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Loose Cable An electrical cable that is not properly secured to structural members. Louver A slat or fin over an opening that is moveable to direct the air coming out of a vent, that is pitched to keep out rain and snow a finned sunshade on a building, the diffusion grill on a fluorescent light fixture. Low Ambient Controllers / Head Pressure Controllers When equipment is required to provide cooling in cold weather the external unit will over condense i.e. Will reject too much heat. To overcome this problem it is necessary to fit a low ambient controller also known as a head pressure controller. This device slows down the condenser fan or uses other methods to prevent over condensing. Some equipment has this fitted as standard others do not. Low Energy House A house designed or retro-fitted with energy savings in mind, to provide overall lower energy consumption. Low Pressure Chiller A chiller that operates the evaporator in a vacuum, measured in inches of Hg (mercury). In some cases relating to entering condenser water temperature, the condenser may also operate in a vacuum. Some low-pressure refrigerants include R-11, R-113, R-114, R-123. Low Slope Application Method of installing asphalt shingles on roof slopes between 2 and 4 inches per foot. Low-Conductance Spacers An assembly of materials designed to reduce heat transfer at the edge of an insulating window. Spacers are placed between the panes of glass in a double- or triple-glazed window. Low-E/Low-Emittance Low Emittance (Low E) coating is microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U factor by suppressing radiative heat flow. The principal mechanism of heat transfer in multilayer glazing is thermal radiation from a warm pane of glass to a cooler pane. Coating a glass surface with a low emittance material and facing that coating into the gap between the glass layers blocks a significant amount of this radiant heat transfer, thus lowering the total heat flow through the window. Low E coatings are transparent to visible light. Different types of Low E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain. Lowest Floor The lowest floor of the lowest enclosed areas of a building, including a basement. Luminous Ceiling A suspended ceiling of translucent materials installed below a system of fluorescent tubes, making the entire ceiling a source of light used to reduce glare and shadows. M Roof A type of roof which is made up of two double-pitch roofs. This type of construction has two advantages it utilizes shorter material for rafters and reduces the elevation of the building. Magnetic Clutch A device operated by magnetism to connect or disconnect a power drive. Magnetic Field Space in which magnetic lines of force exists. Magnetic Gasket A sealing material which adheres due to small magnets inserted in gasket. Magnetism An electronic force which causes a magnet to attract items made of steel. Main A pipe, conduit or circuit leading to or from the branches of a utility system. Main Circuit Circuit that carries a heavy electrical load to the branch circuits of a distribution system. Maintenance Practices An organized schedule of chiller and plant maintenance. Major Repairs/Minor Repairs A major repair will be a repair that is estimated to cost $500.00 or more for material & labor. A minor repair will be under that amount for material and labor. Amount of estimated cost will be determined by assuming the use of a licensed and qualified HVAC/R technician in the area being estimated. Makeup Air Outdoor air supplied to replace exhausted air, brought in through a ventilation system without previous circulation in the system. Manifold, Service" A device equipped with gauges and manual valves, used by serviceman to service refrigerating systems. Manometer An instrument for measuring pressure of gases and vapors. Gas pressure is balanced against column of liquid such as mercury, in u-shaped tube. Mansard Roof A type of roof containing two sloping planes of different pitch on each of four sides. The lower plane has a much steeper pitch than the upper, often approaching vertical. Contains no gables. Mantel The decorative facing placed around a fireplace usually made of ornamental wood and topped with a shelf. Mass A quantity of matter cohering together to make one body, which is usually of indefinite shape. Mastic See asphalt plastic cement Matched System A heating and cooling system comprised of products that have been certified to perform at promised comfort and efficiency levels when used together, and used according to design and engineering specifications. Mean Active Repair Time (MART) This applies to repairable items, and means the average time an item may be expected to be out of service for maintenance and repair, given that the require tools/parts are to hand. Mechanical Equipment Any mechanical device located on the exterior of a structure. Mechanical Extract Ventilation System A ventilation system in which air is extracted from a space so creating an internal negative pressure. Supply air is drawn through adventitious or purpose provided openings. Mechanical Ventilation System A ventilation system in which air is extracted from a space so creating an internal negative pressure. Supply air is drawn through adventitious or purpose provided openings. Meeting Rail The part of a sliding glass door, a sliding window, or a hung window where two panels meet and create a weather barrier. Metal-Clad Windows Exterior wood parts covered with extruded aluminum or other metal, with a factory-applied finish to deter the elements. Microbe An organism of microscopic or ultramicroscopic size. Micron One millionth (10-6) of a metric meter. Microprocessor Electrical component consisting of integrated circuits which may accept, store, control, and output information. Mil One thousandth of an inch, or 0.0254 millimeter. Milling Process that imparts a smooth surface to a piece of lumber process that lends decorative shape to a piece of wood. Mineral Stabilizers Finely ground limestone, slate, trap-rock or other inert materials added to asphalt coatings for durability and increased resistance to fire and weathering. Mineral-Surfaced Roofing Asphalt shingles and roll roofing that are covered with granules. |