Sematech Safety Guide -- Silane

SEMATECH

Application Guide 2.0

for

SEMI S2-93 and

SEMI S8-95

(Formerly the SEMATECH Interpretive Guide)

To purchase a copy of this guidebook, contact

Semiconductor Safety Association1313 Dolley Madison Blvd.

Suite 402McLean, VA 22101

Phone: (703) 790-1745Fax: (703) 790-2672

http://www.semiconductorsafety.org

To purchase a copy of SEMI S2-93 or SEMI S8-95, contact

Semiconductor Equipment and Materials International805 East Middlefield Road

Mountain View, CA 94043-4080Phone: (415) 964-5111

Fax: (415) 967-5375http://www.semi.org

Comments and feedback related to the technical content andformat of this document are welcome. Please forward any

typewritten comments with name and address to

SEMATECHAttention: ESH Operations, S2 Application Guide

2706 Montopolis DriveAustin, TX 78741

Phone: (512) 356-3235Fax: (512) 356-7040

http://www.sematech.org

i

Revision 2.0 Foreword

FOREWORD

It is SEMATECH’s philosophy that no job is so important that it may be performed without

regard for safety, health or protection of the environment. In keeping with that premise,

SEMATECH has endeavored to continue driving improvements in the area of occupational

safety, health and environmental protection throughout all aspects of the semiconductor

industry.

This guidebook evolved out of a desire on the part of SEMATECH's member companies to

eliminate the inconsistencies they observed in the interpretation and application of SEMI S2.

It was their wish to collaborate and develop a mutually acceptable approach to the use of S2

among their respective organizations. The result was the creation of this interpretation

which is meant to enhance and simplify the quality, process, and value of S2 for member

companies, equipment manufacturers, and equipment evaluators. It is expected that

consistent application of these SEMI guidelines creates the shared advantage of reduced

development costs for semiconductor equipment while ensuring that minimum safety,

health and environmental requirements are met or exceeded.

SEMATECH believes that safety responsibility is owned by everyone. It is our intent to

share this material with the industry and continue to support SEMI efforts in the ongoing

improvement of the SEMI guidelines.

William J. Spencer

Chairman and Chief Executive Officer

SEMATECH

ii

Acknowledgements Revision 2.0

iii

Revision 2.0 Preface

PREFACEPurposeThis guidebook provides a set of consistent criteria for the expectations, interpretations, and applicationrecommendations of SEMI S2-93 and S8-95 (S8). It was developed through the cooperative efforts ofrepresentatives of SEMATECH's member companies with the assistance of representatives from keysemiconductor industry segments such as equipment manufacturers, third-party consultants, and SEMI.

S2 is a comprehensive document that addresses a wide range of equipment and ESH criteria. It is not thephilosophy of S2 to provide all of the specific design criteria that may be applied to semiconductormanufacturing equipment, but rather to provide criteria unique to the industry and a roadmap to some of themany international codes, regulations, standards, and specifications that must be used when designingsemiconductor manufacturing equipment. Among the criteria covered by S2 are ergonomic factors. S8provides more detail on these factors and is cited in S2, therefore, interpretations of S8 are included in thisguidebook as Part Two.

Format

This guidebook is composed of two parts:

• Part One: Application Guide for SEMI S2-93: Safety Guidelines for SemiconductorManufacturing Equipment

• Part Two: Application Guide for SEMI S8-95: Safety Guidelines for Ergonomics/Human

Factors Engineering of Semiconductor Manufacturing Equipment

The text in this guidebook has been arranged to facilitate easy reference as follows.• All references to regulatory standards or guides will be highlighted in bold type. Example: NEMA ICS

1.1• All references to text found in SEMI S2-93 or SEMI S8-95 will be indicated by italics and surrounded by

quotation marks. Example: "upon request.”

The title of each section has been reprinted in the lower outside corner of each page to assist in thenavigation of this guidebook.

÷

iv

Preface Revision 2.0

Guidebook Use

This guidebook is a clarification of the contents of SEMI S2-93 and S8-95 and is intended to be used inconjunction with those documents. It is organized so that content follows the same order as the SEMIGuidelines.

Note: If a particular section of S2 or S8 is not included in this guidebook, it is because the original text wasnot regarded to need clarification or elaboration.

The following general guidelines, interpretations, and conditions should be applied when using thisguidebook:

1. While S2 often refers to safety in general terms, it is expected that the recommendations of S2 andthis guidebook will be applied to the full scope of the environment, safety, and health area includingergonomics. Only where a particular section has specific safety applications (e.g., electrical safety)should the interpretation be limited to safety.

2. The phrase "semiconductor manufacturing” applies to any process that is directly related tosemiconductor device production including wafer processing, assembly, test, and R&D. It is notintended to include peripheral systems, equipment, and structures that support the facility orbuilding or that are not directly used in producing or testing semiconductor devices.

3. For purposes of this guidebook, the phrase "upon request” as stated in SEMI S2-93 is interpretedto read as “required.”

4. The terms "qualified” or "qualified professional” describing an S2 evaluator are difficult todefine. For purposes of this guidebook, this term applies more appropriately to the thoroughness ofthe report produced. While it is understood that an evaluator must possess certain basiccredentials, the quality of the final report will ultimately determine the credibility and acceptability ofthe review. SEMATECH and its members expect that this guidebook will reduce the confusion andambiguity associated with the quality, content, detail of information, and data expected in all S2evaluation reports.

v

Revision 2.0 Preface

ACKNOWLEDGMENTSSEMATECH would like to express its gratitude to those who contributed to the development of thisguidebook:

Karl Albrecht, NationalSemiconductorLynne Arnold, MotorolaBob Arsenault, DoDW. Kerry Barbee, MotorolaSteve Barcik, SEMATECHAimee Bordeaux, SEMIDoug Bower, AMDRon Brooks, SEMATECHSteve Burnett, SEMATECHJim Campbell, IntelBrian Claes, LAM Research Corp.Jenni Carter, EORMBarry E. Clayton, IBMBob Desrosiers, IBMRich Engle, IBMJeff Farmer, SEMIGlenn Fishler, EORMAlexis M. Funk, SEMATECHMike Gooch, RockwellJames W. Gordon, AMDJada Gray, MotorolaStephanie Grelle, AMDMark Harralson, Intel

Stan Hughes, Applied MaterialsGeorge Hynes, DigitalEdward Karl, Applied MaterialsJon Karner, AMDKen Knowles, SEMATECHRick Koski, Santa Clara PlasticsMark Krauss, Inchcape TestingServicesAlan Krov, Texas InstrumentsBill LaBonville, IBMJenna Latt, AMDCurt Layman, IntelMike Lewman, PhilipsSemiconductorGreg Lund, SEMATECHBill Marmust, AT&TAndy McIntyre, EORMRick Miller, Hewlett-PackardRamon Nazarian, TexasInstrumentsCarey Newton, AMDIlya Olshan, DigitalSam Pakdel, NationalSemiconductor

Richard Parker, IntelLynne Reardon, Hewlett-PackardRio Rivas, Hewlett-PackardTania Rippy, Texas InstrumentsSue Ross-Whitesell, TexasInstrumentsJamie Rubin, Hewlett-PackardTroy Schroeder, Symbios LogicJoe Selan, Advanced ErgonomicsHomer Selby, IBM - IMDMike Sherman, FSIKaren Silberman, MotorolaKim Spencer, AMDDawn Speranza, DigitalJennifer Spruce, SEMATECHBrett Stringer, AMDTom Tamayo, IBMSteve Tramell, MotorolaJohn Vaughn, EORMStephen Wilcox, IntelCarl F. Williams, TexasInstruments

And to those who also contributed significant effort to produce Revision 2.0 of this guidebook.

Karl Albrecht, National Semiconductor

Ron Brooks, SEMATECH

Steve Burnett, SEMATECH

Bob Desrosiers, IBM

Ruth Frazer, Steag Microtech

George Hynes, Digital

Rich Kaplan, Applied Materials

Ken Knowles, SEMATECH

Rich Koski, SCP Global Technologies

Mark Krauss, Simcom International

Curt Layman, SGS Control Services

Greg Lund, SEMATECH

Kathy Petterson, SEMATECH

Lynne Reardon, Hewlett-Packard

Mike Shemes, SEMI

Homer Selby, IBM

Brett Stringer, AMD

Steve Tramell, Motorola

Steve Wilcox, Intel

Carl Williams, Texas Instruments

vi

Disclaimer Revision 2.0

DISCLAIMER

THIS GUIDEBOOK REFLECTS THE INTERESTS, OPINIONS, AND POSITION OF SEMATECH AND ITS MEMBER

COMPANIES AND DOES NOT NECESSARILY REPRESENT THE POSITION OR VIEWS OF THE SEMICONDUCTOR

INDUSTRY AS A WHOLE. WHILE EVERY ATTEMPT HAS BEEN MADE TO REFERENCE KNOWN APPLICABLE

REGULATIONS, CODES AND OTHER STANDARDS OR REQUIREMENTS, THE EQUIPMENT MANUFACTURER RETAINS

ULTIMATE RESPONSIBILITY FOR ENSURING THAT THE EQUIPMENT IN QUESTION PROVIDES FULL REGULATORY

COMPLIANCE REGARDLESS OF WHETHER SUCH REQUIREMENTS ARE ADDRESSED HEREIN. IN THE EVENT OF A

CONFLICT, COMPLIANCE WITH LEGAL OR REGULATORY REQUIREMENTS MUST SUPERSEDE THE EXPECTATIONS

EXPRESSED IN THIS GUIDEBOOK.

vii

Revision 2.0 Table of Contents

Table of Contents

FOREWORD ------------------------------------------------------------------------------------------------------------- i

PREFACE---------------------------------------------------------------------------------------------------------------- ii

DISCLAIMER ----------------------------------------------------------------------------------------------------------- v

TABLE OF CONTENTS ----------------------------------------------------------------------------------------------vi

PART ONE: S2-93 APPLICATION GUIDE

1. PURPOSE ------------------------------------------------------------------------------------------------------------ 1

2. SCOPE ---------------------------------------------------------------------------------------------------------------- 1

3. SAFETY PHILOSOPHY ------------------------------------------------------------------------------------------- 1

4. GENERAL GUIDELINES ----------------------------------------------------------------------------------------- 1

5. SAFETY-RELATED INTERLOCKS ---------------------------------------------------------------------------- 3

6. CHEMICALS --------------------------------------------------------------------------------------------------------- 5

7. IONIZING RADIATION -------------------------------------------------------------------------------------------- 7

8. NON-IONIZING RADIATION------------------------------------------------------------------------------------- 8

9. AUDIO NOISE ------------------------------------------------------------------------------------------------------11

10. VENTILATION AND EXHAUST ------------------------------------------------------------------------------11

11. ELECTRICAL -----------------------------------------------------------------------------------------------------15

12. EMERGENCY SHUTDOWN-----------------------------------------------------------------------------------19

13. HEATED CHEMICAL BATHS---------------------------------------------------------------------------------20

14. ERGONOMICS/HUMAN FACTORS-------------------------------------------------------------------------20

viii

Table of Contents Revision 2.0

15. ROBOTICS AND AUTOMATION ---------------------------------------------------------------------------- 21

16. HAZARD WARNING-------------------------------------------------------------------------------------------- 21

17. EARTHQUAKE PROTECTION------------------------------------------------------------------------------- 22

18. DOCUMENTATION --------------------------------------------------------------------------------------------- 22

19. FIRE PROTECTION--------------------------------------------------------------------------------------------- 23

20. ENVIRONMENTAL ---------------------------------------------------------------------------------------------- 23

S2 APPENDIX 1 - TERMINOLOGY ------------------------------------------------------------------------------ 26

S2 APPENDIX 3 - SUPPLEMENTAL INFORMATION------------------------------------------------------- 27

APPENDIX A - ELECTRICAL AND MECHANICAL DESIGN CRITERIA ------------------------------- 29

APPENDIX B - LIQUID HAZARDOUS CHEMICAL DESIGN CRITERIA ------------------------------- 95

APPENDIX C - HAZARDOUS GAS AND LIQUID DOPANT DESIGN CRITERIA -------------------- 99

PART TWO: S8-95 APPLICATION GUIDE

5. TERMINOLOGY ------------------------------------------------------------------------------------------------- 115

8. GENERAL GUIDELINES -------------------------------------------------------------------------------------- 116

9. WORKSTATION DESIGN ------------------------------------------------------------------------------------- 116

10. DESIGN FOR MAINTAINABILITY AND SERVICE ---------------------------------------------------- 118

11. LIFTING, STRENGTH, AND MATERIALS HANDLING ---------------------------------------------- 119

13. CONTROLS AND DISPLAYS ------------------------------------------------------------------------------ 120

14. USER-COMPUTER INTERFACE -------------------------------------------------------------------------- 121

APPENDIX A - MANUAL MATERIAL HANDLING RISK ------------------------------------------------- 123

ix

Revision 2.0 Table of Contents

APPENDIX B - NIOSH EQUATION 1991 DRAFT----------------------------------------------------------- 129

APPENDIX C - BIOMECHANICAL MODELS ---------------------------------------------------------------- 139

APPENDIX D - FORCE DATA ----------------------------------------------------------------------------------- 141

APPENDIX E - CLOTHED ACCESS DIMENSIONS -------------------------------------------------------- 161

APPENDIX F - HANDLE DESIGN GUIDELINE-------------------------------------------------------------- 163

APPENDIX G - AWKWARD POSTURES --------------------------------------------------------------------- 165

APPENDIX H - MAXIMUM GRIP FORCES ------------------------------------------------------------------- 167

REFERENCE DOCUMENTS------------------------------------------------------------------------------------- R-1

GLOSSARY ---------------------------------------------------------------------------------------------------------- G-1

ACRONYMS---------------------------------------------------------------------------------------------------------- G-5

Part One

Application Guide for

SEMI S2-93

SEMATECH Application Guide for SEMI S2-93

1

Revision 2.0 S2-93 Application Guide

1. Purpose1.a. For purposes of this guidebook, “minimum set” is defined as the set of minimumrequirements with expectations explained in this guide by the SEMATECH membercompanies.

1.b. SEMI S2-93 (S2) is intended to be performance-based to allow for flexibility of design;however, in some cases, specific codes and standards are cited in this guidebook to meetspecific requirements.

1.c. Areas of consideration include environment, safety, and health (ESH) and alsoergonomics.

1.d. The term “equipment” is defined as that which is used in manufacturing, developing,and testing semiconductor devices. This includes the entire equipment envelope includingdrains, exhaust ducts, and both point-of-use and facility-wide abatement equipment. This isnot intended to include boilers, HVAC systems, chillers, or equipment that supports thefacility.

2. Scope2.a. The phrase “semiconductor manufacturing” is defined as any process that is directlyrelated to semiconductor device production. This includes, but is not limited to, IC waferprocessing, assembly, test, and R&D.

3. Safety Philosophy3.1.

3.1.a. S2 is a comprehensive document that addresses a wide range of equipment andESH criteria. It is not the philosophy of SEMI S2 to provide all of the specific designcriteria that may be applied to semiconductor manufacturing equipment but rather toprovide criteria unique to the industry and a roadmap to some of the many internationalcodes, regulations, standards, and specifications that must be used when designingsemiconductor manufacturing equipment. Design criteria considered to be the “bestpractice” known at the time of this writing have been included in appendices and shouldbe applied to semiconductor equipment during design and evaluation for S2.

3.2.

3.2.a. The term “equipment” does not apply to any process product that may bedamaged or lost as a result of equipment failure.

3.2.b. See the Glossary for definitions of “fail-safe” and “single-point failure.”

3.3.

3.3.a. This list should not be considered all inclusive.

4. General GuidelinesWhile this guidebook is intended to enhance and clarify the performance suggestionscontained in SEMI S2-93, it is strongly recommended that the equipmentmanufacturer make every effort to apply and conform to all portions of thisApplication Guide. During equipment evaluations for S2 conformance, evaluators areencouraged to regard all portions of this guidebook as explicit requirements and to


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S2-93 Application Guide Revision 2.0

measure the equipment against it in full. It is the end-user’s responsibility to acceptor deny any deviations of the equipment from the directions outlined in this guide.

4.1.4.1.a. Any deviation from these requirements should be negotiated with the end-user’sdesignated ESH representative.

4.2.

4.2.a. It is considered the equipment manufacturer’s responsibility to comply with allapplicable codes and requirements; however, the equipment manufacturer may workwith the end-user to identify these requirements.

4.2.b. The intent of this section is to identify hazards for which there are no feasible,technological, or practical means of reduction or elimination. It is not intended as ajustification for avoiding compliance with any of the specific recommendations of S2.(For example, although silane is a hazardous material for which a safer substitute wouldbe preferred, practical options are currently limited so the hazards of silane usage wouldbe documented in this section of the S2 evaluation report.)

4.2.c. The equipment manufacturer should identify and provide means to isolate,block, or bleed, all hazardous energy to which personnel could be exposed duringmaintenance or service operations in a manner that creates minimum impact on theoperation of the equipment. Equipment should be designed to allow hazardous energyisolation at the subassembly (e.g., pump, RF generators, chambers, chillers, gas system)level.

4.2.d. Equipment manufacturers have a responsibility to employ design-for-ESHconcepts during tool development. Worker protection, pollution prevention, and wasteminimization should be primary design goals. A reduction that does not cause increasedconsumption or waste generation in another area would be considered a trueminimization. Actions that would increase resource usage, generation of wastes, orworker risk should not be pursued.

4.2.e. The term “design” includes the development and manufacture of semiconductormanufacturing equipment which, in turn, is subject to S2 evaluation.

4.2.f. As a minimum, “risk analysis” is defined as the S2 evaluation conducted by aqualified party.

4.2.g. The phrase “applicable laws, regulations, and codes in effect at the time of purchase,and to the guidelines presented here or other applicable product safety standards” implies thatthe review of the tool in question will meet the recommendations of SEMI S2-93 as wellas all applicable recognized codes, regulations, standards, and guidelines in effect at thepoint of delivery of the equipment.

4.2.h. In geographic regions where permits are required for installation, it will benecessary for the end-user’s ESH professional to receive critical data several monthsbefore shipment because of the lengthy permitting process.

4.2.i. The term “property damage” does not include lost product.

4.3

4.3.a. Compliance, as defined in this section, applies to the point of delivery of theequipment; however, equipment manufacturers are expected to address significant ESHcompliance requirements in the design and construction of equipment for end-marketsaround the world. While it may not be feasible to meet all requirements for all possibleend-markets, suppliers intent on marketing to internationally structured customers shouldevaluate this design approach and conform with all feasible requirements. The intent and


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end result of such efforts should be driven by an approach of cost reduction associatedwith the following:1. One unified product design as opposed to multiple design configurations.2. Ease of equipment migration by the end-user from the original point of delivery to

locations where there are significant differences in regulatory requirements.4.4.

4.4.a. Although efforts should be made to contact the individuals described, thepurchasing agent is typically recognized as the primary end-user contact.

4.5.4.5.a. See Glossary for definition of “single-point failure.”

4.6.

4.6.a. In this case, “specific chemistry” is defined as specific process parameters thatinclude temperature, chemicals, feed rates, process times, and pressures (e.g.,“recipes”).

4.6.b. While the equipment manufacturer cannot foresee or control how a piece ofequipment will ultimately be used by an end-user, the equipment manufacturer isexpected to respond to this section. For example, the review of a metal etch tool wouldbe expected to include a basic profile and baseline, keeping common manufacturingprocesses in mind.

4.7.

4.7.a. It is strongly recommended that the services of a qualified ESH professional beemployed during equipment development to ensure that proper ESH designconsiderations are incorporated (see 4.2.d. of this guide).

5. Safety-Related Interlocks5.1.

5.1.a. For personal protection, hardware-based interlocks are recommended wheneveraccess can be gained without the use of a tool to an area that would allow inadvertentcontact with hazards such as remote or programmed machine starts, moving mechanicalparts, hazardous potentials, hazardous energy levels, ionizing and nonionizing radiation,hazardous chemicals, or stored electrical energy. Typically, safety interlocks arehardwired between the logic output (switching) device and a fail-safe magnetic devicethat controls the hazardous energy.

5.1.b. Switches, contacts, and other interlock control devices should be connected tothe ungrounded side of the circuit. Listed, tested, recognized or successfully tested anddocumented components are recommended.

5.1.c. Fail-safe interlocks intended for the protection of personnel and equipmentshould be hardware-based (see 5.1.d. of this guide) and should be designed such that afailure of any component in the interlock circuit would not compromise the safety ofpersonnel or the system.

5.1.d. For hardware safety interlocks, electromechanical devices such as contactors,relays and switches are preferred over solid-state devices and non-user programmablecontrols (e.g., transistors, OP-amps, and diodes). If the use of such solid state devicesare justified, they should comply with the applicable requirements of UL 991 and NEMAICS 1.1; such devices also should be self-monitoring and redundant. Computer hardwareis not considered a hardware safety interlock.


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5.1.e. The equipment manufacturer should describe or define in the operations andmaintenance manuals the safe standby condition that all equipment is placed into aftera power interrupt, emergency off, or automatic shutdown.


5


5.1.f. Hydraulic and Pneumatic Systems

Hydraulic and pneumatic systems should be designed for fail-safe operation.

Quick dump valves are to be used such that no cylinders or other actuation deviceswill be left under pressure (cocked) after normal or emergency off (EMO) operation.

Check valves and/or bleeder paths should be employed to eliminate any guillotineaction of mechanical assemblies by gravitational forces.

Hydraulic and pneumatic systems should be designed and built in compliance withthe Joint Industrial Council (JIC) Hydraulic Standard, H-1 or PneumaticStandard, P-1.

5.2.

5.2.a. Where automatic restoration is not reasonably possible, normal operation modeshould not be restored until interlocks are reactivated. Safety interlocks should requirean intentional operation to bypass. The semiconductor manufacturing equipment shouldnot function in normal operation mode without interlocks activated.

Note: The use of interlocks for controlling hazardous energy during service ormaintenance should not be encouraged in the service or maintenance manuals in lieu oflockout/tagout.

5.4.

5.4.a. The list of hazards in 5.4 is not all inclusive.

5.4.b. Personnel should be protected from hazardous moving parts such as pulleys,shafts, sharp edges, and other potential hazards by solid or perforated safety covers thatare interlocked or require a tool for removal. When a wire mesh or perforated cover isused for protection from hazards, the mesh should meet the recommendations of Table5.4 below.

Table 5.4Mesh Shield Sizes

Distance Between Mesh andDanger Point

Maximum MeshOpening

mm inches mm inches

13 - 38 0.5 - 1.5 6 0.250

38 - 64 1.5 - 2.5 10 0.375

64 - 89 2.5 - 3.5 13 0.500

89 - 140 3.5 - 5.5 16 0.625

140 - 165 5.5 - 6.5 19 0.750

165 - 191 6.5 - 7.5 22 0.875

191 - 216 7.5 - 8.5 32 1.250

5.4.c. Personnel should be protected from flying particles, dusts, mists, or otherhazards by inherent design, capture ventilation, or shielding enclosures.

5.4.d. Cover Types

Top covers for electrical enclosures should be provided to prevent objects fromfalling into the machine.


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Bottom covers for electrical enclosures should be provided to contain burningmaterial inside the machine. Mesh may be used, if necessary. Acceptable bottomenclosures may be 1.0 mm (0.040 in.) sheet metal panel in which round holes 1.95mm (0.078 in.) or smaller are no closer together than 3.2 mm (0.125 in.) from centerto center.

Horizontally hinged covers that are likely to present a hazard should be providedwith a fail-safe device to prevent injury.

Sliding covers that move in a vertical plane and are likely to present a hazard shouldbe counterbalanced or provided with a fail-safe device to prevent injury.

Vertical lift-off doors should be secured by mechanical means.5.6.

5.6.a. Refer to section 5.1 of SEMI S2-93 and this guidebook.

5.8.

