During freezing temperatures, salt is commonly used as a de-icer to melt ice and snow from roads, sidewalks, and other surfaces. While salt can be effective at preventing slips and falls, the California Governor’s Office of Emergency Services (Cal OES) would like to remind you that there are several considerations to keep in mind when using salt in freezing temperatures.
How does salt melt ice?
Salt works by lowering the freezing point of water. When salt is added to ice or snow, it creates a saltwater solution that has a lower freezing point than pure water. This causes the ice to melt, creating a brine solution that is less likely to refreeze than plain water. In addition, the saltwater solution can penetrate small cracks and crevices in the ice, helping to break it up and make it easier to remove.
Types of salt used for de-icing
There are several types of salt that are commonly used for de-icing, including:
- Rock salt: This is the most commonly used type of salt for de-icing. It is inexpensive and widely available, but it is not as effective at melting ice as other types of salt. It also has a higher environmental impact than other types of salt.
- Calcium chloride: This type of salt is more effective at melting ice than rock salt and can work at lower temperatures. It also has a lower environmental impact than rock salt.
- Magnesium chloride: This type of salt is similar to calcium chloride but is less corrosive to concrete and metal.
- Potassium chloride: This type of salt is a more environmentally friendly alternative to rock salt, but it is not as effective at melting ice.
Considerations when using salt for de-icing
While salt can be effective at preventing slips and falls, there are several considerations to keep in mind when using salt for de-icing:
- Environmental impact: Salt can have a negative impact on the environment, including harming plants, contaminating water sources, and corroding metal structures. Consider using a more environmentally friendly alternative, such as potassium chloride or a mixture of sand and salt.
- Corrosion: Salt can corrode metal structures and damage concrete surfaces. Use caution when applying salt near these surfaces and consider using a more gentle de-icer, such as calcium magnesium acetate.
- Pet safety: Salt can be harmful to pets if ingested. Consider using a pet-friendly de-icer or cleaning your pet’s paws after they have been outside in areas where salt has been used.
- Storage: Store salt in a dry location to prevent clumping and degradation.