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E COLI One of the coliform group of bacteria. The presence of E. coli in water is indicative of fecal contamination.

ECOLOGY The science of the interrelationship between living organisms and their environment.

ECONOMIZER A heat exchanger in a furnace stack that transfers heat from the stack gas to the boiler feedwater.

EDTA Ethylenediaminetetraacetic acid - a chelating agent widely used as a reagent in hardness determination.

EDUCATOR The mechanical arrangement for the removing of a gas or a liquid from a system by means of a high velocity flow of another gas or water stream through an orifice, etc.

EFFECTIVE AREA Actual flow area of an air inlet or outlet. Gross area minus area of vanes or grille bars.

EFFICIENCY The effectiveness of the operational performance of an ion exchanger. Efficiency in the adsorption of ions is expressed as the quantity of regenerant required to effect the removal of a specified unit weight of adsorbed material, e.g., pounds of acid per kilogram of salt removed.

EFFLUENT Something that flows out, such as a liquid discharged as a waste; for example, the liquid that comes out of a treatment plant after completion of the treatment process.

EFFLUENT LAUNDERS Devices that collect clarified water for discharge.

EFFLUENT WATER Water which leaves a plant water system.

EJECTOR The device used to draw brine from the brine tank into the softener tank, utilizing water pressure as the driving force.

ELASTIC LIMIT Maximum stress that a material will withstand without permanent deformation.

ELECTRICAL CONDUCTIVITY The reciprocal of the resistance in ohms measured between opposite faces of a centimeter cube of an aqueous solution at a specified temperature.

ELECTRICAL COST The electrical cost is the cost of providing electrical energy. If the average electrical cost includes power factor penalties, then a power factor of 1 should be used in electrical energy calculations.

ELECTROCHEMICAL A chemical action that requires the transfer of electrons between anodes and cathodes in an electrolytic solution.

ELECTRODIALYSIS A process by which electricity attracts or draws the mineral salts from sewage.

ELECTROLYTE A substance which dissociates into positive and negative ions when dissolved in water, making it a conductor of electric current.

ELECTROMAGNET Made by winding coil of wire around soft iron core. When electric current is run through wire, coil becomes a magnet.

ELECTROMOTIVE FORCE The driving force that causes electrons to flow through the external circuit in a voltaic cell. Also known as the voltage or cell potential.

ELECTRONICS Field of science dealing with electron devices and their uses.

ELECTRONS Minute negatively charges particles.

ELECTROSTATIC FILTER Type of filter which gives particles of dust electric charge. This causes particles to be attracted to plate so they can be removed from airstream or atmosphere.

ELECTROSTATIC PRECIPITATOR (ESP) A device used in boilers to separate dust from flue gas.

ELIMINATOR BOARD The smallest component in a wood drift eliminator assembly which is usually installed in a fixed position at an angle to the direction of air flow. Also known as Eliminator Baffle (Blade).

ELUTION The stripping of adsorbed ions from an ion exchange material by the use of solutions containing other ions in relatively high concentrations.

ELUTRIATION The washing of a sludge with water to free it of its mother liquor.

EMBRITTLEMENT Lowering of normal metal ductility due to physical or chemical change.

EMPLOYEE A worker employed by an employer in a workplace in SIC Codes 20 through 39 who may be exposed to hazardous chemicals under normal operating conditions or foreseeable emergencies, including, but not limited to, production workers, line supervisors, and repair or maintenance personnel. Office workers, grounds maintenance personnel, security personnel or nonresident management are generally not included unless their job performance routinely involves potential exposure to hazardous chemicals.

EMULSION A colloidal dispersion of one liquid in another.

ENCLOSED FAN COOLED MOTOR An enclosed motor equipped for exterior cooling by means of a fan or fans, integral with the motor but external to the enclosing parts.

ENCLOSED MOTOR An enclosed motor is one so enclosed as to prevent exchange of air between the inside and the outside of the case, but not sufficiently enclosed as to be termed air-tight.

END WALL The wall on the end of the tower structure.

