Dry ice blasting, or dry ice cleaning, is a cleaning process that uses media blasting of dry ice pellets to remove contaminants from equipment, tools, surfaces, etc.
Fundamentally, dry ice blasting works like other forms of media blasting (often referred to informally as “sandblasting”). Media blasting propels a material at high-speed against a surface, typically using compressed air. In most media blasting, the material used to clean the surface is abrasive, scouring the surface clean of any contaminants. However, the material used in dry ice blasting—dry ice pellets—is virtually non-abrasive.
So how does dry ice blasting clean the surface? Through a combination of thermal shock and gas expansion.
A dry ice pellet is a form of solid carbon dioxide with a temperature of −109°F (−78°C). When a dry ice pellet strikes a contaminant, rapid heat transfer occurs. This heat transfer causes the contaminant to contract and detach from the surface. This rapid heat transfer also causes the dry ice pellet to vaporize, changing the pellet from a solid to a gaseous state. This state change is accompanied by rapid expansion, knocking away the loosened debris.
Even though dry ice blasting is virtually non-abrasive, some painted surfaces can be damaged by the process.
Several advantages of dry ice cleaning make it suitable for cleaning food production equipment, food packaging equipment, and the food production environment itself:
Because dry ice is a non-conductive, non-abrasive material, dry ice blasting can be used in industries that rely heavily on semiconductors, like the electronics, aerospace, and medical device manufacturing industries.
Dry ice cleaning can be used in many manufacturing environments to clean production equipment (including printing presses), molds, tooling, and electronic equipment.
Dry ice blasting is effective in remediating mold, smoke, fire, and water damage.
Because it produces no secondary waste, is non-abrasive, is environmentally responsible, and is a dry cleaning method, dry ice blasting is suitable for conservation and historical preservation projects.
While dry ice cleaning is virtually non-abrasive, the material is still being propelled at 80 psi (5.5 bar) or higher, which can damage softer surfaces, like soft woods and soft plastics.
Because dry ice cleaning is virtually non-abrasive, coatings that have strong bonds with the underlying material, e.g. baked-on enamels and some primers, can’t be removed by dry ice blasting.
Some soft contaminants, like oil, can spatter under the pressures involved in dry ice cleaning, so either special collection systems or low-pressure cleaning methods may work better.
As with any media blasting, you must take safety precautions when using dry ice blasting as a cleaning method:
In addition, if cleaning indoors, the room must be well-ventilated. In a poorly-ventilated room, the cleaning process could cause a build-up of carbon dioxide and lead to asphyxiation.