Information: We are in the process of migrating the Winter Parking Lot and Sidewalk Maintenance manual to the Minnesota Stormwater Manual. You can access a pdf version of the maintenance manual here. Other changes and updates to information on salt management will be posted in the What's new page in the manual. Information on road salt and water quality can be found on MPCA's website

This article provides information on preparing for winter operations

Policies and plans

Start now—develop a maintenance policy or plan that guides winter operations. A little planning and communication up-front can help achieve better results throughout the season.

  • Develop a maintenance policy or plan. In the plan,
    • list the key actions to take during a winter event
    • list the order of these actions
    • address the level of service, considering customer expectations, the hours and use of the building, priority access points and environmental concerns in the policy; and
    • spell out any additional strategies such as routes, chemicals, and application rate ranges.
There are several winter maintenance policy plans available in the literature, including plans developed for the cities of Regina, Superior, Wisconsin, and Sandwich, Massachusetts.
  • Review the maintenance policy with the crew.
  • Inform customers of the maintenance policy.
  • Follow the plan.
  • Document actions.
  • Review and update the maintenance policy each year.
Information: dollar symbol Our waters are threatened by contracts which are based on fees for material use. This encourages overuse of materials.
Information: dollar symbol Reduce liability. Establish a maintenance policy and follow it.

Training

Reduce risk by having a solid written winter maintenance policy and training program that utilizes best management practices. Schedule training for supervisors, staff, and customers.

The MPCA has three Smart Salting training classes available:

  1. Level 1 Winter maintenance of roads
  2. Level 1 Winter maintenance of parking lots/sidewalks
  3. Level 2 winter maintenance training for supervisory staff

Check the MPCA website to find out about upcoming training opportunities.

Initial preparation

This section describes initial actions in preparing for winter maintenance.

Getting prepared for winter

  • Calculate the area of the parking lots, service roads, and sidewalks.
  • Understand the environmental problems caused by snow, salt, and sand storage. Determine where and how to best store each item.
  • Understand the properties of various deicers, and then select the type(s) to use.
  • Train the crew on proper application rates.
  • Mark islands, fire hydrants, and other landmarks that could be obscured by snow.
  • Note existing conditions of curbs and other items that might be damaged by winter maintenance activities.
  • Note or mark all catch basins, manholes, sidewalk segments that may cause a hazard to the plow and the operator.

Drainage

Inspect storm drains in the fall. Remove obstructions such as leaves, sticks, and trash to prepare for the spring melt. Because storm drains lead to lakes, rivers, ponds, and wetlands, never use salt to open frozen storm drains. Salt used to thaw frozen drains harms aquatic life. Use non-chemical methods such as heat to open drains.

Poor drainage on the maintenance surfaces will result in icy surfaces and will increase the risk of safety problems. These areas cause the application of salt on non-snow event days in the winter. To remedy this, inventory the site and note drainage problems. Make a checklist so the professional or client can fix these drainage problems in the summer.

Examples of drainage problems:

  • Roof that drips on the steps
  • Downspout discharging on sidewalk
  • Sidewalk segments sloped into a V
  • Potholes or low spots in parking lots
Information: dollar symbol Storm drains lead to the nearest lake, river, pond, or wetland. They do not go to a treatment plant.

Equipment

The trend in winter maintenance is to use less material to accomplish the same results. Following this trend will reduce environmental impacts and save money. Below are listed a few tips, but there are many other innovations in the equipment area that can help to reduce application rates.

  • Purchase a pavement sensor
  • Buy equipment that can deliver very low rates of granular products.
  • Outfit larger trucks with ground speed controls so that the application rate changes automatically as the speed changes.
  • Modify existing equipment so that it can discharge the application rates described in the “Application Rates” section. Older equipment often applies more salt than recommended.
  • Outfit sidewalk spreaders with shields to better direct the spread pattern.
  • Invest in equipment that can deliver liquid deicers.
  • Obtain a tank for liquid storage or find a near-by source of liquids to fill up trucks.

