L-10 Bearing Life: The theoretical number of hours after which 90% of the bearings subjected to a given set of conditions will still be in operation. Also known as B-10.
L/sec: Volume flow rate measured in liters per second.
L-Type Filter: Cartridge filter in which the inlet and outlet port axis are at right angles and the filter elements axis is parallel to either port axis.
LAB PAK®: A selection of precision-woven screens pre-cut and packaged in standard sizes.
Labor Hour: A standard in which one person’s labor is performed in one hour.
Labyrinth Compressor: A special type of oil free, positive displacement reciprocating compressor, working without piston rings. The seal between
piston and cylinder wall is produced by a series of labyrinths.
Lacquer: A deposit resulting from the oxidation and polymerization of fuels and lubricants when exposed to high temperatures. Similar to, but harder, than varnish.
Ladder, Fixed: A ladder which is permanently attached to a building.
Laer (Lowest Achievable Emission Rate): The rate of emissions that reflects either the most stringent emission limit contained in the implementation plan of any state (unless it is proved that such limitations are not achievable, or the most stringent emission limit achieved in practice, whichever is most stringent).
Lag: Time delay between, say, the peak outdoor temperature and the indoor temperature, also applied to the time required for the sensing element of a control system to reach equilibrium with the property being controlled.
Lag of temperature control: The delay in action of a temperature element due to the time required for the temperature of the element to reach the medium temperature.
Lake Haussmann (formerly Drainage Retention Basin): Man-made, lined pond used to capture storm water runoff and treated water at the Livermore site.
Laminar airflow: Non-turbulent flow of air in one direction at a uniform speed.
Laminar Flow: Term synonymous with streamline flow and viscous flow. A flow regime which the flow characteristics are governed mainly by the viscosity of the fluid.
Laminated Glass: Two or more lights of glass permanently bonded together with one or more inter-layers.
Laminated Shingles: Shingles that have added dimensionality because of extra layers or tabs, giving a shakelike appearance. May also be called “architectural shingles” or “three-dimensional shingles.”
Laminating: Bonding together two or more layers of materials.
Land Trust Alliance: An association of hundreds of local land trusts, dedicated to preserving open space and natural habitat, in the United States.
Landfill: A waste management unit at which waste is discharged in or on land for disposal. It does not include surface impoundments or land treatment units.
Landing: A platform between flights of stairs or at the termination of a flight of stairs.
Landlord/Tenant Agreement: Document required for completed application when applicant is a renter. The Agreement is legally binding contract, signed by the tenant, the landlord (or property owner), and the local agency specifying the role and responsibilities of each party. The basic goal of the WAP is to ensure that the benefits of the program accrue to the low-income family. A variety of standard clauses can be incorporated into the Agreement, including clauses on landlord's inability to raise rents for specified period of time, eviction prohibition, and landlord required "participation." Participation can take the form of actual cash, provided labor, and/or in-kind contributions.
Langelier’s Index: Is a technique for predicting whether water will tend to dissolve or precipitate calcium carbonate. If the water precipitates calcium carbonate, scale forming may result. If the water dissolves calcium carbonate, it has a corrosive tendency.
Lap: To extend one material partially over another; also, the distance so extended.
Lap Cement: An asphalt-based cement used to adhere overlapping plies of roll roofing.
(Large) Hydroelectric Power: The process of generating electricity by harnessing the power of moving water is called hydroelectricity. Hydroelectric power (hydropower) is generated by forcing water that is flowing downstream, often from behind a dam, through a hydraulic turbine that is connected to a generator. The water exits the turbine and is returned to the stream or riverbed. Much of the hydroelectricity in the United States is generated at large facilities and in the Pacific Northwest, where it meets about two-thirds of the electricity demand. In the U. S., hydroelectricity contributes about 10 percent of the total electricity supply.
Larynx: A part of the respiratory system positioned between the pharynx and the trachea; the voice box.
Latent: Present but not seen; a latent viral infection is one in which no virus can be found in the blood cells but in which those virus-infected cells can produce virus under certain circumstances.
Latent Cooling Capacity: An A/C system’s capability to remove moisture from the air.
Latent Cooling Load: The net amount of moisture added to the inside air by plants, people, cooking, infiltration, and any other moisture source. The amount of moisture in the air can be calculated from a combination of dry-bulb and wet-bulb temperature measurements.
