ANSI ASSP Z9.2-2018 pdf free download – AMERICAN NATIONAL STANDARD Z9.2 FUNDAMENTALS GOVERNING THE DESIGN AND OPERATION OF LOCAL EXHAUST VENTILATION SYSTEMS.
2.2 NFPA Standards.
NFPA 91 , Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids
NFPA 45, Fire Protection for Laboratories Using Chemicals
NFPA 33, Standard for Spray Operation Using Flammable or Combustible Materials
2.3 Occupational Safety and Health Administration Standards.
Code of Federal Regulations，Title 29,Part1910, Section 94, Ventilation
Code of Federal Regulations，Title 29, Part1910,Subpart z, Toxic and HazardousSubstances
Code of Federal Regulations，Title 29,Part1910,Section 1450,Occupational Exposuresto Hazardous Chemicals in Laboratories
2.4other Recognized Standards andGuidelines of Good Practice.
ASHRAE Handbook Fundamentals. Atlanta,GA:American Societyof_Heating,Refrigerating and Air Conditioning EngineersASHRAE Handbook HVAC Applications.Atlanta，GA: American Society of Heating,Refrigerating and Air Conditioning Engineers
ASHRAE Guideline 1. The HvAC Commis-sioning Process; Guideline 4,Preparation ofO&M Documentation for Building Systems
Heating and Cooling for Man in Industry,American Industrial Hygiene Association
Industrial ventilation: A Manual of Recommended Practice for Design and lndustrialventilation: A Manual of Recommended
Practice for Operation and Maintenance (twovolumes)，Latest Editions. Cincinnati，OH:Committee on Industrial Ventilation of theAmerican ConferenceofGovernmentallndustrial Hygienists
SMACNA publications: Accepted IndustryPractice for lndustrial Duct ‘Construction;Rectangular lndustrial Duct ConstructionStandards;RoundlndustrialDuctConstruction Standards; Guide for SteelStack Construction; Testing,Adjusting,andBalancing HVAC Systems
SEMI S2-1016b,Environmental,Health,andSafety Guideline for Semiconductor Manu-facturing Equipment
SEMI S6-0707E，EHS Guideline for ExhaustVentilation of Semiconductor ManufacturingEquipment
3.DEFINITIONS
The following definitions explain terms usedin this standard.
3.1 Air Cleaning Equipment. A device orcombination ofdevices forseparatingcontaminants from the air handled by an LEvsystem.
3.2 Aspect Ratio. In rectangular exhaustopenings,usually the ratio of the width tolength of the hood opening,e.g.,in slot orface openings; in ductwork, the ratio of theheight to width of the duct cross-sectionaldimensions.
3.3 Baffle, also Flange.Partial enclosures inand around emission sources that improve orenhance airflow patterns at the emissionsource and at the hood.
3.4 Balanced. In LEv, a balanced system isone in which the desired air flowrate isachieved simultaneously in all branches ofthe system.
3.5 Branch. A duct connecting an exhausthood to a main or submain.
3.6 Coefficient of Entry,also known asHood Flow Coefficient.A unitless factor,designated in the literature as Ce，whichrelates static pressure at a hood to thevelocity pressure in the duct serving thehood.The coefficient of entry is usuallycalculated as (VPeve/SPnooo)05.
3.7 Commissioning, Commissioning Plan.process or plan in which a local exhaustventilation systems performance is identified,verified and documented before, during andafter design, construction or remodeling toassure proper operation and compliance withcodes,standards and user intentions.
3.8 Contaminant. Also，Air Contaminant,Stressor. A substance (smoke, dust, fume,mist, vapor or gas) whose presence in air isharmful, hazardous or a nuisance to humans.
3.9Controlvelocity. Also，Capturevelocity. The velocity of air at a point inspace sufficient to prevent contaminantsfrom escaping from an enclosing hood and/orto draw contaminants and contaminated airinto an exhaust hood.
3.10 Design. The process that includescharacterizingthe interactions betweenemissions,workers and the air; determiningappropriate air flowrates,static pressuresand other operational parameters; specifyingequipment and system components.
3.11Designer. Persons charged withdesigning an LEv system; may include
mechanical engineers，industrial hygienistsand others with design education andexperience. See 3.10 for a definition of”design”.
3.12Document;toDocument;Documentation. The formalprocess ofplanning and recording of the rationale fordecisions made by the user, the designer orothers.Also,the writtenproceduresdeveloped foroperating, testingandmaintaining an LEv system.
3.13 Ductwork. Elongated rigid or flexibleenclosures used to convey air and entrainedcontaminants from one location to another.
3.14 Entry.The point at which a segment ofductwork(i.e.， branch or submainy entersanother segment of ductwork (i.e.，submainor main); entry from a hood to a duct; andentry from a plenum to a duct.ANSI ASSP Z9.2 pdf download.