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Standards of good practice: Overview of ANSI Z9 ventilation

asis on ANSI/AIHA Z9.2-2006Fundamentals governing the design and operationof LEV systems

By Jeff Burton,Lou DiBerardinis,Jack Price, Mili Mavely

Why do we need standards of goodpractice?

To answer this important question,we should start by comparing chemicalsafety professionals to other profes-sionals.

Pilots are considered tops amongprofessionals. When piloting a plane-load of people, pilots carefully followchecklists, instructions, and variousstandards of good practice. Surgeonsare top professionals. They followexacting procedures and detailed stan-dards of practice as they perform theirlife-saving work.

Chemical safety professionals arealso top professionals. The lives andwell being of people are in our hands.We also have guidelines, codes, andstandards of good practice which,when followed, make our jobs easierand more successful, and help us avoidthe inevitable litigation associated withpoor or substandard practice.

Chemical health and safety stan-dards fall into two basic classes: man-datory standards (e.g., OSHA

Jeff Burton, CIH, PE is the recipient ofthe 2005 Howard Fawcett Award pre-sented by the Division of ChemicalHealth and Safety, IVE Inc. Bountiful,Utah.

Lou DiBerardinis, CIH, CSP, is Chairof the ANSI Z9, Director, EH&S Office,Massachusetts Institute of Technol-ogy, United States.

Jack Price is Vice Chair of the ANSI Z9,Director, EH&S Office, NortheasternUniversity, United States.

Mili Mavely is a Program Manager atAIHA, Fairfax, VA.

4 � Division of Chemical Health and Safety of the

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regulations) and recommended orconsensus standards (e.g., ACGIHTLV, AIHA WEEL, ISO 14000 stan-dard on environmental management,ANSI/AIHA Z9.2 standard on localexhaust ventilation, ASHRAE 62 stan-dard on indoor air quality, etc.). Bothsets of standards are important.

This article summarizes importantventilation standards promulgated bythe ANSI Z9 Accredited StandardsCommittee (ASC) for Health andSafety Standards for Ventilation Sys-tems.

The scope of ASC Z9 encompassesstandards for the design, operation andmaintenance of equipment to providea safe atmosphere in industrial, man-ufacturing or construction operationsby removing harmful substances byeither local exhaust or general ventila-tion and safely disposing of such sub-stances, and such supplementarystandards on personal protection asmay be necessary to prescribe methodsfor the protection of workers.

The American National StandardsInstitute (ANSI) is responsible foroverseeing the development ofnational consensus standards and ver-ifying that the requirements for dueprocess, consensus, and other criteriafor approval have been met by thestandard’s developer. Consensus isestablished when in the opinion ofthe ANSI Board of Standards Review(BSR); substantial agreement has beenreached by directly and materiallyaffected interests. Substantial agree-ment means much more than a simplemajority but not necessarily unanimity.Consensus requires that all views andobjections be considered and that aconcerted effort be made toward theirresolution.

While the use of an AmericanNational Standard is completelyvoluntary, one should be awarethat some have been adopted as code

American Chemical Society

or regulation by local, state orfederal authorities. They are also con-sidered ‘‘state of the art,’’ or ‘‘bestpractices’’ in the area of contamina-tion control.

The following ten standards havebeen developed by the Z9 committee.Some are in the process of beingrevised.

Overview of current ANSI Z9 stan-dards.

� Z

9.1: ANSI/AIHA Z9.1-2006Open-Surface Tanks Ventilationand Operation—revised standardhas been approved by ANSI and isavailable for sale through AIHA.Chair John Sheehy. This standardestablishes minimum controlrequirements and ventilation systemdesign criteria for controlling andremoving air contaminants to pro-tect the health of personnel engagedin open surface tank operations. It isnot intended to cover fire protection. � Z 9.2: ANSI/AIHA Z9.2-2007 Fun-

damentals Governing the Designand Operation of Local Exhaust Sys-tems: Chair: Jeff Burton: ReaffirmedStandard has been approved byANSI and is available for salethrough AIHA.

