Glossary: U-Z

U-Value: See U-Factor.

U-Channel Molding: A molding that allows water to be channeled up and over the vehicle instead of around the A pillar.

U-Factor: Rate of heat flow-value through a building component, from room air to outside air. Also referred to as U-value. The lower the U-factor, the better the insulating value. U-factor, a rating more generally used in the window industry, is the reciprocal of R-value, a rating commonly used in the insulation industry.

Ultimate Elongation: Elongation at failure.

Ultraviolet light (UV): Invisible rays of solar radiation at the short-wavelength violet end of the spectrum. Ultraviolet rays can cause fading of paint finishes, carpets and fabrics, as well as deterioration of some materials.

Unibody Construction: A type of automobile construction. The strength of unibody construction does not lie only in the structural frame but rather in the strength of the whole.

Uniform Bead: A consistent width and appearance of a substance (adhesive) applied to a surface.

Unleaded Frit: A painted band around the perimeter of the glass applied with unleaded paint. It requires special preparation before bonding.

Urethane Breakdown: Results when urethane is exposed to ultra-violet light. Urethane breakdown appears as a chalky black powder on the surface of the hardened adhesive.

Urethane: A family of polymers ranging from rubbery to brittle. Usually formed by the reaction of a diisocyanate with a hydroxyl; also called polyurethane.

Vacuum Cup: A tool used for picking up glass.

Vacuum Deposition: A process in which glass is placed in a vacuum chamber, electric energy is added, and a magnetic reaction takes place that causes the metal atoms to strike the surface of the glass at high speeds.  The atoms coat the surface of the glass uniformly.

V-Bead: Sealant or adhesive compound applied in a triangular shape to a surface.

Vertical run guide: A weatherstrip or channel that steers the door glass in the frame when the glass is raised or lowered.

Vertical Tempering: When the glass is supported by tongs as it moves vertically through a tempering furnace.

VIN Plate: A permanently installed plate, displaying the vehicle identification number, which is viewable through the windshield from outside the vehicle.

Vinyl: Generic term for polyvinylchloride or PVC, an extruded material used for window and door framing.

Viscosity: The thickness of a liquid material. A measure of the flow properties of a liquid or paste. Example: Honey is more viscous than water. Water, the standard of comparison, has a viscosity of 1⁄100 of a poise. Viscosity is tested by forcing the material through a determined hole and measuring the time it takes to flow.

Vulcanization: A process in which rubber is treated with chemicals to harden and strengthen it.

Warm-edge: A type of insulating glass construction using an airspacer offering lower thermal conductance than traditional aluminum spacer. Warm-edge IG units typically offer higher resistance to condensation and an incremental improvement in window energy performance.

Weatherometer: An environmental chamber in which specimens are subjected to water spray and ultraviolet light.

Weatherstripping: A material or device used to seal the openings, gaps or cracks of venting window and door units to prevent water and air infiltration. An item made of rubber or foam that insulates one space from another.

Wedge Glazing: Interior, flexible, continuous, pressure fit gasket that insures a high compression seal between the glass and aluminum, while applying pressure and seal to the outside architectural glazing tape.

Weep Hole: A small opening in a window or sill member through which water may drain to the building exterior.

Weld: A term used for a type of corner construction, used with vinyl and other types of windows and doors, in which a small amount of material at the two pieces are melted or softened, then pushed together to form a single piece. This also is referred to commonly as a fusion-weld.

Wet Glazing: A method of sealing glass in a frame by use of sealants rather than dry-glazing gaskets.

Wheel Cutter: The most common type of hand glass cutter.

Wind Load: Force exerted by winds on building panels and complete structures; may be inward (positive) or outward (negative).

Windshield Repair: The act of repairing a break in a windshield, or other laminated auto glass part, rather than replacing it. Windshield repair is a permanent process that removes the air from the break and fills it with a curable, optically matched resin. Same as auto glass repair.

Wired Glass: Made by feeding a welded wire net of a particular design into the molten glass just before it enters the roller. The wire holds the lite (or pane) in the sash in case it shatters.

Wiring Harness: A number of wires bundled together, with a common connector, to provide electrical power to various devices.