This document combines several documents related to winter parking lot and sidewalk maintenance. Individual documents can be viewed by clicking on the appropriate link below. Fact sheets are not included in this combined document.

# Background information

The purpose of this manual is to deliver practical advice to those managing parking lots and sidewalks. This manual will help to make proactive, cost-effective, environmentally conscious choices in winter parking lot and sidewalk management. This knowledge will provide the opportunity to become a leader in the industry by operating more efficiently and reducing environmental impacts.

A single approach will not work for the range of conditions Minnesota experiences; different strategies are needed for different regions and different weather conditions. We encourage continuing to test, document, and refine the practices from this manual.

## Making good business choices

Customer service is the key to success. Best Management Practices (BMP) keep parking lots and sidewalks safe and also reduce environmental impacts. Educating customers on the proper methods of snow removal and ice control (and of the value of this approach) can create a good and long-standing relationship.

Customers want reliable service. Providing a well-planned and well-executed winter maintenance program will have a positive impact. Using the latest technologies will increase the ability to provide reliable service.

Customers want to hire educated winter maintenance professionals. This manual will provide the necessary information to increase staff knowledge on the best practices for winter maintenance.

Information: Using the right amount of material at the right time, will save time and money
Information: Certification in Smart Salting is a good reflection on the professional and the organization

Customers and the public want safe parking lots and sidewalks. Understanding the materials, weather and application rates, provide a head start on controlling icy, slippery parking lots, and sidewalks.

Clean and neat parking lots and sidewalks are important to the public. By using less material and increased winter sweeping, pedestrians will track less material into buildings and there will be less damage to flooring. Proper snow storage makes debris removal in the spring easier. Covered storage of deicers will reduce loss of material, protect water, and is more aesthetic. Using BMPs and lower application rates will keep parking lots and sidewalks looking neat.

Customers also want affordable snow and ice control. The use of sophisticated chemicals and equipment may require a larger budget up-front; however, these costs can be balanced by reduced on-going costs. Reducing the need for sweeping, floor and rug maintenance, parking lot striping, and snow and ice maintenance time will allow for cost savings.

Minnesotan’s value water resources and the protection of lakes, streams, and wetlands is important. Educating customers how sustainable winter maintenance protects water resources is necessary.

Information: Using less material is an effective approach to protecting our water resources. It is difficult to recover salt or sand once applied

## Water and environmental impacts

Only 2.5 percent of all of the water on this planet is freshwater (not saltwater). Of that, less than 1 percent is available for use, with the majority of the freshwater frozen in ice (Freshwater Crisis n.d.). There is a limited supply of water on this planet and that water is reused, recycled and dispersed, often over long periods of time (Healthy Rivers, 2004).

Concentration of lake chloride in Twin City lakes and rock salt purchases by State of MN
Distribution of road salt use in Twin cities area
Witches broom branching from salt spray

Because the supply of water can be limiting, it is important to keep it clean. Once polluted, water may become unusable or require cleanup. Elevated concentrations of chloride can diminish the quality of water. Chloride concentrations are increasing in many surface waters and in shallow groundwater across Minnesota.

• In the Twin Cities Metropolitan Area (TCMA), of surface water bodies tested, 39 are on the draft 2014 impaired waters list for chloride exceedances and 38 more are found to be at high risk as of July 2015. (MPCA 2015). Salts (chloride) dissolve in water and move with the water to nearby lakes, streams, and wetlands and also infiltrate into groundwater.
• Chloride does not degrade and cannot be removed from surface waters. It moves with water and can eventually flush out of a water system, but if chloride inputs exceed outputs chloride will accumulate in the environment over time.
• Salt water is heavier than freshwater and may sink to the bottom of lakes. This may cause chemical stratification of the lake and loss of or changes in lake turn over (Stefan et al. 2008).
• Thirty percent of the 270 shallow aquifer monitoring wells tested in the TCMA exceeded the Secondary Maximum Contaminant Level of 250 milligrams per liter (MPCA 2013).
• About 75 percent of Minnesotans rely on groundwater for drinking water. If chloride-enriched water moves from shallow to deeper aquifers, the salt contamination could penetrate sources of drinking water (MPCA 2013).
• The average salt use in the TCMA based on purchasing records is 349,000 tons per year (Sander et al. 2007).