5.8.a. Software safety interlocks include computer hardware (e.g., controllers). Refer tosection 5.1 of SEMI S2-93 and this guidebook.

6. ChemicalsRefer to Appendices B and C of this guide for direction in the design of chemical delivery andcontrol systems.

6.1.

6.1.a. Quantitative NIOSH-approved industrial hygiene (IH) monitoring methods orother nationally recognized procedures should be used.

6.2.

6.2.a. This section applies to equipment that uses hazardous production materials(HPMs) or generates hazardous byproducts.

6.2.b. All sampling points (ports) should be readily accessible.

6.2.c. An assessment should be completed to determine the safe shutdown state ofany HPM distribution system. At a minimum, a means for effective shutdown ofexternally supplied HPMs should be located on the piece of equipment at the incomingtool/facility interface.

6.2.d. Gases

Sample point locations should be recommended by the manufacturer for eachventilated enclosure that has non-welded mechanical connections handling HPMsnear, at, or in the exhaust duct.

The gas supply interface should be deactivated (shut down) during emergencyprocedures by a hardware-based fail-safe interlock, not a software-based system(see 5.1.c. of this guide). No system should be solely reliant upon software foreffective shutdown.

If a gas detection alarm system is provided by the equipment manufacturer, a fail-safe interlock-based interface should allow for both high and low alarm levelsranging from ¼ TLV to three times (3x) TLV.

6.2.e. Documentation:

The equipment manufacturer should provide documentation in the operation andmaintenance manuals identifying the following:


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• All chemicals expected to be used in or generated by the tool duringprocessing (see 4.6.b. of this guide).

• Chemicals that are HPMs requiring detection and the regulation requiringsuch detection. (Local ordinances should be considered. Refer to SEMI S2-93, section 3.1).

• All chambers within the tool that contain an HPM.

• Location of all sample points for each HPM (graphic representation ispreferred).

• Description of fail-safe interlock-based gas shutoff mechanism installed.

6.3.

6.3.a. The intent of this section is to prevent the uncontrolled or unintentional mixing ofchemicals. (Also see section 20.5.1. of SEMI S2-93.)

6.4.

Note: This section can be addressed in conjunction with section 6.6.

6.4.a. The equipment evaluator should consider all parts of the equipment systemenvelope, such as drains and exhaust ducts, that may contain process by-productspresenting exposure hazards to operator or maintenance personnel.

6.4.b. Documentation:

The equipment manufacturer should provide documentation identifying the following:

• All anticipated maintenance activities along with chemical and exposureissues expected to be encountered.

• Chemical exposure levels measured or expected to be encountered alongwith relevant literature citations. (The qualifications of the individualperforming this duty should be included if the person is not a CertifiedIndustrial Hygienist.)

6.5.

6.5.a. All pressurized vessels should be equipped with normally closed valves on boththe inlet and outlet chemical lines for bulk-filled systems and on the outlet line for hand-filled systems. These valves should close when the interlock circuit is actuated. Thevessel should be equipped with a pressure relief device plumbed to containment ordrain. The pressure relief device should actuate at no more than 120% of the workingpressure, but less than the vessel test pressure.

6.5.b. The system should be equipped with a means of relieving pressure beforenormal servicing or maintenance. Vessels containing HPMs should have a means ofrelieving the pressure remotely before servicing the vessel or other components in thecompartment. The gas and vapor should be vented to exhaust.

6.5.c. The supply gas line used to pressurize the vessel should contain a check valveto prevent backflow.

6.5.d. The system should be located in an appropriate enclosure providing secondarycontainment that is equipped with the following:

• Draining capability.

• Liquid level sensor interlocked to close chemical supply valve, depressurize thevessel, and alert the tool operator in case of a leak.


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• All nonwelded fittings and valves associated with the vessel should be located withinthe cabinet.

• Covers/doors should be interlocked to prevent opening while any canister is underpressure. When an interlock is not feasible, transparent internal shields should beused to deflect any sudden pressure release.

6.5.e. Pipes, fittings, and gasket materials that contact any toxic, corrosive, flammable,or reactive chemicals should be resistant to those chemicals.

6.5.f. The equipment manufacturer should demonstrate that pressurized vessels andpiping systems meet the ASME Code for Unfired Pressure Vessels.

6.5.g. The vessel should be equipped with a burst disk-type pressure relief device witha minimum 1/2-in. inner diameter (ID) nipple to allow adequate pressure relief in case offire. The pressure relief device should actuate at no more than 120% of the workingpressure, but less than the vessel test pressure.

6.5.h. The vessel should be located in an enclosed cabinet constructed of compatiblematerials. The cabinet should be under negative pressure. If access ports are present,an average face velocity of 100 linear feet per minute (lfm) with no point less than 80 lfmshould be maintained across the panel face while the access panel is open.

6.6.

Note: This section can be addressed in conjunction with section 6.4.

6.6.a. This information should be provided to the end-user regardless of whether or notit was specifically requested. Please refer to section 4 of this guidebook.

6.7.

6.7.a. For compliance with this section, simply see whether or not a label is present atthe recommended locations, then verify that the labeling is adequate for the enclosureidentified. Labels should be placed on the primary enclosures (“primary” means that thehazard is directly behind the enclosure).

6.7.b. Exception: Hazardous gas enclosures need to have a label only on the outermaintenance access panel. Refer to section 16 of SEMI S2-93 and this guidebook fordirection on specific label recommendations.

6.7.c. Documentation:

The equipment manufacturer should identify all chemical enclosure maintenanceopenings in the maintenance manual.

7. Ionizing Radiation7.1.

7.1.a. In keeping with good industrial hygiene practice, emission levels should be keptAs Low As Reasonably Achievable (ALARA). At no time should emissions exceed theACGIH TLVs.

7.1.b. This section applies to the normal operations, service and/or repair of anyequipment, tool, or device that uses radioactive materials or can produce ionizingradiation.

7.2.

7.2.a. Documentation:


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The equipment manufacturer should provide documentation that includes thefollowing:

• A list identifying

1. all radioactive material, including activity level(s), contained within theequipment.

2. any equipment that generates ionizing radiation above regulatorythreshold levels as well as the measured level of external radiation.

• A copy of the manufacturer’s submittal to the NRC, FDA, or otherappropriate agency. If the manufacturer has exempt status, cleardocumentation indicating such should be provided.

• A copy of the performance guarantee accepted by the NRC or otherapplicable regulatory agency(ies) for the equipment model unless theequipment has been generically exempted by classification.

7.3.

7.3.a. Administrative controls are considered a secondary control measure. All feasibleoptions for primary (engineering) controls such as shielding should be fully appliedbefore instituting administrative control measures.

7.3.b. When used, administrative controls should be documented clearly in alloperation and maintenance manuals and included in appropriate labeling on theequipment. All equipment labeling should comply with sections 16 and 18 of SEMI S2-93,.

7.3.c. Documentation:

When administrative controls are to be used, the equipment manufacturer shouldprovide documentation explaining why primary controls were not feasible.

7.4.

The intent of this section is to minimize the potential for exposure of service personnel toany type of radiation.

7.4.a. All safety-related interlocks should meet the recommendations of SEMI S2-93,section 5.

7.4.b. Nondefeatable interlocks must meet NRC or other applicable regulatory agencyrequirements.

7.4.c. Documentation

A warning label must be placed on any panel that can be removed during repair,maintenance, or servicing. Any non-interlocked panel that can be removed must belabeled and documented in the maintenance manual.

8. Non-Ionizing Radiation8.1.

8.1.a. This section covers normal operations and maintenance of equipment using orgenerating non-ionizing radiation including ultraviolet, visible light, near infrared, radiofrequency/microwave, static magnetic fields, subradio frequency, and lasers.

For Non-laser Equipment:

8.1.b. See section 5 of SEMI S2-93 regarding interlocks.


10


8.1.c. The ACGIH TLVs for ultraviolet, visible, infrared, static electric, and magneticfields, and radio frequency (0-3 KHz) determine the maximum acceptable environmentalexposure levels to non-ionizing radiation. Exposure limits for radio frequency (RF)radiation (3 KHz - 300 GHz) are those found in IEEE C95.1.

8.1.d. In keeping with good industrial hygiene practice, emission levels should be keptAs Low As Reasonably Achievable (ALARA). At no time should emissions exceed theACGIH TLVs.

8.1.e. Safety interlocks incorporated in equipment covered by this standard should beconsistent with all other fail-safe safety interlocks, hard wired, and of fail-safe design.

8.1.f. Equipment using or generating microwave radio frequency/sub-RF should bedesigned to incorporate engineering controls which ensure that radiation exposures topersonnel are As Low As Reasonably Achievable (ALARA). The maximum permissibleemission level is 50% of the IEEE C95.1 limits for Uncontrolled Environments (3 KHz -300 GHz) or 50% of the ACGIH TLVs for frequencies < 3 KHz.

For Laser Equipment:

8.1.g. It is acceptable to establish temporary Class III and IV laser controlled-accessareas during maintenance and service operations. The equipment manufacturer shouldidentify those operations requiring the establishment of such areas in the maintenanceand service manuals.

8.1.h. The reference to “OSHA 29 CFR 1046.10” should read “FDA 21 CFR 1040.10.”

8.2.

8.2.a. Documentation

The equipment manufacturer should identify all non-ionizing radiation sources(including lasers) along with the frequency, wavelength, and energy level in alloperation and service manuals as well as through labeling on the outside skin of theequipment next to the ID plate on the tool. Refer to SEMI S1 for guidance on visualhazard alerts.

For Non-laser Equipment:

8.2.b. Table 8.2 illustrates typical non-ionizing radiation types and the equipment usedto measure their related hazards.


11


TABLE 8.2Non-Ionizing Radiation

Non - IR Type Typical LocationMonitored

Equipment Typically Usedfor Survey

Static MagneticFields

Around source magnet housings. Static magnetic field strengthmeter that measures in Gauss.

UV Light Emissions Lamp housings, view ports,plasma chamber view ports,visible emission points onequipment that uses or producesUV.

Radiometer with UV detector thatweights measured emissions toTLV Relative SpectralEffectiveness Curve.Measurements are in mW/cm2.

RF/MicrowaveFields

Input and output cables,generators, match covers, viewports, chambers, magnetrons,and equipment connected to toolthat may act as an antenna.

Frequency specific probes, E-field(measured in V2/M2) and H-field(measured in A2/M2) probes. UseIEEE C95.1 as guide.

Visible Light andNear-IR

Housing to IR Lamps that havevisible light leakage and ports,lamp arrays during maintenanceviewing.

Radiometer with detectors that arefrequency-specific and coverACGIH-TLV appropriate spectralranges. Measurements are inmW/cm2.


8.2.c. Where ANSI Class III & IV laser light emissions are accessible duringmaintenance, servicing, or repairs, administrative controls should be clearly defined inthe maintenance and service manuals (e.g., procedures for setting up temporary lasercontrolled areas, posting signs, and securing access to area) in compliance with ANSIZ.136.1.

8.4.


8.4.a. The equipment manufacturer should include the initial product report in the S2evaluation report, including the assession numbers received from the CDRH.

8.4.b. The equipment must have a certification label as part of the labelingrequirements outlined in 21 CFR 1040.10(g).

8.5.

8.5.a. Point-of-hazard panels are those that are not intended to be removed duringnormal operation or maintenance (i.e., they require only infrequent service or repair). Allsafety-related interlocks should meet the recommendations of SEMI S2-93, section 5.

8.5.b. Nondefeatable interlocks must meet CDRH requirements.

8.5.c. A warning label is required on any panel that can be removed during repair,maintenance, or servicing.

8.5.d. Any noninterlocked panel that can be removed must be labeled and identified inthe maintenance and operation manuals.


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8.6.

8.6.a. The term “faulty installation” includes the absence of shielding installation. Theequipment manufacturer should make every effort to ensure that all shielding is properlyin place before the equipment can be operated.

9. Audio Noise9.1.

9.1.a Continuous and intermittent noise levels should be maintained at levels lessthan 80 dB(A), slow response. Impact noise, if present, should be maintained at levelsnot to exceed 130 dB peak.

9.2.

9.2.a. This exception applies only to equipment that generates no measurable noiselevels during normal operation (e.g., microscope).

9.2.b. The measurement technique used must comply with ANSI S1.13, Methods forthe Measurement of Sound Pressure Levels. The equipment mode of operationduring the noise level tests must simulate as closely as possible the actual operatingmodes and conditions that may be experienced by the equipment user. Measurementsmust be taken at 1 meter (3.3 feet) distances completely around the equipment and itssupport equipment (e.g., pumps and motors) while equipment is in operating mode. Themicrophone must be held approximately 1.5 meters (4.9 feet) above the ground and 1meter (3.3 feet) from the nearest major equipment surface. For operator-attendedequipment, the microphone must be placed at the operator location for standing (approx.1.5 meters) and sitting (approx. 1.2 meters) positions as measured from thewalking/working surface.

9.2.c. Noise level test measurements from suppliers of components to the equipmentmanufacturer may be included.

9.2.d. Documentation

All noise levels, duration, frequency of occurrence, and meter calibration must beclearly stated in the test results.

10. Ventilation and Exhaust10.1.

10.1.a. “These systems should optimize the use of air flow, as far as practical directingescaping chemicals so they do not impinge on the equipment” or expose personnel.

10.1.b. The following are considered to be modes of operation:

• Normal

• Maintenance

• Failure

10.1.c. Test validations should be performed using all reasonable setups for the threemodes of operation. Testing in maintenance mode should validate flows while one or allmaintenance access panels are opened.

10.1.d. A minimum duct velocity recommendation should be provided to demonstrateefficient and safe control of chemical emissions.


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10.1.e. To achieve optimized equipment exhaust (maintained as low as possible) theequipment should be designed to

• Compartmentalize potential leak points.

• Minimize size and number of potential openings.

• Maintain static pressure in enclosures greater than or equal to a -0.1 incheswater gauge.

• Minimize the total size of enclosures .

• Promote even air flow through enclosures from one end to the other using“design for sweep.”

10.2.

10.2.a. “Primary Safety Control” is defined as the first method used to contain or controla chemical by ventilation (refer to SEMI F6 for further explanation).

10.2.b. “Exhaust loads that require continuous flow [to] external treatment should beminimized.” All exhaust loads should be minimized.


The equipment manufacturer or evaluator should identify the following:

• All HPM, odorous, and irritant chemicals present in equipment.

• Where exhaust is used as the primary safety control (rather than other controlssuch as chemical substitution or tool purging), and provide justification for usingexhaust as the primary safety control.

• Static pressure and flow rates of all continuous flow exhaust along withjustification of levels (the goal is to limit exhaust to a minimum while remainingeffective in all operating modes).

• All nonroutine access enclosures (other than those identified for section 6.7 ofthis guide).

• Where supplementary exhaust is needed during maintenance operations wherefeasible. If not feasible, specific design requirements for exhaust should beprovided to the end-user. Maintenance or supplemental exhaust required formaintenance should be designed into the tool by the equipment manufacturer.Supplemental exhaust should be considered part of equipment maintenance.

10.3.

10.3.a. The chemical list created for section 6.2 should indicate those chemicals with anNFPA 704 hazard rating of 3 or 4 by designating them as Hazardous ProductionMaterials (HPMs).

10.3.b. “The equipment supplier should document when external exhaust is required andspecify the requirements” for both process and standby modes.


The equipment manufacturer should document that all nonwelded connectionscontaining HPMs under pressure are in an exhausted enclosure.

10.4.

10.4.a. Refer to Tracer Gas Analysis Method as described in SEMI F15.

10.5.


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10.5.a. The phrase “these criteria” refers to sections 10.5.1 through 10.5.4 of SEMI S2-93.

10.5.b. Laminar room air flow conditions should exist or be simulated during all tests.The year of publication should be provided for all TLV/PEL levels quoted for tests.

10.5.c. Tracer Gas Analysis (TGA) method (refer to SEMI F15) is preferred for all HPMgas enclosures; however, because using this method can overlook the buildup of gasesover time, supplementary testing methods have been outlined in Table 10.5 for thevarious types of equipment ventilation configurations.

TABLE 10.5ENCLOSURE TESTING METHODS

Type of Enclosure Preferred Performance Test Method

HPM Gas Enclosures:

nonpyrophorics

pyrophorics only

Tracer Gas Analysis (TGA) plus air pattern assessment

TGA, air pattern assessment plus, appropriate air velocityassessment

Lab Hood Face velocity plus air pattern assessment (ASHRAE Lab HoodStandard)

Wet Stations Vapor visualization, face velocity

All other hazardous chemicalenclosures without HPM gases(e.g., bubbler and vacuum systemenclosures, liquid dispensingcabinets, pressurized liquidpumps)

Negative pressure confirmation through air pattern assessment

10.5.d. Documentation

The equipment evaluator should include a complete description of the testingmethods used for

• Visual Pattern Assessment

• Static Pressure

• Capture Velocity

• Duct Velocity

• Face Velocity

Environmental parameters (conditions of the room during testing) should also bedescribed in detail.

10.5.1.

10.5.1.a. Documentation

Measure using the appropriate NIOSH/OSHA method for a representative periodof time— at least 15 minutes or one complete tool cycle. The 1% of ACGIHrecommended TLV or PEL is considered the ceiling limit. At no time shouldthere be an exposure during normal operating conditions.

10.5.2.


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10.5.2.a. See “secondary containment” in Glossary.

10.5.2.b. Vapor visualization tests should be considered for failures involvingliquid releases into secondary containment in the back of wet decks.

10.5.2.c. If NIOSH-approved testing methods are not feasible, professionaljudgment based on visual testing conducted by a CIH or equivalent will suffice.

10.5.3.

10.5.3.a. This section should be addressed in conjunction with sections 6.4 and6.6.

10.5.4.

10.5.4.a. In addition to work areas, exhaust systems, maintenance areas, and anyother locations where measurements are taken should meet this criteria.

Note: For purposes of completing the industrial hygiene evaluation under theconditions described in sections 10.5.1 through 10.5.3, an alternative test guaranteecan be made in writing as an alternative to the NIOSH-approved IH test method. Thequalifications of the individual(s) providing this guarantee should be provided.

10.5.4.b. Documentation

Records of instrument calibrations performed by an accredited lab arerecommended.

10.6.

10.6.a. The intent of this section is to improve exhaust optimization for the equipmentwhile not causing ergonomic stress on maintenance personnel.

10.6.b. Hinged doors are preferred.

10.6.c. Visual ports should be included where possible to eliminate the need to removepanels.

10.7.

10.7.a. The equipment manufacturer should include a picture or schematic in theoperation and maintenance manuals indicating where to sample.

10.8.

10.8.a. Refer to SEMI S6 for specific exhaust application(s).

10.9.

10.9.a. Interlocks systems include components such as the Dwyer Photohelic devicethat place the tool in a safe standby mode if exhaust flow falls below a minimum setpoint.

10.9.b. An alarm for low flow should be visible and audible from both the front and backof the equipment.

10.9.c. The equipment manufacturer should reference “safe standby condition” asdefined in section 5.1.e.

10.9.d. The equipment manufacturer should make the interlock system tamper-proofand include calibration records or recommendations for calibrating the monitoringdevice(s).

10.9.e. Static pressure devices are preferred over velocity monitors for corrosive andaerosol (wet) environments. Monitors are effective for gas boxes. Multiple alarm levelsare desired for static pressure exhaust systems.


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10.9.f. All devices should use the mid-third of their range for normal flow detection.

11. Electrical11.1.

11.1.a. The reference note following type 3 should read: (NFPA 79, EN 60204, UL 1950& 3101, EN 60950).

11.1.b. The supplier should list type 3 or higher electrical hazard tasks by their type (asdefined in SEMI S2-93, section 11.1) in its equipment operation and maintenancemanuals.)

11.1.c. As stated in 11.1, every effort should be made to modify potential type 4 and 5tasks (Hot Work categories) to the lowest possible category. Those tasks that mustremain type 4 or 5 should receive special emphasis in attention to detailed compliancewith the criteria listed in 11.1.

11.1.d. OSHA Confined Space Entry requirements should be considered in type 5tasks.

11.1.e. Type 4 and 5 tasks should be identified in the maintenance manual by icon andtype, with hazards clearly described.

11.2.

11.2.a. Each separate subassembly of the total equipment system (including remote andancillary support equipment receiving power from an equipment supplier-provided powerdistribution panel) must be equipped with a lockable energy isolation device whererequired by OSHA 29 CFR 1910.147. Lockable energy isolation devices integral to theequipment power distribution panel are acceptable if the protected componentequipment is located within 25 feet (7.6 meters) line-of-sight of the panel.

11.2.b. The lockable energy isolation device must be in a readily accessible location andlockable in the de-energized position only.

11.2.c. It is recommended that resetable circuit protection devices be accessible withoutexposing employees to live wiring.

11.3.1.

11.3.1.a. Nonconductive barriers are preferred.

11.3.2.

11.3.2.a Access holes through shields and covers and remote or external testpoints are recommended.

11.3.2.b. Barriers should be provided where

• Service is required with power on and inadvertent contact is likely.

• It is necessary to reach over, under, around, or in close proximity to hazards.

• Dropped tools could cause shorts or arcing.

11.3.3.

11.3.3.a. Refer to SEMI S9 test document for electrical test methods.

11.3.4.

11.3.4.a. The equipment should meet the standard electrical codes of the countryin which it will be used. See section 4.3 of this guide.


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11.3.4.b. All conductors within a harness, wireway, or raceway should haveinsulation rated for use at the highest potential present.

11.3.4.c. The intent of the second paragraph is to address components in thesystem that cannot be certified, listed, or recognized by a testing laboratory.

11.3.4.d. Heat Tapes and Bands

• Should be listed, recognized, or certified.

• Should have complete manufacturer’s use and installationinstructions/specifications.

• Application and integrated use should conform to UL 499 requirements.

• Heat tapes/bands and/or cables should not be modified.

• Should not be installed in applications where flammable chemicals areused or dispensed.

• Should be protected by a ground-fault circuit interrupt designed toprotect personnel.

11.3.5.

11.3.5.a. Refer to NFPA 79 and/or EN 60204 for guidance on color codes.

11.3.5.b. It is acceptable to wrap conductor termination points with appropriatelycolored tape or sleeving reliably secured to conductor. (Sleeving is preferred.)

11.3.6.

11.3.6.a. The equipment supplier should provide appropriate overcurrentprotection.

11.3.7.

11.3.7.a. EXCEPTION:Circuit breakers and circuit protectors are preferred over fuses as overcurrentdevices for the following reasons:

• They can be reset without exposure to energized terminals and, therefore, canbe safely reset by nontechnical personnel.

• The risk of putting an over-rated fuse into a socket is eliminated by the use ofcircuit breaker and protectors that are hardwired into the system.

• Multipole units that open all conductors simultaneously (such as those used onthree-phase circuits when an overload occurs) may be used.

11.3.7.b. The general recommendations of circuit protection devices are asfollows:

1. Amperage - Circuit protection devices should not exceed the amperage rating ofthe components and conductors they protect.

2. Location in circuit - Circuit protection devices should be located at the pointwhere an ungrounded conductor connects to a larger conductor or its supplysource.

Exceptions to the location recommendations should meet one of the following:

EXCEPTION 1: Where the conductor

• Is not over 7.6 meters (25 feet) long.


18


• Amperage rating is at least one-third that of the conductor from which it issupplied.

• Terminates at a single circuit protection device.

• Is protected from physical damage.

Note: The conductor should not connect to any component or device beforetermination at the protection device.

EXCEPTION 2: Where the conductor:

• Is not over 3.05 meters (10 feet) long.

• Amperage rating is at less than the maximum continuous load current of thecircuit.

• Amperage rating is not less than the rating of the device supplied or therating of the overcurrent protective device at the conductor termination.

• Does not extend beyond the control panel enclosure.

EXCEPTION 3: Where the circuit protection device protecting the largeconductor also protects the smaller conductor.

3. Parallel devices - Circuit protection devices should not be connected in parallelto attain recommended amperage capacity.

