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− | + | {{alert|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 [https://www.pca.state.mn.us/sites/default/files/parkinglotmanual.pdf here]. Other changes and updates to information on salt management will be posted in the [http://stormwater.pca.state.mn.us/index.php/What%27s_New What's new] page in the manual. Information on ''road salt and water quality'' can be found on [https://www.pca.state.mn.us/water/road-salt-and-water-quality MPCA's website]|alert-info}} | |
+ | |||
+ | This section provides information on keeping surfaces clear during winter. | ||
==Winter Maintenance Basics== | ==Winter Maintenance Basics== | ||
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{{alert|[[File:Fish logo.png|50px|alt=dollar symbol]] '''Because it uses less materials, mechanical snow and ice removal is the best strategy for protecting the water'''|alert-info}} | {{alert|[[File:Fish logo.png|50px|alt=dollar symbol]] '''Because it uses less materials, mechanical snow and ice removal is the best strategy for protecting the water'''|alert-info}} | ||
− | |||
==Loading/hauling== | ==Loading/hauling== | ||
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==Deicing/Anti-Icing Information== | ==Deicing/Anti-Icing Information== | ||
+ | Anti-icing is the prevention of ice accumulation and build-up on surfaces. Deicing is the removal of ice that has accumulated on surfaces. | ||
===Anti-icing=== | ===Anti-icing=== | ||
− | |||
{{alert|[[File:Fish logo.png|50px|alt=dollar symbol]] '''Anti-icing is the most cost-effective and environmentally safe practice in winter maintenance. This is the direction to pursue.'''|alert-info}} | {{alert|[[File:Fish logo.png|50px|alt=dollar symbol]] '''Anti-icing is the most cost-effective and environmentally safe practice in winter maintenance. This is the direction to pursue.'''|alert-info}} | ||
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===Get started in anti-icing=== | ===Get started in anti-icing=== | ||
− | |||
The basic equipment needed includes: pavement temperature sensor, storage tank, spray truck system, transfer pump, hoses, and fittings. | The basic equipment needed includes: pavement temperature sensor, storage tank, spray truck system, transfer pump, hoses, and fittings. | ||
What to do | What to do | ||
− | *Calibrate | + | *Calibrate |
− | *Use application rates suggested in the Rate section of this manual | + | *Use application rates suggested in the Rate section of this manual |
*Apply with stream nozzles to maintain dry areas between sprayed areas to reduce slipperiness. Stream nozzles work the best for anti-icing. | *Apply with stream nozzles to maintain dry areas between sprayed areas to reduce slipperiness. Stream nozzles work the best for anti-icing. | ||
*If using fan nozzles apply extra light. This makes a dry surface wet and users will have less friction until it dries. | *If using fan nozzles apply extra light. This makes a dry surface wet and users will have less friction until it dries. | ||
− | *Try anti-icing in a low traffic area to build confidence about its properties | + | *Try anti-icing in a low traffic area to build confidence about its properties |
− | *Read some of anti-icing guidelines in the reference section of this manual | + | *Read some of anti-icing guidelines in the reference section of this manual |
Test the application rates and spray pattern to become confident in preventing the bonding of ice without creating a slimy or slippery situation. | Test the application rates and spray pattern to become confident in preventing the bonding of ice without creating a slimy or slippery situation. | ||
Line 227: | Line 227: | ||
===Instructions for using application rate table for calibrated spreaders=== | ===Instructions for using application rate table for calibrated spreaders=== | ||
− | #Using Deicing Application Rate Guidelines for Parking Lots and Sidewalks. Select the row | + | #Using Deicing Application Rate Guidelines for Parking Lots and Sidewalks. Select the row with the appropriate pavement temperature, temperature trend, and weather conditions. |
− | #Select the column | + | #Select the column that has the type of material used. |
− | #Find the box where the row | + | #Find the box where the row and columns intersect to find the application rate. |
− | #Compare those values to the calibration chart for the spreader. | + | #Compare those values to the calibration chart for the spreader. |
#Select the correct spreader setting for the rate calculated. | #Select the correct spreader setting for the rate calculated. | ||
− | + | :'''Example''' | |
#Parking lot is 54,000 sq. ft. | #Parking lot is 54,000 sq. ft. | ||
− | #Temperature: 22ºF and falling. It has finished snowing. | + | #Temperature: 22ºF and falling. It has finished snowing. |
− | #Using salt pretreated with salt brine. | + | #Using salt pretreated with salt brine. |
− | #Find the 20 – 25º ↓ box. Follow it to the right to the column labeled “Salt Pre-wetted/pretreated with salt brine.” Read the rate in the box. The box where the column and row intersect shows a rate of 2.0 /1000 square feet. | + | #Find the 20 – 25º ↓ box. Follow it to the right to the column labeled “Salt Pre-wetted/pretreated with salt brine.” Read the rate in the box. The box where the column and row intersect shows a rate of 2.0 /1000 square feet. |
#Refer to the calibration chart in the vehicle and set the spreader to the setting that most closely matches the 2.0 lbs. /1000 square feet. | #Refer to the calibration chart in the vehicle and set the spreader to the setting that most closely matches the 2.0 lbs. /1000 square feet. | ||
#The mixture is ready to apply. | #The mixture is ready to apply. | ||
