Steam cleaning is a viable solvent alternative for removing oily or greasy residue. High risk factors are often associated with solvent use, and these risks are avoided through the use of this type of system. The use of heat in the steam cleaning process accelerates emulsification, break-down, and removal of dirt and grease. Steam’s high temperature and low specific heat allow surfaces to be heated to relatively high temperatures. High temperature is maintained on the surface long enough for the steam to vaporize or liquefy the oil, grease, or dirt. The residue can then be effectively washed away with the condensate remaining from the condensed steam. Steam cleaning can also be used with a degreasing agent (often a surfactant) that enhances the solubility of grease in water. Steam cleaners are available to perform medium duty (e.g. auto parts, engines, etc.) to heavy duty (e.g. large machinery and oil drilling rigs) cleaning jobs. Steam cleaning units can be electric or fired with gasoline or diesel fuel.

The Mini-Max system, which is manufactured by PDQ Precision, Inc., has been used at many military installations with outstanding results. Unlike the typical steam cleaners, the Mini-Max operates efficiently at high temperature (550°F), while using a minimum amount of water. Waste disposal and chemical costs are almost completely eliminated using the Mini-Max system, which can be used for multiple applications and are available in various sizes.

The wastewater generated from the steam cleaning process may be treated at an industrial wastewater treatment plant, depending on the nature of the dirt and grease removed. Analysis of the wastewater is required prior to disposal.

Steam cleaning allows a facility to use steam in place of solvents. The decrease in toxic and/or ODSs may reduce the on site storage below any of the reporting thresholds of SARA Title III for those chemicals (40 CFR 355, 370, and 372; and EO 12856). In addition, the decrease in toxic chemicals may eliminate the need for a facility to obtain an air permit (40 CFR 70 and 71). Switching from a halogenated solvent (i.e., methyl chloroform, methylene chloride, and perchloroethylene) may also enhance the facility’s compliance with the NESHAPs for halogenated solvent cleaning (40 CFR 63). Using a non-ODS will also help facilities meet the requirements under 40 CFR 82, Subpart D and Executive Order 12843 requiring federal agencies to maximize the use of safe alternatives to class I and class II ozone depleting substances, to the maximum extent practicable. Moreover, steam cleaning will decrease the amount of hazardous waste generated (i.e., no waste solvent generated). Waste reduction is required under RCRA, 40 CFR 262, Appendix. The reduction of hazardous waste may also help facilities reduce their generator status and lessen the number of regulatory requirements (i.e., recordkeeping, reporting, inspections, transportation, accumulation time, emergency prevention and preparedness, emergency response) with which they must comply under RCRA, 40 CFR 262.

The wastewater discharge from steam cleaning operations may require a local wastewater discharge permit. In addition, steam cleaning will increase electricity and water consumption. Under EO 12902, federal facilities are required to reduce energy consumption and implement water conservation programs.

The compliance benefits listed here are only meant to be used as a general guideline and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g. the amount of workload involved.

Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing this technology.

• Reduces the amount of hazardous waste and hazardous air emissions generated compared to solvent degreasing
• Wastewater stream is generally compatible with conventional industrial wastewater plants located at many installations
• Low implementation cost utilizing simple equipment
• Provides solvent cost savings

• Steam cleaning is not recommended for any equipment, component, or material that is temperature or moisture sensitive
• Water can penetrate and/or damage joints, seals, and bonded areas

According to the Naval Air Station North Island, the Mini-Max steam cleaner has been used for many military applications. The system can be found at the Naval Air Warfare Center, Aircraft Division Lakehurst. The Mini-Max steam cleaner is available in several models, and the prices range from $2,000 - $6,000. However, other types of steam cleaners are available which will vary considerably, depending upon the unit type and its application. Capital costs for these systems can range from $5,000 to $12,000.

Assumptions:

Steam Cleaning

• Steam cleaning equipment cost: $5,000
• Labor requirements for cleaning: 5 hr/week or 260 hr/yr at $30/hr
• System electrical requirements: 350 kw-hr/yr at a cost of $0.08/kw-hr
• Process wastewater: 62,400 gal./yr. at a disposal cost of $8.24/1000 gal
• Wastewater: 65,500 gal/yr at a usage cost of $1.94/1000 gal

• Labor requirements for cleaning: 20 hr/week or 1,040 hr/yr at $30/hr
• Solvent usage: 5 gal/week or 260 gal/yr at a cost of $11/gal
• Waste solvent: 50 gal/yr at a cost of $2/gal

Annual Operating Cost Comparison for Steam Cleaning and Solvent Cleaning

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Approval is controlled locally and should be implemented only after engineering approval has been granted. Major claimant approval is not required.