Latent Heat: The energy required to change the state of a unit mass of material from solid to liquid (fusion) or liquid to gas (evaporation), without a change in temperature. This energy is then released, again without change of temperature (provided super cooling does not occur), when the material reverts from gas to liquid or from liquid to solid. (Wh/kg, kJ/kg).
Latent Heat of Evaporation: The amount of heat added to a substance during the change of state.
Lateral (Electric, Gas, Telephone, Sewer and Water): The underground trench and related services (i.e., electric, gas, telephone, sewer and water lines) that will be buried within the trench.
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.
Lath and Plaster: The most common wall finish prior to the introduction of drywall. Thin wood strips (lath) were nailed onto the framing as a base for the sand/lime plaster.
Latitude: The angular distance north (+) or south (-) of the equator, measured in degrees of arc.
Lattice: A framework of crossed wood or metal strips.
Lavatory: Bathroom or washroom sink.
Lb: Pounds.
lb/hr: A volume. Pounds per hour.
LC: Lethal Concentration.
LCD: An abbreviation for a screen type – Liquid Crystal Display.
LC50 (LC50): The concentration of a toxic agent necessary to kill 50 percent of the organisms being tested; it is usually expressed in parts per million (ppm).
LClo: Lethal Concentration, low; the lowest concentration of a toxic agent necessary to cause death.
LCMM: Life Cycle Material Management or Life Cycle Material Manager.
LD50 (LD50 ): The amount of a toxic agent that is lethal to 50% of the test animals exposed to it; it is usually expressed as the weight of the chemical per unit of body weight (mg/kg).
LDlo: Lethal dose, low; the lowest dose which causes death in test animals.
Leach Field: A drain field designed to discharge septic tank effluent below ground into the natural soil for final treatment.
Leachate: (a) Any fluid, formed by the drainage of liquids from waste or by the percolation of liquid through waste. It includes any constituents extracted from the waste and dissolved or suspended in the fluid. Often refers to liquid leaking from landfills which usually contains contaminates. (b) A solution obtained by leaching; e.g. water that has percolated through soil containing soluble substances and that contains certain amounts of these substances in solution. [This term is commonly used in describing water that has percolated through a landfill and contains landfill-related substances in solution.]
Lead (Pb): A heavy metal that is hazardous to health if breathed or swallowed. Its use in gasoline, paints, and plumbing compounds has been sharply restricted or eliminated by federal laws and regulations.
Lead Based Paint: Lead is a highly toxic metal that was used for many years in products found in and around our homes. Lead may cause a range of health effects, from behavioral problems and learning disabilities, to seizures and death. Children 6 years old and under are most at risk, because their bodies are growing quickly.
Leader: See Downspout.
Leaf: Any flat filter element that has or supports the filter septum.
Leaf Filter: A filter housing and device consisting of a plurality of leaves, often place in a vertical position.
Leak Air: A crack or hole that accidentally admits a gas or lets it escape.
Leak Detector Ultrasonic: An instrument designed to detect the ultrasonic emissions and convert them to audible signal.
Leakage Ratio: Measurement of total square inches of infiltration area per 100 feet of building envelope surface area.
Leaktightness: The condition of a system, unit or component where leakage through its pressure boundary is less than a specified maximum value at a specified pressure differential across the pressure boundary.
Lean-To Roof: The sloping roof of a building addition, having its rafters or supports pitched against and supported by the adjoining wall of a building.
LED: Light Emitting Diode.
Ledger Strip: A strip of lumber nailed along the bottom of the side of a girder on which joists rest.
LeeD® (Leadership in Energy and Environmental Design): A voluntary, consensus-based design standard and rating system created in 1999 by the U.S. Green Building Council for developing high-performance sustainable buildings.
LEED Steering Committee (LEED SC): Oversight committee of the USGBC responsible for direction and decisions for the LEED program.
LEED Technical and Scientific Advisory Committee (LEED TSAC): The Technical and Scientific Advisory Committee is a standing LEED committee comprised of six to eight individuals representing a diversity of building community perspectives and technical areas of competency. The Technical and Scientific Advisory Committee provides support for each of the LEED products and advice on topics as assigned by the LEED Steering Committee and the USGBC Board of Directors.
LEED-CI: LEED for Commercial Interiors. One of the six LEED Rating Systems. LEED for Commercial Interiors focuses on tenant improvements in interior spaces in single and multi-tenant buildings.