ENDOTHERMIC Absorbing heat.

ENRICHMENT The addition of nitrogen, phosphorus, carbon compounds and other nutrients into a waterway that increases the growth potential for algae and other aquatic plants. Most frequently, enrichment results from the inflow sewage effluent or from agricultural runoff.

ENTHALPY Thermodynamic property of a substance, defined as the sum of its internal energy plus the quantity pv/J, where P = pressure of the substance, v = its volume, and J = the mechanical equivalent of heat. Formerly called by the obsolescent names total heat and heat content.

ENTHALPY OF EVAPORATION The heat added to the unit weight of water at the saturation temperature causing it to vaporize completely and produce dry saturated steam. Also known as the heat of vaporization.

ENTHALPY OF LIQUID The heat used to raise a unit weight of water from 32° F to the saturation temperature corresponding to the pressure.

ENTHROPY A mathematical expression applying to the limits to the availability of energy; a measure of the random motion of matter.

ENTRAINMENT The transport of water into a gas stream. In a boiler, this is carryover; in a cooling tower, drift.

ENVIRONMENT The physical environment of the world consisting of the atmosphere, the hydrosphere, and the lithosphere. The biosphere is that part of the environment supporting life and which is important to man.

ENVIRONMENT The surroundings or conditions of a system. In cooling water, this may refer to the water itself, and the chemical and physical factors effective therein.

ENZYME A chemical produced by living cells having the ability to reduce large organic molecules to units small enough to diffuse through the cell membrane.

EP TOXICITY Extraction Produced toxicity, as defined by EPA hazardous waste regluations, 21 CFR 261.24.

EPA Environmental Protection Agency.

EPDM Ethylene propylene terpolymer

EPIDEMIOLOGY The science that deals with the study of disease in a general population. Determination of the incidence (rate of occurrence) and distribution of a particular disease (as by age, sex, or occupation) may provide information about the cause of the disease.

EPROM Erasable Programmable Read-Only Memory.

EQUALIZATION Minimization of variations in flow and composition by means of a storage reservoir.

EQUALIZER TUBE Device used to maintain equal pressure or equal liquid levels between two containers.

EQUILIBRIUM REACTIONS The interaction of ionizable compounds in which the products obtained tend to revert to the substances from which they were formed until a balance is reached in which both reactions and products are present in definite ratios.

EQUIVALENT PER MILLION (epm); A unit chemical equivalent weight of solute per million unit weights of solution. Concentration in equivalents per million is calculated by dividing concentration in parts per million by the chemical combining weight of the substance or ion. NOTE: This unit has also been called "milliequivalents per liter" and "milligram equivalents per kilogram." The latter term is precise, but the former will be in error if the specific gravity of the solution is not exactly 1.0.

EQUIVALENT WEIGHT The atomic or formula weight of an ion or radical divided by its valence.

EQUIVALENT, CHEMICAL The weight in grams of a substance which combines with or displaces one gram hydrogen; usually obtained by dividing the formula weight by the valence.

EQUIVALENTS PER MILLION The equivalents of a substance in every million grams of water.

ERODED The affect produced by the washing and/or wearing away of the thin walled cells (usually springwood) from the exposed surfaces of the wood. The remaining ridges of summerwood produce a ridged or washboard effect. Erosion is purely a mechanical or physical effect. However, the cells may become weakened as a result of chemical or biological attack.

EROSION The wearing away by action of rapidly moving water, particularly where entrained gas bubbles or suspended abrasive solids are present.

EROSION-CORROSION The increase in the rate of metal deterioration from abrasive effects, increased by high water velocities and suspended solids.

ESSENCE VITAE A substance necessary for cell life, which if missing, will prevent an organism from proliferating.

ESTUARY Commonly an arm of the sea at the lower end of a river. Estuaries are often enclosed by land except at channel entrance points.

ETCHING In metallography, the process of revealing grain structural details by the attack of reagents on a metal surface. For mild steel, 2% nitric acid in ethyl alcohol (Nital) and 4% picric acid in ethyl alcohol (Picral) are often used.