4. Thermal devices - Thermal devices are not designed for short circuit protectionand should not be used for conductor protection.

5. Grounded conductors - Circuit protection devices should not be connected inseries with grounded or grounding conductors.

6. Accessibility - Circuit protection devices should be readily accessible by servicepersonnel.

7. Enclosures - Circuit protection devices should be enclosed.

8. Labeling - The amperage rating of circuit protection devices should be indicatedin a manner that is clear, durable, and visible after installation.

9. Resets - Automatically resetting circuit protection devices are not desired.

10. Mounting - Circuit protection devices should not be mounted on hinged orremovable access panels.

11. Connection - Circuit protection devices should be connected to the load side ofthe supply circuit disconnection means.

11.3.7.c. Clip-type fuse holders and fuses should meet the followingrecommendations:

1. Use - As branch circuit protection.

2. Rating - Fuse holders should be rated for the amperage and voltage of thefuse and should be a minimum of

• 250V for 120/208 V circuits

• 600V for 277/480 V circuits

3. Enclosures - Fuses should be installed within a NEMA-type enclosure thathas positive deenergization capability before opening.

11.3.7.d. Panel-mounted fuse holders and fuses should meet the followingrecommendations:


19


1. Shock-proof fuse holders should be used.

2. Use - 120 V, 15 A or less, single-phase circuits (less than 2 kVA).

3. Rating - Minimum of 125 V.

4. Wiring - Fuse holders that have exposed metal when the cap is removed(nonshockproof fuse holders) should have the line conductor connected tothe end terminal and the load conductor connected to the side terminal.

5. Disconnect - Provision should be made for deenergization of the fuse duringreplacement.

6. Mounting - Fuse holder should have a D-punched hole, or equivalent, so thatit will not rotate while the fuse is being removed.

Note: In-line fuse holders are not desirable for installation in equipment.

11.3.7.e. Circuit breakers and circuit protectors are not designed and/or listed forthe same function. Circuit breakers should meet the following:

1. Use - Short-circuit and/or over-current protection in any circuit.

2. Method of Operation - Should be manually operable and should clear a faulteven if the handle mechanism were held closed.

3. ON and OFF indication - Should clearly indicate ON (closed) and OFF(open) positions.

4. Mounting position - Should be mounted on a vertical surface with handle upfor the ON position.

EXCEPTION: If horizontally mounted in a commercial distribution panel, thehandle may be toward the center for the ON position.

5. Disconnect - Should open all ungrounded conductors if a fault occurs in anyphase.

6. Installation - The supply conductors should be connected to the line side ofthe breaker.

11.3.7.f. Circuit protectors (circuit interrupters) are recognized as componentappliance controls and are not interchangeable with circuit breakers because theymay not provide short-circuit protection. Circuit protectors should meet the followingrecommendations:

1. Use - Supplementary (branch circuit) overcurrent protection in dataprocessing and other non-industrial application.

2. Method of Operation - Should be manually operable and should clear a faulteven if the handle mechanism were held closed.

3. ON and OFF indication - Should clearly indicate ON (closed) and OFF(open) positions.

4. Mounting position - Should be mounted on a vertical surface with handle upfor the ON position.

5. Disconnect - Should open all ungrounded conductors if a fault occurs in anyphase.

6. Installation - The supply conductors should be connected to the line side ofthe protector.

11.3.8.


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11.3.8.a. EXCEPTION 3:Multiple units mounted separately with no shared hazards and withoutinterconnecting circuits with hazardous potentials or energy levels or otherpotentially hazardous conditions may have

1. Separate sources of power.

2. Separate supply circuit disconnecting means.

3. Separate emergency off (EMO) circuits if they are clearly identified.

11.3.9.

11.3.9.a. SEMI S2-93’s reference to NFPA 79 2-7 is now outdated. Thenumbering system in NFPA 79 has changed. Use the most current revision.

11.4.

11.4.a. Whether integrated within the footprint or not, UPS should comply withsection 11.4.

11.4.b. Any UPS over 240 VA should comply with SEMI S2-93, section 11.1.

11.4.c. Any UPS greater than 240 VA should comply with section 12 recommendationsfor emergency shutdown.

11.4.1.

11.4.1.a. “Output of the UPS” is defined as the UPS power to the tool.

11.4.1.b. The last sentence should state, “The emergency off circuit and the mainequipment breaker should be a hardware-based fail-safe circuit.”

11.4.2

11.4.2.a. “Physically isolated” is defined as properly enclosed and clearlyidentified.

11.4.4.

11.4.4.a. “Separate” is defined as UPS wiring will not be routed with any otherequipment wiring.

12. Emergency Shutdown12.1.

Note: External EMO interfaces should be considered where the equipment is likely to beintegrated and share hazards with other assemblies in the end-user’s facility.

12.1. EXCEPTION: The following sentence should read: “The component installationmanual, however, should provide clear instruction to the system user to connect the componentto the equipment’s emergency off circuit.”

Note: An example of an exception is an RF generator or spin dryer.

12.2.

Note: For examples of circuit design, refer to Figures 25 through 28 of AppendixSupplement A.2: Typical Circuits.

12.2.a. EMO controls in single-phase equipment operating at 120 V or less, with up to2.4 kVA main protection, where hazards are primarily electrical may be operated at linevoltage. These controls should comply with one of the following:


21


• The main supply disconnect switch may be used if it is readily accessible to theequipment operator, clearly labeled, and clearly indicates ON/OFF status.

• A dedicated EMO switch may be used.

12.4.

12.4.a. Refer to SEMI S2-93, section 11.4.1.

12.4.b. Additional EMO buttons should be provided when any operation or maintenancelocation is greater than 3 meters (10 feet) from a button or there is a physical barrier(e.g., wall, floor, service panel) between work locations and a button.

12.4.c. The EMO should be located in an area not subject to accidental activation. If abutton guard is installed, its diameter should be no less than 75mm (3 inches) with thebutton recessed no more than 3mm (0.125 inches) from the front of the guard, orequivalently configured to allow for palm activation.

12.4.d. The switch should not be used in place of the stop (OFF) switch.

12.4.e. The switch should take precedence over all other controls. TEST: See AppendixA section 6.5.1 bullet 4 on page 79.

12.4.f. For labeling requirements, refer to NFPA 79 which requires a yellow backgroundfor EMO.

12.5.

12.5.a. Self-latching EMO buttons should be used. Lockable types will require approvalby the end-user.

12.6.

12.6.a. SEMI S2-93’s reference to NFPA 79, Chapter 11 is outdated. The numberingsystem in NFPA 79 has changed. Use the most current revision.

12.6.b “NOTE” NFPA 79 allows red push buttons for emergency stop, stop, and off.These buttons should be clearly distinguishable from EMO.

13. Heated Chemical BathsNote: Clause 3 of SEMI S3 also addresses external tank heaters and heat exchangers.

13.a. Other heating system designs should also consider the listed applicable criteria.

14. Ergonomics / Human Factors14.a. See Part Two, Application Guide for SEMI S8-95 for direction on ergonomicsconsiderations in equipment design.

Note: A course has been developed to help equipment manufacturers implement ergonomicdesign criteria. For further information, contact SEMI.

14.5.

14.5.a. A machine, when in a standalone condition, should not overbalance when tiltedin each direction to an angle of 10 degrees from its normal position (IEC 1010-1). (SeeFigure 14.5.1.)


22


14.5.b. A machine should not tilt when a force equal to 20% of the machine weight isapplied (see Figure 14.5.2) in either a horizontal or vertical direction at the point ofmaximum moment when hinged frames, drawers, and so on, are extended for service intheir most unfavorable positions.

100

F

Figure 14.5.1Maximum Machine Tilt

F=.2w

F=.2w No Tilt

Figure 14.5.2Maximum Moment Force Tilt

15. Robotics and Automation15.a. Robot E-stops, if used, should be labeled and clearly distinguishable from the EMO.

15.b. EMOs should place the equipment in a safe standby condition and should notincrease the hazard level.

16. Hazard Warning16.a. ANSI Z535 is the preferred standard to be used.

16.b. Shielding

Surfaces exceeding the limits in Table 16 or temperatures below 0°C should be shielded andlabeled appropriately.


23


Table 16Surface Temperature Limits in °C

Material Type

Operator

Accessible Areas

HighlyConductive

(most metals)

ModeratelyConductive

(glass)

SlightlyConductive

(most plastics)

Hand-held1 or Carried 50 55 65

Will Touch2 55 65 75

May Touch3 70 75 90

Service Areas

Will Touch2 55 65 75

No Need To Touch4 80 100 120

1. Operator contact duration is in excess of five seconds.

2. Operator or service personnel will touch the surface for less than 5 seconds at a time.

3. Surfaces where inadvertent contact is possible.

4. Surfaces not likely to be touched during normal operation.

17. Earthquake Protection17.2.

17.2.a. “Tie-ins and attachments” should be capable of accommodating the expecteddisplacement without increasing the hazard.

18. Documentation18.a. The equipment manufacturer or evaluator should provide an evaluation (the S2report) with detailed documentation demonstrating compliance with each section of S2.

18.b. Where the phrase “upon request” is stated throughout this section of SEMI S2-93regarding documentation, such documentation is required.

18.1.

18.1.a. The “equipment owner” is defined as equipment engineer.

18.2

18.2.a. Procedures that should be documented for the end-user include the following:

• Lockout/tagout procedures for the specific equipment (including proper gaspurging and capacitor discharge procedures).

• Energized work procedures (e.g., maintenance and calibration, or robotprogramming).

• Calibration and maintenance of leak, gas, and fire detection equipment andsuppression systems.

• Confined space entry procedures (if applicable).

18.3.


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18.3.a. The explanatory diagram should include a process flow diagram.

18.3.b. Equipment manufacturers should provide a written response to their S2 reportswhen noncompliance is identified. The phrase “Upon request” in this section of SEMI S2-93 means “required.” See the Preface and section 4 of this guidebook for elaboration.

18.4.

18.4.a. “(See Section 20.2)” should read (see sections 20.2, 20.4, and Application Note 4of SEMI S2-93).

18.4.b. “Frequency and level of non-ionizing radiation. (See Section 8.2.)” should readFrequency and level of non-ionizing radiation. (See section 8.2 and Application Note 5.)

19. Fire Protection19.2.

19.2.a. The overall expectation is that flammable or combustible materials should notbe used without adequate justification, and whenever they are used, they should notexceed the parameters stated in 19.2 of SEMI S2-93. (Refer to NFPA 318.)

19.2.1.

19.2.1.a. UL 94V-0 is recommended.

Note: It should not be assumed if the material meets UL 94V-0 that it is non-combustible.

19.3.1.

19.3.1.a. All enclosures should be evaluated for fire protection systems.

19.3.1.b. All fire protection systems, as well as individual components, should beappropriately listed or recognized by an accredited testing lab, and must meetappropriate NFPA standards.

19.3.1.c. The equipment manufacturer should provide appropriate designcalculations for all fire protection systems.

20. Environmental20.1.

20.1.a. In the second paragraph, the words parameters are should be substituted for theterm “chemistry.”

20.1.b. While the equipment manufacturer cannot foresee or control how a piece ofequipment will ultimately be used by an end-user, the equipment manufacturer isexpected to respond to this section. (For example, the review of a metal etch tool wouldbe expected to include a basic profile and baseline, keeping common manufacturingprocesses in mind.) For the baseline process, the manufacturer should specify processparameters including, but not limited to, chemicals, feed rates, temperature, processtimes, pressure, and RF power.

20.2.1.

20.2.1.a. “Upon request” means “as required.”

20.2.1.b. It is expected that this information should be supplied during theequipment selection process unless otherwise requested.


25


20.2.1.c. The following statement should be used in place of the last sentence ofsection 20.2.1 of SEMI S2-93: Permit application information provided by theequipment manufacturer should include chemical requirements, waste water effluentcharacterization, hazardous waste generation rates, solid waste generation rates,exhaust effluent characterization, and on-board effluent control technologies. Thisinformation includes the percentage of process chemical that actually reacts or isdeposited on the product or the percentage of the input chemical that directlycontributes to the desired result. The equipment manufacturer is encouraged to usethe best available technology in generating this information. Refer to ApplicationNote 4 in SEMI S2-93 .

20.2.2.

20.2.2.a. “Spill prevention features” to be designed into the equipment includesecondary containment, seals, automatic shutoff devices and alarms, segregation ofincompatible chemicals or wastes, and features that enhance ease of maintenance,cleaning, loading/unloading, and filling and emptying baths/chambers.Documentation of spill prevention features should address gases, liquids, and solids.

20.2.2.b. Spill containment should be adequate to contain effluents resulting froma single-point equipment or operator failure.

20.2.3.

20.2.3.a. The equipment manufacturer should include the MSDS(s) for thesechemicals with the documentation.

20.2.3.b “Contamination by process” is interpreted as contamination from theprocess.

20.2.3.c. Potential sources of hazardous materials or materials likely to becontaminated during processing should be identified in the S2 report.

20.2.3.d. Equipment design should minimize the change-out of peripheralequipment maintenance fluids in both frequency and volume.

20.2.4.

20.2.4.a. It is also considered the manufacturer’s responsibility to be familiar withlocal requirements; however, the manufacturer may work with the end-user toaddress these requirements and these criteria (see 4.2.a of this guide).

20.2.5.

20.2.5.a. The term “environmental engineer” should be defined as a qualified ESHprofessional. The ESH professional should review the S2 report provided by theequipment manufacturer to ensure that site-specific requirements are met.

20.3.2. Note: Deionized water use should be included in the chemicalminimization strategy.

20.3.3.

20.3.3.a. “less hazardous material” is interpreted as least hazardous material.

20.3.3.b. The term “process chemistries” should be defined as process parameters(see 20.1.a of this guide).

20.4.1.

20.4.1.a. The terms “by-products,” “emissions,” and “effluents” include gases,vapors, mists, and particulates from processing equipment. Consideration should begiven to byproducts that might be formed when chemicals are present, taking intoaccount possible reactions of multiple chemicals used in the equipment. Effluent


26


characterization includes both species and quantity of emissions and should bereported in standard units of measure (e.g., ppm). See Application Note 4 in SEMIS2-93 for an example list of effluent constituents. The supplier should document thetest methods used to characterize the emissions. Characterization includesspecifying the average and maximum emissions that can be expected during normaluse, idle time, and maintenance operations.

20.4.2.

20.4.2.a. Exhaust flow rates should be optimized/minimized (see 10.1).

20.4.3.

20.4.3.a. This evaluation of control/abatement alternatives should include, at aminimum, reviewing current best practices and collecting available test data on theirefficiencies.

20.4.3.b. Control devices may include mist eliminators or condensers to collectliquid from heated chemical baths that condenses in cooler exhaust ductwork andparticulate traps behind furnace chambers or combustion devices. Recycling ofeffluent should be considered whenever possible.

20.4.3.2.

20.4.3.2.a Refer to regulated ODSs, PFCs, and CFCs. To the extent possible,the process should also be designed to operate without the use ofperfluorocompounds (PFCs) such as CF4, C2F6, NF3, C3F8, CHF3, and SF6 (seecomments on Application Note 4 in this guide). PFC use and emissions willlikely be more strictly controlled in the future on an international level. The useor creation of global warming gases (e.g., CO2, NOX, SO2) should also beminimized or eliminated if possible.

20.4.3.3.

20.4.3..3.a. Provisions should be made for separation of exhaust or wastestreams in cases where emissions or effluent are chemically incompatible,individually recyclable, or require separate abatement/treatment procedures.

20.5.

20.5.a. “as to terms of” should be defined as depending upon.

20.6.

20.6.a. Equipment sinks, plenums, and waste lines should use double-contained lines,partitions, or other design features to prevent the mixing of incompatible waste streamssuch as solvents and water.

20.6.b. Effluent discharge of regulated substances should be avoided or minimized.Pollution prevention activities may include:

• Segregating waste streams for the purpose of recycling or reclaiming.

• Increasing process efficiencies/optimization.

• Reducing material usage during idle time.

(See 20.3.3 of this guide)

20.6.1.

20.6.1.a Design should encourage central collection instead of local collection ofchemical wastes.

20.6.3.


27


20.6.3.a. This section applies to cases of equipment point-of-use collection.

20.6.3.b. Level detectors, leak detectors, and related alarms should be installed inequipment. See Appendices B and C of this guide for direction on leak detection.

20.6.4.

20.6.4.a. Equipment should be designed such that maintenance or repair resultsin a minimized amount of waste and involves using the least hazardous cleaningmaterials. The use and disposal of batteries should also be minimized.

20.6.5.

20.6.5.a. “clean up or disposal” is interpreted as decontamination and disposal.

20.6.5.b. Equipment design should incorporate life-cycle considerations such as

• Refurbishment/reuse

• Modular construction

20.7.

20.7.a. All secondary containment should incorporate appropriate gas detection, liquidsensors, and alarms. If incompatible chemicals are used in the same piece ofequipment, secondary containment should be designed to ensure that these chemicalscannot be combined. Automatic shutoff capability for bulk chemical delivery systemsshould be considered (refer to 6.2.c).

20.7.b. Secondary containment should be capable of being connected tocollection/treatment system(s). These systems should be equipped with an alarm.

20.7.c. The Uniform Fire Code (UFC) requires that secondary containment becapable of holding at least 110% of the volume of the largest single container.Note: Refer to the Uniform Fire Code and the Machinery Directive (European document).

S2-93 APPENDIX 1TERMINOLOGYEMO - Emergency Off Circuit. When activated, an EMO places the equipment into a safe shutdown condition and will restrict all hazardous potentials to the main power enclosure. This is astate in which all hazardous voltage has been removed from the equipment, all hazardousproduction materials flow has been stopped, any radiation sources de-energized or totallycontained, any capacitors grounded, all moving parts stopped, and internal and external heatsources shut off, so that the equipment presents minimum hazard to personnel or the facility.

The term “EPO” previously used synonymously with EMO is no longer used in reference toequipment.

Vacuum pump enclosure -a. Equipment - That which is used in manufacturing, developing, and testingsemiconductor devices. See 1.d of this guide.

b. “Heat exhaust” refers to an exhaust system intended solely for the removal of heatfrom equipment in which the exhaust stream is not treated.

Excess Flow Control -“Rupture” is defined as a failure in a piping system which results in excess flow. See“Excess Flow Valve” below.

Excess Flow Valve -


28


Mass flow controllers (MFCs) must not be used as positive shutoffs. A bellows/diaphragmvalve is a typical positive shutoff.

Hazardous Voltage -Hazardous voltage is considered to be any voltage exceeding 42.4 V peak, 30 V RMS, 60 VDC, 240VA or, in wet areas, 10 V AC or DC.

Risk -Refer to SEMI S10 Safety Guideline for Risk Assessment Methodology.

Safe -“Property”is not intended to include products in process.

S2-93 APPENDIX 3SUPPLEMENTAL INFORMATIONApplication Note 4: Environmental Checklist:

The equipment manufacturer is expected to provide this information. This information maybe based on the equipment manufacturer’s baseline process (see sections 6.4, 6.6, and20.2.1 of this guide). The equipment manufacturer should supply information on specific testmethods so specific testing can be conducted by the end-user.

Item 3:

Note: List the process effluents in quantities and rates generated under baseline processconditions, and specify the effluent destination immediately downstream of the tool, if known.

Item 6:In addition to those chemicals listed in SEMI S2-93, the list below should also be evaluated.For all air emissions, determine the presence of and quantify chemical compounds found inthe exhaust stream using, at a minimum, the list below.

Chemical ListNote: The following list is not all-inclusive. The equipment manufacturer is expected to test forother chemicals as applicable. In addition, concentrations of the substances on this list should beprovided, based on testing under controlled conditions. Actual testing is preferred usingapproved, standard testing methods (e.g., EPA) in lieu of data extrapolation; however, if dataextrapolation is necessary, the basis for any concentrations given should be documented. Theequipment manufacturer should recommend the effluent monitoring technique consideredoptimum for the particular tool to enable the user to perform future testing if necessary.

Include in the results a mass balance analysis that accounts for the percentage of the feedchemicals that is emitted in the exhaust stream.

Current approved analytic methods should include FTIR and MS (these methods will befrequently updated).


29


Volatile organic compounds:• acetone

• butyrolactone

• chlorobenzene

• citrus terpene solvent

• ethyl acetate

• glycol ethers

• hexamethyldisilazane (HMDS)

• isopropyl alcohol

• morpholine

• n-butyl acetate

• n-methyl-pyrrolidone

• propylene glycol monomethyl etheracetate (PGMEA, 1-methoxy-2-propanol-acetate)

• VOC-containing resins

• xylene

PFCs:• perfluoroethane (C2F6)

• sulfur hexafluoride (SF6)

• carbon tetrafluoride/perfluoromethane(CF4), tetrafluoromethane, freon 14

• nitrogen trifluoride (NF3)

• perfluoropropane (C3F8)

• trifluoromethane (CHF3)

Others:• ammonia (NH3)

• arsine (and its oxides) (AsH3)

• boron trichloride (B Cl3)

• bromine (Br2)

• bromine chloride (BrCl)

• carbon dioxide (CO2)

• carbon monoxide (CO)

• chlorine (CL2)

• phosgene (COCl2)

• carbonium fluoride (COF2)

• cyanide

• diborane (B2H6)

• heavy metals, e.g., copper, lead, zinc,cadmium

• hydrogen bromide (HBr)

• hydrogen chloride (HCl)

• hydrogen fluoride (HF)

• dichlorodisilazane family (N2SiCl2)

• nitrous oxides (NOx)

• particulate matter (PM)

• phosphine (and its oxides) (PH3)

• silicon tetrafluoride (SiF4)

• chlorosilane (SiHxCly)

• fluorosilane (SiHxFy)

• silicon tetrachloride (SiCl4)

• sulfuryl fluoride (SOF2)

• sulfur dioxide (SO2)

• titanium tetrachloride (TiCl4)


Appendix A 30

Electrical and Mechanical Design Criteria Revision 2.0

Appendix AElectrical and Mechanical Design CriteriaThis appendix consists of a set of supplemental design criteria to assist in theelectrical and mechanical design of semiconductor manufacturing equipment. Itis intended to enhance and expand upon topics addressed throughout the mainbody of the guidebook. It is strongly recommended that the equipmentmanufacturer review the contents of this appendix for applicability to theequipment design in question.

The safety philosophy set forth in these guidelines is that potential hazards in theoperation and maintenance of equipment be identified and engineered out ofequipment during the design and construction phases. Where identified hazardscannot be eliminated, no single-point failure or operational error should allowimmediate exposure of personnel, facilities, or the community to hazards ordirectly result in injury, death, or equipment loss. All equipment should be fail-safe or of a fault-tolerant design.

1.0 General1.1 DiagramsElectrical system diagrams should be provided. They should include, but are not limited to,the following information:

1.1.1 Conductors. Drawings should show

1. All conductors.

2. Conductor color, size, and identification.

3. Multiconductor cables with the color code used, the number of conductors, andthe AWG or metric size (for example, 20/#18.).

1.1.2 Components (Devices). Components should be

1. Identified on the drawing to match the equipment.

2. Shown with all wiring connections.

Note: Internal wiring of subassemblies may be shown on separate drawings.

1.1.3 Terminals. Terminal boards and terminal connections should be identified.

1.1.4 Contacts. Contact symbols should be shown with all utilities off and the equipmentat its normal starting position.

1.1.5 Thermal Overload. The thermal overload location in power and/or control circuitsshould be shown.

1.1.6 Function. The function of all switches and control devices should be shown.

1.1.7 Motors. Size (watts/horsepower) and function should be indicated.

1.1.8 Power Recommendations. Supply voltage, phase, frequency, and amperageshould be shown.


31 Appendix A

Revision 2.0 Electrical and Mechanical Design Criteria

1.1.9 Symbols. The symbols shown in Supplement A.1 are standard National EquipmentManufacturers' Association (NEMA) electrical symbols. For symbols not shown, referto ANSI/IEEE 315.

