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Winter Parking Lot and Sidewalk Maintenance Factsheet

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: fish symbol Use less! About one tsp. of salt contaminates 5 gallons of water.

Melt times for salt (NaCl) at different pavement temperatures

Speed of melting
Speed of melting
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
Lowest practical melting temperature
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
Application rates for deicing
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: Too high an application rate may result in slippery conditions or tracking.

Anti-icing application rates
Anti-icing application rates. Values are a starting point only. Adjust based on experience.
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.