Clean Air Solvent Certification

Rule 1171 (PDF, 59kb) - Solvent Cleaning Operations and Rule 1122 (PDF, 68kb) - Solvent Degreasers are two key components of the SCAQMD’s ozone reduction strategy, as these rules control VOC emissions from numerous uses of solvents in industrial, commercial, and general purpose cleaning and degreasing activities. Recent amendments to Rule 1171 and Rule 1122 lowered the VOC content limits of solvents in several usage categories. Effective January 1, 2003, Rule 1171 and Rule 1122 require cleaning materials used in repair and maintenance operations and cold cleaners, respectively, to contain no more than 25 grams of VOC per liter of cleaning solvent as applied. The most common and effective cleaners that meet this criteria are water-based or aqueous cleaners that contain little or no VOCs, although other options such as VOC exempt compounds are also available to the user.

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).

Manufacturers, suppliers, and users can apply for certification of CAS that meet the qualifications mentioned above. This certification is valid for five years and can be renewed upon approval by the SCAQMD. The certificate becomes invalid if the material is reformulated or changed such that it does not meet the qualifications of a CAS. The procedures for compliance with this provision are outlined in detail under Rule 102 - Definition of Terms (PDF, 121kb), Rule 301 - Permit Fees (PDF, 338kb), and the Clean Air Solvent Protocol.