1.1.9.1 Unique Symbols. Unique symbols should be identified and explained.

1.1.9.2 Schematics. The electrical schematic should be drawn between verticallines that represent the source of control power. All control devices shouldbe shown between these lines. Pilot lights and coils of control devices shouldbe shown connected to the right vertical line (grounded). All contacts shouldbe shown between the coils and the left vertical line (ungrounded). SeeFigure 28 in Supplement A.2.

1.1.10 Component Specifications. Circuit breakers, transformers, fuses, and so on,should indicate applicable values (for example, interrupt capacity, amperage,voltage, and kVA).

1.1.11 Convenience Outlets. Should be represented by a NEMA configuration indicatingvoltage, amperage, and grounding. See Figure 3 and Figure 4.

1.1.12 Grounding (Earth). The main grounding conductor and all component groundingconductors should be shown.

1.1.13 Calibration Points. All test points requiring power for tests or adjustments should beshown.

1.1.14 Design Review. All designs (diagrams) should be submitted for concept approvalbefore start of build and during build when requested by the end-user.

1.2 Labels1.2.1 Warning Signs. Warning signs are expected to identify and locate potential

electrical and mechanical hazards. The need for such warnings is particularlysignificant when

• The hazard may not be immediately apparent.

• Personnel may assume that there is no hazard when, in fact, one exists.

• The hazard may exist only under a certain set of conditions and not otherwise.

1.2.1.1 Hazard Warning. Nonservice personnel should be warned of the presenceof possible hazards in service areas. A sign mounted on a structural memberof the machine warning personnel when there is potential exposure tochemical, electrical, thermal or mechanical hazards. Refer to SEMI S1 forguidance in proper signage.

1.2.1.2 Hazardous Potential Warning. Hazardous potentials (other than linevoltage) above 250 V AC or DC should be identified by a prominent signlocated near the energized parts. The sign applicable to the highest voltagepresent should be used.

1.2.1.3 Line Voltage Warning. Terminals with hazardous potentials present afterthe supply circuit disconnecting means is placed in the OFF position shouldbe identified.

The sign should read "LINE VOLTAGE PRESENT WITH MACHINEPOWER OFF", or "LINE VOLTAGE ALWAYS PRESENT."

The sign should be placed inside the enclosure adjacent to the terminals.


Appendix A 32


1.2.2 Main Control Enclosure. A label indicating the following information should beinstalled near the "SUPPLY CIRCUIT DISCONNECTING MEANS":

• Voltage (V).• Amperage (A).• Phase (pH).• Frequency (Hz).

Note: On multi-phase equipment, insert the measured operating amperage value of thehighest phase.

1.2.3 Circuit Protection Devices. The rated current (in amperes) of circuit protectiondevices should be visibly indicated near the device. Fuses should also indicatetype.

1.2.4 Temperature. Surface temperatures exceeding the limits of Table 16 in section16 of this guide should be labeled.

1.2.5 Components (Devices). Devices should be identified adjacent to (not on) thecomponent with the same designation as shown on the diagram(s).

1.2.6 Functions. The function of each control station component should be identifiedon or adjacent to the component.

1.2.7 Motors (186 Watts (1/4 HP) or Larger). Motors should display

• Direction arrows, where applicable.• "THERMALLY PROTECTED" or "TP," where applicable.• Manufacturer's nameplate.

1.2.8 Radio Frequency (RF). Equipment that requires FCC certification should beclearly indicated by

• FCC Certification labels.• RF labels.• High Voltage labels (maximum power output).

1.2.9 Weight. Equipment, designed for removal to service, exceeding 16 kg (35 lb.)should be clearly labeled with the approximate weight.

1.2.10 Cables. Multiconductor (jacketed) cables containing voltages in excess of 24 Vshould be marked showing their voltage, type, size, and temperature rating ormanufacturer's part number. See section 3.4 of this guide.

1.2.11 Voltage (Nominal). Terminal boards and junction boxes located on units outsiderecognized power compartments, with potentials greater than 24 V, should belabeled to clearly indicate the voltages present.

1.3 Nominal VoltagesNominal voltages for circuits are 24 V AC or DC, 120/208 V AC and 480 V AC. Actualvoltages may vary due to line variations and/or component tolerances.

1.4 Equipment Power RecommendationsTo maximize efficiency, equipment should be designed for 480 V or 208 V, 3 PHpower whenever feasible. Figure 23 and Figure 24 (see Supplement A.2) and Table 1(below) are provided as guides for determining equipment power recommendations.


33 Appendix A


1.5 Mechanical Execution of WorkComponents, conductors, and equipment should be installed in a neat and workmanlikemanner.

Table 1Equipment Power Recommendations

Equipment Power(kW)Recommendations

Recommended Voltage(V) & Phase (pH)

Approx. AmperageRange (A)

0 kW - 3 kW 120 V, 1 pH 0 A - 25 A0 kW - 5 kW 208 V, 1 pH 0 A - 25 A3 kW - 30 kW 208 V, 3 PH 10 A - 80 A15 kW & Over 480 V, 3 PH 20 A & Over

2.0 Components (Devices)Examples:

• Alarms and timers• Boxes and enclosures• Circuit protection devices• Conductors, cords and cables• Connectors, plugs and receptacles• Electromagnetic compatibility (EMC) filters• Fuse holders and relay sockets• Ground buses• Heating units• Indicating lights• Magnetic devices• Power supplies• Switches• Terminal boards and lugs• Transformers and ferroresonant regulators• Tubing and sleeving

2.1 General Recommendations2.1.1 Approval. Components should be approved for the purpose and be listed or

labeled by a nationally recognized testing laboratory.

2.1.2 Installation and Use. Components should be installed and used according toany instructions included in the listing or labeling.

2.1.3 Examination. Components should be suitable for the application and should beexamined for

1. Mechanical strength and durability.

2. Heating effects under normal and abnormal conditions.

3. Arcing effects.

4. Classification by type, size, voltage, current capacity, frequency, andspecific use.


Appendix A 34


5. Any other factors which contribute to safeguarding persons from hazardousexposures.

2.1.4 Protection. Components should be protected so as not to exceed theirmaximum amperage rating by circuit breakers, circuit protectors or fuses.

2.1.5 Temperature. Components should not be exposed to temperatures exceeding90% of their maximum temperature rating.

2.1.6 Marking. Component designation should be plainly identified adjacent to thecomponent with the same designation as shown on the diagram(s).

2.1.7 Mounting. Components should be mounted according to the followingrecommendations:

1. Components should be securely mounted.

2. Components should be located for ease of maintenance.

3. Components requiring periodic adjustment should be readily accessiblewithout disassembly.

4. Components requiring adjustment, calibration, testing, or service with poweron should have external test points or insulated potentiometer extensions tominimize exposure.

5. Components should not be mounted on hinged or removable covers ordoors.

2.1.8 Shields. Shield recommendations are as follows:

1. Shields should be of sturdy construction and should be provided with holesfor inserting test probes.

2. Shields should not support combustion.

3. Shields should be easily removed and replaced by service personnel.

4. Shields should be securely mounted independently of components so thatremoving a shield will not loosen components or devices.

5. Electrical shields should be nonconductive.

6. Components having hazardous potentials or hazardous energy levels andmounted on horizontal surfaces should be shielded.

7. Components having hazardous potentials or hazardous energy levels andmounted on vertical surfaces may require shields. See section 6.2, ServicePersonnel Protection.

8. Lacquer, enamel, sealing compounds, paper, or cotton should not be used inplace of a shield.

2.1.9 Terminals. Terminals should comply with the following:

1. There should be no unshielded terminals having hazardous potentials orhazardous energy levels external to control enclosures, compartments orjunction boxes.

2. Terminals should be sized and used according to Table 2.

3. Terminals on terminal blocks should be numbered in ascending order fromtop to bottom or from left to right.

4. There should not be more than two conductors per lug and two lugs pertermination.


35 Appendix A


Exception: Motor leads and flat, bare metal jumpers. See Figure 1 (below).

5. Terminals should retain conductor strands without damaging the conductor.

6. Approved terminal lugs should be used to connect conductors to componentterminals which are not equipped with wire clamps, pressure plates orequivalent means of retaining conductor strands. (See section 2.2.)

Table 2Maximum Amperage of Screw Terminals

Screw Size Amperage (Terminals perScrew)

Maximum Conductor Size

Metric NC/NF One Two AWG mm2

M3 -- 10.0 7.0 14 1.5-- 5-40 10.5 7.5 14 1.5

M3.5 6-32 14.0 10.0 12 2.5M4 -- 16.0 11.5 12 2.5-- 8-32 21.0 15.0 12 2.5

M5 10-32 35.0 25.0 10 4.0-- 12-24 49.0 35.0 8 6.0

M6 1/4-20 60.0 45.0 6 10.0M8 5/16-18 100.0 70.0 2 35.0

Note: Conductor sizes do not represent exact dimensional equivalents.

Figure 1. Typical Terminals


Appendix A 36


2.2 Terminal Lugs2.2.1 Recommendations. Terminal lugs should

1. Be rated for the circuit amperage.

2. Be sized for both the screw and the conductor.

3. Be used on untied, stranded wire only.

4. Be securely crimped with appropriate tool.

5. Have insulated barrels.

Exception: Grounding conductors or conductors larger than 8.35 mm2 (#8AWG).

2.2.2 Applications. Terminal lugs should be applied according to the following:

1. Ring tongue: Desired for all terminations.

2. Flat spade: NOT desired for terminating hazardous potentials, hazardousenergy levels or for grounding.

3. Flanged spade: Not desired for grounding except on a captive screw.

4. Female tab: Desired only for terminations to fixed male tabs on components.NOT desired for grounding. Should be fully insulated.

2.3 Control Switches2.3.1 General Recommendations. Control switches should meet the following

recommendations:

1. Voltage is restricted to 120 V, maximum.

2. Amperage is restricted to the maximum rating of the device.

3. Exposed parts, including mounting hardware, should be grounded, ofinsulating material, or be adequately covered by insulating material.


37 Appendix A


4. Switches should be labeled for their function.

5. Switch function should comply with section 6.3

2.3.2 Push-Button Type Switches. Push-button type switches should meet thefollowing recommendations:

1. Push-button colors should comply with Table 3.

2. Push-button head types should comply with Table 3.

Example:

Flush Extended Mushroom

2.3.3 Lever Type Switches. Lever type switches should meet the followingrecommendations:

1. Snap Switch: Used for lighting control; not normally used in equipment.

2. Toggle Switch: Used for power control, 120 V or less, 15 A or less.

3. In Line Switch: Not desired.

Table 3Push-button Color Code

Color Function Head TypeBlack or Green Start or Power On Flush or RecessedRed Stop or Power Off ExtendedRed Emergency Off MushroomRed Emergency Stop ExtendedYellow Emergency Return Mushroom


Appendix A 38


2.4 Indicating Lights and Lighted Switches2.4.1 General Recommendations. Indicating lights and lighted switches should meet

the following recommendations:

1. Voltage is restricted to 120 V, maximum.

2. Switches should be installed in 24 V circuits or have voltage-reducingdevices in the light assembly that limits bulb voltage to 24 V maximum.

Exception: Neon lights.

3. Where multiple bulb socket assemblies are used, the bulbs should be ratedfor not more than 24 V and should be connected in parallel.

4. Two terminal lamp sockets should be wired with the shell terminal connectedto the grounded conductor.

5. Switches should be labeled for their function.

6. Exposed parts, including mounting hardware, should be grounded, ofinsulating material, or be adequately covered by insulating material.

7. Lens color should comply with Table 4.

2.4.2 Lighted Switches. Lighted switches should comply with both Table 3 andTable 4.

Table 4Indicating Light Color Code

Color Function IndicationRed Emergency or Warning (for

example, Alarm, Overload, LimitExceeded).

Danger, abnormal, unsafe orwrong condition

Green Satisfactory, Ready, Go orProceed (for example, Power on,Cycle Complete)

Prerequisite, safe, start, testor right condition.

Yellow (Amber) Status, Interrupt, Stop (forexample, Motors ON, HeatersON.)

Attention, caution, standby,or alert condition.

White Information (for example, AC ON,AC OFF, Power OFF, AutoSelect)

Normal conditions otherthan wrong, right or alert.

Notes:1. Other lenses may be any color except red.2. Green may be used when white is not available.3. Flashing indicating lights may be used when the application requires a more compelling indication.

2.5 Electrolytic CapacitorsCapacitors containing polychlorinated biphenyl (PCB) should not be used.

Note: Polarized tantalum electrolytic capacitors may explode and/or ignite when reversewired.

2.5.1 Safety Vent. Capacitor venting recommendations:

1. Capacitors greater than 25.4 mm (1 in.) in diameter or capable of storingmore than four joules should be vented.


39 Appendix A


2. The capacitor vent should be unobstructed for a minimum of 5.1 mm (0.2inches).

3. Capacitors mounted horizontally should have vent holes placed in the upperquadrant (9, 12, 3 o'clock position).

2.5.2 Protection. Capacitor shielding recommendations:

1. Protection from venting or rupture should be provided by mounting orshielding capacitors so that vapors or debris will not be hazardous topersonnel.

2. Terminals should be protected from shorting by tools.

3. Lacquer and sealing compounds should not be relied upon to provideprotection.

2.5.3 Bleeder Resistor. Bleeder resistor recommendations:

1. A bleeder resistor should be provided if operating potential exceeds 60 V orstored energy exceeds 20 joules.

2. Under no load condition, the resistor should reduce voltage to less than 60 Vand stored energy to less than 20 joules in 10 seconds or less.

2.5.4 Energy Calculation. The formula for energy calculation is J = 1/2 CE2 where:

J = energy in joules (watt-seconds).

C = capacitance in farads.

E = DC voltage in volts.

Inserting values in the energy formula gives the maximum allowable voltageand/or capacitance to limit the stored energy.

2.6 TransformersThis section applies to transformers operating at 600 V or less and installed as fieldreplaceable components.

2.6.1 Location. Transformers should be securely fastened, protected from physicaldamage, and accessible for inspection and service.

2.6.2 Protection. All ungrounded conductors in the INPUT (primary) and OUTPUT(secondary) should be protected by an overcurrent device rated at not more than125% of the transformer full load current.

Note: Deviations should comply with ANSI/NFPA 70, Article 450-3(b).

2.6.3 Selection and Use. Table 5, Table 6, and Table 7 are provided as aids forproper selection and use of transformers and associated overcurrent protectiondevices.

2.6.4 Marking. Each transformer should have a nameplate indicating manufacturer,rating, frequency, input voltage, and output voltage(s).

2.6.5 Ventilation. Ventilation should be adequate to dissipate the transformer full loadheat losses without creating an excessive ambient temperature.

2.6.6 Isolation. Transformers should complete isolate the input and output windings.

2.6.7 Auto Transformers. Auto transformers should not be used to develop a controlcircuit from a power circuit because they do not provide complete electrical


Appendix A 40


isolation between input and output windings. They may be used within controlcircuits or within power circuits with the following restrictions:

1. Control Circuits — Auto transformers may be used for varying the voltage ifthe output circuit has a grounded conductor that is electrically connected tothe grounded conductor of the input circuit.

2. Power Circuits — Auto transformers may be used for buck/boostapplications that comply with ANSI/NFPA 70, Article 210-9 and do not raiseor lower the voltage by more than 20%.

2.6.8 Isolated Power Systems. Isolated power systems have limited use inequipment. When used, they should meet the following recommendations:

1. Purpose — To reduce noise by not referencing the output circuit conductorsto ground.

2. Labeling — The transformer and any components (devices) connected tothe transformer output should be clearly labeled to warn operators andservice personnel of the ungrounded condition.

3. Grounding — All conductive metal should be effectively bonded to theequipment grounding conductor.

4. Ground Fault Detection — Ground detection lights, a ground-fault circuit-interrupter (GFCI), or a line isolation monitor should be installed in theoutput circuit to indicate an isolation fault condition.

2.6.9 Guarding. All exposed hazardous potentials or hazardous energy levels shouldbe guarded by shields or enclosures.

2.6.10 Bonding Conductive Metal. Exposed noncurrent-carrying conductive metalshould be effectively bonded to the equipment grounding conductor as specifiedin section 4.

2.6.11 Output (Secondary) Grounding. The secondary(s) of transformers should begrounded (see Figure 2 below) and comply with the following:

1. 150 V or less — The secondary of the transformer should have one of theconductors referenced to ground, at the transformer, with a groundingconductor.

Exception: 1: Transformers feeding rectification devices.

Exception: 2: Isolated power systems, see section 2.6, Isolated PowerSystems.

2. Over 150 V single-phase — The phase conductors should not be grounded.

Exception: Transformers feeding common market equipment may haveone output phase grounded provided that the secondary is isolated from theprimary.


41 Appendix A


3. Over 150 V multiphase — The phase conductors should not be grounded. Ifthe transformer is a WYE type, the center point of the secondary should bereferenced to ground, at the transformer, with a grounding conductor.

Figure 2. Transformer Secondary Grounding


Appendix A 42


Table 5Full Load Current, Three-phase Transformers

kVA 208 V 240 V 380 V 480 V 3.0 8.3 7.2 4.6 3.6 4.0 11.1 9.6 6.1 4.8 5.0 13.9 12.0 7.6 6.0 6.0 16.7 14.4 9.1 7.2 9.0 25.0 21.7 13.7 10.8 15.0 41.6 36.1 22.8 18.0 20.0 55.5 48.1 30.4 24.1 22.0 61.1 52.9 33.4 26.5 25.0 69.4 60.1 38.0 30.1 30.0 83.3 72.2 45.6 36.1 37.5 104.1 90.2 57.0 45.1 45.0 124.9 108.3 68.4 54.1 50.0 138.8 120.3 76.0 60.1 60.0 166.5 144.3 91.2 72.2 75.0 208.2 180.4 114.0 90.2

Table 6Full Load Current, Single-phase Transformers

kVA 24 V 120 V 208 V 240 V 277 V 380 V 480 V VAINRUSH

0.050 2.08 0.4 0.2 0.2 0.2 0.1 0.1 2400.100 4.17 0.8 0.5 0.4 0.4 0.3 0.2 5750.150 6.25 1.3 0.7 0.6 0.5 0.4 0.3 9500.250 10.4 2.1 1.2 1.0 0.9 0.7 0.5 22000.500 20.8 4.2 2.4 2.1 1.8 1.3 1.0 50000.750 31.3 6.3 3.6 3.1 2.7 2.0 1.6 110001.0 41.7 8.3 4.8 4.2 3.6 2.6 2.1 180001.5 62.5 12.5 7.2 6.3 5.4 3.9 3.1 240002.0 16.7 9.6 8.3 7.2 5.3 4.23.0 25.0 14.4 12.5 10.8 7.9 6.35.0 41.7 24.0 20.8 18.1 13.2 10.47.5 62.5 36.1 31.3 27.1 19.7 15.69.0 75.0 43.3 37.5 32.5 23.7 18.8

10.0 83.3 48.1 41.7 36.1 26.3 20.815.0 125.0 72.1 62.5 54.2 39.5 31.320.0 166.7 96.2 83.3 72.2 52.6 41.725.0 208.3 120.2 104.2 90.3 65.8 52.130.0 250.0 144.2 125.0 108.3 78.9 62.537.5 312.5 180.3 156.3 135.4 98.7 78.145.0 375.0 216.3 187.5 162.5 118.4 93.850.0 416.7 240.4 208.3 180.5 131.6 104.260.0 500.0 288.5 250.0 216.6 157.9 125.075.0 625.0 360.6 312.5 270.8 197.4 156.3


43 Appendix A


Table 7. Transformer SummaryProtection Color Code

Type V/PH Ratio Primary Secondary Pri. Sec.

(ex) Pri. Sec. Ip:Is I F C I F C H-N H-N

Isolation 120/1 120/1 1:1 25.0 A P 25.0 A P B-W B-W(3 kVA) 208/1 208/1 1:1 14.4 O X 14.4 O X 2B-W 2B-W

208/3 208/3 1:1 8.3 O X 8.3 O X 3B-W 3B-W480/1 480/1 1:1 6.3 O X 6.3 O X 2B-W 2B-W480/3 480/3 1:1 3.6 O X 3.6 O X 3B-W 3B-W

Control 120/1 24/1 1:5 8.3 A P 41.7 A P B-W R-W(1 kVA) 208/1 24/1 1:8.7 4.8 O X 41.7 A P 2B- R-W

277/1 24/1 1:11.5 3.6 O X 41.7 A P B-W R-W480/1 24/1 1:20 2.1 O X 41.7 A P 2B- R-W208/1 120/1 1:1.7 4.8 O X 8.3 A P 2B- R-W277/1 120/1 1:2.3 3.6 O X 8.3 A P B-W R-W480/1 120/1 1:4 2.1 O X 8.3 A P 2B- R-W

Step- 208/1 120/1 1:1.7 14.4 O X 25.0 A P 2B- B-WDown 277/1 120/1 1:2.3 10.8 O X 25.0 A P B-W B-W(3 kVA) 480/1 120/1 1:4 6.3 O X 25.0 A P 2B- B-W

480/3 208/3 1:2.3 3.6 O X 8.3 O X 3B-W 3B-WStep- 120/1 240/1 2:1 25.0 A P 12.5 O X B-W 2B-Up 240/1 480/1 2:1 12.5 O X 6.3 O X 2B- 2B-(3 kVA) 208/3 480/3 2:1 8.3 O X 3.6 O X 3B-W 3B-Legend:

A = Acceptable.B = Black.C = Circuit Breaker.E = Voltage.

F = Fuse.G = Ground.H = Hot Phase(s).I = Current.N = Neutral.O = Optional— Fuses acceptable if not operator accessibleP = Preferred.R = Red.W = White.X = Required.

Formulas:

Ep Is ---- = ---- or (Ep)(Ip) = (Es)(Is) Es Ip

Ep = Primary Voltage. Es = Secondary Voltage. Ip = Primary Current. Is = Secondary Current.

(E)(I) 1 PH: kVA = ----------- 1000

(E)(I)(1.73) 3 PH: kVA = ---------------- 1000


Appendix A 44


2.7 Plugs, Connectors and Receptacles2.7.1 Typical Uses. Typical uses for these devices are as follows:

1. Attachment plugs and cord connectors are used on power attachment cordsand cables.

2. Connectors are used for power distribution to components andsubassemblies within the equipment or system.

3. Receptacles are used for

• Power distribution to black boxes to facilitate their replacement.

• Convenience outlets, when required, on the equipment.

2.7.2 General Recommendations. Attachment plugs, cord connectors, andreceptacles should meet the following general recommendations:

1. Receptacles and cord connectors should not accept an attachment plug witha different voltage or current rating.

Exception: a 20 A "T" slot receptacle may accept a 15 A plug of the samevoltage.

2. The number of contacts should be the same as the number of connectedconductors.

3. The grounding terminal should be used only for grounding purposes.

4. Female cord connectors should be used only to supply power to fixed malereceptacles. Cord sets are permitted, but extension cords are not.

5. Designs should ensure that grounding reliability is maintained.

6. The grounded conductors should be terminated on the "identified" terminalof the device. The identified terminal should be white or stamped "W" or"WH."

7. The standard NEMA configuration should be used. See Figures 3 and 4.

8. Special configurations should comply with all the recommendations of thissection.

2.7.3 Plugs and Connectors. Plugs and connectors should comply with the following:

1. Should be designed so that the grounding connection is made first andbroken last.

Exception: Nonhazardous potentials and energy levels.

2. Should have a nonconductive body or be internally grounded.

3. Should be of "DEAD FRONT" construction.

4. When disconnected, should not have hazardous potentials or energy levelson exposed contacts.

5. Power and control circuits should not be carried in the same plug orconnector.

6. Input (line) and output (load) power circuits should not be carried in the sameplug or connector.

7. Should be equipped with strain relief. See section 5.8, Strain Relief.


45 Appendix A


8. Should be grounding type.

Exception: When supplying power to double insulated equipment. Seesection 4.9, Exceptions.

