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Degreasing Operations

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.

The low VOC requirement of the rules and the availability of the new solvents generate a new class of solvent called Clean Air Solvent (CAS). In order to be qualified, the clean air solvent has to meet all of the following criteria:

  1. VOC concentration is no more than 25 grams of VOC per liter of material, as applied;
  2. Composite vapor pressure is no more than 5 mm Hg of VOC at 20°C (68°F);
  3. Reactivity is not higher than toluene; and,
  4. Contains no compounds classified as Hazardous Air Pollutants (HAPs) by the federal Clean Air Act, Ozone-Depleting Compounds (ODCs), or Global Warming Compounds (GWCs).

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.

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U.S. EPA Significant New Alternatives Policy (SNAP) Resources

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