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I/O Input/Output.

IARC International Agency for Research on Cancer.

ICE MELTING EQUIVALENT The amount of heat absorbed by one pound of ice at 32 F in liquefying to water at 32 F, 144 Btu.

IDENTIFY To determine the exact chemical nature of a hazardous polluting substance.

IDENTITY Any chemical or common name which is indicated on the MSDS for the chemical. The identity used shall permit cross-references to be made among the required list of hazardous chemicals, the label, and the MSDS.

IGNITABLE A solid, liquid, or compressed gas waste which exhibits a "characteristic of ignitability," as defined by RCRA, may be regulated (by U.S. EPA) as a hazardous waste.

IMMINENT FAILURE A deformed or altered condition, such as bulges or sever pitting which will lead to a failure in a short period of time.

IMMUNE A state of existence that renders an organism safe from attack by an aggressor.

IMMUNOSUPPRESSIVE THERAPY Medical therapy that suppresses the body’s ability to reject foreign substances, such as transplanted organs and bacteria.

IMPACT (1) An impact is a single collision of one mass in motion with a second mass which may be either in motion or at rest. (2) Impact is a word used to express the extent or severity of an environmental problem; e.g., the number of persons exposed to a given environment.

IMPERVIOUS Impenetrable, with reference to a film or coating. Indicates ability to keep water away form a metal surface.

IMPINGEMENT ATTACK A form of corrosion in which velocity negatively affects the protective copper oxide film, causing increased metal loss.

IMPULSE FORCE A force exerted in the same direction as the direction in which the body exerting the force is moving.

INCIDENCE OF FUNGI In our Microbiological Laboratory this term designates an arbitrary rating given to the prevalence of fungus hyphae in the tracheids and ray cells of the wood under observation. The following ratings are used. 0 none + sparse 1 low 2 moderate 3 high 4 very high

INCLUSIONS Particles of impurities, usually oxides, sulfides and silicates, that are held mechanically, formed during solidification, or formed by subsequent reaction within the solid metal.

INCOMPATIBLE Materials which could cause dangerous reactions from direct contact with one another are described as incompatible.

INCUBATION The act of growing cultures within a controlled environment.

INDIRECT DESUPERHEATING Lowering superheated steam by removing heat from the steam.

INDUCED AIR FLOTATION Processes that use atmospheric air to float light solids to the surface.

INDUCED DRAFT Unit with the air mover on top of the tower pulling the air up through the fill and out through the top, normally by an axial fan. In Mechanical Draft Towers, and Atmospheric Towers.

INFILTRATION Inleakage of groundwater into sewage piping.

INFLUENT The solution which enters an ion exchange unit.

INFLUENT WATER Water which enters a plant water system.

INGESTION The swallowing of a substance in the form of an gas, vapor, fume, mist, or dust.

INHALATION The breathing of vapors, gases, mists, aerosols, fumes and/or dusts.

INHIBITOR Refers to material or materials in water solutions that prevent or minimize corrosion.

INJECTION QUILL Specialized nozzle that extends into the center of a water line and is used to inject chemicals into the water flow insuring good mixing.

INLET AND OUTLET VALVE Is a gate valve on the inlet or outlet piping of a water conditioner.

INLET CONNECTION (Inlet Flange) Fitting to which the circulating water supply piping is connected to serve the tower distribution system.

INSTALLATION SEQUENCE Sometimes it is necessary to install more than one piece of water conditioning equipment to properly condition the untreated water. When this is necessary, it is imperative for the equipment to be installed in the proper sequence to insure satisfactory operation.

INSULATION, THERMAL Substance used to retard or slow flow of heat through wall or partition.

INTERCOOLING Removal of heat from compressed gas between compression stages.

INTERGRANULAR (INTERCRYSTALLIINE) Occurring between the grains or crystals of a material.

INTERGRANULAR CORROSION Type of corrosion that progresses preferentially along the grain boundaries of a metal. Attack usually occurs because the grain boundary regions contain material anodic to the central regions of the grains. Caustic embrittlement and hydrogen embrittlement cause this form of attack.