9. Should be rated for not less than the amperage of the connected circuit.

10. All connectors should be keyed or otherwise identified to prevent misstatingof similar connectors in adjacent areas.

2.7.4 Receptacles. Receptacles should comply with the following:

1. Voltage and current rating should not be less than that of the supply circuit.

2. When installed for convenience use, should be rated at not less than 15 A at125 V.

3. When installed for power distribution, should not have a connected loadexceeding 80% of its rating.

4. Should be grounding type specification-grade receptacles.

5. Should be enclosed.

6. Should be securely mounted to a vertical surface or to a horizontal surfacewith face plate down.

7. Should be accessible to service personnel.

8. Should be accessible without removing covers or opening doors wheninstalled as a convenience outlet for operator use.

9. Should be protected by a ground-fault circuit-interrupter (GFCI) wheninstalled in a damp or wet location (for example, hose wash-down area).

10. Should be under the control of the emergency off (EMO) circuit.

11. Faceplates should be flush with outer edges of the box.

12. Faceplate screws or faceplate screw holes should not be used for receptaclemounting unless other provisions are made to counteract the plug insertionpressure.

2.7.5 Temporary Power Taps. Temporary power taps should not be used forinstallation in/on equipment.

2.7.6 Multioutlet Assemblies. Multioutlet assemblies (strips) should comply with thefollowing:

1. Should be listed or labeled by a nationally recognized testing laboratory.

2. Should contain specification grade receptacles.


Appendix A 46


3. Should be grounded according to the recommendations in section 4,Grounding.

4. Should be a minimum size of 70 mm (2.75 in.) X 36.6 mm (1.44 in.) forNEMA receptacle installation (for example, wiremold #3000).

2.7.7 Boxes. Boxes should comply with the following recommendations:

1. All boxes should be suitable for their environment.

2. Boxes that are accessible to nonservice personnel should not haveknockouts.

3. Boxes should be securely mounted.

4. Box size should be sufficient to allow free space for all enclosed conductorsand devices. See ANSI/NFPA 70, Article 370.

5. Metal boxes should be grounded by the main incoming grounding conductoraccording to the recommendations in section 4, Grounding.


47 Appendix A


Figure 3. NEMA Configurations for Straight Blade Wiring Devices


Appendix A 48


Figure 4. NEMA Configurations for Locking Type Wiring Devices


49 Appendix A


2.8 MotorsThis section applies to AC and DC motors, 600 V or less, 186 watts (1/4 HP) and larger.

2.8.1 General Recommendations. Every motor and motor circuit should have thefollowing:

1. Means of disconnecting all ungrounded conductors.

2. Circuit protection not exceeding conductor amperage rating in eachungrounded conductor.

3. Circuit arrangements so that a fault will cause circuit protection devices toopen all ungrounded conductors.

4. Conductors rated for at least 125% of motor full load amperage (FLA).

5. Thermal overload protection.

Exception: Portable motors

2.8.2 Labels. The following labels are recommended.

1. Thermal Protection — Motors with integral thermal protection should bemarked "Thermally Protected" or "TP."

2. Direction arrow — Where rotation is critical, a direction arrow should beinstalled.

2.8.3 Mounting. Motors should be mounted so that they

1. Are accessible for lubrication, maintenance, and replacement.

2. Have sufficient air circulation to maintain temperature below 90% of rating.

2.8.4 Grounding. Motors should be grounded as specified in section 4, Grounding.

2.8.5 Guarding. All motor driven couplings, belts, and chains should be suitablyguarded.

2.8.6 Undervoltage Protection. Undervoltage protection should be provided for allmotors that could initiate hazardous equipment motion when power is returnedafter an undervoltage condition.

2.8.7 Overload Protection Devices. Overload protection devices should comply withthe following:

1. One of the following protective devices is recommended for all motors:

• A manual motor starter with thermal overload protection.

• A magnetic motor starter with manual reset thermal overload protection.

• A manual reset thermal protective device integral with the motor.

• An automatic reset thermal protection device integral with the motor.


Appendix A 50


2. The resetting of the thermal overload device should not restart the motorunless there are no exposed moving parts (for example, enclosedrefrigeration compressors, and close coupled pumps).

2.8.8 DC Motors

1. DC motors should have thermal protection integral with the motor controller.

2. Shunt and compound wound DC motors should be equipped with field lossprotection to prevent excessive motor speed when this condition exists.

2.8.9 Portable Motors. Portable motors equipped with attachment plugs do notrequire thermal overload protection since they are considered to be protected bythe receptacle branch circuit protection device. See Figure 5.

2.8.10 Single-Phase AC Motors. Single-phase AC motors should have thermaloverload protection meeting the following recommendations:

1. 120 V motors — protection installed in the ungrounded conductor. SeeFigure 6.

2. 208 V motors — protection installed in both of the ungrounded conductors.See Figure 7.

Exception: 208 V motors with manual motor starters may have a thermalsensor in only one ungrounded conductor; however, the starter shoulddisconnect both ungrounded conductors.


51 Appendix A


2.8.11 Three-Phase AC Motors. Three-phase AC motor recommendations are asfollows:

1. All motors equal to or greater than 559 watts (3/4 HP) should be three-phase.

2. Thermal overload protection should be installed in all ungroundedconductors. See Figure 8.

2.8.12 Motor Selection. Table 8 is to be used as a guideline to aid in balancing phaseloads when selecting electric motors. Specific amperage recommendations formotors can be determined by manufacturer's specifications or by the tables inANSI/NFPA 70.

Table 8Motor Selection Guidelines

Motor SizeRecommendedVoltage, Phase

TypicalAmperage

1/6 to 3/4 HP 120 V, 1 PH 4.4 to 13.8 A 208 V, 1 PH 2.4 to 7.6 A

3/4 to 5 HP 208 V, 3 PH 3.1 to 16.7 A 5 HP or More 480 V, 3 PH 7.6 A and Up

2.9 Magnetic DevicesTable 9 is provided for information only to show typical inrush and sealed currents.

2.9.1 Relays. Relays are typically used for logic and switching in control circuits.

1. Coil should be 120 V or less.

2. Contacts should switch 120 V or less.

3. Contacts should not switch more than their rated "break" amperage.


Appendix A 52


2.9.2 Contactors Contactors are typically used for switching in power circuits.


Exception: Coils with inrush of 240 VA or more should be in the powercircuit and controlled by a pilot contactor.

2. Contacts should not switch more than their rated break amperage.

3. Contactor should be appropriately selected for inductive or resistiveswitching applications.

2.9.3 Motor Starters Motor starters are typically used for switching motor loads.


Exception: Coils with inrush of 240 VA or more should be in the powercircuit and controlled by a pilot contactor.

2. Contacts should not switch more than their rated break amperage.

3. Motor starter should have thermal overloads sized for motor full loadamperage (FLA).

2.9.4 Solenoids Solenoids are typically used for converting electrical signals tomechanical motion.

1. Solenoids with coil inrush of less than 240 VA may be connected in controlcircuits but should be separately fused.

2. Solenoids with coil inrush of 240 VA or more should be in power circuits,controlled by a contactor and individually protected for overcurrent.

Table 9Typical Magnetic Device Coil Data (in Volt-Amps)

National Equipment Mfg. Association (NEMA) SizeContactor

ManufacturerCoilState 00 0 1 2 3 4 5

Allen Bradley Inrush 60 106 185 216 578 996 1948 Sealed 15 17 21 30 43 65 97

Arrow Hart Inrush 135 135 135 340 720 2800 5500 Sealed 22 22 22 62 105 130 235

Cutler Hammer Inrush 81 105 154 550 900 960 1925 Sealed 11 42 46 86 90 87 207

Furnas Inrush 54 204 204 480 480 1044 1656 Sealed 13 26 26 49 49 82 125

General Electric Inrush 144 144 144 528 1152 1248 3600 Sealed 24 24 24 60 83 87 276

ITE Inrush 198 198 198 360 790 1400 Sealed 24 24 24 41 57 70

Square "D" Inrush 118 160 170 465 800 1490 2800 Sealed 11 30 40 80 150 140 290

Westinghouse Inrush 160 160 160 160 625 625 Sealed 25 25 25 25 50 50


53 Appendix A


2.10 Supply Circuit Disconnecting MeansAll equipment should have a supply circuit disconnecting means mounted on the equipment.See Figure 14 (section 5.8).

Note: The facilities disconnecting means does not negate this recommendation.

2.10.1 Single Source of Power. Equipment should not have more than one source ofpower.

Exception: When frequencies in addition to 60 Hz are required and ALL theexpectations of section 7 are applied.

2.10.2 Disconnect Rating. The supply disconnect overcurrent protection should berated at not more than 150%, and not less than 115% of the total normaloperating full load current of the machine.

2.10.3 Disconnect Connection. Supply conductor connections to the disconnectingmeans should comply with the following:

1. The supply conductors should be connected directly to the disconnectingmeans in the main electrical control enclosure with no connection to terminalblocks or other devices.

2. There should be no exposed live parts when the disconnecting means is inthe open position.

3. All ungrounded conductors of the supply circuit should be disconnectedsimultaneously.

4. Grounded conductors (neutral) should not be disconnected.

Exception: The grounded conductor (neutral) may be disconnected for validsafety and design recommendations, providing that it is disconnectedsimultaneously with the ungrounded conductors.

5. Grounding conductors (earth) should not be disconnected.

2.10.4 Disconnect Mounting. The disconnecting device should not be mounted onhinged or removable access covers or doors.

2.10.5 Disconnect Handle. The disconnect handle:

1. Should not be more than 1.98 m (6.5 ft.) or less than 0.5 m (1.5 ft.) abovethe operating floor line.

2. Should clearly indicate the ON and OFF positions.

3. Should be accessible from the front of the enclosure.

4. Should be readily accessible by the equipment operator when it is used asthe emergency off (EMO) switch.

5. Should not disengage from the disconnect device when the enclosure dooris opened.

6. Mechanism of hardwired equipment should be lockable in the OFF position.

7. Mechanism should be either mechanically or electrically interlocked with theenclosure door.


Appendix A 54


2.10.6 System Disconnecting Means. When disconnects are mounted in separateenclosures (each supplying power to one unit of a system), the followingprovisions should be made:

1. The disconnecting device in each of the separate system units should de-energize all hazardous potentials or hazardous energy levels within that unit.

2. A main disconnecting device should be furnished to de-energize the entiresystem.

2.10.7 Disconnect Type. The type of disconnecting means desired is based onequipment power specifications.

2.10.7.1 Small Equipment Single-phase equipment operating at 120 V or lesswith up to 2 kVA main protection should have one of the followingdisconnecting means:

1. Switch and fuse. See Figure 9.

2. Circuit breaker with a minimum of 5,000 amperes interrupt capacity(AIC). See Figure 10.

Exception: The power attachment plug may be used as thedisconnecting means for self contained (free standing) units under0.25 kVA if they have the following:

3. A POWER ON indicator light on the unit.

4. Adequate overcurrent protection within the unit.

2.10.7.2 Large Equipment Multiphase equipment and equipment operating at120 V with 2 kVA or more main protection should have a circuit breakerwith a minimum of 10,000 AIC for the disconnecting means.


55 Appendix A


2.11 Circuit ProtectionCircuit breakers and circuit protectors are preferred over fuses as overcurrent devices for thefollowing reasons:

• They can be reset without exposure to energized terminals and, therefore, can be safelyreset by nontechnical personnel.

• They provide more assurance that ratings cannot be inadvertently changed, as whenfuses are used.

• Multiple units (such as used on three-phase circuits) can be obtained, which open allconductors simultaneously when an overload occurs on any conductor.

2.11.1 General Recommendations. General recommendations for circuit protectiondevices are as follows:

1. Amperage — Circuit protection devices should not exceed the amperagerating of the components and conductors they protect. See section 3, Tables12 and 13.

2. Location in circuit — Circuit protection devices should be located at the pointwhere an ungrounded conductor connects to its supply source or to a largerconductor.

Exception 1: Where all the following conditions are complied with. Theconductor

a) Is not over 7.6 m (25 ft.) long.

b) Amperage rating is at least one-third that of the conductor from which itis supplied.

c) Terminates at a single circuit protection device.

d) Is protected from physical damage.

Note: The conductor should not connect to any component or devicebefore termination at the protection device.

Exception 2: Where all the following conditions are complied with. Theconductor

a) Is not over 3.05 m (10 ft.) long.

b) Amperage rating is not less than the maximum continuous load currentof the circuit.

c) Amperage rating is not less than the rating of the device supplied or therating of the overcurrent protective device at the conductor termination.


Appendix A 56


d) Does not extend beyond control panel enclosure.

Note: For conductor derating factors, see section 3.2, SingleConductors.

Exception 3: Where the circuit protection device protecting the largerconductor also protects the smaller conductor according to Table 12.

3. Parallel devices — Circuit protection devices should not be connected inparallel to attain required amperage capacity.

4. Thermal devices — Thermal devices are not designed for short circuitprotection and should not be used for conductor protection.

5. Grounded conductors — Circuit protection devices should not be connectedin series with grounded or grounding conductors.

6. Accessibility — Circuit protection devices should be readily accessible byservice personnel.

7. Enclosures — Circuit protection devices should be enclosed. See section5.2, Electrical Enclosures.

8. Labeling — The amperage rating of circuit protection devices should beindicated in a manner that is clear, durable, and visible after installation.

9. Resets — Automatically resetting circuit protection devices are not desired.

10. Mounting — Circuit protection devices should not be mounted on hinged orremovable access panels.

11. Connection — Circuit protection devices should be connected to the loadside of the supply circuit disconnection means.

2.11.2 Clip Type Fuse Holders and Fuses. Clip type fuse holders and fuses shouldmeet the following recommendations:

1. Use — As branch circuit protection.

2. Rating — Fuse holders should be rated for the amperage and voltage of thefuse and should be a minimum of

• 250 V for 120/208 V circuits.

• 600 V for 277/480 V circuits.

3. Enclosures — Fuses should be installed within a NEMA type enclosure thathas positive de-energization capability before opening.

2.11.3 Inline Fuse Holders and Fuses. Inline fuse holders are discouraged forinstallation in equipment.

2.11.4 Panel-Mounted Fuse Holders and Fuses. Panel-mounted fuse holders andfuses should meet the following recommendations:

1. Shock proof fuse holders should be used.

2. Use — 120 V, 15 A or less, single-phase circuits (less than 2 kVA).

3. Rating — Minimum of 125 V.

4. Wiring — Fuse holders that have exposed metal when the cap is removed(non-shockproof fuse holders) should have the line conductor connected tothe end terminal and the load conductor connected to the side terminal.

5. Disconnect — Provision should be made for de-energization of the fuseduring replacement.


57 Appendix A


6. Mounting — Fuse holder should have a D-punched hole, or equivalent, sothat it will not rotate while the fuse is being removed. (See fuse holder

below.)

2.11.5 Circuit Breakers. Circuit breakers and circuit protectors are NOT designedand/or listed for the same function. Circuit breakers should meet the followingrecommendations:

1. Use — Short circuit and/or overcurrent protection in any circuit.

2. Method of operation — Should be manually operable and should clear afault even if the handle mechanism were held closed.

3. ON and OFF indication — Should clearly indicate ON (closed) and OFF(open) positions.

4. Mounting position — Should be mounted on a vertical surface with handleup for the "ON" position.

Exception: If horizontally mounted in a commercial distribution panel, thehandle may be toward the center for the ON position.

5. Disconnect — Should open all ungrounded conductors if a fault occurs inany phase.

6. Installation — The supply conductors should be connected to the line side ofthe breaker.

2.11.6 Circuit Protectors (Circuit Interrupters). Circuit protectors are recognized ascomponent appliance controls and are not interchangeable with circuit breakersbecause they MAY NOT provide short circuit protection. Circuit protectors shouldmeet the following recommendations:

1. Use — Supplementary (branch circuit) overcurrent protection in dataprocessing and other nonindustrial applications.

2. Method of Operation — Should be manually operable and should clear afault even if the handle mechanism were held closed.

3. ON and OFF indication — Should clearly indicate ON (closed) and OFF(open) positions.

4. Mounting position — Should be mounted on a vertical surface with handleup for the "ON" position.

5. Disconnect — Should open all ungrounded conductors if a fault occurs inany phase.

6. Installation — The supply conductors should be connected to the line side ofthe protector.


Appendix A 58


2.12 Electrical Heating Units2.12.1 General Recommendations

1. This section applies to standalone heating units and heating units containedwithin equipment such as furnaces, ovens, and tanks.

2. All materials used with the unit and associated equipment should be suitablefor the chemical, thermal, and/or physical environment.

3. Heating elements should be protected from physical damage.

4. Hot surfaces should be physically shielded, isolated, or insulated to protectagainst personnel contact.

2.12.2 Circuits

1. Heating units contained within equipment should be powered from the loadside of the equipment supply circuit disconnecting means. See section 2.10,Supply Circuit Disconnecting Means.

2. Heating units contained within equipment should be controlled by theequipment control circuits.

2.12.3 Controls

1. Appropriate safety controls should be installed to shut down heating unitsindependently of the normal machine controls.

2. Immersion heater applications may require redundant level and temperaturecontrols.

2.13 Power SuppliesThis section applies to standalone power supplies and power supplies contained withinequipment.

2.13.1 Circuits

1. Power supplies contained within equipment should be powered from the loadside of the equipment supply circuit disconnecting means.

2. Power supplies contained within equipment should be controlled by theequipment control circuits.

2.13.2 Protection. Power supply outputs may be protected by overcurrent and/orvoltage variation circuits provided that the safety of these circuits is equivalentto that obtained by circuit breakers, circuit protectors, fuses, or thermal devices.

2.13.3 Marking. Each power supply should have a nameplate indicating manufacturer,rating, input voltage, and output voltage(s).

2.13.4 Guarding. Power supplies should be securely fastened and protected fromphysical damage. All exposed hazardous potentials or hazardous energy levelsshould be guarded by shields or enclosures.

2.13.5 Ventilation. Ventilation should be adequate to dissipate the full load heat losseswithout creating an excessive ambient temperature.

2.13.6 Isolation. Power supplies should provide complete electrical isolation betweeninput and output circuits. They should be designed to minimize faults that couldcause unexpected hazardous potentials or hazardous energy levels to bepresent on circuits or components.


59 Appendix A


2.13.7 Discharge. Power supplies should meet the discharge recommendationsspecified for capacitors in section

2.14 Grounding2.13.8 Enclosure. Power supplies having outputs greater than 600 V DC and capable

of supplying over 5 mA, through a 500 ohm test load, should be enclosed in arigid compartment equipped with interlocks and a shorting bar.

2.13.9 Ferroresonant Regulators

1. Ferroresonant regulators should not have potentials of more than 550 V atline voltage.

2. Resonant circuits up to 275 V can be connected to other circuits if groundedand the maximum voltage to ground is less than 150 V.

3. Resonant circuits greater than 275 V potential should not be connected toany other circuit.

2.13.10 Grounding

1. Exposed noncurrent-carrying conductive metal should be effectively bondedto the equipment grounding conductor as specified in section 4, Grounding.

2. DC common should be connected to an isolated bus (isolated from ground).When referencing to ground is required, one circuit grounding conductorshould be used to connect the isolated DC common bus to ground.

3.0 ConductorsConductors that do not have hazardous potentials or hazardous energy levels and that donot directly control potential safety hazards are exempt from the recommendations of thissection.

3.1 General Recommendations3.1.1 Conductor size — Conductors used in power or power control circuits should

not be smaller than 0.823 mm2 (#18 AWG).

3.1.2 Separation — All conductors within a harness, wireway, or raceway should haveinsulation rated for use at the highest potential present.

3.1.3 Parallel conductors — Conductors should not be connected in parallel to attainrequired amperage capacity.

Note: Deviations should comply with ANSI/NFPA 70, Article 310-4.

3.1.4 Temperature — Conductors should not be exposed to temperatures greaterthan 90% of their rating.

3.1.5 Insulation — Conductor insulation should be continuous and undamagedbetween terminations.

3.1.6 Installation — Installation of conductors should comply with the wiring methodsin section 5, Electrical Enclosures and Wiring Methods.


Appendix A 60


3.1.7 Identification:

1. Each conductor should be identified by a number, letter, or number-lettercombination.

2. All common circuit conductors should have the same identification at allterminals and termination points.

3. The identification should not be used in more than one circuit.

3.2 Single ConductorsSee ANSI/NFPA 70, Article 310.

3.2.1 MTW (THHN/THWN). Type MTW or equivalent conductors.

1. Minimum expectations:

• 0.823 mm2 (#18 AWG).

• Stranded copper.

• 600 V, 90 ° C (194 °F) rated insulation.

2. Uses — Suitable for all circuits unless special insulation or shielding isrequired.

3.2.2 E, EE, K, KK. Type E, EE, K, KK or equivalent conductors.

1. Minimum expectations:

• 0.823 mm2 (#18 AWG).

• Stranded copper, nickel, or silver-coated.

• 600 V, 90 °C (194 °F) rated Teflon insulation.

2. Uses — Suitable only for hookup wire within control enclosures; not suitablefor installation in raceways.

3. Installation — Laced, harnessed, or installed in nonmetallic wireways.

3.2.3 Marking. Conductors should be durably marked on the surface at intervals notexceeding 610 mm (24 in.) to indicate

1. The maximum rated voltage for which the conductor was listed.

2. The proper type letter or letters for the conductor.

3. The manufacturer's name or trademark.

4. The size of the conductor in circular mils or AWG.

Exception: Conductors having insulation that cannot be marked arepermitted if the above information is marked on the conductor spool and isdocumented as part of the permanent equipment record.

3.2.4 Amperage. Conductors should be protected for their maximum amperage ratingby circuit protection devices sized according to the table and notes in Table 12.

3.2.5 Derating. The maximum amperage of conductors should be derated accordingto the number of conductors installed in a bundle, harness, stack, raceway,wireway, or wiring duct. See Table 12.

1. Fill. Conductors installed in raceways, wireways, and wiring ducts shouldcomply with the following:


61 Appendix A


2. Raceways — The sum of the cross-sectional areas of all containedconductors should not exceed 25% of the interior cross-sectional area of theraceway. See Table 10.

Exception: Raceway fill may be increased to 40% when modifying existingequipment.

3. Wireways — The sum of the cross-sectional areas of all containedconductors should not exceed 20% of the interior cross-sectional area of thewireway. See Table 11.

4. Plastic wiring ducts — The sum of the cross-sectional areas of all containedconductors should not exceed 50% of the interior cross-sectional area of thewiring duct. See Table 11.

Note: The tables in Chapter 9 of ANSI/NFPA 70 provide information forcalculating the fill for multiple conductor sizes and types.

Table 10Number of Conductors in Raceways

Conductor Size Raceway Size -Inches-Centimeters

0.50 0.75 1.00 1.25 1.50AWG mm2 1.27 1.91 2.54 3.18 3.8114 2.08 8 15 24 43 5812 3.31 6 11 18 32 4310 5.26 4 7 11 20 278 8.36 2 3 5 10 136 13.3 1 2 4 7 94 21.1 1 2 4 63 26.7 2 3 52 33.6 1 3 41 42.4 2 31/0 53.5 1 22/0 67.4 1 23/0 85.0 1

Note: Table shows maximum number of MTW allowed for 25% raceway fill.


Appendix A 62


Table 11Number of Conductors in Wireways and Ducts

Size ConductorsInches Centimeters Wireway Wiring Duct

1.0 x 1.0 2.54 x 2.54 8 20 1.0 x 2.0 2.54 x 5.08 16 40 1.0 x 3.0 2.54 x 7.62 24 60 1.5 x 2.0 3.81 x 5.08 24 60 1.5 x 3.0 3.81 x 7.62 36 90 2.0 x 2.0 5.08 x 5.08 32 80 2.0 x 3.0 5.08 x 7.62 48 120 2.5 x 3.0 6.35 x 7.62 60 150 3.0 x 3.0 7.62 x 7.62 72 180 4.0 x 4.0 10.16 x 10.16 128 320 5.0 x 5.0 12.70 x 12.70 200 500 6.0 x 6.0 15.24 x 15.24 288 720

Note: Table shows maximum number of 2.08 mm2 (#14 AWG) MTW conductors allowed for 20% wirewayfill and 50% wiring duct fill.