Deicers can be very damaging to both soil and vegetation. Efforts to keep salt off vegetation are needed. Examples include driving slower when applying deicers, turning down spinner speeds to reduce spread pattern, using drop spreaders on sidewalks, storing snow piles on hard surfaces, and reducing application rates. One source of information about salt-tolerant plants is the Plant Selector from Minnesota Department of Transportation.

Information: Salt spray damages budding and branching of trees

# Preparing for winter operations for winter parking lot and sidewalk maintenance

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: Our waters are threatened by contracts which are based on fees for material use. This encourages overuse of materials.
Information: 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: 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

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: Calibration 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: Apply wisely. The chemicals applied cannot be recovered.
Information: 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

Setting Date: Spreader #: Material: 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

Setting Pounds per minute Date: August 8, 2015 Spreader #: A4219 Material: Rock salt 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

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

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

A B C D E F G Equipment: Material: Date: 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: 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: 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

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: 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.

### 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: 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: 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: 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.

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: 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

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.

• 2007-2008 - The district used 196 bags of ice melt; The total was $1,552.32 Reduction in ice melt use: 33.3% Reduction in cost: 33.1% ### University of Minnesota (UMN) - Twin Cities campus - Jim Weber - U of M Facilities Management Over the past few years, the UMN recognized the need to become much more environmentally conscious with winter maintenance and storm water management. They made many changes in their snow removal program; two key areas were employee training and calibration of equipment. By increasing awareness of proper application rates, they were able to significantly decrease the amount of deicing chemical used. They started an aggressive anti-icing program with liquid magnesium chloride for their sidewalks and salt brine for the streets and loading docks. Pre-storm applications were extremely successful in reducing the bond of snow and ice to walks as well as giving them more response time on the front end of snow events. They focused on mechanical removal of snow as their first line of defense and they have changed the main deicer for walks from a blended material to straight magnesium chloride. They dramatically reduced the sand in their sidewalk and street program which has saved them time and money in spring clean-up and long term savings are expected in storm sewer maintenance. Small amounts of sand are still used as pattern indicators for their sidewalk trucks and for use during extreme cold weather. The numbers speak for themselves: Material # 1 – Rock Salt • 1997 - 2005 average: 775 tons of salt • 2006 - 2008 average: 462 tons of salt • Net Average Reduction: 313 tons • Percent Reduction: 41% • Material Cost:$48.53/ton
• Amount Saved: $15,193 average per year (2006 – 2008) Material #2 – Ice Melt (Magnesium Chloride - MgCl2) • 1997 - 2005 average: 131 tons • 2006 - 2008 average: 64 tons • Net Average Reduction: 67 tons • Percent Reduction: 51% • Material Cost:$410/ton
• Amount Saved: $27,470 average per year (2006 – 2008) Material #3 – Sand • 1997 - 2005 average: 1965 tons • 2006 - 2008 average: 18 tons • Net Average Reduction: 1,947 tons • Percent Reduction: 99% • Material Cost:$8.30/ton
• Amount Saved: $16,160 average per year (2006 – 2008) ### Net-Work Services Company (NSC) - Bob Rush – Director of Operations NSC is a national facility management company that services commercial properties in 22 states. NSC’s responsibility is to manage all building services which include hiring and managing winter maintenance contractors. While working in his prior role as Regional Manager for Minnesota and North Dakota, Bob Rush required all of his Minnesota winter maintenance contractors to be trained and certified on the best practices. As Director of Operations he has implemented a regional training program based on the Minnesota program. This allowed NSC to expand the best practices training to all winter maintenance contractors in cold weather states. Bob has taken many steps to reduce the impacts of winter maintenance and to improve the safety of his operations Bob required all suppliers in the seven county metro area to switch to a standardized treated salt for parking areas. He helped calibrate all truck mounted spreading equipment to ensure they were not over-applying the deicer. Bob required all Twin City Metro and Duluth area suppliers to switch to a mag/hex for sidewalks. This standardized the deicer which helped the suppliers determine the correct application rates per sq. ft. based on temperature and location of the sidewalk. He requested that all Twin City Metro suppliers attend the MPCA snow training program. He rewarded the suppliers that were able to show their certifications. NSC held regional training sessions with all contractors, reviewed best practice for snow removal, and discussed the proper techniques and timing for deicer application. Bob requires preseason re-training of large suppliers to refresh them on the best practices. He expanded the material that was developed by the MPCA and trained his 14 Regional Managers on best practices, impact on the environment, and the need for continual training. They, in turn, introduced the training material into the larger markets such Salt Lake City, Denver, Omaha, and Boise. They eliminated sand use in Minneapolis and Denver and continue to educate the maintenance contractors on the impact that sand has on the environment. In the first year of the program, NCS reduced deicer use by 15-20% in parking lots and by 20-25% on sidewalks. They hope to see additional reductions in the amount of wasted material by continuing to help the teams understand the use of technology and best practices. Bob developed a working group to continue to research better practices and material with the goal of reducing deicer use and our impact on the environment. ### Joe’s Lawn and Snow - Joe Mather - Owner Joe’s Lawn and Snow is a small company located in the Twin Cities area. Joe attended the certification class in the winter of 2013-2014 and sent four employees. The changes were implemented for the last half of the season. They normally would have expected to use 20 tons of salt and only used 9 tons. Prior to attending the class, they relied on application rates listed on the deicers and their best judgment to determine how much material to apply and did not calibrate their equipment. They learned a lot in the class and implemented many practices in their first year. Practices implemented included: • Purchased new spreader • Calibrated equipment • Made a “bowl” to catch any excess salt at spinner and reuse this • Made modifications to spreader to get more even spread and prevent salt piles • Reduced application rates • Tested application rates and results and kept refining • Purchased hand-held and truck mounted temperature sensors • Use temperature to help determine rates and materials • Identify drainage patterns and appropriate snow storage areas prior to winter • Use sediment traps to contain solids in runoff and they clean out manholes • Experimented with anti-icing using liquids and will continue to experiment They were not able to reliably calibrate and adjust their old spreader so they purchased a new one. He plans to add mud flaps with pockets to prevent salt from going all over the truck and catch extra salt which they will reuse. They tested areas in parking lots to determine the best application rates. Before winter, they mark the edges of their parking lots with blue poles and used a different color to indicate where snow should be stacked. They have a covered salt storage area on one of their properties. It is a 20 x 30’ concrete walls and “tarp-type” top. It has a subfloor and a capture drain. It was a$20,000 investment. They had this prior to training. They do spring and fall sweeping.