INTERGRANULAR CRACKING Cracks or fractures which follow along the grain boundaries in the microstructure of metals and alloys.

INTERLOCK With two or more units, automatically regenerated by a signal from a water meter, counter or sensor, it is possible that all units may be in regeneration at the same time. To avoid having no soft water available, an electrical "interlock" will delay the signal until another unit has returned to service.

INTERMITTENT FEED Feed of chemicals at separate, generally set intervals. Not continuous.

INTERNAL DECAY That type of decay which is restricted to the internal areas of the wood. The decay produced may be stringy, cubical, pocket or delaminated. The causal organism of this type are not necessarily restricted to the interior or any member. This type of decay is characteristic of the species of fungi in the class Basidiomycetes.

INTERSTICES Openings or voids between the beads of resin or pieces of gravel. Interstices are normally filled with water but can be filled or partially filled with fines or foreign matter, thus adversely affecting distribution and pressure drop.

ION An atom or radical in solution carrying an integral electrical charge either positive (cation) or negative (anion).

ION EXCHANGE A reversible process whereby ions are exchanged between a solid and a liquid with the solid undergoing no substantial physical change.

ION FLOW-THROUGH The ability of a chemical program to move the primary deposit formers - calcium, iron, and magnesium - through a boiler

ION STRENGTH A measure of the strength of a solution based on both the concentrations and valences of the ions present.

IONIC BOND One or more electrons transfer from the valence shell of one atom to the valence shell of another atom.

IONIZATION The dissociation of molecules into charges particles.

IONIZATION CONSTANT An expression in absolute units of the extent of dissociation into ions of a chemical compound in solution.

IRON A metal of construction widely used in coming water systems.

IRON BACTERIA A specific group of bacteria that convert ferrous iron to ferric iron. The organisms frequently form filaments surrounded by a sheath containing precipitated ferric hydroxide and use oxygen as a terminal electron acceptor.

IRON FOULING When iron accumulates in or on the resin, the capacity is reduced and the resin is "iron-fouled".

IRON OXIDES A reaction product of iron with orthophosphate. Sometimes active as a barrier type inhibitor.

IRON PHOSPHATE A reaction product of iron with orthosphosphate. Sometimes active as a barrier type inhibitor.

IRON ROT Deterioration of wood in contact with iron, a problem associated with iron fastenings, or other iron-wood assembly junctures.

IRRITANT A chemical substance or mixture which is not corrosive but which causes a reversible inflammatory effect on living tissue by chemical action at the site of contact.

ISOKINETIC FLOW A condition where steam flow is in equilibrium at the nozzle and header.

ISOTONIC A water solution containing salts at the same concentration as found within a cell. The use of an isotonic solution allows for the dilution of suspected samples prior to incubation, resulting in minimal cell death and allowing for an accurate count of living cells.

J

JACKETING A containment for temperature control of or heat absorption from a confined bath or fluid stream.

JACKSON CANDLE TURBIDITY An empirical measure of turbidity based on the measurement of the depth of a column of water that is just sufficient to extinguish the image of a burning standard candle observed vertically.

JAR TEST Testing clarification chemicals and techniques on a jar-sized sample of raw water.

JOISTS (or Beam) Framework member; a horizontal support for live and dead loads such as fan decks, drift eliminators, elevated basins, piping. One of a series of parallel beams used to support floors or decking and supported in turn by larger beams.

K

KIDNEY TOXIN A chemical that causes kidney damage or alters kidney function. Technically called a nephrotoxin.

KILOGRAIN A unit of weight equal to 1000 grains.

KILOMETER A metric unit of linear measurement = 1000 meters.

KILOWATT Unit of electrical power, equal to 1000 watts.

KRAFT Alkaline chemical pulping process, using salt cake as makeup.

L

L Liter; a metric unit of capacity, A U.S. quart is about 9/10 of a liter.

LAMINAR FLOW Non-turbulent water flow.

LAMINATIONS Metal defects with separation or weakness that is aligned parallel to the surface of the metal.