Table 12Maximum Amperage of Single Conductors

ConductorSize

Number of Conductors(see notes)

EquipmentGround

AWG mm2 1-6 7-24 25-42 43-UP AWG mm2

18 0.82 10 9 8 6 18 0.82 16 1.31 13 11 10 8 16 1.31 14 2.08 15 15 14 11 14 2.08 12 3.31 20 19 16 14 12 3.31 10 5.26 30 25 22 18 10 5.26 8 8.36 40 35 30 25 10 5.26 6 13.3 55 48 41 34 10 5.26 4 21.1 70 61 52 43 8 8.36 3 26.7 80 70 60 50 8 8.36 2 33.6 95 83 71 59 8 8.36 1 42.4 110 96 82 68 6 13.3 1/0 53.5 125 108 93 77 6 13.3 2/0 67.4 140 124 107 89 6 13.3 3/0 84.97 160 143 123 102 6 13.3

Notes1. All ungrounded conductors in the same bundle, harness, stack, raceway, wireway or wiring duct should

be counted.2. The grounded conductor (neutral) should be counted in single-phase and unbalanced three-phase

circuits.3. The grounding conductor should not be counted.4. The table is based on ANSI/NFPA 70, Table 310-16, 100% loading.5. The table is for 600 V, 90 °C (194 °F) rated conductors.6. The table values are derated to 91% for 40 °C (104 °F) ambient temperature and:

• Derated to 80% for 6 conductors or loading• Derated to 70% for 7-24 conductors.• Derated to 60% for 25-42 conductors.• Derated to 50% for 43 or more conductors.

7. Conductors derated according to this table will be compatible with the 60 °C (140 °F) rating of CircuitBreakers and Switches.

8. For conductors larger than 3/0, use ANSI/NFPA 70 tables with proper derating factors for temperatureand number of conductors.


63 Appendix A


3.3 Flexible CordsThis section only applies to the types of flexible cords listed below.

3.3.1 Suitability. Flexible cords should be suitable for the conditions of use andlocation according to ANSI/NFPA 70, Article 400.

3.3.2 Types. Flexible cords should be type S, SO, ST or STO with insulation rated fora minimum of 600 V, 60 °C (140 °F).

Exception 1: 120 V circuits, protected at 10 A or less with no more than twocurrent carrying conductors, may use type SJ, SJO, SJT or SJTO cords with 300V, 60 °C (140 °F) rated insulation.

Exception 2: Counter-top or rack-mounted equipment having 120 V circuits,protected at 10 A or less with no more than two current carrying conductors mayuse type SVO, SVT, or SVTO cords with 300 V, 60 °C (140 °F) rated insulation.

3.3.3 Marking. Flexible cords should be durably marked on the surface at intervalsnot exceeding 610 mm (24 in.) to indicate

1. Type designation.

2. Number of conductors.

3. Size.

3.3.4 Amperage. Flexible cords should be protected for their maximum amperagerating by circuit protection devices sized according to Table 13.

3.3.5 Color Code. Flexible cords should comply with Table 14.

3.3.6 Uses Permitted. Flexible cords are permitted

1. When equipped with an attachment plug and powered from an accessiblereceptacle outlet

• To connect movable equipment to facilitate frequent interchange.

• When the fastening means and mechanical connections of equipmentare designed to permit removal for maintenance or repair.

2. When not equipped with an attachment plug, to prevent the transmission ofnoise or vibration.

3.3.7 Uses Not Permitted. Flexible cords

1. Should not be used for internal machine wiring.

2. Should not be used as an extension cord.

3. Should not be used as a substitute for fixed wiring.

4. Should not be used to connect stationary equipment to power source.

3.3.8 Restrictions. Flexible cords

1. Should not be attached to equipment surfaces.

2. Should not be coiled but should be of the shortest feasible length, not toexceed 2.44 m (8 ft.).

3. Should not have any splices.

4. Should not be inaccessible.


Appendix A 64


5. Should not run through unprotected holes. See section 5.5, MechanicalProtection.

6. Should be installed in protected (bushed) holes that are large enough toallow cord connector (attachment plug) passage.

7. Should have strain relief at terminations to connectors or equipment that willprevent any mechanical stress on the cord from being transmitted to theconductors or terminals. See section 5.8, Strain Relief.

Table 13Maximum Amperage of Cords and Cables

Conductor Size Number of Current Carrying Conductors AWG mm2 2 3 4-6 7-24

18 0.75 10 7 5.6 4.9 16 1.0 13 10 8.0 7.0 14 1.5 18 15 12.0 10.5 12 2.5 25 20 16.0 14.0 10 4.0 30 25 20.0 17.5 8 6.0 40 35 28.0 24.5 6 10.0 55 45 36.0 31.5 4 16.0 70 60 48.0 42.0 2 35.0 95 80 64.0 56.0 0 50.0 135 120 90.0 84.0

Note: Conductor sizes do not represent exact dimensional equivalents.

Table 14Conductor Color Code for Cords and Cables

Phase Wires Voltage Phase A Phase B Phase C Neutral Ground1 2 1 120 Black 2 --- --- White 5 ---1 2 1 208 Black Red 3 --- --- ---1 3 120 Black 2 --- --- White 5 Green 6

1 3 208 Black Red 3 --- --- Green 6

1 4 208/480 Black Red --- White 5 Green 6

3 4 208/480 Black Blue 3 Red --- Green 6

3 5 208/480 Black Blue 4 Red White 5 Green 6

Notes:1. For double insulated equipment only.2. Preferred color, Brown may be used.3. The White or Natural Gray conductor may be used if the color is permanently changed.4. Preferred color, Orange may be used.5. Preferred color, Natural Gray or Blue may be used.6. Green/Yellow may be used:

• Green/Yellow should be Green with one or more yellow stripes.• Green = 50 to 70%, Yellow = 50 to 30%.• Green/Yellow is the only color internationally accepted for use as an equipment grounding conductor.• Green or Green/Yellow must only be used for grounding conductors.


65 Appendix A


3.4 Multiconductor (Jacketed) Cables3.4.1 Description. Multiconductor electronic wire and cable, such as communication

and control cable, instrumentation cable, electrical cable, and computer cable.Some have shields; many have PVC-insulated jackets.

3.4.2 Restriction. The following types of cables are not acceptable for equipmentwiring:

1. Armored cable (AC).

2. Integrated gas spacer cable (IGS).

3. Flat conductor cable (FCC).

4. Mineral-insulated, metal-sheathed cable (MI).

5. Metal-clad cable (MC).

6. Nonmetallic-sheathed cable (NM or NMC).

7. Shielded nonmetallic-sheathed cable (SNM).

8. Service entrance cable (SE or USE).

9. Underground feeder and branch circuit cable (UF).

Notes:

1. See ANSI/NFPA 70 for definitions.

2. BX and ATC are a type of armored cable (AC).

3.4.3 Marking. Should be marked with the manufacturer's name and part number orthe following data:

1. Maximum rated voltage.

2. Type.

3. Temperature rating.

4. Size.

3.4.4 Amperage. Multiconductor cables should be protected for their maximumamperage rating by circuit protection devices sized according to Table 13.

3.4.5 Power Usage. If multiconductor cable is used for power circuits (greater than100 V), the insulation should be rated for at least 600 V, 80°C (176°F).

3.4.6 Connectors. Multiconductor cable connectors used in circuits having hazardouspotentials or hazardous energy levels should meet all the recommendations ofsection 2.7, Plugs, Connectors and Receptacles.

3.4.7 Color Code. Should comply with the following recommendations:

1. Multiconductor cables used for power circuits should comply with Table 14.

2. Multiconductor cables used for control circuits should have color codeidentified on drawings.


Appendix A 66


3.5 Special ConductorsOther conductors installed in equipment should comply with the requirements ofANSI/NFPA 70.

3.5.1 Insulation. When required by ambient conditions, appropriate conductorinsulating material should be used. For example, conductors installed on oradjacent to heat generating equipment, such as furnaces, ovens, heat treatingequipment, and so on, should have UL-approved, type AVA, SFF2, or equivalentinsulation.

3.5.2 Bus Bars (Noninsulated). Noninsulated bus bars should be sized according toTable 15, which is based on the following:

1. Material — copper @ 98% conductivity.

2. Temperature — 40°C (104°F) ambient.

3. Current density — 1000 amperes per square inch.

4. Spacing — See Article 384 of ANSI/NFPA 70.

NEC 1994, Table 384-36Minimum Spacing Between Bare Metal Parts

Opposite PolarityWhere Mounted on theSame

Opposite PolarityWhere Held free

Live Parts

Surface in Air to Ground*<125 volts 3/4 in. 1/2 in. 1/2 in.<250 volts 1-1/4 in. 3/4 in. 1/2 in.<600 volts 2 in. 1 in. 1 in.

*For spacing between live parts and doors of cabinets, see section 373-11(a)(1), (2), and (3).


67 Appendix A


Table 15Noninsulated Bus Bar Sizes

Thickness Width Area Amperagemm inches mm inches mm2 inches2 A

1.59 0.063 12.7 0.50 20.0 0.031 31 19.1 0.75 30.3 0.047 47 25.4 1.00 40.6 0.063 63 38.1 1.50 60.6 0.094 94 50.8 2.00 80.6 0.125 125 76.2 3.00 121.3 0.188 188

3.18 0.125 12.7 0.50 40.6 0.063 63 19.1 0.75 60.6 0.094 94 25.4 1.00 80.6 0.125 125 38.1 1.50 121.3 0.188 188 50.8 2.00 161.3 0.250 250 63.5 2.50 201.9 0.313 313 76.2 3.00 241.9 0.375 375

101.6 4.00 322.6 0.500 500 6.35 0.250 12.7 0.50 80.6 0.125 125

19.1 0.75 121.3 0.188 188 25.4 1.00 161.3 0.250 250 38.1 1.50 241.9 0.375 375 50.8 2.00 322.6 0.500 500 63.5 2.50 403.2 0.625 625 76.2 3.00 483.9 0.750 750 88.9 3.50 564.5 0.875 875

101.6 4.00 645.2 1.000 1000 127.0 5.00 806.5 1.250 1250 152.4 6.00 967.7 1.500 1500

9.53 0.375 12.7 0.50 121.3 0.188 188 19.1 0.75 181.3 0.281 281 25.4 1.00 241.9 0.375 375 38.1 1.50 363.2 0.563 563 50.8 2.00 483.9 0.750 750 63.5 2.50 605.2 0.938 938 76.2 3.00 725.8 1.125 1125 88.9 3.50 847.1 1.313 1313

101.6 4.00 967.7 1.500 1500 12.7 0.500 19.1 0.75 241.9 0.375 375

25.4 1.00 322.6 0.500 500 38.1 1.50 483.9 0.750 750 50.8 2.00 645.2 1.000 1000 76.2 3.00 967.7 1.500 1500

101.6 4.00 1290.3 2.000 2000

3.6 Conductor Color CodeNote: Some local jurisdictions must adhere to NFPA-79.

See the following:

ANSI/NFPA 70, Article 210-5.

• Grounded conductor: white or natural gray.

• Equipment grounding conductor: green, green/yellow, or bare.

OSHA 29 CFR 1910.304.

• Grounded conductors and equipment grounding conductors should beidentifiable and distinguishable from all other conductors.


Appendix A 68


3.6.1 Alternating Current (AC) Conductors. AC conductors should comply with thefollowing:

3.6.1.1 Ungrounded Conductors

1. Power circuit conductors: A continuous black outer finish along theentire length of the conductor.

2. Control circuit conductors: A continuous red outer finish along theentire length of the conductor.

3.6.1.2 Grounded Conductors (neutral)

1. 13.3 mm2 (#6 AWG) or smaller: A continuous white or natural grayouter finish along the entire length of the conductor.

2. Larger than 13.3 mm2 (#6 AWG): Any color except green, identifiedby a distinctive white marking at the termination points.

3.6.1.3 Grounding Conductors (earth)

1. 13 mm2 (#6 AWG) or smaller: A continuous green or green/yellowouter finish along the entire length of the conductor.

2. Larger than 13.3 mm2 (#6 AWG): Colored, marked, or taped greenor green/yellow at each end and at every point where the conductoris accessible.

Exception: Mechanical equipment grounding (bonding) conductorsmay be bare copper or copper braid.

3.6.2 Direct Current (DC) Conductors. DC conductors should comply with thefollowing:

3.6.2.1 Ungrounded Conductors

1. Power conductors exceeding 50 V DC: Orange.

2. Power conductors, 50 V DC or less: Violet.

3. Control conductors: Blue.

3.6.2.2 Grounded Conductors (common). Brown.

3.6.2.3 Grounding Conductors (earth). Should comply with therecommendations of section 3.6

3.6.3 Exceptions to Color Code. Exceptions are allowed:

1. For internal wiring on individual components, such as motors, transformers,meters, solenoid valves, power supplies, and black boxes.

For flexible cords. (See section 3.3)

2. For multiconductor cables with more than five conductors. (See Table 14)

3. When the proper color is not available for special conductors. Seesection 3.5.

4. To the AC color code as follows:• Ungrounded control circuit conductors in small equipment, at line

voltage, may be black.

• Grounded conductors may be further identified with a colored tracer thatcorresponds with the associated ungrounded conductor.

• Interlock control conductors wired from an external power source maybe yellow.


69 Appendix A


• Equipment built in Europe may have brown ungrounded conductors andlight blue grounded conductors.

5. To the DC color code in section 3.6 with the following restrictions:

• Colors other than those designated for AC circuits should be used.

• The colors and voltages should be identified on the drawings.

4.0 GroundingThe terms ground and grounding are used to refer to noncurrent-carrying, mechanicalequipment grounding conductors, bonding jumpers, and circuit grounding conductors.

Figures 12 and 13 illustrate the general layout of typical grounded systems.

4.1 Resistance4.1.1 All grounding circuits within a machine should ensure a resistance of one tenth

ohm (0.1 Ω) or less at any point.

4.1.2 To test grounding resistance, attach one lead of a digital ohmmeter at the maingrounding termination and use the other lead to probe all conductive metal. Seesection 4.5.

4.2 Terminations 4.2.1 The main grounding conductor should be secured to a single designated

termination that will not be disturbed by any other conductor terminations.

4.2.2 Mounting hardware and cover screws that may be removed for normal servicingshould not be used for grounding terminations.

4.2.3 All protective coatings, such as paint or enamel, should be removed fromcontact surfaces where grounding conductors and bonding conductors terminate.

4.2.4 Unless prohibited by location recommendations, an external tooth (star)lockwasher should be installed between the grounding lug and the surface to begrounded to maintain the position of the lug and to ensure effective penetration throughany dirt or corrosion on the contact surface.

Exception: The lockwasher is not required if the termination complies with section 2.1.

The disconnection or removal of any component (device) should not interferewith or interrupt the grounding continuity to any other component (device).

4.2.5 When terminal lugs are used for grounding, they should be a ring tongue type.


Appendix A 70


Exception: A single, locking spade lug may be used for connection to a captivedevice grounding screw.

4.2.6 Terminal lugs used for grounding are not required to be insulated.

4.2.7 Grounding terminations should not depend on solder or welds for mechanicalstrength or for electrical continuity.

Exception: Multi-pin connectors with solder pins (subject to resistance check).

4.2.8 An insulated terminal block (barrier strip) should not be used as a grounding bus.

4.2.9 Commercial type ground buses should be used for multiple ground connections.

4.3 Conductors4.3.1 Grounding conductors should be green, green with a yellow tracer, or bare

copper wire or braid.

4.3.2 All grounding conductors should be stranded copper wire.

4.3.3 Grounding conductors and connectors should be compatible in current rating tothe associated ungrounded conductors and connectors. See Table 12.

4.3.4 Metallic bases, frames, or bonds should not be used as current carryingconductors between subassemblies.

4.3.5 Raceways, hinges, covers, enclosures, and frames should not be used in lieu ofgrounding or bonding conductors.

4.3.6 The grounding conductors should be run with the current carrying conductors.

4.3.7 The grounding conductor should not be intentionally used as a current carryingconductor.

4.4 Splicing4.4.1 The grounding conductors should be unspliced and continuous from termination

to termination.

4.4.2 A terminal block, ground lug, or ground bus is acceptable for connecting twogrounding conductors. Butt splices, soldered connectors, and wire nuts areundesired.

4.5 Conductive Metal4.5.1 All machine frames, enclosures, raceways, covers, doors, or panels with

components having hazardous potentials or hazardous energy levels shouldhave a grounding conductor termination.

4.5.2 All metal clad components mounted external to enclosures and havinghazardous potentials or hazardous energy levels should have a groundingconductor termination. Examples:

• Transformers• Solenoid valves• Motors• Subassemblies


71 Appendix A


• Lamps• Switches• Cable connectors• Capacitors (mounting base)• Outlet boxes

4.6 ReceptaclesThe incoming grounding conductor should terminate at the device box. A groundingconductor (jumper) should run from the termination on the box to the grounding screw onthe receptacle.

4.7 Interconnecting CablesEvery cable having hazardous potentials or hazardous energy levels, whichinterconnects subassemblies, units, or equipment should contain a grounding conductorto assure effective grounding with any combination of connected equipment.

4.8 Isolation4.8.1 Grounded conductor (neutral) should be isolated from grounding conductors.

Exception: Reference ground at source transformer. See section 2.6,Transformers.

4.8.2 DC common should be connected to an isolated bus (isolated from ground). Onecircuit grounding conductor should be used to connect the isolated DC commonbus to ground.

Exception: Isolated DC power systems. See section 2.6, Transformers.

4.8.3 Maximum leakage current on grounding conductor should not exceed 3.5 mA.

Exception: Current from an EMC filter should not exceed 5% of input current or1 A. A label stating high grounding conductor current should be attachedadjacent to the power requirement label.


Appendix A 72


4.9 Exceptions4.9.1 Totally plastic encased units designed for two wire cord.

4.9.2 Double insulated units that are marked with one of the symbols shown below orlabeled:

Notes: 1. Dead front cap, longer grounding pin. 2. Any of the approved flexible cords with grounding

conductor. 3. Approved strain relief. 4. The main equipment ground should terminate first

at the equipment frame on a stud, screw orground bus.

5. Mounting panels for electrical/electronic

components having hazardous potentials orhazardous energy levels should be groundedwith a grounding conductor.

6. Bolted or hinged panels with electrical/ electronic

components on them having hazardouspotentials or hazardous energy levels should begrounded with a grounding conductor.

Double insulated,Grounding not required.


73 Appendix A


5.0 Electrical Enclosures and Wiring Methods5.1 General Recommendations

Enclosures, raceways, wire ways, and wiring ducts should be suitable for the applicationand compatible with the environment that the equipment is to be operated in.

5.2 Electrical EnclosuresElectrical enclosures should be NEMA type or equivalent. Supplement A.3 contains apartial list of NEMA type electrical enclosures.

5.2.1 Components. The following components should be contained in electricalenclosures:

1. Supply circuit disconnecting means

2. Branch circuit protection

3. Control transformer

4. Control relays

5. Contactors

6. Motor starters

7. Conductors

8. Distribution terminal blocks (control terminals and power terminals should besegregated)

5.2.2 Recommendations. Enclosures should have

1. Clear space for connection and testing of components

2. Clear space for future use. (15% minimum)

3. Spare terminal space. (10% minimum)

4. Barriers for all arcing devices

5. Clearances between bare terminals and grounded parts as follows:

• 250 V or less: 12.7 mm (0.50 in.)• 251 V to 600 V: 25.4 mm (1 in.)

6. Sufficient wire bending space at terminals. See ANSI/NFPA 70, Article 373.

5.2.3 Recommendations. Enclosures should have

1. A removable panel for component mounting.

2. Hinged doors that swing horizontally and open a minimum of 165 degrees.

5.2.4 Restrictions. Enclosures should not have any

1. Components mounted on hinged doors or removable covers.

Exception: Control circuit components for operator use.

2. Piping containing air, gas, or liquids.

3. Unused or ineffectively closed openings.


Appendix A 74


5.2.5 Access. Enclosures should have access covers or doors that meet the followingrecommendations:

1. Covers or doors that allow access to hazardous energy levels or hazardouspotentials should require a tool to open or should be interlocked. See section6.2, Service Access Areas.

2. Covers or doors with an area of more than 0.3 m2 (3 ft.2 ) should be hinged.

5.2.6 Main Electrical Control Enclosure. When equipment geometry dictates a needfor more than one power and power control device enclosure, the main electricalcontrol enclosure should

1. Contain main supply circuit disconnecting means. See section 2.10 andFigure 14.

2. Contain all components and circuits that have hazardous energy levels orhazardous potentials after the operation of the EMO switch(es).

3. Require a tool to open.

5.3 Electrical Enclosure Wiring5.3.1 All enclosure wiring should be routed, harnessed, appropriately laced, or in

plastic wiring ducts.

5.3.2 The number of conductors installed in wiring ducts should comply with section3.2, Single Conductors.

5.3.3 The wiring duct material should

1. Not support combustion.

2. Be nonwarping.

3. Be an insulator.

4. Be rated for the highest voltage applied to any conductor contained within.

5.3.4 Wiring ducts should not have exposed metal parts, except for mounting screws.

5.4 Equipment Wiring5.4.1 Conductors inside of equipment should be routed, laced, harnessed, in wiring

duct, in wireways, or in raceways.

5.4.2 Conductors outside of equipment should be in approved, enclosed wireways orraceways.

Note: Supplement A.3 lists acceptable raceway types.

5.4.3 All conductors in the same bundle, harness, raceway, wireway, or wiring ductshould have insulation rated for use at the highest potential present.

5.4.4 When AC power conductors are installed in metal raceways or wireways, allphase conductors, the grounding conductor and, where used, the groundedconductor (neutral) should be grouped together to minimize induced current.

5.4.5 Conductors installed in raceways should not be smaller than 2.08 mm2 (#14AWG).


75 Appendix A


5.4.6 The maximum number of conductors installed in raceways, wireways and wiringduct should comply with section 3.2, Single Conductors.

5.5 Mechanical Protection5.5.1 Conductors that remain energized with the supply disconnect OFF should be

isolated from other conductors by jackets, conduits, or raceways.

5.5.2 Any surfaces that conductors may contact should be free of burrs, sharp edges,threads, insulation-damaging roughness, and other deteriorating agents.

5.5.3 All raceways and wireways should be supported within 305 mm (1 ft.) of eachend and at 1.37 m (4.50 ft.) intervals.

5.5.4 There should be at least 25.4 mm (1 in.) clearance between moving parts ofequipment and flexible conduit or cables. If maintaining the clearance isimpossible, a barrier should be provided.

5.5.5 All conduit joints and fittings should be threaded, compression or rain tight, andhave insulated throats or bushings.

5.6 Conductor Length5.6.1 The external length of power attachment cords or flexible conduit should be as

short as possible but should not exceed 2.44 m (8 ft.).

5.6.2 The length of the grounding conductor between the strain relief and theterminating screw should be such that in case of strain relief failure, thegrounding conductor is the last to be under strain.

5.6.3 At least 152 mm (6 in.) of free conductor should be left inside outlet, switch, andjunction boxes.

5.6.4 Wherever hardwiring makes access to a drawer or compartment difficult, wiringloops should be provided to allow access for service.

5.7 Splicing5.7.1 Conductors, cords, and cables should be run without splices from termination to

termination.

5.7.2 Connections to leads on motors, solenoid valves, transformers, and so on shouldbe made within an accessible enclosure by approved devices other than buttsplices, soldered connectors, or wire nuts. For ease of maintenance, terminalblocks should be used.

