SCAQMD VOC limitation
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SCAQMD is the Californian South Coast Air Quality Management District, based in Diamond Bar and covering Orange County and parts of Los Angeles, Riverside and San Bernadino counties.
SCAQMD limitation of VOC content in adhesives, sealants, and architectural coatings has gained importance even outside California because it is referenced by LEED and other sustainable building ranking schemes in the world.
The purpose of this limitation is to protect urban outside air against smog, especially against formation of ground level ozone. California Air Resources Board ARB offers a list with different VOC Limits for Architectural Coating categories that are valid in different California Districts, and a VOC calculator for achieving VOC content in agreement with their rules.
LEED v4 of the US Green Building Initiative specifies limit values both for VOC content and for VOC emission into indoor air, mainly based on California Section 01350 specification, with alternative European pathways.
SCAQMD limit values
SCAQMD regulations cover a.o.:
- SCAQMD Architectural coatings, see rule 1113.
- SCAQMD Adhesives and sealants, see rule 1168.
Total volatiles are determined by monitoring weight loss during 1 hour heating at 110 °C. Reactive products are allowed to stand open for 1 hour after mixing before start of test for allowing first curing to happen. Here you can download an illustration.
"VOC minus Water"
Total volatiles will comprise both total volatile organic compounds, but also water. Therefore water fraction is subtracted from the result. VOC content is related only to the non-aqueous fraction of the coating. Products containing a large amount of water will show higher VOC content in California than under European Decopaint Directive. As a consequence, modern water-based dispersion coatings and adhesives are treated more stringently than old solvent-based formulations.
"... minus Exempt Compounds"
A number of exempt compounds are subtracted because these are known NOT to contribute to ground level ozone formation. There are different lists with exempt compounds available from different authorities in the USA, but for this purpose only the Californian list of exempt compounds on pages 4 - 6 of SCAQMD rule 102 is accepted. Products containing a large amount of exempt compounds will show lower VOC content in California than under the European Decopaint Directive.
Technical problems with testing
Earlier, only the above mentioned testing methods are accepted, even though not optimal, especially not for reactive coatings and for coatings with low VOC and high water content. But in the meantime SCAQMD started accepting also GC testing (ASTM D6886 or SCAQMD method 313 (revised in 2016)), to stop delivery of non-reliable or even erroneous results for a number of low VOC products. Most recent information is available on a "VOC Working Group" section of the SCAQMD homepage.
Such testing could easily be combined with a test for European Decopaint Directive and is preferred by Eurofins VOC labs.