EUTROPHIC WATERS Waters with a good supply of nutrients. These waters may support rich organic productions, such as algal blooms.

EUTROPHICATION Enrichment of water, causing excessive growth of aquatic plants and an eventual chilling and deoxygenation of the water body.

EVAPORATION Change of state from liquid to vapor.

EVAPORATION LOSS Water evaporated from the circulating water into the atmosphere by the cooling process.

EVAPORATION RATE The rate at which water is being evaporated in a system, expressed as a given mass or volume per unit of time.

EVAPORATIVE CONDENSER A device which uses open spray or spill water to cool a condenser. Evaporation of some of the water cools the condenser water and reduces water consumption.

EVAPORATIVE COOLING Heat transfer where a liquid condenses into its gaseous state thereby giving up latent heat. The simplest example of this basic premise of cooling tower operation: wet the back of your hand then blow on the wetted surface. The drop in temperature on your skin is due to evaporative condensation.

EVAPORATOR The evaporator is the heat exchanger which removes heat from the cooling load and transfer it to the refrigerant by the evaporation of the liquid refrigerant.

EXCESS AIR The amount of air used in excess of the theoretical precise amount of air necessary to sustain combustion.

EXCHANGE CAPACITY Weight quantity of ions removed per Unit Volume of swollen resin. Expressed in terms of Kilograins as CaCO₃ per cubic foot of resin. 7 Kilograin = 1 pound.

EXCHANGE VELOCITY The rate at which one ion is displaced from an exchanger in favor of another.

EXCHANGER SITE Each tiny resin bead has a multitude of pores or exchange sites on its surface as well as inside the bead. Each site has ion-exchange properties.

EXFOLIATION Form of corrosion that parallels the surface of the metal, causing elevated layers of the metal by the formation of corrosion products. This type of corrosion is commonly found in cupro-nickel alloys and aluminum.

EXHAUST AIR The mixture of air and its associated vapor leaving the tower.

EXHAUST WET-BULB TEMPERATURE Average wet bulb temperature of the air discharged from the tower.

EXHAUSTED When the resin has reached the limit of its capacity to remove hardness, and requires regeneration, it is termed, "exhausted".

EXHAUSTION The state in which the resin is no longer capable of useful ion exchange; the depletion of the exchanger’s supply of available ions. The exhaustion point is determined arbitrarily in terms of : (a) a value in parts per million of ions in the effluent solution; (b) the reduction in quality of the effluent water determined by a conductivity bridge which measures the electrical resistance of the water.

EXIT BASIN TEMPERATURE Temperature of the circulating water leaving the cold water basin. If blowdown is removed from or make-up added to the basin, the temperature will be affected accordingly.

EXIT DIAMETER (Natural Draft Tower) Diameter of the shell at the top.

EXOTHERMIC Evolving heat.

EXPANDED SCALE THERMOMETERS A thermometer that has a limited temperature range; e.g. 20° F over the entire thermometer.

EXPANSION VALVE A device in refrigerating system which maintains a pressure difference between the high side and low side and is operated by pressure.

EXPLOSION-PROOF MOTOR An enclosed motor whose enclosure is designed and constructed to withstand the explosion of a specified gas or vapor which may occur within it and to prevent the ignition of the specified gas or vapor surrounding the motor by sparks, flashes or explosions of these specified gas or vapor which occur within the motor casing. Class I, Group C & Group D.

EXPLOSIVE LIMITS The range of concentrations over which a flammable vapor mixed with proper proportions of air will flash or explode if an ignition source is present.

EXTERNAL EQUALIZER Tube connected to low pressure side of an expansion valve diaphragm and to exit of evaporator.

EXTRACTIVES Generally refers to those natural substances in wood that are soluble in water and therefore can be dissolved out.

EXTRAPOLATE To project data into an area not known or experienced, and arrive at knowledge based on inferences of continuity of the data.