LAN Local Area Network

LAND ACID DEW POINT METER In boiler systems, a device usually placed in the duct work between the economizer and air preheater that measures the potential for cold end corrosion.

LANGELIER’S INDEX A technique of predicting whether water will tend to dissolve or precipitate calcium carbonate. If the water precipitates calcium carbonate, scale formation may result. If the water dissolves calcium caronate, it has a corrosive tendency. To calculate Langelier’s Index, the actual pH value of the water, and Langelier’s saturation pH value (pHs) are needed. Langelier’s saturation pH value is determined by the relationship between the calcium hardness, the total alkalinity, the total solids concentration and the temperature of the water. Langelier’s Index is then determined from the expression PH-pHs.

LANGELIER SATURATION INDEX An index used to predict the scaling or nonscaling characteristics of a water. A plus value indicates scale forming tendency; a negative value is nonscaling. The index is the algerbraic difference between the actual pH from test and the calculated pH of saturation for calcium carbonate, CaCO₃.

LATENT HEAT Heat energy absorbed in process of changing form of substance (melting, vaporization, fusion) without change in temperature or pressure.

LATENT HEAT OF EVAPORATION The heat necessary to overcome the attractive forces between water molecules in the liquid state. This heat, about 1000 BTU/lb, is removed from the liquid water remaining, lowering the water temperature.

LATERAL HEADER (Counterflow Tower) A pipe or flume to distribute water from the distribution header to nozzles or other points of discharge to the filling area.

LC Lethal Concentration; the concentration of a substance being tested that will kill a test animal.

LC₅₀ Lethal Concentration; the concentration of a material in air which on the basis of laboratory test has been shown to kill 50 percent of a group of test animals when administered as a single exposure (usually 1 or 4 hours). The LC₅₀ is expressed as parts of material per million parts of air, by volume (ppm) for gases and vapors, or as micrograms of material per liter of air (mg/L) or milligrams or material per cubic meter of air (mg/M³) for dusta and mists, as well as for gases and vapors.

LD Lethal Dose; a concentration of a substance being tested to kill a test animal.

LD₅₀ Median lethal concentration maintained for a given period of time that will kill on-half (50%) of a group of test animals, using a specified test produce. (Expressed in mg/L, ppm or mg/m³.)

LD₅₀ Median lethal dose needed to kill on-half (50%) of the group of test animals, using a specified test procedure. (Expressed in mg/kg.)

LCD Liquid Crystal Display.

LE CHATELIER’S PRINCIPLE An increase in temperature at constant pressure causes an equilibrium to be displaced in the direction in which it absorbs heat, i.e., and equilibrium will always be displaced in such a way as to minimize a change from the outside.

LEACHED This loss of extractives from the wood, either hot water, cold water or organic extractibles. In the case of cooling towers it will usually pertain to the warm and cold water extractibles -usually the simple sugars, color, etc.

LEACHING The act of extracting a soluble constituent from a material by dissolving action of water.

LEAK DETECTOR Device or instrument such as a halide torch, an electronic sniffer; or soap solution used to detect leaks.

LEAKAGE The presence in the effluent of a species of ions in the feed to an ion exchanger.

LED Light-Emitting Diode

LEGIONELLA The name given to a genus of bacteria, a serogroup of which was responsible for the deaths of American Legion members during a convention in Philadelphia, PA in 1976, from whence it obtained its name.

LEGIONELLA-LIKE Species of bacteria that resemble Legionella in growth, size, chemical staining and other characteristics but are not Legionella.

LEGIONELLA PNEUMONIA Pneumonia caused by a type of Legionella other than L. pneumophila, serogroup 1.

LEGIONELLA PNEUMOPHILA SEROGROUP 1. The species of Legionella implicated in many deaths worldwide. Found in more lung tissues after death than other Legionella species or serogroup.

LEGIONELLOSIS Illness caused by all Legionella.

LEGIONNAIRES’ DISEASE A sometimes fatal disease caused by L. pneumophila, serogroup 1.