LEED-CI Reference Guide: The LEED-CI Reference Guide is a supporting document to the LEED-CI Green Building Rating System. The Guide is intended to assist project teams understand LEED-CI criteria and the benefits of compliance with the criteria.
LEED-CS: LEED for Core and Shell. One of the six LEED Rating Systems. LEED for Core and Shell focuses on buildings being developed where the developer is responsible for the core and shell of the structure and has no responsibility for the design and decisions concerning the interior space fit-outs.
LEED-EB: LEED for Existing Buildings. One of the six LEED Green Building Rating Systems. LEED for Existing Buildings establishes a set of performance standards for the sustainable upgrades and operation of existing buildings.
LEED-H: LEED for Homes. One of the six LEED Green Building Rating Systems. LEED for Homes is under development and will address single-family homes, both detached and attached, and multifamily residential buildings with up to three stories, developed on a single lot.
LEED-NC: LEED for New Construction. One of the six LEED Green Building Rating Systems. LEED for New Construction focuses on the design and construction process for new construction and major reconstruction of buildings.
LEED-NC Reference Guide: The LEED-NC Reference Guide is a supporting document to the LEED-NC Green Building Rating System. The Guide is intended to assist project teams understand LEED-NC criteria and the benefits of compliance with the criteria.
LEED-ND: LEED for Neighborhood Developments. One of the six LEED Green Building Rating Sytems. LEED for Neighborhood Developments is under development and will address the design and location of new, multi-lot residential, commercial, or mixed-use developments.
LEED® Green Building Rating System: The LEED (Leadership in Energy and Environmental Design) Green Building Rating System is a voluntary, consensus-based, market driven building rating system based on existing proven technology. The LEED Green Building Rating System represents the USGBC’s effort to provide a national standard for what constitutes a “green building.” Through it's use as a design guideline and third-party certification tool, the LEED Green Building Rating System aims to improve occupant well-being, environmental performance and economic returns of building using established and innovative practices, standards, and technologies.
Legionella: Legionellosis is an infection in humans caused by inhalation of bacterial species of Legionella. This bacteria can cause two types of infections: Legionnaires’ disease, which was named for the noted 1976 outbreak in Philadelphia, and Pontiac fever.
Legionnaires’ Disease (Legionellosis): A form of pneumonia caused by the bacterium Legionellae; first discovered in 1976 from infected persons attending the Legionnaires meeting in Philadelphia.
LEL: Lower Explosive Limit. The minimum percent by volume of a gas which when mixed with air at NTP, will form a flammable mixture.
Less than Detection Limits: Phrase indicating that a chemical constituent was either not present in a sample, or is present in such a small concentration that it cannot be measured by a laboratory’s analytical procedure, and therefore is not identified or not quantified at the lowest level of sensitivity.
Let-In Brace: Nominal 1 inch-thick boards applied into notched studs diagonally.
Lethal Concentration (LC50): The concentration of a substance needed to kill half of a population at a specific time of observation.
Lethal Dose (LD): The amount of a toxic agent which is lethal to 50% of the test animals exposed to it.
Lethargy: A condition of abnormal drowsiness or torpor; a great lack of energy; apathy.
Leukotriene Modifier: Medication that blocks chemicals called leukotrienes in the airways. Leukotrienes occur naturally in the body and cause tightening of airway muscles and production of excess mucus and fluid. Leukotriene modifiers work by blocking leukotrienes and decreasing these reactions. These medications are also helpful in improving airflow and reducing some COPD symptoms.
Level: Term use to describe any horizontal surface whereby all sides are at the same elevation.
Level (Carpenter’s Level): A tool used to check for level.
Level A Clothing: Should be worn when highest level of respiratory, skin and eye protection is needed.
Level B Clothing: Should be worn when highest level of respiratory protection is needed, but a lesser level of skin protection.
Level C Clothing: Should be worn when the criteria for using air-purifying respirators are met.
Level D Clothing: Should be worn only as a work uniform and not on any site with respiratory or skin hazards.
Level Payment Mortgage: A mortgage with identical monthly payments over the life of the loan.
Leveling Rod: A rod with graduated marks for measuring heights or vertical distances between given points and the line of sight of a leveling instrument. They are longer than a yardstick and are held by a surveyor in a vertical position.