General coverage: This importantstandard describes fundamental goodpractices related to the commissioning,design, selection, installation, opera-tion, maintenance, and testing of localexhaust ventilation (LEV) systemsused for control of employee exposureto airborne contaminants. It isintended for use by LEV system own-ers, employers, industrial hygienists,facilities engineers, maintenance per-sonnel, testing and balancing person-nel, ventilation system designers, andothers with responsibility for LEV sys-tems. It is compatible with the ACGIHIndustrial Ventilation Manual and

1871-5532/$32.00

doi:10.1016/j.jchas.2008.02.001

other recognized standards of goodpractice.

Section coverage: Although someoverlap exists, the first ten sectionscover system design, construction,and installation; the last four sectionscover operation, maintenance, andtesting.

See Table 1, a summary of therequirements contained in the stan-dard.

Format: The Standard is presentedin a two-column format. The left col-umn presents the requirements of thestandard; the right column providesclarification and explanation of therequirements plus ‘‘how to comply’’information. Appendix provides sup-plementary information by Standardparagraph number.

Flexibility: Requirements can beconsidered minimum criteria andadapted to the needs of the Userestablishment. Demonstrably equalor better approaches are acceptable.When deviating from the standard,documentation should be provided.

Auditing: The Standard is auditableby those trained in local exhaust ven-tilation. An Audit Form is provided inAppendix.

� Z

Jo

9.3: ANSI/AIHA Z9.3-2007 SprayFinishing Operations—Safety Codefor Design, Construction, and Ven-tilation: Revised and issued in Fall,2007. Chair: G.M. Adams. This stan-dard is intended to help manufac-turers and users protect the health ofpersonnel from injurious effects ofcontact with gases, vapors, mists,dusts, powders, or solvents used in,or created, released or disseminatedduring or by spray finishing opera-tions.

� Z 9.4: ANSI/AIHA Z9.4-1997 Abra-

sive-Blasting Operations Ventila-tion and Safe Practices for FixedLocation Enclosures: Chair work-ing on updating draft. Chair: Kath-leen Paulson. This standardapplies to all operations in fixedlocation abrasive-blast enclosuresin which an abrasive forcibly comesin contact with a surface by pneu-matic or hydraulic pressure or bycentrifugal force. It does not applyto steam blasting, steam cleaning, orhydraulic cleaning methods in

urnal of Chemical Health & Safety, May/Jun

which work is done without the aidof abrasives. It also does not apply toabrasive blasting conducted out-doors (e.g., bridges, water towers)even though temporary enclosuresmay be built at such locations.

� Z 9.5: ANSI/AIHA Z9.5-2003

Laboratory Ventilation: StevenCrooks, Chair. Subcommittee is cur-rently being formed and review stan-dard for revision. This standard setsforth the requirements for the designand operation of laboratory ventila-tion systems.

� Z 9.6: ANSI/AIHA Z9.6-1999

Exhaust Systems for Grinding, Buff-ing and Polishing: Draft standard isready to be sent for public review.Chair: Mark Rollins. The rules andengineering principles described inthis standard represent the mini-mum criteria intended to protectthe health of personnel engaged inand working in the vicinity of grind-ing, polishing, and buffing opera-tions; and to control contaminantsgenerated by those operations.

� Z 9.7: ANSI/AIHA Z9.7-2007 Recir-

culation of Air from Industrial Pro-cess Exhaust Systems: Revisedstandard has been approved byANSI and is available for salethrough AIHA. Chair: Lou DiBerar-dinis. This standard establishedminimum criteria for the designand operation of a re-circulatingindustrial process exhaust ventila-tion system used for contaminantcontrol.

� Z 9.8: ANSI/AIHA Z9.8-draft status.

