Coefficient of Entry (Ce) is a measure of the efficiency of a hood's ability to convert static pressure to velocity pressure.Ĭonfined Space - An enclosure such as a storage tank, process vessel, boiler, silo, tank car, pipeline, tube, duct, sewer, underground utility vault, tunnel, or pit that has limited means of egress and poor natural ventilation and that may contain hazardous contaminants or be oxygen deficient.Ĭontaminant - A harmful, irritating, or nuisance material that is foreign to the normal atmosphere.ĭensity - Density is the weight of a unit volume of a substance: OSHA BREATHING ZONE DEFINITION PLUSThe information is recorded on the system drawing when the system is installed and started up.īlast Gate - A sliding sheet metal valve used in ducts to create additional pressure loss in the duct and restrict flow.īrake Horsepower (bhp) - The actual horsepower required to move air through a ventilation system against a fixed total pressure plus the losses in the fan.ĬFM - An abbreviation for cubic feet per minute.Ĭapture Velocity - The air velocity required to capture suspended dusts or aerosols and draw them into an exhaust hood.Ĭarcinogen - A physical, chemical or biological agent that is capable of inducing cancer in humans or animals.Ĭoefficient of Entry (Ce) - The hood captures, contains, or receives contaminants generated at an emission source by converting static air pressure to velocity pressure. This is the reference point where the system must be returned to when the network gets unbalanced. ANSI/AIHA Z9.7-2007 for Recirculation of Air for Industrial Process Exhaust Systems.ĪSHRAE - American Society of Heating, Refrigerating, and Air-Conditioning Engineers.īaseline - Measurements from the Local Exhaust Ventilation (LEV) duct network static pressures and airflow measurements that prove all points on the network are within design parameters. Common types of anemometers include the rotating vane, the swinging vane, and the hot.ĪNSI - American National Standards Institute publishes consensus standards on ventilation, e.g. Specific heat of dry air = 0.24 btu/lb/F.Īnemometer - A device used to measure air velocity. This is substantially equivalent to 0.0757 lb/ft 3. Examples include filters, scrubbers, electrostatic precipitators and cyclones.Īir Horsepower (ahp) - The power required to move air through a ventilation system against a specific pressure.Īir, Standard - Dry air at 70☏ and 29.92 in (Hg) barometric pressure. Aerosols include mists, smokes, fumes, and dusts.Īir Changes Per Hour - The number of times indoor air is theoretically replaced by outdoor air during an hour.Īir Cleaner - A device to separate contaminants from an air stream. OSHA BREATHING ZONE DEFINITION MANUALACGIH - American Conference of Governmental Industrial Hygienists publishes a guidebook for industrial ventilation: Industrial Ventilation Manual, A manual of Recommended Practice.Īerosol - Particles (solid or liquid) that remain suspended in air for a period of time.
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