Leverage Activity: The actions of the state and local agencies to obtain and account for resources provided to supplement or supplant federal funding being used to weatherize dwelling units.
LFFV: See loose-fitting facepiece / visor.
LFM: Linear Feet per Minute: a measurement of air speed.
Lien: An encumbrance that usually makes real or personal property the security for payment of a debt or discharge of an obligation.
Life Cycle Analysis (LCA): The assessment of a product's full environmental costs, from raw material to final disposal, in terms of consumption of resources, energy and waste.
Life Cycle Cost (LCC) Method: A technique of economic evaluation that sums over a given study period the costs of initial investment (less resale value), replacements, operations (including energy use), and maintenance and repair of an investment decision (expressed in present or annual value terms).
Life Cycle Inventory (LCI): An accounting of the energy and waste associated with the creation of a new product through use and disposal.
Life Cycle of a Product: All stages of a product’s development, from extraction of fuel for power to production, marketing, use and disposal.
Life-Cycle Assessment: The comprehensive examination of a product’s environmental and economic effects throughout its lifetime, including raw material extraction, transportation, manufacturing, use and disposal.
Life-Support Systems: According to the World Conservation Union (IUCN), the biophysical processes “that sustain the productivity, adaptability and capacity for renewal of lands, waters, and/or the biosphere as a whole.”
Lifetime HEPA Filtration: This refers to the Dyson HEPA filter that will last the lifetime of the vacuum cleaner without requiring replacement.
Lift: The distance between the seat and disc seating surfaces when a valve is open.
Light: Electromagnetic radiation within the visible spectrum (wavelengths between approx 400-800 nm).
Light, Perceived: Universal and essential attribute of all perceptions and sensations that are peculiar to the visual system. (Notes: light is normally, but not always, perceived as a result of the action of a light simulation of the visual system.)
Light Fuel Oil (LFO): Fuel suitable for use in liquid-fuel burning equipment without preheating, primarily domestic-type burners (includes Type 0, 1 and 2). Virtually all petroleum used in internal combustion and gas turbine engines is light oil.
Light Pollution: Excess “waste” light given off by outside sources (or sources visible from the outside) at night.
Light Shelf: A daylighting strategy that allows natural light to bounce off a shelf located in a window and onto the building to bring light deep into a space.
Light-Duty Vehicle (LDV): Any motor vehicle with a gross vehicle weight of 6000 pounds or less.
Light-Emitting Diode: A long-lasting illumination technology used for exit signs which requires very little power.
Lightwell Absorption Fraction: The fraction of solar radiation that directly heats the air after it is transmitted through the glazing and after each reflection from interior surfaces. It is intended to simulate the presence of lightweight objects that absorb solar radiation and rapidly convect heat to the air.
Lignite: A brownish-black coal of low rank with high inherent moisture and volatile matter (used almost exclusively for electric power generation). It is also referred to as brown coal. Comprises two groups classified according to the following ASTM Specification D388-84 for calorific values on a moist material-matter-free basis.
Limit Control: A control used to make a change in a system, usually to stop it when predetermined limits of pressure or temperature are reached.
Limit of Detection (LOD): The lowest concentration of a substance that can reliably measured.
Limit Switch: A safety control that automatically shuts off a furnace if it gets too hot. Most also control blower cycles.
Limiting Nutrient: The nutrient in shortest supply in a particular ecosystem.
Line Losses: The amount of energy lost during transmission and distribution of electricity, including unaccounted for uses.
Line Pressure: Inlet pressure, upstream pressure. The pressure in the supply line.
Line Set: A term used for tubing sets furnished by the manufacturer.
Lineal Foot: A unit of measure for lumber equal to 1 inch thick by 12 inches wide by 12 inches long. Examples: 1” x 12” x 16’ = 16 board feet, 2” x 12” x 16’ = 32 board feet.
Linear Actuator: Air cylinder.
Linear Feet per Minute (LFM): A unit of measurement. The velocity of the air.
Liner: A continuous layer of natural or artificial materials or a continuous membrane of artificial material installed beneath or on the sides of a waste management unit, which acts as a barrier to vertical or lateral fluid movement.
