U-Z

Spray Coating and Foam Glossary U-Z

January 18, 2010

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.