Clean Air Solvent Certification Protocol

September 2009


This protocol contains information on how an applicant may obtain a Clean Air Solvent (CAS) Certificate. Primarily, the CAS is considered a water base solvent containing no more than 25 grams per liter (g/L) Volatile Organic Compounds (VOCs) with the remainder being water, and is used to perform solvent cleaning, finishing, or surface preparation operations, or activities.

The South Coast AQMD will notify the applicant of the findings of laboratory analysis within 90 to 180 days of the receipt of all requested information. A CAS Certificate will be issued within 30 days of such notification if the product is approved as a CAS by the South Coast AQMD.

Information Required

  • Name of the product (including chemical name, if any);

  • name, address, telephone and Fax number of the applicant (and contact person, if different);

  • formulation data sheet for the product, if available (will be treated as confidential if requested);

  • material safety data sheet for the product, if available;

  • sealed, unopened sample of product, 1 quart or more:

  • complete user instructions on how the product is intended to be used, including concentration or dilution ratio, temperature, and any other relevant factor.

Fee Required

At the time of filing for a CAS Certificate, the applicant must submit with the sample product a fee for each product to be tested. This fee includes the GC/MS analysis for 5 or fewer compounds, density measurement, one (1) hour time and material, and the CAS certificate.

Adjustments may be made to the submitted fee with the applicant receiving a refund or being billed for additional analysis needed of the sample. A refund will be made if the actual testing fee is less than the submitted testing fee; or additional billing will be made if the actual testing fee is greater than the submitted testing fee. In addition, if the candidate product does not qualify for the certificate, appropriate adjustments will be made and monies refunded to the applicant, where warranted. This refund will include the certificate fee and any unused portion of the analysis fee.

These fees are taken from District Rule 301 and will be based on the current version of the rule at the time of submittal.

Submittal Address

CAS Certification
Planning, Rule Development & Area Sources
Attn: Melissa Gamoning
South Coast Air Quality Management District
21865 Copley Drive
Diamond Bar, CA 91765-4182


The certifiability of the product will be determined by testing the unopened submitted product. Analysis will be performed by the South Coast AQMD Laboratory using the most recent version of SCAQMD Method 313, Determination of Volatile Organic Compounds (VOC) by Gas Chromatography/Mass Spectrometry (GC/MS).

A copy of Method 313 may be found in Appendix I. The detection limit for the individual components of this method is 0.01%. However, only compounds that are 0.1% or greater will be considered in the identification and quantitation of compounds. These compounds will be included in the calculations for VOC and VOC composite partial pressure (CPP).

The certification process (also see Process Diagram below) will entail the following steps by evaluating the GC/MS data obtained by using Method 313:

  1. Evaluate the GC/MS data of the sample for the presence of Volatile Organic Hazardous Air Pollutants (VOHAPs), or Ozone Depleting Compounds (ODCs) and Global Warming Compounds (GWCs). If any VOHAP, or ODC and GWC is detected in the sample, no certificate will be issued.

    A list of Hazardous Air Pollutants (HAPs) as contained in Section 112 (b)(1) of the 1990 Clean Air Act Amendment may be found in Appendix II.

    A list of ODCs may be found in Appendix III and a list of compounds having global warming potentials is in Appendix IV.

  2. If VOHAPs, ODCs, and GWPs are not present, determine if a component with Maximum Incremental Reactivity (MIR) value higher than toluene is detected. If a component with MIR value higher than that of toluene is detected, no certificate will be issued.

    The MIR values may be obtained from the Maximum Incremental Reactivity List found in Appendix VIII of the ARB's "California Exhaust Emission Standards and Test Procedures for 1988 and Subsequent Model Passenger Cars, Light-Duty Trucks and Medium-Duty Vehicles" as amended on September 22, 1993.

    A list sorted in decreasing MIR values may be found in Appendix V.

  3. If all the components have MIR values lower than that of toluene, quantitate each detected VOC component and calculate the total VOC in g/L of the product at the recommended use dilution. If the VOC is greater than 25 g/L, no certificate will be issued.

  4. If the VOC is less than 25 g/L, use the formula in Section (b)(43) of Rule 1171 to calculate the VOC composite partial pressure (CPP). If the CPP is greater than 5 mm Hg at 20°C, no certificate will be issued.

If the above procedures are successfully completed, a CAS certificate will be issued.


A CAS certificate shall be valid for five years from the date of issuance and may be renewed upon recertification. The recertification fee shall be according to the fees specified in the most current Rule 301 fees. Any person utilizing a CAS shall comply with the conditions of use stated on the certificate. If the original CAS is reformulated, a new CAS certificate must be obtained and the original CAS Certificate will be considered invalid.

The Executive Officer may determine compliance from time to time by sampling an unopened concentrated product in the field. If the results of laboratory analysis show that the product does not meet the original certification criteria, the Executive Officer may revoke the CAS Certificate.


Rule 1171 Solvent Cleaning Operations
Product Certification Process Diagram

Product Certification Process Diagram
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