Lint: Lint is nothing more than tiny bits of fiber from fabrics, plants, paper, etc. Typically, these fibers are found clumped together in the clothes dryer or maybe even in your belly button. Lint that doesn’t end up in navel nirvana can be found floating around in the air. Although not nearly as troublesome as asbestos fibers, lint fibers can sometimes cause an allergic reaction in people. Lint is removed by Nordic Pure’s MERV 12, electrostatically charged, pleat design air filters.
Lintel: A horizontal structural member that supports the load over an opening such as a door or window.
Lipid Solubility: The maximum concentration of a chemical that will dissolve in fatty substances. Lipid-soluble substances do not dissolve in water.
Liquated Damages: A monetary amount agreed upon by two parties to a contract prior to performance under the contract that specifies what either party owes the other if that party defaults under the contract.
Liquid-Applied Membrane: Generally applied to cast-in-place concrete surfaces in one or more coats to provide fully-adhered waterproof membranes which conform to all contours.
Liquid Flowrate: The amount of water or “scrubbing liquid” introduced into a wet collector.
Liquid Line: A term applied in the industry to refer to the tubing or piping from the condenser to the expansion device.
Liquid Piston: A liquid piston compressor is a rotary compressor in which a vaned rotor revolves in an elliptical casing, with the rotor spaces sealed by a ring of liquid rotating with it inside the casing.
Liquid Receiver: A container in the refrigeration system where liquid refrigerant is stored.
Liquid Ring Rotary Compressor: A liquid piston compressor is a rotary compressor in which a vaned rotor revolves in an elliptical casing, with the rotor spaces sealed by a ring of liquid rotating with it inside the casing.
Liquid State: One of three states of matter characterized by limited freedom of molecules and by substantial incompressibility.
Liquid-to-Liquid Heat Pump: A heat pump which absorbs heat from a liquid and also rejects it to a liquid.
Liquefaction: Changing a solid into a liquid.
Liquefied Natural Gas (LNG): (See Alternative Fuels.)
Liquefied Petroleum Gas (LPG): (See Alternative Fuels.)
Liquor: Material to be filtered. Also referred to as concentrate, feed influent, intake mud, prefilt, slime or sludge.
Lite: (Not the beer!) Another term for a pane of glass. Also spelled “light” in industry literature.
Litres per Minute (Lpm): A measure of flow rate expressed in metric units.
Live Load: Loads produced by use and occupancy of the building or other structure and do not include construction or environmental loads such as wind load, snow load, ice load, rain load, seismic load, or dead load.
Live Steam Sterilization: Sterilization by flowing saturated steam through a vented vessel or system, usually at 257ºF and 20 psi (Can be performed up to 284ºF and 35 psi.).
Livermore Water Reclamation Plant (LWRP): City of Livermore’s municipal wastewater treatment plant, which accepts discharges from the LLNL Livermore site.
Living Will: A legal document in which you can state what kind of medical care you desire to receive or what life-support procedures you would like to withhold if you became physically or mentally unable to communicate your wishes.
LMDC (Lower Manhattan Development Corporation): In collaboration with city, state, and federal agencies and civic organizations, it develops and sponsors programs and resources to enhance the quality of life in post-9/11 lower Manhattan. www.renewnyc.com
Load: See heat load.
Load Bearing Wall: A wall which is supporting its own weight and some other structural elements of the house such as the roof and ceiling structures.
Load Calculation: Assessed by a dealer, the calculation factors in a number of criteria in your home (square footage, number of windows, year-round weather concerns) and determines what size components you should include as part of your total comfort system.
Load Collector Ratio (LCR): The ratio of the building load coefficient to the projected area.
Load Estimate: A series of studies performed to determine the heating or cooling requirements of your home. An energy load analysis uses information such as the square footage of your home, window or door areas, insulation quality and local climate to determine the heating and cooling capacity needed by your furnace, heat pump or air conditioner. When referring to heating, this is often known as a Heat Loss Analysis, since a home’s heating requirements are determined by the amount of heat lost through the roof, entry ways and walls.
Load Factor: The ratio of actual mean load to a maximum load of maximum production capacity in a given period.
Loaded: A filter element that has collected a sufficient quantity of insoluble contaminates such that it can no longer pass rated flow without excessive differential pressure.
Loading: This term refers to the accumulation of particles in a filter in a vacuum cleaner or air purifier. As a filter loads its efficiency gradually decreases until it reaches the point where replacement is necessary.
Loan: The amount to be borrowed.