They reduced their application rates by about ½ and then adjusted them up based on results as needed. With the changes made, they were able to reduce their salt usage by about 50% without reducing their results.

### Cadwell Lawn and Landscaping - Charles Cadwell – Owner

After attending the Parking Lot Training in 2005, Charles Cadwell’s company examined their procedures for applying salt and deicing chemicals at Ridgedale Center and found areas that were candidates for improvement. Practices in previous years included using salt rather carelessly and applying it to attempt to keep snow from accumulating during a storm. As such, it was quite common to apply 12 to 14 tons of salt during a given storm. Since training, they examined their practices and have taken measures to reduce usage of salt products.

They reduced the speed setting on our auger to slow the feed rate of salt to the wheel. At the same time, they maintained the speed of the wheel and that made for better dispersion of the salt (more even dispersion of salt and greater coverage in a given load).

They inspected the truck tailgate because in previous years, they had a problem with spillage that resulted in "piles" of salt being dropped at random during turns or when hitting potholes or speed bumps. They found gaps between the tailgate sander and the truck bed that they filled with weather stripping. That forced all salt to be fed through the auger and baffle so that spillage was eliminated. That further increased the coverage per given load that was achieved.

Based on the information provided in training, they no longer apply salt or other chemicals during a storm. Salt is applied after the snow has been mechanically removed. The one exception to this is where some material might be needed to provide traction and permit traffic safety at stop signs or on slopes. In these situations, the materials are applied only sparingly after plowing is done.

