SteamMaster began utilizing dry-ice blasting over three years ago. Gary Gilman, president of SteamMaster, had researched dry-ice blasting approximately 15 years earlier for possible use in fire restorations and industrial cleaning. Since they purchased their Cold Jet dry-ice blasting system, the firm has successfully completed over 50 dry-ice blasting projects. Most of the company's mold remediation projects, which employ the use of this cutting edge technology, include removing mold from attic and crawl space sheathing, trusses and framing.

Tight-Spot Challenges

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.”

With regard to mold remediation, it is important to note that applying a biocide to a contaminated surface to kill the mold does not replace the need for an effective cleaning. The allergens in mold are not always being eliminated with a biocide, rendering dead mold as allergenic and in need of removal. Typically, enough spores are left behind that if the moisture problem is not corrected, the mold will re-grow in time. In addition, these biocides are typically registered pesticides and are potentially harmful to those using them. The EPA and OSHA do not recommend routine use of bleach or other biocides in mold remediation. To eliminate the allergenic properties associated with mold, it is necessary to remove it from the contaminated surface. This can be done with the traditional method of sanding and scraping, or with the more thorough and more efficient option of dry-ice blasting. Dry-ice evaporates completely as a gas, so only the mold being removed must be disposed of.

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.

Dry-ice blasting will typically remove about 3 percent of the wood's surface being cleaned, so it is using kinetic energy and a scrubbing action to clean. This blasting application effectively removes the contaminant, while rarely altering the structural integrity of the wood. Since there is no secondary waste stream to attend to, the only thing left to do is vacuum the residual contaminant and wood that was removed from the blasting.

Necessary Precautions

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.

Dry-ice blasting is a fresh approach to Restoration and is currently being used by many remediators in various parts of the country. Its ability to clean surfaces thoroughly and efficiently is an irresistible alternative to sanding and scraping. While there are costs associated with buying the equipment, these costs are outweighed by the labor-saving benefits. Generally speaking, these blasting systems have reduced the time it takes to complete restoration projects. Because of the drastic reduction in cleaning time resulting from dry-ice blasting, firms can dramatically boost their revenues as well.

Gary Gilman is president and founder of SteamMaster Restoration & Cleaning, Vail, Colo. He is a Certified Mold Remediator and has been remediating mold from structures since 1984. Contact him at 800-527-1253, www.steammaster.com.

Tina Moore is the marketing specialist at Cold Jet, LLC. For more information on dry-ice blasting, call 513-831-3211, www.coldjet.com.