Field glossaryPsychrometry / GPPThe science of the air-moisture relationship; GPP is grains of water vapor per pound of dry airUsed across 2 Anvilfield field guides, most in Plumbing. Where this shows upPlumbingWater damage restoration field guidePlumbingWater mitigation and drying guide Related termsCategory 1 / 2 / 3Class 1 to 4Dry standardDew pointRelative humidity (RH)Vapor pressure Back to the full field glossary