Solvent degreasing (cleaning) is the physical process of using solvents to remove contaminants (grease, carbon deposits, oils, waxes, fluxes or tars) from various metal, glass or plastic items. The selection of a solvent is largely dependent on what is being cleaned, what contaminants are being removed, and what tolerances are acceptable. Degreasing equipment can range in size from bench-top to much larger units.
Classes of solvents include:
- Aqueous (surfactants)
- Semi-Aqueous (includes water soluble organics such as N-Methyl-2-Pyrolidone (NMP))
- Hydrocarbon (mineral spirits)
- Hydrofluorocarbon (HFC)/Hydrofluoroether (HFE)/Hydrochlorofluoroolefin (HCFO)
- Chlorinated (Trichloroethylene)
- Brominated (N-Propyl Bromide)
- Oxygenated (Acetone)
- Microbial (microorganisms)
The use of some solvents may also require some mechanical action. Ultrasonic cleaning works in conjunction with certain solvents as well.
Please refer to the manufacturers list [PDF] of cleaning compounds to begin investigating friendlier alternatives to the cleaning agents currently used.
Organic solvents are known as volatile organic compounds (VOC). VOCs contribute to the formation of ground-level ozone and related public health problems. Some VOCs do not significantly contribute to the formation of ground-level ozone and could potentially be substitutes in part or total.
326 IAC 8-3, Organic Solvent Degreasing Operations requires the use of certain equipment standards and work practices to reduce evaporative losses of VOCs from cold cleaner, open top vapor, and conveyorized degreasing operations.
For further assistance, Compliance and Technical Assistance Program (CTAP) staff are available to provide confidential phone and on-site assistance giving an overall assessment of the facility’s compliance with environmental regulations including degreasing operations. CTAP can assist with general or specific questions and concerns as well as to assist in understanding applicable environmental regulations.
Compliance with 326 IAC 8-3
Effective February 27, 2013, the Indiana Department of Environmental Management (IDEM) revised 326 IAC 8-3, Organic Solvent Degreasing Operations to reduce emissions from Volatile Organic Compounds (VOCs) as a result of cold cleaner, open top vapor, and conveyorized degreasing operations. Degreasing equipment can range in size from bench-top units to industrial-sized cold cleaners. VOCs evaporating from organic solvent degreasing operations contribute to the formation of ground-level ozone and related public health problems.
Facilities should review Safety Data Sheets (SDS) of the organic solvents used in their degreasing operations, and determine whether or not the solvents contain hazardous chemical compounds.
When using organic solvents containing hazardous chemical compounds in a degreasing operation, a facility is required to track the amount of spent product accumulated each month and dispose of it as hazardous waste.
If a facility determines the organic solvent it uses contains hazardous chemical compounds, the facility may want to evaluate replacing the solvents with non-hazardous versions. The following are some of the common, hazardous chemical compounds found within spent halogenated and non-halogenated organic solvents used in degreasing operations:
- 1,1,1 Trichloroethane
- Carbon Tetrachloride
- Chlorinated Fluorocarbons
- Low flash point mineral spirits
- Methylene Chloride
- Methyl Ethyl Ketone
- Methyl Isobutyl Ketone
Limitations on Solvents Used in Cold Cleaner Degreasers
A “cold cleaner degreaser” is defined as a tank containing organic solvent at a temperature below the boiling point of the solvent used to spray, brush, flush, or immerse an article for the purpose of cleaning or degreasing. Wipe cleaning activities are not considered cold cleaner degreasers.
Cold cleaner degreasers are prevalent and can be located throughout a business. Ones utilized for maintenance purposes are usually small and generally use mineral spirits. They are often times overlooked and not thought of as being regulated.
326 IAC 8-3 restricts the maximum vapor pressure of the organic solvent used within a cold cleaner degreaser to less than one (1) millimeter of mercury (nineteen-thousandths (0.019) pound per square inch) measured at twenty (20) degrees Celsius (sixty-eight (68) degrees Fahrenheit). This limit is currently in effect for Clark, Floyd, Lake and Porter counties, and takes effect state-wide beginning January 1, 2015. Except for those four (4) counties, 326 IAC 8-3 is not applicable to solvents where the VOC is less than one percent (1%) by weight excluding VOCs having been determined not to significantly contribute to the formation of ground-level ozone.
Halogenated Volatile Organic Compounds
As of December 1997, degreasing operations utilizing chlorinated solvents in a container with a capacity greater than two (2) gallons or a solvent having a chlorinated content of five percent (5%) or more must follow the applicable regulations under the federal National Emission Standard for Halogenated Solvent Cleaning, 40 CFR 63, Subpart T [PDF] and 326 IAC 20-6, Halogenated Solvent Cleaning. Subpart T requires degreasing operations to install equipment and implement standardized work practices to reduce emissions from the following chlorinated solvents.
- Methylene Chloride (Dichloromethane)
- Tetrachloroethylene (Perchloroethylene)
- Trichloroethylene (Trichloroethane)
- 1,1,1-Trichloroethane (Methyl Chloroform)
- Carbon Tetrachloride (Perchloromethane)
- Chloroform (Trichloromethane)
- Cold Cleaner Degreaser Information Sheet [PDF]
- Conveyorized Degreaser Information Sheet [PDF]
- Open Top Vapor Degreaser Information Sheet [PDF]
- Solvent Alternatives/Additives for Degreasers [PDF]
U.S. EPA Significant New Alternatives Policy (SNAP) Resources
- Metal Cleaning
- Electronics Cleaning
- Precision Cleaning
- Development of Safer Cleaning Alternatives in the Aerospace, Printing and Coating Industries [PDF], June 2004
- The U.S. Solvent Cleaning Industry and the Transition to Non Ozone Depleting Substances [PDF], September 2004
- Electronic Code of Federal Regulations (e-CFR), Title 40 Protection of the Environment
- Clean Tool: European database for cleaning and degreasing
- Guidebook of Part Cleaning Alternatives: Making Cleaning Greener in Massachusetts [PDF], March 1997
- Halogenated Solvents Industry Alliance
- Solvent Alternatives Guide (SAGE)
- Toxics Use Reduction Institute (TURI) Cleaner Solutions Database
- U.S. EPA Air Toxics website: Rule and Implementation Information for Halogenated Cleaning Solvents (Degreasing Organic Cleaners)