F

FACULTATIVE ANAEROBE An organism that although fundamentally an anaerobe can grown in the absence of free oxygen.

FACULTATIVE DECOMPOSITION Decomposition of organic matter by facultative microorganisms.

FACULTATIVE ORGANISMS Microbes capable of adapting to either aerobic or anaerobic environments.

FAHRENHEIT A thermometric scale in which 32 degrees denotes freezing and 212 degrees the boiling point of water under normal pressure at sea level (14.696 psi).

FALSE BOTTOM A steel plate horizontally welded near the bottom of a softener tank. The plate is often drilled and tapped or half couplings are welded in to receive strainer nozzles.

FALSE BOTTOM An additional surface provided in the vessel that supports the resin bed in an ion exchange vessel. The underdrain distribution system could be either embedded or placed over this surface.

FALSE FLOORING Condition occurring in cold lime softeners due to the cementation of precipitated hardness comounds.

FAN An air foil rotating to move air through a cooling tower normally parallel to the axis of the fan shaft.

FAN DECK Surface enclosing the top of an induced draft tower. In a counterflow tower, the fan deck covers the entire top surface of the tower. In a crossflow tower, the fan deck covers only the tower plenum area, leaving the distribution system exposed. An extended fan deck encloses the distribution system and covers the entire top surface of the tower, except of course, the cut for fan diameter.

FAN DRIVE ASSEMBLY Mechanical components furnishing power to the fan, usually consisting of driver, drive shaft, speed reducer, and supporting members.

FAN DRIVE OUTPUT Brake horsepower output of the driver to the drive shaft. (Fan driver input) X (motor efficiency).

FAN DRIVER INPUT Horsepower input to the driver. For 3-phase alternating current (ac) motors. Hp = (amps) (volts) (3) (Power Factor) (Efficiency) ö 746.

FAN GUARD A protective screen installed either at the inlet of a forced draft fan or at the exit of an induced draft fan.

FAN PITCH The angle which a fan blade makes with the plane of rotation; degrees from horizontal.

FAN STACK Cylindrical or modified cylindrical structure enclosing the fan discharge in induced draft towers. Usually constructed of fiberglass materials, wood and metal are also utilized.

FATIGUE Failure of a metal due to a repeated cyclic stressing considerably below the ultimate tensile strength.

FATIGUE CRACK Progressive fracture that starts from a point where there is a high concentration of cyclic stress.

FDA Food and Drug Administration.

FEED PUMP A mechanical contirvance for adding a liquid chemical to a water system by centrifugal, piston, or diaphram action.

FEEDING Injecting a chemical into a suspension to encourage coagulation or flocculation.

FEEDWATER A blend of makeup water and condensate that enters the boiler.

FERMENTATION The conversion of organic matter to CO₂, CH₄, and similar low-molecular-weight compounds by anaerobic bacteria.

FERRIC IRON A form of iron oxidized to its trivalent, most stable state. Very slightly soluble in water.

FERRITE Solid solution in which alpha iron (body-centered cubic crystal) is the solvent. Generally, the light areas in normal, etched, low-carbon steel microstructure. It is also the basic component of magnetic 300 series stainless steel.

FERROUS IRON A form of iron oxidized to a divalent state.

FIELD ERECTED BOILER A boiler assembled, installed and tested on-site.

FIFRA Federal insecticide, Fungicide, and Rodenticide Act; regulations administered by U.S. EPA under this Act require that certain useful poisons may vary for the same material depending on the method used, so the test method is indicated when the flash point is given (150° F PMCC, 200° F TCC, etc.)

FILAMENTOUS Long and thread-like in shape.

FILL See Packing

FILL BARS The assembly of splash bars comprising the tower filling. Fill bars intercept the downward fall of water at regular intervals, forming splash surfaces which cause water drops to break into smaller droplets, and provide wetted surfaces for air-water contact.

FILL DECK The assembly of splash bars comprising the tower filling. See FILL BARS for description of operation in a Crossflow Tower.

FILL HANGER Support system in a Crossflow Tower for fill bars which hold fill in place.

