| ULEF | Ultra Low Emitting Formaldehyde. |
| ULEF Emission Table | Table 2 page 12 http://www.arb.ca.gov/regact/2007/compwood07/fro-final.pdf |
| ULEF from CARB | From CARB: “Ultra-low-emitting formaldehyde (ULEF) resins” means resins formulated such that average formaldehyde emissions are consistently below the Phase 2 emission standards in section 93120.2, as provided in section 93120.3(d). |
| Ultrasonics | (See Stress-Wave Timing) |
| Urea-formaldehyde | From Wikipedia: Urea-formaldehyde, also known as urea-methanal, named so for its common synthesis pathway and overall structure[1], is a transparent thermosetting resin or plastic, made from urea and formaldehyde heated in the presence of a mild base such as ammonia or pyridine. These resins are used in adhesives, finishes, MDF, and molded objects. Urea-formaldehyde resin's attributes include high tensile strength, flexural modulus and heat distortion temperature, low water absorption, mould, high surface hardness, elongation at break, and volume resistance. |
| USGBC | The U.S. Green Building Council (USGBC) is a non-profit composed of leaders from every sector of the building industry working to promote buildings that are environmentally responsible, profitable and healthy places to live and work. Our more than 10,000 member organizations and our network of 75 regional chapters are united to advance our mission of transforming the building industry to sustainability. (www.usgbc.org) |
| U-Value (Btu/hr-ft2-F) | The reciprocal of R-value (that is, 1/R-value). This measures the energy flowing through a wall, roof, window, door, or floor per hour per each degree of temperature difference between the inside and outside air temperatures. |