Winter Parking Lot and Sidewalk Maintenance Factsheet

This factsheet provides information for winter parking lot and sidewalk maintenance. Link to pdf version.

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 15^oF.

Information: 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.