Calibration

This graph of Steps for Calibrating an auger or conveyor system
Steps for Calibrating an auger or conveyor system

Calibration is an essential procedure to understand how much material will be discharged at a given setting. No matter how sophisticated or simple the operation, calibrate each piece of equipment in the fall of the year. Contact manufacturer for calibration instructions.

Simple calibration for salt spreaders

If the equipment has different settings, it must be calibrated for each setting and for each product, as they all flow differently. It generally takes a team of two or three people to calibrate equipment efficiently.

Ground speed controlled spreaders

Ground speed controlled spreaders are run by a computer in the cab and are tied to the speedometer and an auger or conveyor sensor in the rear of the truck. The application rate is set and the computer regulates the amount of salt discharged (regardless of the speed traveled) consistently. Most equipment used for winter maintenance of roads have ground speed controls. These are more effective and efficient systems than the manually controlled systems.

The equipment vendor will have specific calibration instructions for the operation based the type and brand of equipment. Contact them; it is in their best interest to provide instructions to calibrate and correct product use. This is the basic principle behind calibrating a ground speed controlled spreader:

  • The speedometer input (sensor) lets the controller know how fast or slow the truck is traveling.
  • The auger or conveyor input (sensor) tells the controller how fast or slow the auger is turning.
  • To calibrate a ground oriented controller, input the pounds discharged per revolution.
  • Once the computer knows the pounds/ revolution, it will calculate the necessary auger speed needed to hit the target application rates at the speed the truck is traveling.
Information: dollar symbolCalibration allows accurate deicer use

Manual controlled spreaders

Manual controlled spreaders fall into two categories. Those that have an auger or conveyor and those that are gravity fed. They operate by selecting a setting that changes the size of the discharge opening and/or the auger or conveyor speed. More or less salt may be discharged depending on the speed of application. Most parking lot and sidewalk spreaders fit into one of these two categories.

The basic principle behind calibrating an auger/conveyor spreader is to choose a setting, run the spreader for a timed interval, and weigh the discharge. Record the discharge and repeat for all settings. In the end, there will be data that tells the operator how much material will be delivered at each setting. With this information, the operator can choose the proper setting. Without this information, they have no guidance on which setting to use. Calibration is different for gravity fed spreaders..

Information: dollar symbol Apply wisely. The chemicals applied cannot be recovered.
Information: dollar symbol Surfaces such as pervious asphalt, pervious concrete, and pervious pavers do not experience refreeze. All melted snow and ice travel to the storage layer below the surface. Salt is generally not needed on these surfaces and sand should be avoided.

Example calibration for manual control spreaders

The following calibration example applies to manual control spreaders.

Step #1, blank calibration form

See the References and Resources section for a full size form to copy for calibration. This is how the empty form looks.(Keep a stack of these on a clipboard when ready to begin the calibration.)


Calibration Chart for auger or conveyor systems
Link to this table

Date:
Spreader #:
Material:
Setting Pounds per minute 5 mph (X12) 10 mph (X6) 15 mph (X4) 20 mph (X3)
1
2
3


Step #2, calibration form filled out during calibration

Fill in the header information and column 2, the discharge weight per setting.


Step 2 Calibration Chart for auger or conveyor systems
Link to this table

Date: August 8, 2015
Spreader #: A4219
Material: Rock salt
Setting Pounds per minute 5 mph (X12) 10 mph (X6) 15 mph (X4) 20 mph (X3)
1 10
2 22
3 34


Step #3, calibration form ready to put in truck for road application

Back in the shop, do the calculations to fill in the rest of the blanks. Multiply the weight in column 2 with the multiplier in the top row. This provides the pounds per mile that needed to fill in the table.


