by Ron Joseph
Definition of VOC and HAP
Q. In the U.S if Ethylene Glycol and Propylene Glycol are used in a latex
paint formula are these considered to be VOCs?
The definition of VOC is " ... any organic compound that participates
in a photochemical reaction, except those that have negligible photochemical
reactivity. ..." In other words, ANY organic compound that evaporates into
the air is, by default a VOC unless it is listed by the EPA as Exempt Compound.
Acetone, PCBTF, Methyl Acetate, Methylene Chloride and Volatile Methyl Siloxanes
are the solvents most commonly used in painting operations, that are exempt.
Since Ethylene Glycol and Propylene Glycol are volatile compounds and are not
listed as exempt, they are, by default VOCs.
EPA Method 24 provides a list of ASTM methods that are used to determine VOCs
experimentally. ASTM D2369 is the definitive test for experimentally determining
VOC status. If either of the two solvents you mentioned evaporate, or even partially
when subjected to 230oF (110oC) for one hour, then they are VOCs.
Please note that some glycol ethers are listed by EPA as Hazardous Air Pollutants
(HAP). The definition of HAPs is given in Sections 112(b)(2) and (3). The original
list of 189 HAPs (now reduced to 188 compounds) can be found at http://www.epa.gov/ttn/atw/orig189.html.
I hope this helps you.