FILL PACKING Baffling placed within the casing of the tower to provide large water surface areas for heat transference. Two classes of materials are used. Splashbars of wood, metal, transite, plastic, or film pack (cellular fill) made of thin section. The splash type cools water droplets bouncing down in the vertical or horizontal air stream, while film packing turns the droplets into thin films for highly efficient cooling by producing a larger surface area for the air movement to cool.

FILLER Clay, calcium carbonate, or other minerals added to cellulose fiber in the production of certain grades of paper or board.

FILLET Concave junction of two surfaces such as a weld.

FILM A very thin coating or layer of material.

FILM BOILING Formation of a stable steam film at a tube surface due to excessive heat input. It occurs when there is a departure form nucleate boiling with continual high heat input.

FILMING AMINES A volatile additive used primarily to chemically inhibit condensate system corrosion by forming a waterproof, protective film between the condensate and metal surfaces.

FILTER Device for removing small particles from a fluid.

FILTER - AG This is a mineral used in the clarifier to physically filter out the suspended matter in some water supplies. This ceramic-like granular material, insoluble, back washes most freely with less water than sand and other similar filter material.

FILTRATE The liquid remaining after removal of solids as a cake in a filter.

FILTRATION The process of passing a liquid through a porous medium for the removal of suspended material by a physical straining action.

FILTRATION The process of separating solids from a liquid by means of a porous substance through which only the liquid passes.

FIN An extended surface to increase the heat transfer area, as metal sheets attached to tubes.

FINES Extremely small particles of ion exchange materials.

FIREBOX Area of a boiler where fuel is burned.

FIRETUBE BOILER Boiler design with hot gases in the tubes and water/steam outside the tubes on the shell side.

FISH EYE A gel that forms when the outer portion of a polymer granule gets wet, sticks to adjoining granules, and does not dissolve.

FISSION In biology, the process of reproduction by cell splitting.

FIXED MATTER Residues remaining after ignition of particulate or dissolved matter or both.

FLAMMABLE MATERIAL A chemical that falls within any of the following categories:

1. Flammable aerosol - A substance release from it container as a mist, spray or foam by a propellant under pressure which is capable of forming a flame exceeding 18 inches at full valve opening or a flashback (a flame extending back to the valve) at any valve opening under prescribed methods of testing.
2. Flammable gas - A gas which at normal temperature and pressure forms a flammable mixture with air at a concentration of 13% or less by volume, or forms a range of flammable mixtures with air wider than 12% by volume regardless of the lower limit.
3. Flammable liquid - A liquid having a flash point below 100°F (37.8° C).
4. Flammable solid - A solid, other than an explosive, that can cause a fire through friction, absorption of moisture, spontaneous chemical change, or retained heat from manufacturing or processing, or that can be readily ignited and continue to burn by itself.

FLASH The portion of a superheated fluid converted to vapor when its pressure is reduced.

FLASH GAS The gas resulting from the instantaneous evaporation of refrigerant in a pressure-reducing device to cool the refrigerant to the evaporation temperature obtaining at the reduced pressure.

FLASH POINT The minimum temperature at which a liquid gives off a vapor in sufficient concentration to ignite when tested by prescribed methods.

FLASH TANK A receiving tank for boiler blowdown that reduces fluid pressure and permits steam to flash from the water.

FLASHING Spontaneous conversion of pressurized fluid (water) into vapor (steam).

FLEXIBLE COUPLING Resilient connecting assembly that transmits the power in the fan driver to the gear unit through the drive shaft.

FLOAT VALVE Type of value which is operated by sphere or pan which floats on liquid surface and controls level of liquid.

FLOC Something occurring in indefinite masses or aggregates. A clump of solids formed in sewage when certain chemicals are added.

FLOC MATTE Floc that has been bridged into a close formation and sinks as a single mass.

FLOC SHEAR The breaking up of fragile, newly-formed floc into smaller particles.

FLOC SKIMMINGS The flocculent mass formed on a quiescent liquid surface and removed for use, treatment, or disposal.

