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Clean Air Solutions for Dust & Mist Processes

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EFFECTIVE STACK HEIGHT: The height at which a plume becomes essentially level. It is the actual stack height plus the plume rise.

EFFICIENCY: The relative ability of an air cleaner to collect contaminants, usually expressed in percent. There are many methods used to measure air cleaner efficiency. Results achieved with different methods and contaminant samples may not be directly comparable. Both the basis and test method must be fully stated if efficiency figures are to be meaningful.

EFFICIENCY, MECHANICAL TOTAL: The ration of fan output to the power applied to the fan. Can be helpful in selecting fan size, type or manufacturer for the same application: ME = TP x CFM 6,356 x BHP

EFFICIENCY, STATIC: The ratio of fan output less the kinetic energy (outlet-velocity pressure) leaving the fan to the power applied to the fan: SE = SP xCFM 6,356 x BHP

EFFLUENT: A discharge or emission of a fluid (liquid or gaseous).

ELECTROSTATIC DUST: Particles that tend to receive and retain a static charge, such as fiberglass, paint pigments, plastics, etc.

ELECTROSTATIC ATTRACTION: Mutual attraction caused by static electricity, by which particles tend to draw together or adhere.

ELECTROSTATIC PRECIPITATOR: The two types of electrostatic precipitators are the Cottrell-type (single-stage) and the Penny-type (two-stage). The Cottrell-type combines ionization and collection in the same field while the Penney-type places the ionizer and the collection plates. With either type, particles entering the ionization field receive an electrostatic charge. These charged particles are then collected on the grounded collection plates. The Cottrell single-stage precipitator operates at ionization voltages from 40,000 to 70,000 colts DC. It may also be called a high voltage precipitator and is used to collect particles in application such as utility boilers. The Penney two-stage precipitator uses DC voltages from 11,000 to 14,000 for ionization and is frequently referred to as low voltage precipitator. It is used to collect contaminants in applications such as welding or oil mist and smoke from machining operations. UAS manufactures the SMOG-HOP line of Penney-type, two-stage electrostatic precipitators.

ELEVATION: The distance of the subject site above or below sea level.

EMISSION: Release of pollutants into the air from a source.

EMISSION CONTROL DIAGNOSTICS: Computerized devices placed on vehicles to detect malfunction of emissions controls and notify the owner of the need for repair.

EMISSION CONTROL EQUIPMENT: Machinery used to remove air contaminants from the discharge of industrial exhaust streams.

EMISSION FACTOR: The statistical average of the amount of a specific pollutant emitted from each type of polluting source in relation to the unit quantity of material handled; processed or burned. For example, the emission factor of oxides in nitrogen in fuel oil combustion is 119 lbs., over 1,000 gallons of fuel oil used. By using the emission factor of a pollutant and specific data regarding quantities of material used by a given source, it is possible to compute emissions for that source—information necessary for an emission inventory.

EMISSION INVENTORY: A list of primary air pollutants emitted into a given community’s atmosphere, in amounts (commonly tons) per day by type of source. The emission inventory is basic to the establishment of emission standards. Also see Emission Factor.

EMISSION STANDARD: The maximum amount of a pollutant that is permitted to be discharged from a single polluting source; such as the number of pounds of fly ash per cubic foot of gas that may be emitted from a coal-fired boiler. Rule or measurement established to regulate or control the amount of a given pollutant that may be discharged to the outdoor atmosphere from its source.

ENTHALPY: The heat content per unit mass of a substance.

ENTRY LOSS: The loss in pressure caused by air flowing into a system; normally expressed in fractions of velocity pressure.

EPA: Environmental Protection Agency.

EQUIVALENT DUCT DIAMETER: For rectangular duct with sides “a” and “b” is: D = (4ab/p)0.5

EVAPORATION: The physical transformation of a liquid to a gas at any temperature below its boiling point.

EVASE: A diffuser at the fan outlet that gradually increases in area to decrease velocity and to convert kinetic energy to static pressure (regain).

EXCESS AIR: Air in excess of the amount necessary to combust all the available fuel.

EXHAUST GAS: The gases emitting from an industrial process, generally a combustion process.

EXHAUST STACK TEMPERATURE: The temperature of the exhaust gas, measured in the discharge stack.

EXHAUST VOLUME: The amount of exhaust gas (air, products of combustion and water vapor) leaving the exhaust stack; usually measured in ACFM.

EXPLOSION RELIEF PANEL (VENT): Relief device designed to vent the pressure created during an explosion.