amounts recommended for grounds maintenance, the threat to grass, trees and shrubs is minimal. In fact, The Institute for Safety Analysis concluded in its major study, "Benefits and Costs in the Use of Salt to Deice Highways," that: "There is no evidence that road salting produces permanent ecological effects. What salinity build-ups occur are due almost entirely to improper storage rather than application".
An objective review of the performance capabilities of common ice melting compounds finds significant differences in their performance. As a result, firms should always make their purchasing decisions with full knowledge of exactly which compound(s) are in the products they choose.
Rock salt typically costs substantially less than calcium chloride, magnesium chloride, or sodium acetate by weight. Yet, a 50-pound bag of these products will deice at least twice the area as a 50-pound bag of rock salt -- and work at colder temperatures. Also, calcium chloride, magnesium chloride, sodium acetate, CMA, potassium chloride, and urea only require half the storage space as rock salt, and a single, all-around deicer can reduce inventory headaches.
Labor is the biggest cost of winter maintenance, so overall effectiveness should always be the guide. In addition to an ice melter's primary effectiveness, any residual refreeze protection can save a crew time and energy when winter is fiercest. But first, always consider the potential to help prevent slips, because that is what winter site management is all about.
The two main reasons for requesting a contract from us are to guaranteed product and guaranteed price.
Bulk salt is brought into the Twin Cities by barge on the Minnesota River. Obviously we cannot get a barge in during the winter, so our supply for the winter is somewhat limited. If we do need more product, we need to have it trucked up at a considerably higher rate than the barged product. By signing a contract you know that your price will not go up if there is a salt shortage.
Also, if we are very short of product you know that we would be required to have product brought in to fill your demand. Without a contract, you could be denied product in the event of a shortage.