Step 3 Calibration chart for auger or conveyor systems
Link to this table

Date: August 8, 2015
Spreader #: A4219
Material: Rock salt
Setting Pounds per minute 5 mph (X12) 10 mph (X6) 15 mph (X4) 20 mph (X3)
1 10 1201 60 40 30
2
2 22 264 132 88 66
3 34 408 204 136 102

1 top half of each row = lbs/lane mile. To get this number, multiply lbs/min by the factor shown for each speed
2 bottom half of each row = lbs/1000 sq ft. To find this, divide the number in the top half by 63

Information: dollar symbol Some fish species are affected by concentrations of less than 1000 ppm NaCl, about 1 to 1.5 tablespoons of salt in 5 gallons of water.


Step #4, calibration form ready to zip tie to hand spreader or put in truck for parking lot application

Divide by 63 to convert pounds per lane mile to pounds per 1,000 square feet. This is very useful for parking lot and sidewalk applications.


Step 4 Calibration Chart for auger or conveyor systems
Link to this table

Date: August 8, 2015
Spreader #: A4219
Material: Rock salt
Setting Pounds per minute 5 mph (X12) 10 mph (X6) 15 mph (X4) 20 mph (X3)
1 10 1201 60 40 30
1.92 1.0 0.6 0.5
2 22 264 132 88 66
4.2 2.1 1.4 1.0
3 34 408 204 136 102
6.5 3.2 2.2 1.6

1 Top half of each row = lbs/lane mile. To get this number, multiply lbs/min by the factor shown for each speed
2bottom half of each row = lbs/1000 sq ft. To find this, divide the number in the top half by 63

Gravity flow equipment

This is applicable for equipment that does not have a motorized delivery system such as an auger. This type of equipment might be a pickup mounted spreader, gator mounted spreader or a hand push spreader. Gravity flow equipment is typically controlled by gate opening and speed of application.

Calibration example for gravity flow equipment

The following step-by-step process describes an example calibration for a gravity flow spreader.

Step 1: Calculate discharge rate
  • Mark out a 10-foot stretch of pavement. (By increasing the size of the test area i.e., the longer the test area, the more accurate the results will be).
  • Sweep it clean of sand or any other material.
  • Using a constant speed, apply one pass of material to the test area.
  • Measure the width the material is spread or bounces, in feet.
  • Sweep up and weigh the material that is within the marked 10-foot stretch.
  • Record the lever position/setting for the gate/chute. If there are no numbers for the positions, make permanent marks on the equipment to identify the positions.
  • To improve accuracy, repeat this two more times and calculate the average weight of material applied.
  • Record results in columns A, B, C, and D.
Step 2

Repeat step #1 for various settings  

Step 3: Fill out chart
  • Fill out columns E, F, and G in the chart below
  • If using more than one type of material, repeat the test for each material.
  • Place the completed calibration chart with the equipment.


Example calibration chart for gravity flow equipment
Link to this table

Equipment:
Material:
Date:
A B C D E F G
Speed Lever position or gate setting Pounds spread in 10 feet1 Spread width in feet Coverage area in sq. ft. (D x 10)* Application rate in lbs./1000 ft2 (1000/E x C) Application rate in lbs./lane mile (12’ width) (F x 63.4)
Example
20 MPH Half-closed 0.4 lbs 13 feet 130 sq. ft. 3.1 lbs. per 1000 sq. ft. 196 lbs./mile

1If changing the test strip length, adjust the title in column C and the multiplier in column E.


The following shortcuts can be used in calibrating the spreader.

  • Put down a tarp over the application area; this makes it quicker to recover and weigh material.
  • After the first pass, put a bag around spreader to catch discharge material. The first pass is needed to determine the spread width.

What if calibration is not a practice?

Even without calibrating the equipment, the amount of material to use can be determined but will take more time to calculate. Know the material, the size of the area to be treated, and the pavement temperature, then consult the application rate chart (application rate section) and do the math. Without calibration, the way to evenly distribute the recommended amount across the maintenance area must be determined by the professional. This approach may work well for treating sidewalks using the “chicken feed” method. For example:

  • 20oF degrees pavement temperature and rising
  • Using dry salt
  • Sidewalk is 2,000 square feet
  • Table recommends 2.25 lbs. per 1,000 square feet (for this situation)
  • Measure about 4.5 lbs. of salt
  • Figure out a way to spread it evenly over the 2,000 sq. ft. surface
Information: dollar symbol Sand fills in lake bottoms, accelerating the aging process of lakes. Lakes get shallower as they age, some eventually becoming wetlands.

