Glossary: U


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TermDefinition
U of CUniversity of California, an independent fire-testing laboratory.
U ValueCoefficient of heat transfer, “U” equals 1 divided by (hence, the reciprocal of) the total of the resistances of the various materials, air spaces and surface air films in an assembly. See Thermal Resistance.
UBCUniform Building Code – document promulgated by the International Conference of Building Officials.
ULUnderwriters Laboratories Inc., founded by NBFU, and now operated in affiliation with American Insurance Assn. UL is a not for profit laboratory operated for the purpose of testing devices, systems and materials as to their relation to life, fire and casualty hazard in the interest of public safety.
Ultimate StrengthThe maximum stress, such as tensile, compressive, or shear, that a material can withstand.
Ultimate Tensile StrengthThe maximum tensile stress of a  material up to the point of rupture.
Ultrasonic TestingA method of non-destructive testing of materials that uses high frequency sound vibrations to find defects in the material.
Under-Carpet WiringA flat, insulated electric wire that is run under the carpet.
UnderlaymentSheet material, such as hardboard, that is laid over the subfloor to provide a smooth, stiff surface for the finish flooring.
UnderpinningPlacing a new foundation below the existing foundation.
Unfibered GypsumA neat gypsum. It has no additives.
Uniform LoadAny load that is spread out evenly over a large area.
Unreinforced ConcreteConcrete placed without steel-reinforcing bars or welded-wire fabric.
USASIUnited States of America Standards Institute, now American National Standards Institute.