American Coatings Association

SCAQMD Adopts New VOC Test Methods for AIM Coatings


California’s South Coast Air Quality Management (SCAQMD) recently adopted two new test methods for volatile organic compound (VOC) content in its Rule 1113 for Architectural and Industrial Maintenance Coatings (AIM). The test methods — ASTM D6886 and SCAQMD Method 313—  are intended to be used to analyze the VOC content of coatings less than 150 g/L (“material “or “actual” VOC content). While coatings manufacturers can use formulation data to determine the VOC content of a product, SCAQMD will likely use Method 313 for enforcement purposes.

SCAQMD will likely add these methods to all its coating VOC rules in the future.

Currently, most coating VOC rules define VOC based on the U.S. Environmental Protection Agency’s (EPA) Method 24. Method 24 defines a VOC as a compound that evaporates after 1 hour at 110 degrees C (minus water and exempt VOCs).

ACA is concerned that the high injection port temperatures of ASTM D6886 and Method 313 tend to breakdown, decompose or “disassociate” larger compounds — including resins, preservatives, and other raw materials — resulting in higher VOC contents. In addition, Method 313 utilizes a VOC Marker (Methyl Palmitate) that likely results in more compounds being identified as VOC, compared to EPA Method 24. In SCAQMD Method 313, compounds that elute before Methyl Palmitate are defined as VOCs versus compounds that elute after Methyl Palmitate are not considered VOCs. Many “semivolatiles” that companies would not consider VOC based on formulation data or that would might not evaporate via Method 24 may be counted as VOCs under Method 313. As such, ACA is concerned that a coating that was compliant based on formulation data or EPA Method 24 may or may not be complaint under SCAQMD Method 313.

Additionally, apart from SCAQMD, there are no commercial labs that run Method 313. Even while ASTM D6886 produces somewhat similar results to Method 313, the repeatability (i.e., how well the method performs on the same instrument) and reproducibility (i.e., how close the results are from two separate labs) statistics for Method 313 have not been developed, so it is very difficult to correlate SCAQMD Method 313 results and results of others labs (if they were to run Method 313).

At ACA’s request, SCAQMD is actively engaged with industry labs in a roundrobin study to determine reproducibility and repeatability of Method 313. ACA is also working with SCAQMD to develop an “Exclusion Pathway” to exclude compounds that elute before, but are likely less volatile than Methyl Palmitate.

It is important to note that other California air districts and other states across the United States will likely adopt ASTM D6886 and SCAQMD Method 313 in the future. In fact, in February 2017, the District of Columbia proposed to add these two test methods for determining VOC content of all District of Columbia coatings rules.

ACA recommends that its members analyze a few of their coatings that are less than 150 g/L material VOC via ASTM D6886 (since there are no commercial labs that perform Method 313), especially if the VOC content of the products are very close to the Rule 1113 limits.

Contact ACA’s David Darling for more information.