For the purpose of determining compliance with the VOC content limits in the Table of Standards in § 774.10, the VOC content of a coating shall be determined by using the procedures described below in paragraphs (a) or (b), as appropriate. The VOC content of a tint base shall be determined without colorant that is added after the tint base is manufactured as follows:
VOC Content = (Ws - Ww - Wec)/
(Vm - Vw - Vec)
where:
VOC content = grams of VOC per liter of coating;
Ws = weight of volatiles, in grams;
Ww = weight of water, in grams;
Wec = weight of exempt compounds, in grams;
Vm = volume of coating, in liters;
Vw = volume of water, in liters; and
Vec = volume of exempt compounds, in liters; or
VOC Content (ls) = (Ws - Ww - Wec)/
(Vm)
where:
VOC Content (ls) = the VOC content of a low solids coating in grams per liter of coating;
Ws = weight of volatile, in grams;
Ww = weight of water, in grams;
Wec = weight of exempt compounds, in grams; and
Vm = volume of coating, in liters.
To determine the physical properties of a coating in order to perform the calculations in § 778.1, the reference method for VOC content is U.S. EPA Method 24, except as provided in § 778.3 and 778.4. An alternative method to determine the VOC content of coatings is SCAQMD Method 304-91 (Revised February 1996), adopted by reference in § 778.5(j). The exempt compounds content shall be determined by SCAQMD Method 303-91 (Revised August 1996), adopted by reference in § 778.5(h)(3). To determine the VOC content of a coating, the manufacturer may use U.S. EPA Method 24, or an alternative method, as provided in § 778.3, formulation data, or any other reasonable means for predicting that the coating has been formulated as intended including but not limited to quality assurance checks and record keeping. However, if there are any inconsistencies between the results of a Method 24 test and any other means for determining VOC content, the Method 24 results will govern, except when an alternative method is approved as specified in § 778.3. The Department may require the manufacturer to conduct a Method 24 analysis.
Alternative test methods may be used if they are demonstrated to provide results that are acceptable for purposes of determining compliance with § 778.2, and have been reviewed and approved in writing by the Department and the U.S. EPA.
Analysis of methacrylate multi-component coatings used as traffic marking coatings shall be conducted according to a modification of U.S. EPA Method 24 in 40 C.F.R. Part 59, Subpart D, Appendix A. This method has not been approved for methacrylate multi-component coatings used for purposes other than traffic marking coatings or other classes of multi-component coatings.
The following test methods are incorporated by reference herein, and shall be used to test coatings subject to the provisions of §§ 773 through 778:
D.C. Mun. Regs. tit. 20, r. 20-778