LEL, OR LFL Lower Exposure Limit or Lower Flammable Limit of a vapor or gas; the lowest concentration (lowest percentage of the substance in air) that will produce a flash of fire when an ignition source (heat, arc, or flame) is present. At concentrations lower than the LEL, the mixture is too "lean" to burn. Also see "UEL."

LEUKOCYTE See White Blood Cells

LIGNIN Substance forming an essential part of wood. Constitutes the binder of wood structure.

LIME A common water treatment chemical. Limestone, CaCO₃, is burned to produce quicklime, CaO, which is mixed with water to produce slaked, or hydrated, lime, Ca(OH)₂.

LIME CONTROL NUMBER A value indicating the excess hydroxide in a treated water sample.

LIMESTONE A common rock of the earth composed primarily of calcium. It combines with carbon dioxide in ground water to form calcium carbonate and causes hardness.

LIMIT CONTROL Control used to open or close electrical circuits as temperature or pressure limits are reached.

LIMIT STOPS Several types of deaphragm valves have adjustments to control flow rates. They may be used on the backwash, fast rinse or brine dilution valves when brine is pumped.

LIMIT TIMER A user settable timer on a controller that times out a preset point. Used primarily for bleed and chemical feed.

LINE NOISE Any extraneous signal or noise occurring on a transmission line which tends to obscure or interfere with the desired signal.

LIPOPHILIC Having an affinity for oil. The opposite of hydrophilic; (i.e., hydrophobic).

LIQUID END The wetted parts of metering pump.

LIQUID INDICATOR Device located in liquid line which provides a glass window through which liquid flow may be observed.

LIQUID LINE The tube or pipe carrying the refrigerant liquid from the condenser or receiver of a refrigerating system to a pressure-reducing device.

LIQUID RECEIVER A vessel permanently connected to a system by inlet and outlet pipes for the storage of (condensed) refrigerant.

LIVER TOXIN A chemical that causes liver damage or alters liver functions. Technically called hepatotoxin.

LOAD 1. Reading a computer program or data from external storage and storing it in a computer’s RAM. 2. Any component, circuit, subsystem, or system that consumes power desired signal.

LOAN The time-rate of heat flow imposed on a refrigerating system or the required rate of heat removal.

LOAN FACTOR The load factor is the ratio of the cooling load in the current case to the base case.

LOCAL EXHAUST A system for capturing and exhausting contaminants from the air at the point where the contaminants are produced (welding, grinding, sanding, other processes, or operations). Also see "general exhaust."

LOG MEAN TEMPERATURE DIFFERENCE The log mean temperature difference is the average temperature difference between the hot and cold fluids of a shell and tube heat exchanger.

LONGITUDINAL Always measured parallel to air intakes and perpendicular to air flow.

LOUVER Baffles used for the purpose of changing the direction of air flow in a uniform parallel manner. Also utilized to prevent water droplets from splashing out of the tower on their descent through the structure.

LOW SALT See "High Salting".

LOW SIDE Parts of a refrigerating system at or below evaporator pressure.

LOW SIDE FLOAT VALVE Refrigerant control valve operated by level of liquid refrigerant in low pressure side of system.

LOW SIDE PRESSURE Pressure in cooling side of refrigerating cycle.

LOW SIDE PRESSURE CONTROL Device used to keep low side evaporating pressure from dropping below certain pressure.

LPD Liters per day.

LUMBER, BOARD Wood that is nominally less than 2" thick and two or more inches wide.

LUMBER, DRESSED SIZE The dimensions of lumber after being surfaced with a plaining machine. The dressed size is usually 1/2" to 3/4" less than a nominal or rough size.

LUMBER, NOMINAL SIZE As applied to timber or lumber, the size by which it is known and sold in the market; which differs from the actual or dressed size.

LUMBER, ROUGH Lumber which has not been dressed (surfaced) but has been sawed, edged, and trimmed.

LUMBER, SHIPLAPPED Lumber that is edged dressed to make a lapped joint produced by placing one member partly over another and bonding the overlapped portions.

LUMBER, TIMBERS, BEAMS Lumber that is nominally 5" or more in least dimension.

LUNG TOXIN A chemical that damages lung tissue or causes a decrease in lung function.

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