2006-05-01 - Dry Ice Blasting: The Icing on the Restoration Cake
Time is of the essence in a fire restoration project or a mold remediation project. Insurance companies, real estate and title companies, and general contractors are all watching the clock when it comes to restoring a building or home. The quicker the problem is alleviated, the quicker the residents of the building can return. Dry ice blasting allows the contractor to restore the contaminated building faster than any other method. Therefore, the displacement costs experienced by the insurance company are greatly reduced.
Speeding up Restoration
Dry ice blasting benefits the restoration contractor because it grants access to tight and hard-to-reach areas in confined spaces, such as attics or crawl spaces. Conventional cleaning methods require the contractor to manually sand, scrape, or wire brush the mold or smoke damage from contaminated surfaces. This can be a slow, tedious, and generally unpleasant process. Dry ice blasting results in the complete removal of contaminants from these surfaces in less time than any other method. Dry ice blasting saves the contaminated wood, which with conventional cleaning methods, may have had to have been replaced.
Dry ice blasting is particularly effective where engineered roof or floor joists and decking are impregnated with mycelium, which is a tangled network of mold filaments. In a single pass, crews can effectively and efficiently remove mold from multiple right-angled surfaces that would be cumbersome and time-consuming to access with sanding or scraping. Brian Greenwood, a restoration technician, does most of the blasting for SteamMaster. He says, "The dry-ice blasting system provides our remediation crews with access to clean tight areas that may otherwise be unreachable, such as three- to four-inch gaps in framing and rim joists above concrete-stem walls." He goes on, "Dry-ice blasting makes our job much easier and more thorough and we can complete the job in less than half the time."
Thermal Shock Effect
As it accelerates dry ice particles into a pressurized air stream to impact the surface being cleaned, it will not interrupt any electric compounds or wiring and it will not cause toxic harm to the operator. Traditionally, dry ice blasting has been used to clean specific production applications for its thermal shock effect. The dry ice is at a temperature of minus 109.3 degrees Fahrenheit or minus 78.5 degrees Celcius , and as it blasts against the contaminant it causes it to shrink and lose its adhesion from the substrate. With regard to cleaning a wood surface, dry ice blasting works somewhat like sandblasting or high-pressure water blasting, but with superior results, as there will be no media residue to clean up at the completion of the project.
With any restoration project, it is crucial to take the necessary precautions with regard to the safety of the remediation crew. Proper personal protective equipment should be worn and the area being treated will need to be properly sealed off so that the contaminant does not fly into other nearby, non-contaminated areas. Caution must be employed to manage oxygen levels in confined areas. Restoration crews should vent fresh air into the work area and exhaust the build-up of carbon dioxide gas to the outside. A negative air flow environment with HEPA filtration is recommended in confined attics and crawl spaces to ensure the operator’s safety.
Dry ice blasting is a more efficient cleaning method than sanding or scraping. It is also better suited for mold remediation than any other type of blasting, such as sand blasting, water blasting, or soda blasting. Sand blasting is known as an effective cleaning method. However, it is far too abrasive and damaging to the underlying surface being treated. So, after dry ice blasting the structural integrity of the surface being cleaned is usually left in tact. Water and steam blasting do not provide as thorough a clean as dry ice blasting does, and there is a greater chance of causing further damage to the substrate, due to the water vapor and moisture component. Soda blasting is an effective, although messy, cleaning method with regards to restoration. However, the main drawback with soda blasting applies to the other blasting methods as well. It leaves behind a secondary waste stream to be attended to, creating additional cleaning to be done and adding time and cost onto the project. With dry ice blasting, the carbon dioxide gas sublimates into the atmosphere after it impacts the surface being cleaned, leaving no additional waste streams to dispose of.