Upcycle

The process of converting an industrial nutrient (material) into something of similar or greater value, in its second life. Aluminum and glass, for example, can usually be upcycled into the same quality of aluminum and glass as the original products.

Ultra violet radiation

Electromagnetic radiation, usually from the sun, that consists of wavelengths in the range of 4 to 400 nanometers; shorter than the violet end of the visible spectrum. UV radiation is a health hazard that can lead to skin cancer or cataracts.

Universal design

An approach to the design of products, services and environments to be usable by as many people as possible regardless of age, ability or circumstance.

Urban growth boundary

A boundary which identifies urban and urbanizable lands needed during a specified planning period to be planned and serviced to support urban development densities, and which separates these lands from rural lands.

Urea-formaldehyde

A combination of urea and formaldehyde that is used in some glues and may emit formaldehyde at room temperature.

Urethanes

A family of plastics (polyurethanes) used for varnish coatings, foamed insulations, highly durable paints, and rubber goods.

USGBC

US Green Building Council: non-profit organization dedicated to sustainable building design and construction. Developers of the LEED building rating system (see LEED).

U-value

A measure of the rate of heat loss or gain through a material. The reciprocal (inverse) of R-value. U = 1/R. The lower the U-value, the greater the material’s resistance to heat flow and better its insulating value. Also known as U-factor.