Exception: Wire nuts may be used in motor terminal housings that are too smallto accommodate another type of connector.

5.8 Strain ReliefStrain relief should be provided for all raceways, cords, and cables. The strain reliefdevice should comply with the following:


Appendix A 76


5.8.1 Strength — The device should be capable of withstanding a 16 kg (35 lb.) pullfrom any direction without allowing movement that could damage the insulationor strain the conductor terminations.

5.8.2 Length — The cord or cable jacket should extend into the strain relief device atleast one cable diameter.

5.8.3 Type — The strain relief device used should be approved for use on theraceway, cord or cable. See Figure 15 for examples.

Note: Type NM (two screw) connectors are not desired for use on flexible cordsor cables.

6.0 Access Areas and ControlsThis section addresses access to electrical and mechanical hazards.

6.1 Operator Access Areas6.1.1 Definition. Any area

1. That can be accessed without the use of a tool.

2. That is defined by the manufacturer as an operator service area.

3. Where the means of access is deliberately provided to the operator.

6.1.2 Operator Exposure. Operators should not be exposed to

1. Energy levels of 240 VA or more.

2. Stored energy levels of 20 joules or more.

3. Potentials in excess of 42.4 V peak (30 V RMS) or 50 V DC in dry areas.


77 Appendix A


4. Potentials in excess of 10 V AC or DC in wet areas.

6.1.3 Operator Protection. The operator(s) should be protected from electrical andmechanical hazards by one or more of the following:

1. Enclosures, shields, and covers that require a tool to open. See Table 17 formaximum opening sizes.

2. Interlock switches on doors, shields, or covers.

3. Grounded or insulated handles, levers, knobs, shields, and covers that aretouched, held, or actuated in normal use.

6.2 Service Access Areas6.2.1 Definition. All areas not defined as operator access areas that skilled service

personnel should gain access to service or maintain the equipment.

6.2.2 Service Personnel Exposure. Service personnel should not be exposed to

1. Inadvertent contact with hazardous potentials or hazardous energy levels.See section 6.1.

2. The unexpected energization or startup of equipment.

3. The unexpected release of stored energy.

6.2.3 Service Personnel Protection. Protection should be provided:

1. Where service is required with power on and INADVERTENT CONTACT islikely.

2. Where it is necessary to reach over, under, around, or in close proximity tohazards.

3. Where dropped tools could cause shorts and arcing.

6.2.4 Types of Protection. Protection should be provided by one or more of thefollowing:

1. Lockable energy isolating devices.

2. Interlocks.

3. Grounded or insulated handles, levers, and knobs.

4. Grounded or insulated shields and covers.

5. Access holes through shields and covers.

6. Remote or external test points.

7. Insulated potentiometer extensions.

8. Separation of low voltage and line voltage terminal blocks and relays.

6.2.5 Manual Adjustments. Equipment requiring manual adjustments should be sodesigned that adjustment does not expose personnel to electrical or mechanicalhazards.

6.2.6 Maintenance Access. Maintenance access should be provided for servicingequipment.

1. Machines that require service and have access covers should have aminimum of 711 mm (28 in.) clear space. This does not apply to movableunits.


Appendix A 78


Note: Clear space is measured from equipment protrusions and auxiliary units tothe walls or other fixed obstructions.

2. Large equipment like automatic transfer machines, web coaters, stackercranes, and conveyors should be equipped with maintenance cat walks,access ladders, crossovers, and so on to facilitate safe access to valves,motors, dampers, pumps, motor drives, and other components.

6.2.7 Working Space. Sufficient working space should be provided for servicingelectrical equipment having energized hazardous potentials or energy levels.

1. Depth — Working space should be at least 914 mm (36 in.). When voltagesexceed 150 V to ground, the depth may have to be increased. SeeANSI/NFPA 70, Article 110.

2. Width — Working space should be 760 mm (30 in.) wide in front of theexposed voltage.

3. Access — There should be at least 711 mm (28 in.) of clear access to theworking space.

4. Clear space — Working space should remain clear and should not be usedfor equipment or storage.

6.3 General Recommendations6.3.1 General Recommendations Equipment should have adequate operatorcontrols.

1. The quantity and type of controls are dictated by equipment size andcomplexity.

2. "Power On" conditions and equipment operation status should be visuallyand reliably indicated.

3. Visual and/or audible signals should alert operators to conditions that areunsafe or require intervention.

4. Circuit breakers or circuit protectors should not be used as operator controlsfor on/off or start/stop functions.

5. Control switches should comply with 2.3.

6.3.2 Start (ON) Switch

1. Operator controlled equipment should have a start (ON) switch.

2. The switch should be located or designed to prevent accidental operation.

3. The switch should be a momentary contact push button with recessed orflush type head.

6.3.3 Stop (OFF) Switch.

1. Operator controlled equipment should have a stop (OFF) switch.

2. The switch should be located or designed to prevent accidental operation.

3. The switch should be a momentary contact push button with extended typehead.

4. Mushroom head switches should not be used.

5. The switch should take precedence over the associated start (ON) switch.TEST: See item 4 under section 6.5.


79 Appendix A


6.3.4 Two Hand Cycle Start Controls. When dual series-connected hand controlsare required to isolate the operator from hazards, the hand controls and/orcontrol circuit should comply with the following:

1. The hand controls should be momentary contact push button switches withblack or green heads.

2. Each hand control should be protected against unintended operation.

3. Each hand control should be arranged by design, construction, and/orseparation so that the use of both hands is required to start the machinecycle. Typically, they should be mounted at least 610 mm (24 in.) apart inthe same vertical and horizontal planes.

4. Both hand controls should be depressed within one second of each other forthe machine to cycle.

5. Both hand controls should be held depressed until the hazard no longerexists.

6. The control system should incorporate an anti-repeat feature that limits themachine to one cycle for each depression of the hand controls.

7. The control system should incorporate an anti-tie-down feature that requiresthe release of both hand controls between cycles.

8. For typical circuit, see Figure 16.

Note: Timer 1TR should be: one second, fixed, time delay on release.

6.4 Machine Controls6.4.1 Undervoltage Protection. Undervoltage protection should be provided for all

equipment that could initiate a hazardous motion when power returns after anundervoltage condition.

6.4.2 Solid State and Programmed Controls. Solid state and programmed controlsmay be used for machine controls. Circuits which are critical to personnel orequipment safety, however, should be directly controlled by fail-safeelectromechanical devices. Deviations should comply with NEMA ICS 1.1.


Appendix A 80


6.5 Fail-Safe Controls and Switching Devices6.5.1 All controls and switching devices should be applied in a fail-safe design that

complies with the following:

1. Should start through energization.

2. Should stop through de-energization.

3. Stop switches should take precedence over associated start switches.

4. TEST:

• Hold stop/off switch open.

• Close start/on switch.

• Equipment should not start, power up, turn on or cycle.

6.6 Control Location6.6.1 Operator Controls. Operator controls should be within easy reach in normal

operating position.

6.6.2 Non-operator Controls. Non-operator controls should be located such thataccidental or unauthorized operator adjustment or operation is unlikely and willnot create a hazard.

6.6.3 Control Enclosures. Control enclosures should be designed to preventaccidental operation of controls by the equipment or the operator. It should besecurely mounted in a clean and dry location.

7.0 Control Circuits

7.1 General RecommendationsCircuits that do not have hazardous potentials or hazardous energy levels and that donot directly control potential safety hazards are exempt from this section.

7.1.1 Fail-Safe Design. Circuits should be so designed that a failure of anycomponent in the system will prevent unsafe operation of the system.

7.1.2 Connection of Control Devices. Control devices should be connected asfollows:

1. Contacts should not be connected in parallel to attain required amperagecapacity.

2. Control device contacts should open all ungrounded conductors of a circuit.

3. Indicator lamps and operating coils of control devices should have oneterminal directly connected to the grounded side of the circuit.

4. Switches, contacts, and other control devices should be connected to theungrounded side of the circuit.

Exception: Motor overload relay contacts may be connected to thegrounded side of the circuit if no part of the circuit extends beyond thecontrol enclosure.


81 Appendix A


7.1.3 Emergency Stop (E-Stop). Automated equipment and systems havinghazardous mechanical interfaces may require unique and special E-Stopcontrols that remove the physical hazard at the interface but do not shut off theassociated equipment. E-Stop controls should

1. Not be used in place of an EMO.

2. Be accessible to the person located at the hazardous interface position.

3. Stop all hazardous mechanical motion at the equipment interface.

4. Not create any unsafe conditions.

5. Be designed to stop through de-energization, rather than energization ofcircuits.

6. Take precedence over associated start controls.

E-Stop must be clearly distinguishable from an EMO.

Exception: The label should read "EMERGENCY STOP."

7.1.4 Shunt Trip Units. Shunt trip units should not be used in control circuits becausethey are not fail-safe.

7.1.5 Multiple Sources of Power. Equipment with multiple sources of power (seesection 2.10) should comply with ALL of the following recommendations:

1. Each source of power should have a separate main electrical controlenclosure. See section 5.2.

2. Each main electrical control enclosure should

• Be clearly and permanently labeled. (See section 1.2.)

• Have a lockable supply circuit disconnecting means that is interlockedwith the enclosure door and de-energizes all hazardous potentials andhazardous energy levels within that enclosure.

• Have an EMO contactor that de-energizes all hazardous potentials andhazardous energy levels leaving that enclosure.

• Have an interlock circuit such that loss of power from any source will tripthe EMO circuit.

3. Hazardous potentials from each main electrical control enclosure should becontained in separate conduit, cables, enclosures, and junction boxes.

4. Control circuits should

• Be supplied by the 60 Hz power source.

• Have nonhazardous potentials.

7.2 Large Equipment and Systems1. Multiphase equipment and equipment operating at 120 V with 2 kVA or more

main protection.

2. Two or more units connected together to form a system.

7.2.1 Recommended Control Circuits. Control circuits in large equipment andsystems should comply with the following:

1. Equipment and systems should have an EMO control circuit.


Appendix A 82


2. Equipment and systems should have a power control circuit.

3. An EMO contactor should be used to minimize the hazardous potentials andhazardous energy levels inside the electrical enclosure when the EMOswitch is operated.

Notes:

1. See Figure 28.

2. EMO circuits and power control circuits at same voltage level may becombined.

7.2.2 Control Circuit Limits. Control circuit limits for large equipment and systemsare as follows:

1. EMO control circuit should not be over 24 V, nominal, or 240 VA.

2. Power control circuits should not be over 120 V AC or 50 V DC.

Notes:

1. To minimize exposure to operators and service personnel, all controlcircuits should be limited to 24 V.

2. Circuits over 24 V should be designed, built, installed, enclosed,grounded, protected, and inspected for strict compliance with thisstandard.

7.2.3 AC Control Circuits. AC control circuits in large equipment and systems shouldbe derived from a control transformer that complies with all therecommendations of section 2.6 and the following:

1. Should be sized to support the VA inrush of the circuit components. SeeTable 6 in section 2.6 and Table 9 in section 2.9.

2. Should be connected to the load side of main supply disconnect.

7.2.4 DC Control Circuits. DC control circuits in large equipment and systems shouldcomply with the following:

1. Should be designed for complete electrical isolation between AC and DCcircuits.

2. Should be properly protected for overcurrent.

3. Should be powered from the load side of the main supply disconnect.

7.3 System Circuit Recommendations7.3.1 Units Mounted in or on other Units. Units in this type of system

1. Should have the same source of power. (See section 2.10.)

2. Should have the same supply circuit disconnecting means. (See section2.10.)

3. Should have the same EMO circuit.

7.3.2 Multiple Units With Interconnecting Circuits. Multiple units havinginterconnecting circuits with hazardous potentials or energy levels

1. Should have the same source of power. (See section 2.10.)


83 Appendix A


2. Should have the same supply circuit disconnecting means. (See section2.10.)

3. Should have the same EMO circuit. (See sections 7.1 and 7.3.)

7.3.3 Multiple Units Mounted Separately. Multiple units mounted separately with NOinterconnecting circuits with hazardous potentials or energy levels

1. May have separate sources of power.

2. May have separate supply circuit disconnecting means.

3. May have separate EMO circuits.

8.0 Temperature Limits

8.1 ConductorsConductors should not be exposed to a temperature greater than 90% of their rating.

8.2 ComponentsComponents should not be exposed to temperatures greater than 90% of their rating.


Appendix Supplement A.1 84

Typical Graphic Symbols Revision 2.0

APPENDIX SUPPLEMENT A.1 TYPICAL GRAPHIC SYMBOLS

Figure 18 Typical Graphic Symbols for Electrical Diagrams, Part 1


85 Appendix Supplement A.1

Revision 2.0 Typical Graphic Symbols








Revision 2.0 Typical Graphic Symbols








Revision 2.0 Typical Circuits

Appendix Supplement A.2 Typical Circuits

Figure 23 Typical 120/208 VoltFacilities Power

Figure 24 Typical 277/480 VoltFacilities Power



Typical Circuits Revision 2.0

Figure 25 Typical 120 Volt Single-Phase Circuit




Figure 26 Typical 208/480 Volt Single-Phase Circuit



Typical Circuits Revision 2.0

Figure 27 Typical 208/480 Volt Three-Phase Circuit




Figure 28 Typical 208/480 Volt Three-Phase Circuit


Appendix Supplement A.3 94Enclosure Raceway Types Revision 2.0

APPENDIX SUPPLEMENT A.3ENCLOSURE RACEWAY TYPES

Partial List of NEMA Type Electrical EnclosuresGeneral Purpose (Type 1) A general purpose enclosure is primarily intended to preventaccidental contact with the enclosed apparatus. It is suitable for indoor applications where itis not exposed to unusual service conditions.

Weatherproof (Type 3) A weatherproof enclosure is intended to provide suitable protectionagainst specified weather hazards. It is suitable for outdoor use.

Watertight (Type 4) A watertight enclosure is designed to exclude water applied in the formof a hose stream. It is suitable for application where the apparatus may be subjected to astream of water during cleaning operations.

Watertight-Corrosion Resistant (Type 4X) A watertight-corrosion resistant enclosure isintended for indoor and outdoor use to provide protection against corrosion, windblown dustand rain, splashing water, and hose directed water.

Hazardous Locations, Class I (Type 7) These enclosures are designed to meet theapplication requirements of ANSI/NFPA 70 for Class I Hazardous Locations. The typedesignation is incomplete without a suffix letter or letters (A, B, C, or D) that indicate theparticular group or groups of hazardous locations (as defined in ANSI/NFPA 70) for whichthe enclosure is designated.

Hazardous Locations, Class II (Type 9) These enclosures are designed to meet theapplication requirements of ANSI/NFPA 70 for Class II Hazardous Locations. The typedesignation is incomplete without a suffix letter or letters (E or G) that indicate the particulargroup or groups of hazardous locations (as defined in ANSI/NFPA 70) for which theenclosure is designed.

Industrial Use (Type 12) An industrial use enclosure is designed for use in thoseapplications where it is desired to exclude such materials as dust, lint, fibers, and oilseepage, or coolant seepage.

Dust-Proof (Type 13) A dust-proof enclosure is intended primarily to prevent accidentalcontact with the enclosed apparatus and is so constructed that dust that may enter will notinterfere with the operation of the apparatus. The construction of the enclosure can bedefined only in relation to the apparatus and to the amount and kind of dust present.

Acceptable Raceway TypesSee ANSI/NFPA 70 for definitions.

• Rigid metal conduit• Rigid nonmetallic conduit• Electrical metallic tubing• Liquid-tight flexible metal conduit• Liquid-tight flexible nonmetallic conduit

Note: Flexible metal conduit or flexible metallic tubing without nonmetallic jacket should not beused.


95 Appendix B

Revision 2.0 Liquid hazardous Chemical Design Criteria


Appendix B 96

Liquid hazardous Chemical Design Criteria Revision 2.0

Appendix BDesign Criteria for Equipment Using Liquid HazardousChemicalsThis appendix consists of a set of supplemental safety criteria intended toenhance and expand upon liquid hazardous chemical distribution and controltopics addressed throughout the body of the guidebook. It is stronglyrecommended that the equipment manufacturer review the contents of thisappendix for applicability to the equipment design in question.

The safety philosophy set forth in these guidelines is that potential hazards in theoperation and maintenance of equipment be identified and engineered out ofequipment during the design and construction phases. Where identified hazardscannot be eliminated, no single-point failure or operational error should allowimmediate exposure of personnel, facilities, or the community to hazards ordirectly result in injury, death, or equipment loss. All equipment should be fail-safe or of a fault-tolerant design.

1.0 General Safety1.1 Equipment designed to use wet chemicals should provide a method for purging

chemicals from the internal components before performing maintenanceprocedures.

1.2 Spill and leak containment should be provided for all liquids used in the tool.

2.0 Components2.1 All electrical and pneumatic components of a chemical tool should be

• Shielded from splashing or spillage.• Provided with adequate enclosures, based on the potential exposure (e.g.,

splash-proof, water-tight, or Class 1, Groups A through D as applicable,explosion-proof, etc.).

2.2 All components that could be exposed to flammable vapors should maintainground continuity to eliminate the possibility of buildup and discharge of staticelectricity. At a minimum, the components should meet Article 500 of theNational Electrical Code (Class 1, Electrical Components and Wiring) and atleast one of the following:

• Be free of or isolated from ignition sources or open electrical components.• Contain intrinsically safe electrical components and/or contain sealed

nitrogen-purged electrical enclosures according to Article 500-1 of theNational Electrical Code.

• Rendered safe by

a) Providing an exhaust monitor that will place the tool in a safe conditionupon exhaust failure (e.g., to drop power to the tool and cover thetanks).


97 Appendix B

Revision 2.0 Liquid hazardous Chemical Design Criteria

b) Providing a flammable vapor detector which upon detection of 10% ofthe lower flammable limit (LFL) will warn of the condition and will placethe tool in a safe condition upon detection of 20% of the LFL.

2.3 Tanks, support structures, piping components, drip pans, exhaust plenums, andducts used for flammable solvents should, if technically feasible, be built usingferrous materials according to NFPA regulations. If these components must bemade of combustible materials because of corrosion concerns (e.g., contact withflammable/corrosive process chemicals), appropriate fire suppression (e.g.,water, CO2) should be supplied for portions of the tool in which combustiblematerial is used. Ferrous materials are preferred for other structural components(facades, decks, backboards) where possible.

2.4 Plastic filter housing should not be used for flammable liquids.

2.5 Piping components and filter housing should not be exposed to temperatures orpressures exceeding the manufacturer’s recommendations. Sources of heatinclude heated chemicals, external heating, and heat produced by chemicalreaction. Particular attention should be paid to the heat potentially released whencertain chemicals mix with water in drain systems.

2.6 Fail-safe over-temperature protection should be provided to prevent heatedchemicals from exceeding the temperature rating of the tooling components.(See SEMI S3, Heated Chemical Baths.)

2.7 Fittings, unions, filter housings, flexible piping, pumps, and waste lift stationsthat handle toxic, reactive, or corrosive liquids at elevated pressure should beshrouded or located within an enclosure designed to contain leaks. Weldedferrous metal piping systems are excluded. Shrouds should be considered toprotect personnel when working within the enclosure.

2.8 Metal compression tubing fittings should be comprised of parts produced by asingle manufacturer.

3.0 Chemical Sensing3.1 Equipment designed for wet chemical use should contain and sense internal

leaks. The sensing equipment should provide an audible and visual alarm andshut down the chemical supply upon leak detection. Tanks should be eitherdrained or provided with secondary containment that can hold at least 110% ofthe volume of the tank. To protect downstream waste lines, cooling capabilityshould be provided on drain lines that carry hot chemicals from heated tanks.The tool may be allowed to finish processing the run after a leak is detected onlyif at least 110% leak containment is provided.

3.2 Equipment using flammable chemicals should conform to all NEC and NFPArequirements regarding sensing devices and functions.

4.0 Exhaust4.1 The use of internally or externally adjustable ventilation is discouraged.

Equipment should be designed to distribute exhaust using properly sizedplenums and ducts. If there is no practical way to avoid the use of dampers, theyshould be capable of being locked out after the exhaust capture has been testedand accepted by the end-user.


Appendix B 98

Liquid hazardous Chemical Design Criteria Revision 2.0

4.2 Equipment ventilation design should minimize exhaust volumerecommendations while maintaining required velocity.

4.3 Tool exhaust should be designed to function properly within the limits of the end-user’s static pressure capabilities. The equipment manufacturer should consultwith the end-user to confirm the site’s exhaust capabilities.

4.4 All tool enclosures should be designed to provide sufficient exhaust ventilation toensure that the concentration of flammable vapors is <20% of the LFL. If thiscannot be assured by design, flammable vapor detectors should be installed inany portion of the tool in which flammable vapors can exceed 20% LFL. Thedetectors should be capable of placing the tool in a safe standby condition if thedetection limit is exceeded.

4.5 Tools should be designed to trap or scrub condensate which could have adestructive effect on the end-user’s exhaust system.

5.0 Tanks5.1 Tanks should be built using chemically compatible materials. For flammable

chemicals, a ferrous alloy such as stainless steel should be used.

5.2 To minimize leakage, tank penetrations (e.g., resistance temperature detectorresistivity probes, bubbler tubes, and heating coil lead probes) should beconstructed of material compatible with the tank.

5.3 Where tank heaters penetrate the tank below the fluid level, the constructionmaterials should have a coefficient of expansion that precludes opening of thejoint during heat up and cool down.

5.4 Tanks with surrounding jacket heaters should have walls of sufficiently thickmaterial or reinforcement to prevent deformation or buckling from thermalstress.

5.5 Tanks with bulk supplied chemicals should have a momentary fill switch and afail-safe high-level sensor or a gravity drain overflow. Automated wet stationsshould provide overfill protection by means of a high-level sensor interlocked toclose the supply valve.

5.6 In tanks where agitation is provided by pressurized gas, the tubes or manifolddischarge holes should point downward. Gas flow should be adjusted to theminimum acceptable flow when the tank is full using a lockable or tamper-proofneedle valve and a separate on/off valve. Tanks containing flammable processchemicals should use an inert gas such as nitrogen for agitation. Chemicalagitation lines should have a check valve to prevent back flowing into the gassupply line during pressure loss. The check valve and gas line should becompatible with the process chemical. The discharge holes on a filterrecirculator distribution loop should be directed to the bottom of the tank.

5.7 All chemical tanks should be covered when not in use. Automated tools shouldclose covers automatically in case of an exhaust failure.

5.8 To reduce emissions, it is recommended that chemical tanks be capable ofbeing covered when not in use.

5.9 In tools where incompatible chemicals are used or in which both combustibleliquids and DI water are used or in which condensation can come in contact withcombustible liquids, all tanks, plenums, and secondary containment should bedesigned to ensure that they will not become mixed.


99 Appendix C

Revision 2.0 Hazardous Gas and Liquid Dopant Design Criteria


Appendix C 100

Hazardous Gas and Liquid Dopant Design Criteria Revision 2.0

Appendix C

Design Criteria for Equipment Using Hazardous Gasesand Liquid DopantsThis appendix consists of a set of supplemental safety criteria intended toenhance and expand upon hazardous gas and liquid dopant distribution andcontrol topics addressed throughout the body of the guidebook. It is stronglyrecommended that the equipment manufacturer review the contents of thisappendix for applicability to the equipment design in question.

The safety philosophy set forth in these guidelines is that potential hazards in theoperation and maintenance of equipment be identified and engineered out ofequipment during the design and construction phases. Where identified hazardscannot be eliminated, no single-point failure or operational error should allowimmediate exposure of personnel, facilities or the community to hazards, ordirectly result in injury, death, or equipment loss. All equipment should be fail-safe or of a fault-tolerant design.

1.0 General Safety1.1 Equipment designed to use HPM gases or liquid dopants should be provided

with a method for purging chemicals from the internal components beforeperforming maintenance procedures.

