where:
Ppc = VOC composite partial pressure at 20ºC, in mm Hg.
Wi = Weight of the "i"th VOC compound, in grams, as determined by ASTM "Standard Practice for Packed Column Gas Chromatography" (see 9VAC5-20-21).
Ww = Weight of water, in grams as determined by ASTM "Standard Test Method for Water Content of Coatings by Direct Injection Into a Gas Chromatograph" (see 9VAC5-20-21).
We = Weight of the "i"th exempt compound, in grams, as determined by ASTM "Standard Practice for Packed Column Gas Chromatography" (see 9VAC5-20-21).
Mwi = Molecular weight of the "i"th VOC compound, in grams per g-mole, as given in chemical reference literature.
Mww = Molecular weight of water, 18 grams per g-mole.
Mwe = Molecular weight of the "i"th exempt compound, in grams per g-mole, as given in chemical reference literature.
VPi = Vapor pressure of the "i"th VOC compound at 20ºC, in mm Hg, as determined by subsection C of this section.
9 Va. Admin. Code § 5-40-8600
Statutory Authority: § 10.1-1308 of the Code of Virginia; §§ 110, 111, 123, 129, 171, 172, and 182 of the federal Clean Air Act (40 CFR Parts 51 and 60).