Links to calibration charts

Use the following links to access the calibration charts discussed above

Calculating parking lot or sidewalk area

The amount of deicer needed is based on the size of the parking lot or sidewalk. Here are simple ways to calculate the area of the parking lot or sidewalk.

  • Ask the property owner for a scaled map of the facility to calculate areas.
  • Ask the property owner for the size of the area to be treated.
  • Measure the parking lot.
  • Use an internet mapping tool to calculate areas.

The area, or square feet, of a square or rectangle is equal to the length (L) times the width (W).
The area, or square feet, of a circle is equal to πr2, where π (pi) equals 3.1416 and r is half of the distance across the circle.
The area, or square feet, of a right triangle is equal to the length (L) times the width (W) divided by 2


Information: dollar symbol Measuring the area, along with knowing the pavement temperature, will allow the use of the application rate charts. This will help to reduce the amount of chemicals applied

Practices

This section provides best practices and tips for winter parking lot and sidewalk maintenance.

Storage of snow piles

  • Store snow in an area where the solids can be recovered after the snow melts.
  • Locate snow piles down-slope from salt and sand storage to prevent snow melt from flowing through salt or sand storage areas.
  • Avoid pushing snow into lakes, ponds, wetlands, rivers, or other natural areas.
  • Do not store snow having elevated chloride concentrations in areas of stormwater infiltration. Improper storage of salts can lead to groundwater cantamination.

Storage of salt and salt-sand piles

This photo of salt storage uncovered and downhill from snow pile
Salt storage uncovered and downhill from snow pile
  • Storage areas can result in groundwater or surface water contamination if not properly managed. When locating new storage for liquid or granular products be aware of local visual screening ordinances.
  • Indoor storage is recommended.
  • Store on an impervious (water proof) surface.
  • The floor should be sloped away from the door.
  • Sweep loading areas back into the pile.
  • Store away from lakes, rivers, ditches, storm drains, infiltration practices, and wetland edges.
Information: dollar symbol Salt storage areas are often a source of groundwater contamination. To reduce risk, have a covered storage area on an impervious pad. Take measures to keep salt or salt brine from leaving storage area.

Storage of salt bags

  • Protect from rain or snow
  • Dispose of bags properly
  • Seal all open bags

Storage of liquids

  • Know the freezing point of the liquid. This will determine if it can be stored outdoors. Salt brine (sodium chloride - NaCl) will freeze at -6o F.
  • Tanks should be double-walled or have secondary containment. Secondary containment is like creating a bath tub around the tank so if the tank leaks, the “tub” captures the spill.
  • Label the tank documenting its contents.
  • Click here for more information on storage tanks.

Storage of sand piles

  • Winter sand is typically mixed with some deicer to prevent freeze-up of the pile; therefore, sand pile storage should be the same as salt pile storage.
  • Store leftover winter sand for next year. Do not use it for other purposes.
Information: dollar symbol Prevent groundwater contamination. Do not locate storage areas near wells. Limestone regions with fissures and sinkholes are very prone to groundwater contamination, as are those with sandy soils.

Sidewalk tips

Always remove snow prior to applying deicers. Plow, blow, or sweep first; the chances of refreeze diminish and slush build-up is minimized.

  • Sidewalks are the most over-salted areas in winter maintenance.
  • Use drop spreaders, not rotary spreaders. If using a rotary spreader, install shields to restrict the spread pattern. This minimizes the application rate and protects the vegetation.
  • Many slip and fall incidents occur within 10 ft. of the curb lines. Adjust practices to include proactive measures like anti-icing.
  • If the professional is not responsible for sidewalk maintenance, consider providing this information to the responsible party.
  • Focus on aggressive mechanical removal of snow. The less snow, the less deicer required. This will lend itself to a safer surface.
  • Deicers can harm heated sidewalks.
  • Abrasives can harm permeable pavers or permeable concrete.
Information: dollar symbol Salt only needs to melt 1/16 inch to prevent the bond between the pavement and the ice. Save money by applying salt before the ice bonds to the surface it doesn’t need to melt through the ice.

