- U Value - Overall thermal conductance. U value is equal to the inverse
of the sum of the R-values in a system (U = 1/R total). Units are °K·m2/W (°F·ft2·hr/Btu).
- UBC - Uniform Building Code. Model building code generated by ICBO.
- Underlayment - A material that is laid down as a substrate for the
sprayed polyurethane foam to make the surface smooth or to give a
specific rating for interior fire exposures.
- UV - An abbreviation for ultraviolet. (See also: ULTRAVIOLET RADIATION)
- Viscosity - The thickness or resistance to flow of a liquid. Viscosity generally decreases as temperature increases.
- Ventilation - The intentional flow of air into occupied spaces or behind
cladding/roofing to move heat and moisture in a desirable manner.
- Volatile Organic Compounds (VOC) - Any compound containing carbon and
hydrogen or containing carbon and hydrogen in combination with other
elements that has a vapor pressure of 1.5 pounds per square inch
absolute (77.6 mm Hg) or greater under actual storage conditions.
- Water Absorption - The percent increase in weight of a specimen after contact with water for a specified time.
- Wet Film Thickness - The thickness, expressed in mm or mils, of a coating or mastic as applied but not cured.