‘‘Fundamentals Governing the Man-agement, Operation, Testing, andMaintenance of HVAC Systems forMaintaining Acceptable Indoor AirQuality in Non-Industrial EmployeeOccupancies through Dilution Ven-tilation.’’ Chair: Jeff Burton. Anidentically named AIHA Guidelinewas created from drafts of this pro-posed standard. Both describerecommended practices for themanagement, operation, testingand maintenance of HVAC systemsused to provide acceptable indoorair quality (IAQ) using dilution ven-tilation. It applies to non-industrialemployee occupancies where healthmaintenance is the major concernwith comfort being a secondary con-

e 2008

cern. The subcommittee will main-tain AIHA Guideline No. 2 and pro-ceed with the draft standard asconditions permit. Guide availablefor sale through AIHA.

� Z 9.9: BSR/AIHA Z9.9 (Draft

approved, available early 2008) Por-table Ventilation Systems: Draft newstandard has been out for publicreview and will be published in thesummer, 2008. Chair: Neil McMa-nus. This Standard discusses porta-ble ventilation equipment andsystems used for the reduction, con-trol or prevention of exposure tohazardous atmospheres or airbornesubstances in the occupationalenvironment, and for provision ofcomfort to employees.

� Z 9.10: BSR/AIHA Z9.10 (Draft

approved; available early 2008.)Fundamentals Governing theDesign and Operation of DilutionVentilation Systems in IndustrialOccupancies: Few changes to bemade to the draft before it goes outfor ASC Z9 and public review, ChairJeff Burton. This Standard estab-lishes minimum requirements forthe commissioning, design, specifi-cation, construction, installation,management, operation, mainte-nance and testing of dilution venti-lation systems (including demanddilution ventilation) used for thereduction, prevention and controlof employee exposure to harmful air-borne substances in the industrialenvironment.

� Z 9.11: BSR-AIHA Z9.11 New

Laboratory DecommissioningStandard: standard has beenapproved and will be published inthe spring of 2008. Co-chairs: LouDiBerardinis and Farhad Mezmar-adeh. This standard provides aroadmap for the decommissioningprocess of biological researchlaboratories that can assist an insti-tution in developing its own Decom-missioning Plan.

More information about ANSI Z9standards is available from:

AIHA, Secretariat, 2700 ProsperityAvenue, Ste. 250, Fairfax, VA 22031-4319, United States. Tel.: +703 8498888; fax: +703 207 3561.

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APPENDIX A

Table 1. Table 1. Summary of requirements for ANSI/AIHA Z9.2-2006—fundamentals governing the design and operation oflocal exhaust systems

Section 4. General Requirements4.1 Responsible persons are trained or have experience4.2 Ventilation design based on emission, air, and worker behavior4.3 Review plans and specifications before construction4.4 Meets this or demonstrably equal standards4.5 Commissioning Plans are used4.6 Exhaust air is diluted to safe concentrations4.7 SP losses estimated before construction4.8 Construction materials chemically-compatible4.9 Performance monitoring provided4.10 Equipment redundancy provided4.11 LEV systems are clean and maintained for a lifetime4.13 When to claim compliance instructions

Section 5. Plant Layout and Construction5.1 Design considers plant layout/construction/locations5.2 Buildings okay for hazardous operations/meet local building and fire codes5.3 Surfaces permit cleaning/draining5.4 Incompatible contaminants exhausted separately5.5 Radioactive systems comply w/ NRC+ regulations

Section 6. Makeup Air System6.1 Air exhausted is replaced6.2 SP relationships in space considered.6.3 Optimizes supply-to-exhaust airflow6.4 Recirculated air meets ANSI Z9.7-19986.5 Makeup air does not reduce LEV performance6.6 Intake location prevents uptake of contaminants6.7 Makeup air filtered to protect ventilation equipment.6.8 Appropriate air volume flowrates at all times6.9 Monitors warns of malfunction of makeup system6.10 Makeup air is clean6.11 Thermal comfort meets ASHRAE and AIHA standards.6.12 Direct-fired heaters provisions: safe, follow codes and Manuf1s rec.6.13 Makeup air is not 3push air2 in a push-pull LEV system