− | + | :'''Instructions for using application rate table for spreaders that are NOT calibrated''' | |
Using the example above: | Using the example above: | ||
− | #Calculate size factor: Divide the parking lot size (54,000 sq. ft.) by 1,000 sq. ft. | + | #Calculate size factor: Divide the parking lot size (54,000 sq. ft.) by 1,000 sq. ft. 54,000/1,000 = 54. The size factor is 54. |
− | 54,000/1,000 = 54. The size factor is 54. | ||
#Find application rate (2.0). | #Find application rate (2.0). | ||
#Multiply application rate by size factor 2 x 54 = 108. | #Multiply application rate by size factor 2 x 54 = 108. | ||
Line 252: | Line 251: | ||
#Determine the best method to spread the 108 pounds evenly across the parking lot. | #Determine the best method to spread the 108 pounds evenly across the parking lot. | ||
− | {{alert|[[File:Fish logo.png|50px|alt=dollar symbol]] '''Once chlorides enter the ground or surface water, they | + | {{alert|[[File:Fish logo.png|50px|alt=dollar symbol]] '''Once chlorides enter the ground or surface water, they can persist in the water for a very long time.'''|alert-info}} |
+ | |||
+ | <noinclude> | ||
+ | ==Related pages== | ||
+ | *[[Background information for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Preparing for winter operations for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Keeping surfaces clear for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Evaluating the effectiveness for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Environmental tips for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Cost savings tips for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Results and evaluation for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Material conversions for winter parking lot and sidewalk maintenance]] | ||
+ | *[[References for winter parking lot and sidewalk maintenance]] | ||
+ | *[[Additional resources and links to websites for winter parking lot and sidewalk maintenance]] | ||
+ | </noinclude> | ||
+ | |||
+ | [[Category:Level 2 - Management/Winter management]] | ||
+ | [[Category:Level 2 - Pollutants/Chloride]] |
This section provides information on keeping surfaces clear during winter.
Anti-icing is the prevention of ice accumulation and build-up on surfaces. Deicing is the removal of ice that has accumulated on surfaces.
Anti-icing is a proactive approach. It should be first in a series of strategies for each winter storm. Applying a small and strategic amount of liquid on the pavement before a storm will prevent snow and ice from bonding to the pavement. This buys time for the clean-up efforts.
Anti-icing is like frying eggs: grease the pan and the eggs come out easily with no mess to clean up. Like greasing the frying pan, the purpose of anti-icing is to keep snow from sticking to the pavement. Anti-icing provides safer pavement during the event and faster clean up after the event.
Anti-icing requires about ¼ the material and 1/10 the overall cost of deicing. It can increase safety at the lowest cost, and is effective and cost-efficient when correctly used and approached with realistic expectations.
Anti-icing prevents formation of frost. It can be effective for up to several days depending on the weather conditions.
The basic equipment needed includes: pavement temperature sensor, storage tank, spray truck system, transfer pump, hoses, and fittings.
What to do
Test the application rates and spray pattern to become confident in preventing the bonding of ice without creating a slimy or slippery situation.
Tip: Stream nozzles prevent slippery conditions better than fan spray.
Tip: Too little CaCl2 or MgCl2 is safer than too much.
What not to do
Deicing is a reactive operation where a deicer is applied to the top of an accumulation of snow, ice, or frost that has already bonded to the pavement surface and can no longer be physically removed. Deicing costs more than anti-icing in materials, time, equipment, and environmental damage. Deicing is the “traditional” approach to winter maintenance.
Removing ice that has already bonded to the pavement is difficult. Removing it mechanically can damage equipment and surfaces. Generally, enough ice must be melted chemically to break the bond between the ice and the pavement. This requires larger amounts of chemical, making deicing much less efficient than anti-icing.
Use the application rate table to help with deicing. Using recommended rates will help with these common problems:
Tip: The goal is not to melt everything. The goal is to penetrate through the ice and snow and break the bond so the pavement can be plowed.
Pre-wetting and pretreating both mean getting dry material wet. Salt only melts snow and ice when it is in solution (dissolved). Dry salt does nothing until it is dissolved. Liquids applied to dry salt jump-start the melting process and penetrate ice and snow pack faster. Wet materials stick to the pavement and are less likely to end up in the nearby vegetation.
When integrating the liquids, decrease the application rate of the granular product. This is a common mistake made by new users of liquids.
Pretreating is mixing a liquid deicer into the stockpile of salt or sand. It can be purchased as a product already mixed and ready to use or can be created. To create a pre-treated stockpile, add liquids conservatively. The dry material can only hold so much liquid before leaching occurs. Watch the storage area to make sure it can contain the wet salt pile. Test mixing skills and observe the amount of leaching on a small stockpile before doing this on a large scale.
Pre-wetting is combining liquid from a tank to dry material from the hopper at the point of discharge. The most common set up is on a truck but it can be configured for smaller equipment. The liquid and granular usually come together at the spinner or auger.