Building entrances

Steps are often the most over-salted area in all of winter maintenance. This overabundance of deicer causes damage to floors inside the building as salt and/or sand is tracked in. It causes problems outside of the building with deterioration of concrete and metal structures. Over applying deicer costs more money than necessary, pollutes the water, and does not provide any additional safety. The right amount of deicer and proper mechanical removal of snow and ice will yield better results.

A free short video for small site winter maintenance (scroll down on page) is available. It is designed for those that do winter maintenance of small sites such as stairs, curb cuts, and handicap ramps. The video is a visual instruction tool useful for those who apply granular deicer to small areas outside building entrances. It recommends:

  • Do site assessments, document drainage problems, and fix them in the summer (e.g., roof that drips on steps, downspout that drains to sidewalk).
  • Always remove snow prior to applying deicers. The less snow, the less deicer required for a safer walking surface.
  • Use the proper tool for snow and ice removal:
    • Push shovel (no sides) for pushing snow.
    • Scoop shovel (sides) for lifting snow.
    • Broom or blower for light fluffy snow.
    • Ice scraper for use under ice and compaction.
    • Ice chisel for breaking open compaction, or under ice and compaction.
  • Use hand-held spreaders to disperse deicers. Spreaders:
    • Provide more even distribution.
    • Reduce amount needed.
    • Reduce tracking into buildings.
    • Save money with reduced salt application.
    • Save infrastructure: less salt, less corrosion.
  • Look for opportunities to close extra building entrances during the winter. High maintenance, non-essential entrances are perfect candidates.

To determine the amount of deicer needed for steps, stairs, and small sites:

  • Refer to the application rate chart.
  • For those who do maintenance as a small part of their job, it is unlikely they will ever use an application rate chart. Here are some guidelines to get them closer to the proper rates. The goal should be:
    • Even spread pattern with granules no farther than 3 in. apart
    • Even spread pattern with no granules touching each other
    • No piles of deicer
    • No deicer on dry pavement
    • No deicer in vegetation
Information: dollar symbol Handheld spreaders and shakers, not scoops, should be used to apply deicer to steps and building entrances. This will save at least 50% of the salt normally used per winter without reducing the level of safety.

Parking lot tips

  • It is hard to walk and push shopping carts through salt and sand accumulations in parking lots. Sand is ineffective once it is on the pavement. Sweep it up to prevent a slippery situation.
  • Handicap parking spots are often over-salted and over-sanded. They should get the same amount of salt or sand as other areas.
  • Sand/salt mix generally isn’t advised; however, it may help in freezing rain situations.
  • Always plow before applying materials.
  • It may be possible to use a lower rate in high traffic areas. Traffic tends to help mix and melt.
  • Store snow downhill from any salt storage areas. Avoid water running through salt storage.

Materials

All products have pros and cons. No one material is suitable for every condition. It is best to have a variety to choose from to select the one that works the best, with the least amount applied, in a specific situation. Understand the melting properties of the deicers; do not use the product without understanding how it works.

The best way to reduce impacts, save money and maintain customer satisfaction is to:

  • Know what is in the product.
  • Know the product’s practical melting range.
  • Use it only when it will be effective.
  • Use the minimum amount needed to get the job done.
  • Seek out products that allow for smaller application rates.

Types of materials

This sections provides a discussion of the most commonly used materials for deicing.

Abrasives

  • Sand is an abrasive; it does not melt snow and ice.
  • Abrasives provide traction on top of packed snow or ice.
  • Abrasives and deicers typically work better alone, rather than together.
  • A small amount of salt must be mixed in the sand to keep it from freezing in the pile (less than 10%).

