U

UDL
Stands for uniformly distributed load.
U-factor (U-value)
This is a measure of the rate of heat loss of a building component. It is expressed as watts per square meter, per degree Kelvin, W/m2K.
ULTRA-violet (UV absorbing glass}
Ultra-violet radiation is absorbed by normal glass. Where ultra-violet transmission is required, quartz glass is used
UV transmittance
Determines the percentage of solar energy in the form of ultra-violet radiation transmitted by glazing.
U-value
A measure of the rate of heat loss of a building component.
United Inches
The addition of the dimensions of one length and one width of a lite of glass. Example: A window that is 24" wide and 72 high is 96 U.I.