While pre-wetting requires some equipment changes, it provides flexibility to switch the amount and type of liquid.
Tips:
Use winter sand and other abrasives when temperatures are too cold for deicing chemicals to be effective. But be aware that sand does not melt anything. It provides temporary traction and only when it is on top of snow and ice. When sand is in contact with the pavement, sweep it up. It is no longer useful and can only harm the environment. Sand on dry pavement can cause skidding.
Sweep the sand from the parking lot areas midwinter as well as in the spring. Trailer-type power sweepers are available that can be hauled behind a pickup truck. Smaller power brooms or sweepers may be used on sidewalks. Workers should wear a dust mask to avoid inhalation of the fine dust particles.
Effective application rates are based on many factors, including type and rate of precipitation, air and pavement temperature, forecast and temperature trend, humidity, dew point, type of surface and subsurface material, and sun exposure. The application rate tables used in this book have been taken from the Minnesota Snow and Ice Control Field Handbook for Snowplow Operators, Second Revision (LRRB 2012). They were converted from gallons or pounds per lane mile to gallons or pounds per 1000 square feet.
These application rates are not perfect but are to be used as goal to work toward. Develop specific application rate tables to standardize performance. Track application rates measure and improve performance. Modify the practices incrementally over time to fit the needs. Make it a goal to reduce application rates and keep surfaces safe.
One application rate will not fit all situations; how long an application lasts depends on:
Anti-icing application rates. These are a starting point only. Adjust based on experience.
Link to this table
Condition | Gallons/1000 sq. ft. | Other Products | |
---|---|---|---|
CaCl2 or MgCl2 | Salt Brine(NaCl) | ||
1. Regularly scheduled applications | 0.2 - 0.4 | 0.3 – 0.6 | Follow manufacturers’ recommendations |
2. Prior to frost or black ice event | 0.2 - 0.4 | 0.3 – 0.6 | |
3. Prior to light or moderate snow | 0.2 - 0.4 | 0.3– 0.8 | |
CAUTION: Too high an application rate may result in slippery conditions or tracking. |
How to use the anti-icing rate table above:
Example: The parking lot is 20,000 square feet. The chart tells how much to apply for 1,000 square feet. The plan is to apply brine prior to light or moderate snow. Do a calculation to see how much brine is needed:
Tip: To convert from gallons to ounces: multiply the result by 128.
These rates are based on road application guidelines (LRRB 2012).
Develop specific application rates by adjusting the current rates incrementally downward toward the guidelines. Where temperature categories overlap, select the rate most applicable to the present situation.
Application rates for deicing
Link to this table
Pavement Temp. (ºF) and Trend (↑↓) | Weather Condition | Maintenance Actions | Application Rate in lbs./per 1000 square foot area | |||
---|---|---|---|---|---|---|
Salt Pre-wetted/Pretreated With Salt Brine | Salt Pre-wetted/ Pretreated With Other Blends | Dry Salt | Winter Sand (abrasives) | |||
>30º↑ | Snow | Plow, treat intersections only | 0.75 | 0.5 | 0.75 | not recommended |
>30º↑ | Frz. Rain | Apply chemical | 1.25 | 1.0 | 1.5 | not recommended |
30º↓ | Snow | Plow & apply chemical | 1.25 | 1.0 | 1.5 | not recommended |
30º↓ | Frz. Rain | Apply chemical | 1.5 | 1.25 | 1.75. | not recommended |
25 - 30º ↑ | Snow | Plow & apply chemical | 1.25 | 1.0 | 1.5 | not recommended |
25 - 30º ↑ | Frz. Rain | Apply chemical | 1.5 | 1.25 | 1.75 | not recommended |
25 - 30º ↓ | Snow | Plow & apply chemical | 1.25 | 1.0 | 1.5 | not recommended |
25 - 30º ↓ | Frz. Rain | Apply chemical | 1.75 | 1.5 | 2.25 | 3.25 |
20 - 25º ↑ | Snow or Frz. Rain | Plow & apply chemical | 1.75 | 1.5 | 2.25 | 3.25 for frz. rain |
20 - 25º ↓ | Snow | Plow & apply chemical | 2.0 | 2.0 | 2.75 | not recommended |
20 - 25º ↓ | Frz. Rain | Apply chemical | 2.5 | 2.0 | 3.0 | 3.25 |
15º to 20º↑ | Snow | Plow & apply chemical | 2.0 | 2.0 | 2.75 | not recommended |
15º to 20º↑ | Frz. Rain | Apply chemical | 2.5 | 2.0 | 3.0 | 3.25 |
15º to 20º↓ | Snow or frz. rain | Plow & apply chemical | 2.5 | 2.0 | 3.0 | 3.25 for frz. rain |
0 to 15º ↑ ↓ | Snow | Plow, treat with blends, sand hazardous areas | not recommended | 3.0 | not recommended | 5.0 spot treat as needed |
< 0º | Snow | Plow, treat with blends, sand hazardous areas | not recommended | 4.5 | not recommended | 5.0 spot treat as needed |
All application rates are based on thoroughly cleared surfaces
Using the example above:
This page was last edited on 6 December 2022, at 15:43.