Difference between revisions of "Winter Parking Lot and Sidewalk Maintenance Factsheet"
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| − | This factsheet provides information for winter parking lot and sidewalk maintenance. | + | This factsheet provides information for winter parking lot and sidewalk maintenance. [https://www.pca.state.mn.us/sites/default/files/p-tr1-20.pdf Link to pdf version]. |
==Key information needed== | ==Key information needed== | ||
| − | *Pavement | + | *Pavement temperature (it will be different than air temperature) |
*Parking lot area (or drive lane distance) = Length x Width | *Parking lot area (or drive lane distance) = Length x Width | ||
*Amount of material your truck or sander delivers at each setting and speed | *Amount of material your truck or sander delivers at each setting and speed | ||
| Line 13: | Line 13: | ||
*Sand only works on top of snow as traction. It provides no melting. | *Sand only works on top of snow as traction. It provides no melting. | ||
*Anti-icing chemicals must be applied prior to snow fall. | *Anti-icing chemicals must be applied prior to snow fall. | ||
| − | *NaCl | + | *Sodium chloride (NaCl; road salt) does not work on cold days, less than 15<sup>o</sup>F. |
| + | |||
| + | {{alert|[[File:Fish logo.png|50px|alt=fish symbol]] Use less! About one tsp. of salt contaminates 5 gallons of water.|alert-info}} | ||
==Melt times for salt (NaCl) at different pavement temperatures== | ==Melt times for salt (NaCl) at different pavement temperatures== | ||
| Line 23: | Line 25: | ||
{{:Lowest practical melting temperature}} | {{:Lowest practical melting temperature}} | ||
| − | == | + | ==Variables affecting application rate== |
Increase the application rate if | Increase the application rate if | ||
*Compaction occurs & cannot be removed mechanically | *Compaction occurs & cannot be removed mechanically | ||
| Line 36: | Line 38: | ||
These rates are adapted from road application guidelines (Mn Snow & Ice Control Field Handbook, Manual 2005-1). Develop your own application rates using the guidelines as a starting point and modify them incrementally over time to fit your needs. The area should first be cleared of snow prior to applying chemical | These rates are adapted from road application guidelines (Mn Snow & Ice Control Field Handbook, Manual 2005-1). Develop your own application rates using the guidelines as a starting point and modify them incrementally over time to fit your needs. The area should first be cleared of snow prior to applying chemical | ||
| − | {{: | + | {{:Application rates for deicing}} |
| + | |||
| + | ==Anti-icing guidelines== | ||
| + | Consider the following table to be a starting point only. Adjust based on your experience. To determine the amount of material needed, take the application rate x parking lot area / 1000 ft<sup>2</sup> . Example: Given a 300,000 sq. ft. parking lot and an application rate of 1.5 lbs/1000ft<sup>2</sup>, 1.5 x 300,000 = 450,000; 450,000/1000 = 450 lbs (nine 50 lb. bags). | ||
| + | |||
| + | {{alert|CAUTION: Too high an application rate may result in slippery conditions or tracking.|alert-warning}} | ||
| − | + | {{:Anti-icing application rates}} | |
| − | |||
| − | + | [[Category:Level 2 - Management/Winter management]] | |
| + | [[Category:Level 2 - Pollutants/Chloride]] | ||
Latest revision as of 15:32, 23 November 2022
This factsheet provides information for winter parking lot and sidewalk maintenance. Link to pdf version.
Contents
Key information needed
- Pavement temperature (it will be different than air temperature)
- Parking lot area (or drive lane distance) = Length x Width
- Amount of material your truck or sander delivers at each setting and speed
Tips
- De-icers melt snow and ice. They provide no traction on top of snow and ice.
- Anti-icing prevents the bond from forming between pavement and ice.
- De-icing works best if you plow before applying material.
- Pick the right material for the pavement temperatures.
- Sand only works on top of snow as traction. It provides no melting.
- Anti-icing chemicals must be applied prior to snow fall.
- Sodium chloride (NaCl; road salt) does not work on cold days, less than 15oF.
Information: 
Use less! About one tsp. of salt contaminates 5 gallons of water.
Use less! About one tsp. of salt contaminates 5 gallons of water.Melt times for salt (NaCl) at different pavement temperatures
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 |
Melting characteristics
Caution: Pick your material based on lowest practical melting temperature, not eutectic temperature which is often listed on the bag.
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 | ||
Variables affecting application rate
Increase the application rate if
- Compaction occurs & cannot be removed mechanically
- There is a lot of snow left behind
Decrease the application rate if
- Light snow or light freezing rain
- Pavement temperature is rising
- Subsequent applications
Deicing application rate guidelines for parking lots and sidewalks
These rates are adapted from road application guidelines (Mn Snow & Ice Control Field Handbook, Manual 2005-1). Develop your own application rates using the guidelines as a starting point and modify them incrementally over time to fit your needs. The area should first be cleared of snow prior to applying chemical
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 |
Anti-icing guidelines
Consider the following table to be a starting point only. Adjust based on your experience. To determine the amount of material needed, take the application rate x parking lot area / 1000 ft2 . Example: Given a 300,000 sq. ft. parking lot and an application rate of 1.5 lbs/1000ft2, 1.5 x 300,000 = 450,000; 450,000/1000 = 450 lbs (nine 50 lb. bags).
Caution: CAUTION: Too high an application rate may result in slippery conditions or tracking.
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. | |||
This page was last edited on 23 November 2022, at 15:32.