FLOC WATER Water freed from sludge after chemical conditioning with coagulants.

FLOCCULATION The process by which certain chemicals form clumps of solids in sewage.

FLOCCULATION The process for separating solids from water by developing a froth in a vessel in such fashion that the solids attach to air particles and float to the surface for collection.

FLOCCULATION ZONE An area in a unit operation where flocculation occurs.

FLOCCULATORS A series of slowly churning paddles that encourage flocculation.

FLOODBACK (refrigeration system) The condition of refrigerant liquid returning, usually from an overfed evaporator, to the compressor through the suction line.

FLOODED SYSTEM Type of refrigerating system in which liquid refrigerant fills evaporator.

FLOTATION A process for separating solids from water by developing a froth in a vessel in such fashion that the solids attach to air particles and float to the surface for collection.

FLOW CONTROL VALUE A manually controlled valve generally located in the hot water supply line.

FLOW CONTROLLER Any device that can limit the flow of a liquid. Some types control flows, regardless of variations in water pressure others are manually adjustable.

FLOW RATE The movement of water expressed in velocity units such as feet per second.

FLOW RATE The volume of solution passing through a given quantity of resin within a given time. Usually expressed in terms of gallons per minute per cubic foot of resin, as milliliters per minute per milliliter of resin or as gallons per square foot of resin per minute.

FLOW RATE The volume of water passing through a given quantity of resin in a given amount of time. Flow rate is usually expressed as "gallons per minute per square foot of cross-section" or "gallons per minute per cubic foot of resin."

FLOW REGULATOR This is a mechanical or automatic device used to regulate the flow of water at a specified flow rate.

FLUID Gas, vapor, or liquid.

FLUME A trough which may be totally enclosed or open at the top. Flumes are sometimes used in cooling towers to distribute the hot water over the fill.

FLUORESCENT The ability to glow. When bacteria are subjected to certain dyes, they incorporate these dyes and glow when subjected to ultraviolet light and viewed under a microscope. This is one tool used in identification of Legionella.

FLUSHING The act of cleaning out a system, using a flow of water generally at high rates.

FLUX, MAGNETIC Lines of force of a magnet

FLUX-BRAZING, SOLDERING Substance applied to surfaces to be joined by brazing or soldering to free them from oxides and facilitate good joint.

FOAMING Formation of small, stable bubbles or froth in a liquid due to increased surface tension and/or excessive agitation.

FOG Saturated air being discharged from the cooling tower under atmospheric conditions whereby the ambient atmospheric temperature cannot absorb all of the moisture as vapor, and excess fog condenses. The intensity of the fog plume is a function of the heat rise of air passing through the tower and the temperature and humidity of the ambient air. Fog plumes are normally permissible since there are not droplets of water raining out of the discharge area. However, on large industrial sites this could cause icing of the roads in the winter and restricted visibility which could necessitate corrective action.

FOOT VALVE A check valve used on suction lift applications and located at the bottom of the suction assembly. Keeps the suction line full of liquid.

FORCE Force is accumulated pressure and is expressed in pounds. If the pressure is 10psi on a plate of 10sp. In area, the force is 100 pounds.

FORCED CIRCULATION BOILERS Boilers that use a pump to maintain positive circulation.

FORCED CONVECTION Forced heat transfer that creates a flow of one of the fluids.

FORCED DRAFT Design whereby the air intake is at the bottom forcing the air up and through the tower, normally by a centrifugal blower.

FORCES CONVECTION Movement of fluid by mechanical force such as fans or pumps.

FORMULA The conventional scientific designation for a material (water H₂O, sulfuric acid is H₂SO₄, sulfur dioxide is SO₂ etc.,)

FOULANTS Any obstructive material in a cooling system other than scale-forming precipitates.

FOULING Act of obstructing flow of water or its evaporation by materials entering into or developing in the water. Generally but not necessarily associated with biogrowth.