Loan to Value Ratio: The ratio of the loan amount to the property valuation and expressed as a percentage; e.g. if a borrower is seeking a loan of $200,000 on a property worth $400,000 it has a 50% loan to value rate. If the loan were $300,000, the LTV would be 75%. The higher the loan to value, the greater the lender's perceived risk. Loans above normal lending LTV ratios may require additional security.
Lobe: A type of journal bearing in centrifugal air compressors.
Local Agency: Also referred to as the sub grantee, contractor, service delivery network member, or local service provider, a local agency is a nonprofit organization or unit of local government responsible for providing WAP services in a specified political subdivision.
Local Exhaust Ventilation: A ventilation system that captures and removes the contaminants at the point they are being produced before they escape into the workroom air
Lock Up: Device that will lock either a column, elements or the body of a housing in place.
Log Reduction Value: The logarithm to the base of 10 of the ratio of organisms in the feed to the organisms in the filtrate. Example: Log 1o [10 9/101.7] = 7.3. Also used as a ratio of in/out bioburden in other sterilization methods such as autoclaving.
Long-wave Radiation: Radiation emitted between roughly 5000 and 30000 nm wavelength, as in thermal radiation from the surfaces of a room, or from the outside surface of the roof.
Longitude: The arc of the equator between the meridian of a place and the Greenwich meridian measured in degrees east or west.
Longitudinal Sampling: A method of sampling a population in which a large number of comfort votes is sought from each of relatively few subjects (cf Transverse sampling).
Lookout: A short wood bracket or cantilever to support an overhang portion of a roof or the like, usually concealed from view.
Loose-fitting Facepiece / Visor (LFFV): The portion of a respirator that forms a partial seal with the face, does not cover the neck and shoulders and may or may not offer head or eye protection; see inlet covering; refer to CSA Z94.4 for the definition.
Loose Laid: In roofing, a membrane “laid loosely,” i.e. not adhered, over a roof deck or Burm.
Lot: A parcel of ground with boundaries determined by the county.
Louver: An opening with a series of horizontal slats arranged so as to permit ventilation but to exclude rain, sun. light, or vision. See also Attic Ventilators.
Louvre (system): An assembly of sloping vanes intended to permit air to pass through and to inhibit transfer of water droplets. Also used as an solar control, either external to the building or internally (e.g. venetian blinds).
Low Biocide: Paint that does not contain toxic additives, such as fungicide or pesticide.
Low Boy: Low Boy is a type of furnace configuration in which the furnace is lower in height and occupies more floor space.
Low Emission Vehicle (LEV): A vehicle that meets the ARB’s low emission vehicle standards.
Low Emission Vehicle II (LEV II): California exhaust emission standards for 2004 and subsequent model passenger cars, light-duty trucks and medium-duty vehicles.
Low Energy Building: A very good insulated and passive solar building, with a very low remaining heating and cooling demand.
Low Interfacial Tension: Where the interfacial tension of one liquid over the other liquid would be less than 25 dynes/cm at 70 degrees F.
Low NOx Burners: One of several combustion technologies used to reduce emissions of nitrogen oxides.
Low Pressure Coat: In spray painting, the process of applying the final coat of paint at a lower air pressure. Used to uniform a finish or blending.
Low Pressure Drop High Efficiency Air Filters: Extended surface pleated air filters that allow greater air filtration without a significant increase in horsepower requirements.
Low Risk (biosafety level 2): Risk level of agents and/or operations having minimal effect on personnel, animals or plants under ordinary use.
Low Water Cutoff: A float-operated control for turning the burner off if a steam boiler is low on water.
Low-E: Short for “low emissivity,” which means the characteristic of a metallic glass coating to resist the flow of radiant heat.
Low-e Glass: Glazing with a low thermal transmittance (U-value), due to a heat reflecting coating(s) applied in the gap of double glazing. The applied coatings are visually transparent.
Low Emissivity Windows: Windows with special coatings that transmit most of the sun's light but block heat radiation from passing through.
Low-Emittance (Low-E) Windows: Windows with a thin, invisible, metallic coating on one or more glazing surfaces that reduces the radiation of heat from windows. Low-e glass has a thin, invisible coating that reduces the flow of radiant heat through windows. The most common coating reduces solar heat gain and increases resistance to radiant heat loss through windows.