Section 7. Exhaust Hoods7.1 Hoods control routine and anticipated emissions7.2 Consider and document Para. 7.2 factors: vortices, equip-people, capture velocity, thermal behavior, contaminant

behavior7.3 Hoods 3control2 unplanned emissions7.4 Airflow monitoring provided7.5 Before use, performance tested7.6 Selection of Q = f (emission capture and/or control)7.7 Selection of hood = f (performance needed)7.8 Uniform flow of air into the hood7.9 Enclose to the extend possible; capture hoods close7.10 Avoid fires and explosions7.11 Consider/documents important factors: shape, material, He, Kh, Ce, Sph, Vc, slot dimensions and Vs7.12 Prebuilt hoods provide info: Q, Ce, Kh, Sph, perf. tests, physical parameters

Section 8. Ductwork and Stacks8.1 Design by those trained and qualified8.2 SP losses estimated throughout system8.3 Balanced-design approach (dampers okay)8.4 Duct materials compatible with contaminants

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8.5 Duct velocities avoid settling/cleaning8.6 Round duct on upstream of fan8.7 Fire dampers meet local/NFPA codes.8.8 Stack location: avoid re-entrainment/exposure on roof8.9 Stack outlet well above air intake8.10 Stack velocities avoid backdrafting8.11 Vibration isolators at fan inlet8.12 Separate air streams for incompatibles (e.g., PCA + organics)

Section 9. Air Cleaning Equipment9.1 Obtains permits first9.2 Selection based on air contaminants9.3 Testing and maintenance programs used9.4 Handling/disposal meet RCRA, DOT, etc.

Section 10. Fans and Air Moving Devices10.1 Selection factors include: Q, FTP, d, contaminant, type, size, drive, class, couplings, mounting, rain, stack, location10.2 Design considers system effect losses10.3 Fan SOP on a steep forward part of fan curve.10.4 Use O&M procedures and safety programs10.5 Considers long-term contaminant effects on fan10.6 Fans on clean-air side of air scrubber10.7 Safety when cleaning/inspecting wheel10.8 Precautions against ignition of flammable contaminants10.9 Mesh screen no smaller than necessary10.10 Correct rotation of the fan wheel10.11 Fan on/off switches located within view10.12 Outlet duct no leaks/not routed thru occupied spaces

Section 11. Management of LEV systems11.1 Written management policies11.2 Work practices program11.3 Written LEV maintenance program11.4 Testing and monitoring program

Section 12. Construction and Installation12.1 Commissioning approach used12.2 Constructed for safety, economics, ease of maint.12.3 Materials of construction compatible w/process/cont.12.4 Effective operation over lifetime.12.5 Airtight construction (e.g., upstream, in buildings)12.6 Ductwork is accessible for inspection/maint.12.7 Damper used for air shutoff, balancing system; is fixed12.8 Approved equipment for specific hazards (NEC fixtures)12.9 Additional duct runs okay to be added when

(1) in original design/approved(2) no deterioration of performance

12.10 Where IDLH levels possible, interlock process/LEV

Section 13. Operations and Maintenance13.1 Program of safe operating procedures13.2 Operated to manufacturer’s instructions13.3 Employees instructed13.4 Not operated when malfunctioning13.5 Particulate? Inlets open13.6 Maintained in good working order13.7 Maintenance instructed13.8 Maintenance people trained to ‘‘troubleshoot’’13.9 Provide preventive and scheduled maintenance13.10 Follow manufacturers’ recommendations13.11 Keep records

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13.12 Drawings/specifications kept up-to-date13.14 Use lock-out, tag-out programs

Section 14. Testing, Balancing, and Operational Checks14.1 Performance/operating criteria established (for testing)14.2 Test methods/instruments measure criteria of Para 14.114.3 After construction or modification, LEV system is tested14.4 Periodically tested and monitored on a schedule14.5 Hood meets User performance criteria14.6 Tests confirm capture and containment performance14.7 LEV system is balanced regularly14.8 Testers are qualified by training/experience/certification14.9 Instrumentation is suitable for measurements14.10. Instruments calibrated14.11 Records of testing and balancing14.12 Makeup also included in testing14.13. Testing equipment is safe14.14 Testing results available to those with a need to know

Summary of requirements by section paragraph.

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