In using Practice D 3960 to measure the regulatory VOC content of coatings, precision tends to be poor for low VOC content waterborne coatings because the VOC weight fraction is determined indirectly. The present method first identifies and then quantifies the weight fraction of individual VOCs directly in low VOC content waterborne air-dry coatings. The total VOC weight fraction can be obtained by adding the individual weight fraction values (Note 3).

Note 3—An effort is currently underway in California to consider changing mass-based VOC regulations for architectural coatings to reactivity-based VOC regulations. In California, reactivity based regulations have already been implemented for aerosol coatings, that is, MIR-indexed regulations (California Air Resources Board). Reactivity based regulations would require knowing the weight fractions of each individual volatile compound present in a coating.

SPME/GC makes it possible to identify very low levels of volatile compounds in a coating and could serve to make it possible to identify the presence of hazardous air pollutants (HAPs).

1.1 This test method is for the determination of the weight percent of individual volatile organic compounds in low VOC content waterborne latex air-dry coatings. The method is intended primarily for analysis of waterborne coatings in which the material VOC content is below 5 weight percent. The method has been used successfully with higher VOC content waterborne coatings.

1.2 This method may also be used to measure the exempt volatile organic compound content (acetone, methyl acetate, and p-chlorobezotrifluoride) of waterborne coatings. The methodology is virtually identical to that used in Test Method D 6133 and similar to that used in Test Method D 6438.

1.3 Volatile compounds that are present at the 0.05 weight percent level or greater can be determined. Solid phase microextraction will detect volatile compounds at lower levels.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.