Low-flow Toilet: A toilet that uses less water than a traditional unit, therefore lowering costs by using water more efficiently.
Low-level Waste: Waste defined by DOE Order 5820.2A, which contains transuranic nuclide concentrations less than 100 nCi/g.
Low-pressure Drop Air Filers: High-efficiency air filters with an extended surface, which allows for more filtration without an increase in horsepower.
Low-Slope Application: Method of installing asphalt shingles on roof slopes between 2 and 4 inches per foot.
Lower Explosive Limit (LEL): The lower limit of flammability of gas, vapor, or dust or any combination of these at ambient temperatures. For gases and vapors, this is expressed as a percentage in air by volume. For dusts, this is expressed as weight of dust per volume of air.
Lower Flammable Limit (LFL): The least amount of a flammable vapor or gas that will support combustion when mixed with air. The LFL is usually expressed in volume per cent. Mixtures that contain less than the LFL of a material are too lean to burn.
Lower Limit of Detection: Smallest concentration or amount of analyte that can be detected in a sample at a 95% confidence level.
Lowest Achievable Emission Rate (LAER): Under the Clean Air Act, the most stringent emission limitation derived from either (1) the most stringent emission limitation in the implementation plan of any state for such source or category of source; or (2) the most stringent emission limitation achieved in practice by such class or category of sources.
Lowest Observed Adverse Effect Level (LOAEL): The lowest level of a stressor that causes statistically and biologically significant differences in test samples as compared to other samples subjected to no stressor.
Lox Cleaning: Process of cleaning for liquid oxygen service.
Lpm: See litres per minute.
LSCHP: Laboratory Safety and Chemical Hygiene Plan.
Lubrication: A material (such as oil) used between moving parts of machinery to make the surfaces slippery and reduce friction.
Lubricator: An instrument designed to add lubrication into the compressed air line.
Lubricity: A measure of the ability of an oil or other compound to lubricate (reduce friction) between two surfaces in contact.
Lumbar: The section of the lower vertebral column, immediately above the sacrum. Located in the small of the back and consisting of five large lumbar vertebrae. It is a highly stressed area in work situations and in supporting the body structure.
Lumber: The product of the sawmill and planing mill not further manufactured other than by sawing, re-sawing, and passing lengthwise through a standard planing machine, crosscutting to length, and matching.
Lumen (lm): SI unit of luminous flux: luminous flux emitted in unit solid angle (steradian) by a uniform unit source having a luminous intensity of 1 candela. Equivalent definition: luminous flux of a beam of monochromatic radiation whose frequency is 540 x 1012 hertz and whose radiant flux is 1/683 watt.
Luminance: The physical measure of the brightness of a surface such as a lamp, a reflecting material or the sky in a given direction. Luminance is the luminous intensity emitted by an area of a surface. Units : candela per square meter (cd/ m2).
Luminous Efficacy of Radiation: Quotient (K) of the luminous flux by the corresponding radiant flux.
Luminous Environment: Lighting considered in relation to physiological and psychological effects.
Luminous Flux: Quantity derived from radiant flux evaluating the radiation according to its action upon the CIE stand photometric observer.
Luminous Intensity (of a source in a given direction): Quotient of the luminous flux dFv leaving the source and propagated in the element of solid angle containing the given direction, by the element of solid angle.
Lung Transplantation: A surgical procedure in which a healthy lung from a donor replaces the recipient’s unhealthy lung. Lung transplant as a treatment option for COPD is reserved for carefully selected patients.
Lung Volume: See total lung capacity.
Lung Volume Reduction Surgery: Surgery in which damaged areas of the lungs are removed so the remaining portion of the lungs can function better. Lung volume reduction surgery is performed only for people with certain types of COPD, and after careful testing and evaluation.
Lux (SI unit of illuminance): Illuminance produced on a surface, area 1 square meter by a luminous flux of 1 lumen uniformly distributed over that surface lm/m2. Latex: Pronunciation (lā′teks). (1.) An emulsion or suspension produced by some seed plants; it contains suspended microscopic globules of natural rubber. (2.) Similar synthetic materials such as polystyrene, polyvinyl chloride, etc. [L. liquid].
LVP: Large Volume Parenteral. Intravenous injection packaged in containers of 100 – 1000 mL used to correct electrolytic imbalances, replace body fluid and provide general nutrition.
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