Salts

  • Sodium chloride (NaCl), magnesium chloride (MgCl2), potassium chloride (KCl), and calcium chloride (CaCl2) are all considered salts.
  • Salt is a deicer; it will melt snow and ice.
  • Salt lowers the freezing point of water from 32° F to a colder temperature.
  • Salt must be dissolved to work; therefore, liquids act faster than solids.
  • Salts have different melting characteristics, depending on the selection.
  • Road salt (NaCl) is a granular product and is mined from the earth.
  • Magnesium chloride (MgCl2) and calcium chloride (CaCl2) can naturally occur as liquids.
  • MgCl2 and CaCl2 are hygroscopic, drawing moisture from the air to the pavement.
  • Salt brine (NaCl) is commonly used at a 23.3 percent concentration as this has the lowest freezing point and can be stored and handled down to -6°F.

Acetates

  • Acetates are chemically manufactured, not mined from the earth.
  • Acetates are more expensive than chloride salts.
  • Acetates are less corrosive than salts.
  • They have a wide melting range, depending on the selection.
  • They are not better or worse than chloride salts, they are different.

Plant-based additives

Corn, beet, molasses, or other organic additives are added to salt or salt brine to change its performance, though how they function as an ice melting agent is not well understood. Clear Roads (2015), a national resource consortium of state agencies, is studying this issue.

  • Often have very low ice melt capacity.
  • May be used to reduce corrosion.
  • Are sticky and may help dry material stay on the surface longer.

Testing the material

When ordering a liquid product in bulk, test it. If it is NaCl brine it should be 23.3 percent. If it is another liquid, use the vendor recommended density and test to confirm. Hydrometers are the tools for testing the density of liquids. They are inexpensive and look similar to a thermometer. Research the product, understand the practical melting temperature, and know the list of ingredients. Take time to test the materials to ensure that they perform as expected. Product labeling can be confusing; some list the eutectic temperature while others list the lowest practical melting temperature.

The list of ingredients may or may not be included. Often, the percentage of each ingredient is not included. Do not rely solely on the bag or on the manufacturer’s literature. There are no labeling requirements; manufacturers can choose to label products in their own way.

Cost and availability of materials

Of the deicers, NaCl is typically the cheapest and easiest to find. Because of this, it is widely used and overused. Sodium chloride is only effective at pavement temperatures above 15oF. Because it doesn’t work well at colder temperatures, it is often over-applied in attempts to increase its effectiveness. At temperatures lower than 15oF degrees, switch to a different deicer.

Non-chloride deicers are more difficult to find and often cost more. Take the time to source and try non-chloride products if there are concerns from the professionals or customers about the long-term effects of chlorides on the lakes and rivers. All deicers have environmental impacts but the impacts of chlorides are very long-term.

Salt and sand mixes are commonly used to stretch the salt budget. This is an ineffective practice. Salt and sand work against each other. To save money, use deicers when melting is needed and sand for temporary traction to buy time at temperatures too low for deicers to be effective. Pre-wetted sand has shown to be effective in keeping sand in place longer on icy surfaces.

Information: dollar symbol Using 50/50 salt/sand mix is generally half right or half wrong. Using a salt/sand mix leads to over application of both materials.

Conditions affecting winter maintenance

The following conditions affect winter management strategies and options.

Weather

Know existing and potential weather conditions for a successful snow and ice control operation. Monitor the weather closely to prepare to act early in storm situations. Check the National Weather Service, local TV stations, or website weather. A Road Weather Information System (RWIS) is available for free on-line at. The RWIS provides real time pavement temperatures and other information from locations around the state.

Pavement temperature

This photo of Hand held temperature sensor
Hand held temperature sensor

Pavement and air temperature are different. Know the pavement temperature to determine the proper amount and type of material to apply. Weather stations report air temperature which is measured at least 6 ft. in the air. The air temperature is not helpful when trying to determine what to apply to surfaces on the ground.

Air temperature measurements are generally the same in a given area, but pavement temperatures in the same general location can vary greatly. Pavement temperatures are influenced by exposure to sun, pavement type, and subsurface materials.

