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Laminated Glass Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken. Used for safety glazing and sound reduction. Laminated Shingles Strip shingles containing more than one layer of tabs to create extra thickness. Also called three-dimensional shingles. Lap To cover the surface of one shingle or roll with another. Lap Cement An asphalt-based cement used to adhere overlapping piles of roll roofing. Lap Joint The overlapping of two adjoining pieces of timber, wallpaper or other material. Also called butt joint. Lap Siding Siding used to finish the exterior surface of a house or other structure. Also called ship lap siding. Lapping Smoothing a metal surface to high degree of refinement or accuracy using a fine abrasive. Large Opening A hole or gap in a building envelope, which is generally purpose, made for example, a door window or vent. Latent Heat Heat given off or absorbed during phase change (condensation, evaporation, solidification, melting, or sublimation). Heat energy absorbed in process of changing form of substance (melting, vaporization, fusion) without change in temperature or pressure. Latent Heat Transfer Heat added or removed during a change of state of a substance i.e. Solid, to a liquid to a gas or vice versa, the temperature remaining constant. Lateral Relating to the side. Of or pertaining to a side anything situated at , proceeding from or directed to a side any line that branches off or extends from a main line. E.g., the laterals of a septic system, an irrigation distribution ditch or pipe. Lateral Brace A wall brace which stiffens a structure against loads acting on the side walls. Lath A building material of wood, metal, gypsum or insulating board that is fastened to the frame of a building to act as a plaster base. Lattice An openwork screen of crossed strips, rods or bars of wood or metal. Lavatory Another name for bathroom Lay-Up The process of winterizing a tower or condenser system when not in use. Lead Boot See collar Leak Detector Device or instrument such as a halide torch, an electronic sniffer or soap solution used to detect leaks. Leakage Area The actual open area of a hole or gap. Leakage Path A route by which air enters or leaves a building or flows through a component. Lean-To A small structure with a pitched roof, usually erected against the outside wall of a larger structure. Lean-To-Roof A sloping roof that is supported on one side by the wall of an adjoining building. Legionella A bacterium of the genus legionella, especially pneumophila, that can cause Legionnaires' disease - an acute, sometimes fatal respiratory disease caused by and characterized by severe pneumonia, headache, and a dry cough. Level To determine if a surface is exactly horizontal or if two or more points are exactly the same height. Life Expectancy The number of additional years that an item can be expected to remain functional based on statistical data. Lift Handle for raising the lower sash in a double-hung window. Also called sash lift. Light A window pane a section of a window sash a single pane of glass. Light A window, a pane of glass within a window. Double-hung windows are designated by the number of lights in upper and lower sash, as in six-over-six. Also spelled informally lite. Light Well A well-like open area within a building that provides light and ventilation to inside rooms. An open, subsurface space around a basement window that provides light and air. Light-To-Solar-Gain Ratio A measure of the ability of a glazing to provide light without excessive solar heat gain. It is the ratio between the visible transmittance of a glazing and its solar heat gain coefficient. Abbreviated LSG. Limit Control A control system in which, for reasons of comfort or efficiency, the controlled variable is prevented from exceeding or dropping below a certain value. A control used to open or close electrical circuits as temperature or pressure limits are reached. Lintel A horizontal structural member that supports the load over an opening such as a door or window. Lintel A horizontal member above a window or door opening that supports the structure above. Liquid Absorbent Chemical in liquid form which has the property to ""take on"" or absorb moisture. Liquid Crystal Glazing Glass in which the optical properties of a thin layer of liquid crystals are controlled by an electrical current, changing from a clear to a diffusing state. Liquid Piping Refrigerant piping from the condenser outlet to the evaporator inlet. Liquid Refrigerant The compressor coolant used in the refrigerant cycle of a chiller for heat transfer. Liquid Refrigerant Stacking This condition occurs can be caused by mechanical failure or low head pressure in the condenser and evaporator caused by low condenser water temperature. Live Load The total of all moving and variable loads which may be placed upon a structure. Load Amp load is compared to full load and the percentage value equals the load of the chiller. Actual amps divided by full load amps is the percentage of full load design. Load Bearing Member A structural member designed to carry the live and dead loads of a building. Load Swing A large or radical change in cooling load requirements, i.e., weather or building operations requirements. Locknut Nut used to hold a threaded part in position or to prevent another nut form turning on a screw or bolt. Loft An attic-like space below the roof of a house or barn. Log Mean Temperature Difference A specialized average temperature difference used to determine the heat transfer rate. Long-Wave Infrared Radiation Invisible radiation, beyond red light on the electromagnetic spectrum (above 3.5 micro meters), emitted by warm surfaces such as a body at room temperature radiating to a cold window surface. |