Average salt usage for a given snow event is now five to six tons. That is based on the number of loader buckets put in the truck where one bucket is considered to be one ton (Ridgedale does not have a scale). That form of measurement is standard for what they did in previous years and from one contractor to another.

They were able to further reduce salt applications the winter of 2007 -2008 by educating the customer on the mechanical removal being the major step and only when that is complete is it reasonable to apply salt to the pavement. The mall was very receptive to only using salt when absolutely necessary. Supporting this approach, they were also able to maintain good performance in terms of the number of slip-and-fall incidents that occurred due to ice or snow. That supported the approach of using mechanical removal and then salt application as a standard process.

# Material conversions

## Material conversions

Salt - sand yard to ton conversions
Link to this table

Yards Sand (tons) Salt (tons)
1 1.4 1.1
2 2.8 2.2
3 4.2 3.2
4 5.6 4.3
5 7.0 6.4
6 8.4 6.5
7 9.8 7.6
8 11.2 8.6
9 12.6 9.7
10 14.0 10.8
11 15.4 11.9
12 16.8 13.0
13 18.2 14.0
14 19.6 15.1
15 21.0 16.2
16 22.4 17.3
17 23.8 18.4
18 25.2 19.4
19 26.6 20.5
20 28.0 21.6

The following formulas and the above quick reference table will help to convert between tons and cubic yards. Weights will vary depending upon moisture content.

1. To convert tons of clean sand to cubic yards: # tons divided by 1.4 = cubic yards
2. To convert cubic yards of clean sand to tons: # cubic yards multiplied by 1.4 = tons
3. To convert tons of winter sand to cubic yards: # tons divided by 1.37 = cubic yards
4. To convert cubic yards of winter sand to tons: # cubic yards multiplied by 1.37 = tons
5. To convert tons of straight salt to cubic yards: # tons divided by 1.08 = cubic yards
6. To convert cubic yards of straight salt to tons: # cubic yards multiplied by 1.08 = tons

Use these tables to convert application rates between pounds per lane mile and pounds per 1000 square feet.

## Lane mile conversions

Conversion of pounds per lane mile to pounds per 1000 square feet
Link to this table

lbs./ lane mile lbs./1000 square feet
25 0.4
50 0.8
75 1.2
100 1.6
125 2.0
150 2.4
175 2.8
200 3.2
225 3.5
250 3.9
275 4.3
300 4.7
350 5.5

Conversion of pounds per 1000 square feet to pounds per lane mile
Link to this table

lbs./1000 square feet lbs./ lane mile
0.5 32
0.75 48
1 63
1.25 79
1.5 95
1.75 111
2 127
2.25 143
2.5 159
2.75 174
3 190
3.25 206
5 317

## Common Conversions

• 1 lane mile (12’ x5280 ft.) = 63360 square feet
• Average size parking spot: 9 x 20 feet or 10 x 20 feet = 180 – 200 square feet
• Driving isles (2-way) = About 25 feet wide
• 1 acre = 43,560 square feet
• 1 ton = 2000 lbs.
• 1 cup of salt (NaCl) = 0.6 lbs.
• Salt (NaCl) weighs 72 – 84 lbs./ft3 depending upon moisture and granule size
• 1 gallon = 128 ounces
• 1 cubic yard of salt = 1.1 ton
• 1 cubic yard of sand = 1.4 tons
• 1 cubic yard = 27 cubic feet
• 1 square yard = 9 square feet

## Definitions

• °C – degrees Celsius
• °F – degrees Fahrenheit
• brine – liquid deicer made from water and rock salt (NaCl)
• lbs. – pounds
• LTAP – Local Technical Assistance Program
• mg/l – milligrams per liter
• Mn/DOT – Minnesota Department of Transportation
• MPCA – Minnesota Pollution Control Agency
• mph – miles per hour
• ppm – parts per million
• psi – pounds per square inch
• sq. ft. – square feet

# References

This page was last edited on 23 November 2022, at 15:31.