FOULING FACTOR An allowance made in the design of a heat exchanger to address the reality that the water side surfaces will rarely be perfectly clean. The fouling factor is a factor which relates the performance of a clean heat exchange with the performance of a dirty heat exchanger. Typically, this value will be in the range of 0.001+/-Hr-ft²-§ F/BTU. Suggested design values for a variety of process fluids and conditions can be found in the current edition of Standards of the Tubular Exchanger Manufacturers Association (TEMA).

FOULING INDEX A measure of the tendency of a water to foul a reverse osmosis membrance, based on timed flow through a membrane filter at constant pressure.

FOUNDATIONS (Natural Draft Tower) Support material beneath the tower cross struts and cooling section. Foundations can be caissons, spread footing (tension ring) or piles.

FOURDRINIER A design of paper machine using a continuous wire for forming the sheet.

FRAMEWORK MEMBERS The structural members designed to support all live and dead loads imposed. They consist of columns, horizontal ties, diagonals, and joists and beams.

FREE AVAILABLE CHLORINE RESIDUAL Residual consisting of hypochlorite ions (Ocl^-), hypochlorous acid (HOCl), or a combination thereof.

FREE CARBON DIOXIDE Carbon dioxide in water that is not associated with the bicarbonate ion.

FREE CHORINE RESIDUAL The residual in circulating water consisting of hypochlorite ion or hypochlorous acid or a combination thereof which is established by chlorine treatment.

FREE FERRITE Ferrite formed from austenite during cooling without formation of carbide.

FREE INHIBITOR RESIDUAL An excess of inhibition in the bulk water.

FREE MINERAL ACIDITY The quantitative capacity of aqueous media to react with hydroxyl ions to pH 4.3.

FREE SETTLING Large particles sinking in calm water with no interference from contact with other particles.

FREE WATER Water that readily separates from sludge during sedimentation process.

FREEBOARD That distance between the top of the resin bed and the top horizontal welded seam of the tank. Its purpose is to allow the resin to expand during the backwash so that good resin is not washed out.

FREEBOARD The space provided above the resin bed in an ion exchange column to allow for expansion of the bed during backwashing.

FREEZE-UP Failure of a refrigerating unit to operate normally due to formation of ice at the expansion device. A valve may freeze shut or open, causing improper refrigeration either case. On a coil, frost formation to the extent that air flow stops or is severely restricted.

FREEZING (Fusion) POINT Temperature at which a given liquid substance will solidify or freeze upon removal of heat. Freezing point for water is 32F.

FREON Trade name for a family of synthetic chemical refrigerants manufactured by DuPont De Nemours Inc.

FRESH WATER Water having less than approximately 1,000 mg/liter of dissolved matter.

FREUNDLICH ISOTHERM The plot of test data related to the removal of colloidal matter from water showing the process to be adsorption.

FRICTION FACTOR The friction factor is a factor which relates the fluid flow rate through a smooth pipe with the fluid flow rate through a rough pipe.

FROST BACK Condition in which liquid refrigerant flows from evaporator into suction line; indicated by frost formation on suction line.

FRUITING BODY(Sporophore) A specialized structure produced by the organism to bear the spores. This structure will produce thousand of spores. The size, shape, and color will vary with different species.

FULL LOAD AMPERAGE Amps drawn by an electric motor at its rated horsepower under full load.

FUMES An aerosol with solids as the dispersed colloids.

FUNCTIONAL CHARGE The net charge of a polymer: cationic, anionic, or nonionic.

FUNGI A lower form of plant life, filamentous and without chlorophyll. Responsible for slime and destruction of cooling tower wood.

FUNGI As applied to water, these are simple, one-celled organisms without chlorophyll, often filamentous; molds and yeasts are included in this category.

FUNGICIDE A preparation formulated to control the growth of fungi and normally used in systems employing wooden cooling towers or heat rejectors. Copper, chromium and mercury compounds are known fungicides.

FUSIBLE PLUG A plug or fitting made with a metal of a known low melting temperature, used as safety device to release pressures in case of fire.

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