The same air temperature in November and January will often accompany very different pavement temperatures.

The hand-held temperature sensors can be purchased from auto part stores for less than $100. Some temperature sensors only accurately monitor in the warm temperature range, confirm the one purchased measures in the cold temperature range. Mirror-mounted temperature sensors are also available; they are less likely to be lost or stolen, but do cost more and are generally not available at an auto parts store. RoadWatch by Commercial Vehicle Group, Inc. is one example of this type of sensor. A small investment in equipment will improve performance.

Information: dollar symbol Knowing the pavement temperature allows the application of the proper amount of material for each situation.

Speed of melting

Will the road salt used have time to work or is it better to switch to a different deicer? This chart will aid in making that decision.

Speed of melting
Link to this table

Pavement Temp. ºF One Pound of dry Salt (NaCl) melts Melt Times
30 46.3 lbs. of ice 5 min
25 14.4 lbs. of ice 10 min.
20 8.6 lbs. of ice 20 min
15 6.3 lbs. of ice 1 hour
10 4.9 lbs. of ice Dry salt is ineffective and will blow away before it melts anything
5 4.1 lbs. of ice
0 3.7 lbs. of ice
-6 3.2 lbs. of ice
Information: dollar symbol Do not use dry road salt below 15º F. This wastes money and time.

Practical melting temperature

Use care when reading the melting temperature on bags of deicers. The package often lists the eutectic temperature, which is the lowest possible melting temperature. At this temperature, it would take a very long time to melt ice. Instead, use the lowest practical melting temperatures in the chart below or ask the supplier for the practical melting temperature and the time it takes to melt ice at that temperature. It should be noted that there is not a standard measure for determining the lowest practical melting temperature. Across the literature there are a range of values. In the References and Resources section there are lists of several websites to learn more about the lowest practical melting temperature.

Lowest practical melting temperature
Link to this table

Chemical Lowest Practical Melting Temp. Eutectic Temp. Optimal Concentration
NaCl (Sodium Chloride) —Delivered as rock salt, can be made into a brine. The basis of many bagged blends. Corrosive. Inexpensive. Very available. Most commonly us used without a corrosion inhibitor added, but corrosion inhibited products are available 15º F -6º F 23%
MgCl2 (Magnesium Chloride)—Delivered primarily as a liquid, other forms available. Used for anti-icing, pre-wetting and stockpile treatments. Corrosive. Higher cost. Often has a corrosion inhibitor added. Often added to salt brine. -10º F -28º F 27 to 30%
CaCl2 (Calcium Chloride)—Delivered as flakes, pellets, or liquid. Corrosive. Most effective ice melter at very cold temperatures. Sometimes used incorrectly to open storm drains. Higher cost. Often has a corrosion inhibitor added. Often added to salt brine. -20º F -60º F 30%
CMA (Calcium Magnesium Acetate)—Delivered as a powder, crystals, pellets, or liquid. Liquid CMA is used mainly on automated bridge deicing systems. Non-corrosive to steel, biodegradable. Alternative for areas where chloride use must be limited. Higher cost. 20º F -18º 32%
KAc (Potassium Acetate)—Delivered as a liquid. Often used on automated bridge deicing systems and airports. Use for anti-icing, deicing. Non-corrosive to steel but corrosive to galvanized, biodegradable. Alternative for areas where chloride use must be limited. Higher cost. -15º F -76º F 50%
Blends— Both chlorides and acetates exist in blends. Talk to the supplier and determine the lowest practical melting temperature, the optimal concentration and the basic components in the blend. Most blends are centered on rock salt since it is cheap.
Winter Sand/Abrasives—Winter sand has salt mixed in it to keep it from freezing. Abrasives should be used for cold temperatures when deicers are not effective. Want to minimize salt % in sand. Never melts—provides traction only


Related pages

This page was last modified on 26 April 2017, at 11:33.

Minnesota Pollution Control Agency | 651-296-6300, 800-657-3864 | Assistance | Web site policy