1.2 Spill or leak containment should be provided for all liquids in the tool.

2.0 Components2.1 Hardware - Pressurized Gas Systems

2.1.1 Control Assemblies

• Should be provided by the equipment manufacturer and leak tested.

• Should be labeled for the specific gas to be used.

• Each component of panel-mounted assemblies should be labeledand identified on an accompanying diagram.

• Certification of pressure and vacuum testing should be supplied.

2.1.2 All wetted surfaces should be compatible with gases contained.

2.1.3 All components should be pressure rated as follows:

• High pressure: 1.5 times maximum cylinder pressure

• Low pressure: 2 times maximum delivery pressure.

2.1.4 Components and tube fittings should be welded in sub-assemblieswherever feasible, with face seal fittings to be used between sub-assemblies.


101 Appendix C


2.1.5 Components installed downstream of a regulator should have a highpressure rating unless protected by redundant pressure sensing and ahigh pressure, normally-closed pneumatic valve, which should shutwhen delivery pressure exceeds 1.5 times normal. The pressure sensorsshould be installed adjacent to the regulator output.

2.1.6 Process gas shut off valves should have a packless diaphragm orbellows seal with a static seat seal with non-rotating stem tip. Unlessotherwise noted, valve operators should be normally-closed pneumaticwith 60-80 psig (5 - 6.5 bar) actuation pressures to open. Other designswhich provide equivalent reliability are acceptable.

2.1.7 Components subject to plugging, such as filters and flow controllers,should be provided with evacuation and purge capability on both sides.If a bypass is used for this purpose, the bypass valve should

• Be pressure rated the same as any shutoff valve being bypassed.

• Be interlocked to prevent opening while gas supply valve is open.

2.1.8 Piping in HPM gas systems under pressure should include at least oneof the following:

2.1.8.1 For tools where process chambers operate under vacuum,piping with HPM gases under pressure should have

• Containment in an exhausted enclosure or coaxial piping.

• Process chamber vacuum monitor interlocked to preventgases from flowing unless base pressure recommendationsare met.

2.1.8.2 For tools in which the process chambers operate at atmosphericpressure, piping with HPM gases under pressure should provide

• Containment in an exhausted enclosure or coaxial piping.

• Gas leak detection located as close as possible to thescavenger area of the tool.

2.1.9 The gas isolation box and the equipment gas panel enclosure should besized to provide adequate clearance for operation of manual controlsand the removal, replacement, and testing of components usingstandard tools.

2.1.10 All gas wetted surfaces should be cleaned for oxygen service as aminimum and purged with dry nitrogen and capped.

2.1.11 Access

2.1.11.1 An access door is an opening sized to permit access to allcomponents within an equipment gas panel enclosure or gasisolation box. Access doors to enclosures housing HPM shouldbe interlocked according to SEMI S2-93, section 5, Safety-Related Interlocks.

2.1.11.2 An access port is an opening sized to permit one handoperation or routine operation of a component. Interlocking isnot required if the system complies with section 10.1 of thisguide.


Appendix C 102


2.2 Hardware - Liquid/Vapor Systems Including Bulk Delivery Systems

2.2.1 Control Assemblies

2.2.1.1 Should be vendor-supplied and leak tested to 2X the liquidvapor pressure and carrier gas maximum pressure.

2.2.1.2 Certification of leak testing should be supplied.

2.2.1.3 Should be labeled for the specific liquid or vapor to be used.

2.2.1.4 Each component should be labeled and identified on anaccompanying diagram.

2.2.2 All wetted surfaces should be compatible with the liquids and/or vaporscontained.

2.2.3 All components should be pressure rated according to 2X the maximumcarrier gas pressure or the liquid vapor pressure, whichever is higher.

2.2.4 Flexible hose may be used in non-combustible liquid systems. Ferrousmaterial is necessary for flammable sources and carrier gases. Whenferrous tubing cannot be used because of compatibility concerns,flexible tubing inside a protective jacket should be used (e.g., Teflonwith braided stainless steel shielding).

2.2.5 Components and tube fittings should be made in welded subassemblieswhere feasible, with face seal fittings to be used betweensubassemblies.

2.2.6 Manual shutoff valves on source container ports may be plug or balltype with sliding seals. Other types of valves with equivalent reliabilityare acceptable.

2.2.7 Process liquid/vapor shutoff valves should have packless bellows ordiaphragm seal with a static seat seal with non-rotating stem tip. Unlessotherwise noted, valve operators should be normally closed pneumaticwith 60-80 psig (5 - 6.5 bar) actuation pressures. Other valve designsthat provide equivalent reliability are acceptable.

2.2.8 Bubblers using flammable or otherwise hazardous carrier gases shouldincorporate redundant shutoff valves in the gas supply to the sourcecontainer. Redundant valves are preferred in most delivery systems butare not recommended where condensation is possible.

2.2.9 Container assemblies should be secured in the source compartment andpositioned to provide visibility if a viewing port is provided. Sourcecontainer should be able to be changed without disturbing fittings in anyrigid portion of the assembly.

2.2.10 Purge and relief vents should terminate inside the exhaust duct andshould contain no components or restrictions.

2.2.11 The source compartment should be sized to provide adequate clearancefor the operation of manual valves and removal, replacement, andtesting of components using standard tools.

2.2.12 A mechanism for removing all liquids or vapors in the delivery linesbefore disconnecting the source container or other components isrecommended. For highly toxic liquid source lines, automatic andmonitored vacuum/pressure purging is recommended before bubbler orline disconnects.


103 Appendix C


2.2.13 Acceptable methods for source liquid replenishment are

• Direct replacement of the source container.

• Manual or automatic refill from another container through deliverylines.

2.2.14 Where the carrier gas or source liquid is flammable or flammable underoperating conditions, the recommendations in section 8 of this appendixshould be met.

3.0 Labeling3.1 Labeling recommendations are as follows:

• Caution signs stating that toxic gas delivery systems are to be shut downand purged before entry and that only trained personnel are allowed accessare recommended on each gas isolation box and equipment gas panelenclosure.

• Gas, vapor, and liquid lines should be clearly labeled at entry and outlet andwithin compartments as necessary for clear identification. Valves should belabeled (numbered) as referenced in piping diagram and equipment manual

• Piping diagrams identifying each line and component by their contentsshould be readily available.

• Leak detectors should be labeled with the sensor identification and thechemical being monitored.

• A diagram of the tool layout with the location of each sensor should beposted.

• Exhaust failure and leak detector alarms, if present, should be labeledclearly identifying the alarm condition and the appropriate action to be taken.

• Interlocked doors and panels should be clearly labeled as such.

4.0 Exhaust VentilationExhaust air recommendations should conform to section 10, Ventilation and Exhaust, of

this guide.

4.1 The following should be exhausted:

4.1.1 Each gas isolation box and equipment gas panel enclosure (externalcylinder gas supply) utilizing HPM gases (NFPA rating of 3 or 4 forhealth fire or reactivity).

4.1.2 Each tool cylinder gas compartment (internal cylinder gas supply) usingHPMs.

4.1.3 Each liquid source compartment including cabinets for liquidreplenishment systems.

4.1.4 Any portion of the tool that contains HPMs above atmospheric pressurethat is not in coaxial piping.

4.1.5 A lip exhaust around process chambers open to atmosphere duringloading (i.e., process chambers without loadlock chambers).


Appendix C 104


4.1.6 Vacuum pump discharges per the recommendations of sections 10.7and 10.8 of SEMI S2-93.

4.1.7 Vacuum pump enclosure as part of the equipment installation (ifrequested by the end-user). One drop can exhaust both the vacuumpump discharge and the enclosure.

4.2 Exhaust flow rates for the first four items above should be according section10.5 of this guide.

4.3 Exhaust flow rate for pyrophoric gases should be at least 100 linear feet perminute (lfm).

NOTE: Current research suggests that air velocity may not be a significantfactor in mitigating the hazard of pyrophoric gas ignition; however, bestpractice currently encourages this minimum exhaust velocity.

4.4 Exhaust air flow should meet the recommendations of the most hazardous gasin the enclosure.

4.5 The lip exhaust recommended for process chambers open to atmosphere duringloading should provide sufficient volume to remove toxic out-gassing when thechamber is opened. Slot exhausts should have 2000 fpm (10 m/s) minimum slotvelocity and should provide adequate capture velocity across the entire opening.

4.6 Exhaust air flow through enclosures should be sufficient volume, velocity, andeven distribution to ensure that no “dead spaces” allow gas pockets to develop incase of a leak.

4.7 Exhaust air flow should minimize the impingement of a corrosive gas leak onother components.

4.8 Each exhaust drop should be monitored according to section 10.9 of this guide.

5.0 Toxic/Corrosive Gas5.1 Gas Isolation Box (when part of the equipment)

Each toxic (NFPA Health Hazard = 2, 3, or 4) gas delivery system containing agas isolation box adjacent to the equipment gas panel enclosure should allow forlocal shutoff, purging of the toxic gas supply to the tool and lockout/tagoutcapability. Note: This section applies to manufacturers of gas isolation boxes orequipment suppliers who incorporate a gas isolation box in their tool.

5.1.1 Common Exhaust - The gas isolation section may share a commonexhaust with the equipment gas panel enclosure. A barrier between thegas isolation section and the equipment gas panel enclosure shouldprovide adequate exhaust velocity and distribution for the gas isolationsection.

5.1.2 Redundant Shutoff Valves - Each delivery line in the isolation boxshould contain two shutoff valves with a pressure/vacuum indicator tomonitor the section between the valves for maintenance of vacuumisolation. The first valve should be a high pressure shutoff valve.Note: The intent if the pressure/vacuum indicator is to allow a personworking within the compartment to assure that the gas lines are purgedand the upstream valves are not leaking.


105 Appendix C


5.1.3 Gas Line Location - Locate corrosive gas lines in the isolation box sothat exhaust air flow will minimize the impingement of a corrosive gasleak on other components in box.

5.1.4 Isolation Box Construction - The box should be constructed of non-combustible materials with exhaust air flow according to section 4 of thisappendix. The access door should be interlocked to shut gas flow whenopened, according to section 5 of this guide.

5.1.5 Hardware should consist of the following:

5.1.5.1 The box should be able to accept a double-walled inlet line fromthe source gas cabinet.

5.1.5.2 A high pressure pneumatic shutoff valve.

5.1.5.3 A pressure/vacuum gauge or indicator visible from the exteriorof the isolation box through an opening or fire-retardanttransparent panel. Pressure transducers and remote display arean acceptable alternative.

5.1.5.4 A second pneumatic shutoff valve.

5.1.5.5 An automatic purge/vent mechanism capable of evacuation andpressure cycling.

• A nitrogen eductor discharging into the exhaust duct is thepreferred vacuum source.

• The nitrogen purge and eductor inputs should contain ameans of preventing back flow.

• Incompatible gases should have independent purge sourcesand be interlocked to prevent mixing of purge/exhauststreams.

• Interlock vent valves with high pressure valves to preventpotential cylinder discharge and with eductor nitrogen inputto prevent air/gas reactions.

5.1.5.6 The tool gas compartment should be capable of accepting adouble-walled outlet line.

5.1.6 Controls - Typical controls for a gas isolation box are shown in Figure 1.

Figure 1 Gas Isolation Box(see page 116 for symbol legend)

Cylinder orHouse N2

Exhaust

NC NO

COM

Cylinder

N2

HPGas

Out

Gas

In


Appendix C 106


5.2 Equipment Gas Panel Enclosure

Gas lines, fittings, and components within the tool that may be subjected toabove atmospheric pressure during normal tool operations or in a single failuremode are to be segregated into a dedicated compartment or enclosure.

5.2.1 Construction - The compartment should be constructed of non-combustible materials with exhaust air flow according to section 4 of thisappendix.

5.2.2 Components - Components for each gas supply should includeredundant shutoff valves, pressure/vacuum sensing, flow controls, and ameans of preventing back-pressure or back-flow from the manifold orreaction chamber in a failure mode.

5.2.3 Gas Line Location - Locate corrosive gas lines so that exhaust air flowwill minimize the impingement of a corrosive gas leak on othercomponents. Access doors and ports should be as defined in theGlossary.

5.2.4 Recommended Compartments - Only one equipment gas panelenclosure is recommended if it meets the recommendations of the mosthazardous gas present.

5.2.5. Low-Toxic Gases - The following is recommended for HPM gases withan NFPA health hazard = 0 or 1.

5.2.5.1 A low pressure pneumatic shutoff valve.

5.2.5.2 For inert purge gases, one of the following:

• A low pressure normally closed pneumatic shutoff valvewhere a purge gas flow after tool shutdown would introducea safety hazard.

• A low pressure normally open pneumatic valve where failureof the purge gas would introduce a safety hazard.

5.2.5.3 The recommended flow controls.

5.2.5.4 A mechanism to prevent backflow.

5.2.6. Toxic Gases - For HPM gases with an NFPA health hazard rating of2,3, or 4, the following is recommended.

5.2.6.1 Toxic gas delivery line terminating in the compartment. The pointof termination should accommodate coaxial line.

5.2.6.2 Redundant low pressure pneumatic shutoff valve to cycle onand off as the tool calls for gas.

5.2.6.3 An optional point-of-use filter per process recommendations,with purging capability according to section 2.1, ComponentsHardware - Pressurized Gas Systems.

5.2.6.4 A pressure/vacuum sensor to verify line pressure and purgesequences, readable without opening gas compartment accessdoor. A pressure transducer and remote display are anacceptable alternative. (See section 5.1.5.3 of this appendix).

5.2.6.5 Tool flow controls with purging capability according to section2.1 of this appendix.


107 Appendix C


5.2.6.6 A check valve or pneumatic shutoff valve to prevent backflowwhere manifold pressure is above atmospheric during normaltool operations.

5.2.6.7 Capability of locking out process gas flow to individual chamberson multi-chamber tool to allow for maintenance operations onselected chambers during normal tool operations.

5.2.7 Controls - Typical controls for an equipment gas panel enclosure areshown in Figure 2.

Figure 2 Typical Controls for ToolGas Compartment

(see page 116 for symbol legend)

5.3 Internal Cylinder Toxic Gas Supply Systems

This section applies to tools using HPM gases (NFPA health hazard = 2/3/4)supplied from a cylinder regardless of pressure, which are housed within the tool(e.g., ion implanters).

5.3.1 Cylinder Gas Supply System - The cylinder gas supply system shouldconsist of

5.3.1.1 A metal compartment containing all cylinders, gas lines, fittings,and components under positive pressure. Access doors to thecompartment should be interlocked to shut off gas flow when thedoor is opened, according to section 5 of this guide.

5.3.1.2 Gas cylinders should be secured in place with metal constrainingdevices. The cylinders should be equipped with normally closedpneumatic valves with manual shutoff capabilities.

5.3.1.3 A remotely controlled cross-purge assembly, securely mounted,with the following components:

• A CGA cylinder connection with flexibility to allow forcylinder variations, as with a tubing coil.

• A high pressure, normally closed, pneumatic isolation valve.

• A high pressure, normally closed, pneumatic inert purge gasvalve connected to an eductor or a vacuum pump and avacuum monitoring device.


Appendix C 108


• A high pressure, normally closed, pneumatic inert purgevalve.

• The eductor discharge line to exhaust should be one sizelarger than the vacuum inlet.

• A pressure/vacuum sensor to monitor purge cycles andabort the sequence if not correct.

5.3.1.4 A pressure regulator with the following components:

• An inlet particulate filter, if not included in the regulator.

• A metal tied diaphragm.

• A bonnet vent line to exhaust.

• A reduced pressure indicator. (Note: A pressure regulator isnot required for cylinders with gases at subatmosphericpressures.)

5.3.1.5 Two pressure sensors set at 2X the delivery pressure of 10 psig(1.7 bar) minimum, to shut the cylinder valve and isolation valveon excess pressure.

5.3.1.6 A gas filter per process recommendations.

5.3.1.7 A high pressure, pneumatic, shutoff valve.

5.3.2 Typical Controls - A typical cylinder gas supply system is shown inFigures 3 and 4.

Figure 3 Typical Controls for HighPressure Toxic Internal Cylinder

Gas Supply(see page 116 for symbol legend)

Figure 4 Typical Controls for Sub-atmospheric Pressure ToxicInternal Cylinder Gas Supply


IPT

PT

House

N2

HP

HP

Exhaust

ToolControlBypass

ToProcess

Cylinder N2

MFC

PT

IPT

House

N2

HP HP

HP

HP

OPT

Exhaust

ToolControlBypass

ToProcess

Cylinder N2


109 Appendix C


5.4 Liquid and Vapor Dopant Supply Systems

This section applies to tools using toxic vapor supplied from evaporation orbubbler sources and to liquid dopant injection systems.

5.4.1 Source Compartments - The following are recommendations for sourcecompartments:

5.4.1.1 Toxic liquid sources and related delivery controls should behoused in non-combustible compartment with exhaust air flowaccording to section 4, Exhaust Ventilation. Where sourcecontainers are refilled by piping from a supply container, thiscontainer should be located in a similar compartment.

5.4.1.2 The compartment exhaust should be interlocked according tosection 5 of this guide to isolate the source container and, ifrecommended, drop power.

5.4.1.3 If spillage or leakage is possible and secondary containment isnot provided, the compartment should contain 110% of the liquidvolume of the source container.

5.4.1.4 Liquid or vapor leak detection.

5.4.2 Source Containers - The following are recommendations for sourcecontainers:

5.4.2.1 Source containers should be DOT/UN approved shippingcontainers unless specifically designed for bulk replenishmentsystem.

5.4.2.2 Ports should have shutoff valves to isolate the source when thecontainer is removed and transported.

5.4.2.3 Port fittings must be designed to prevent interchanging ofconnections fittings (i.e., connecting containers to the wrong lineor reversing the inlet and outlet connections.)

5.4.2.4 Containers with automatic refilling should have an interlockedhigh level sensor appropriately interlocked with the dispensesystem to prevent overfilling.

5.4.2.5 Containers should have secondary containment capable ofcontaining 110% of the liquid volume, equipped with a viewingport and a means of detecting a leak.

5.4.3 Carrier Gas Supply System

The following are recommendations for carrier gas supply systems:

5.4.3.1 Carrier gases may be used to transport vapors in a bubblersystem.

5.4.3.2 An inert carrier gas should be used as a purge source.

5.4.3.3 The carrier gas supply system should include:

• A pressure regulator sized to provide a maximum deliverypressure lower than the allowable pressure rating of thesource container.

• A pressure indicator located at the source cabinet.

• A check valve to prevent reverse flow.


Appendix C 110


• A pressure relief device, if any component of the delivery orreplenishment system does not comply with section 2.2.1.This device should relieve three-fourths of the workingpressure of the lowest rated component and discharge intothe compartment exhaust.

5.4.3.4 A typical inert carrier gas control system is shown in Figure 5.

Figure 5 Typical Controls for Inert Gas for LiquidSource Vapor Supply System


5.4.4 Liquid Dopant Sources

5.4.4.1 Liquid injection systems should be designed to allow purgingbefore maintenance or servicing. For highly toxic liquid sourcelines, automatic and monitored vacuum/pressure purging isrecommended before maintenance or servicing.

5.4.4.2 The delivery line should contain a shutoff valve and means ofverifying that the line has been purged before maintenanceactivities, according to section 2.2.

5.4.4.3 A typical evaporation system is shown in Figure 6.

Figure 6 Typical Controls for Liquid Dopant InjectionCompartment


5.4.5 Evaporation Systems - The following are recommended:

5.4.5.1 Evaporation systems should be designed to allow purging beforemaintenance or servicing For highly toxic liquid source lines,automatic and monitored vacuum/pressure purging isrecommended before maintenance or servicing.

R

N2

Exhaust

To SourceContainer

LFC ICV

MF

C

OPTLiquidDopant

N2 Purge Gas

Inert Gas

Bypass

ToProcess

To Pump

Exhaust


111 Appendix C


5.4.5.2 The deliver line should contain a shutoff valve according tosection 2.2.

5.4.5.3 A typical evaporation system is shown in Figure 7.

Figure 7 Typical Controls for Liquid Source VaporSupply Evaporator


5.4.6 Bubbler Systems - The following are recommended:

5.4.6.1 The carrier gas supply should have a flow control device.

5.4.6.2 A bypass should be provided to purge the bubbler before achange. For highly toxic liquids, automatic and monitoredvacuum/pressure purging is recommended. Bubbler systemsshould be designed to allow for purging lines and bubblers formaintenance and servicing.

5.4.6.3 Non-inert carrier gases should be purged from the bubblerbefore a change.

5.4.6.4 Carrier gas supply and delivery lines should both contain shutoffvalves, according to section 2.2.

Exhaust

FromReplenishmentSystem(optional)

LiquidSourceContainer

Secondary ContainmentWith Viewport

To Process (vacuum)


Appendix C 112


5.4.6.5 A typical bubbler system with an inert carrier gas is shown inFigure 8.

Figure 8 Liquid Source Vapor Supply Bubbler withInert Carrier Gas


5.4.6.6 A typical bubbler system with a flammable carrier gas is shownin Figure 9.

Figure 9 Liquid Source Vapor Supply BubblerSystem with Flammable Carrier Gas


5.4.7 Liquid Replenishment Systems - The following are recommended:

5.4.7.1 Containers should be DOT/UN approved shipping containers.

5.4.7.2 The source container should have shutoff valves and non-interchangeable fittings, according to section 5.4, SourceContainers.

5.4.7.3 The source outlet line should be designed to minimize spillageof liquid during a reservoir change.

Liquid SourceContainer

MFCN2

Exhaust

Bypass

To Process(atmospheric) FromReplenishment System (optional)

Secondary ContainmentWith Viewport

Exhaust ToProcess

N2

H2

Liquid SourceContainer

Secondary Containmentwith Viewport


113 Appendix C


5.4.7.4 Provide a vent to exhaust any positive pressure before areservoir change.

5.4.7.5 Provide a pressure relief valve set at < 3/4 of the designpressure rating of the lowest rate component in the system.

5.4.7.6 Input and delivery lines should both contain shutoff valves,according to section 2.2.6.

5.4.7.7 Capability should be provided to purge all liquid from the linesfor canister replacement.

5.4.7.8 A typical replenishment system is shown in Figure 10.

Figure 10 Liquid Source Supply Liquid ReplenishmentSystem


6. Interlocks and ControlsAll interlocks and controls should be fail-safe according to SEMI S2-93.

6.1 Failure Detection - When a failure is detected

6.1.1 The interlock circuit should shut off the chemical flow.

6.1.2 The interlock circuit should be designed to interface with externalcontrols (e.g., normally closed 24 VDC circuit to actuate a central alarmsystem).

6.1.3 Tool circuits should remain intact to allow removal of residual chemicals.

6.2 Shutoff, External Gas Supply System - Failure detection shutoff for a tool withan external gas supply system should be as follows.

6.2.1 A tool shutdown shuts the gas off at the high pressure valve in theisolation box (when provided) or the first facilities control valve upstreamof the equipment and at least one other low pressure valvesimultaneously. A tool shut down circuit opens upon

6.2.1.1 Normal tool shutdown.

6.2.1.2 Loss of process vacuum.

6.2.1.3 Loss of vacuum pump purge gas or dilution of flammable orpyrophoric gases.

R

Exhaust

N2To Liquid Source

Liquid

Secondary Containmentwith Viewport


Appendix C 114


6.2.1.4 Loss of tool exhaust.

6.2.1.5 Loss of vacuum pump enclosure exhaust, when provided.

6.2.1.6 Vacuum pump enclosure door open, when provided.

6.2.1.7 Tool gas compartment door open.

6.2.1.8 Actuation of gas detector alarms where requested by the end-user.

6.2.2 A system shutdown shuts the gas off at the first facilities control valveupstream of the equipment and at the tool as described above. A systemshutdown circuit opens upon

6.2.2.1 Loss of electricity.

6.2.2.2 Tool emergency shutdown.

6.2.2.3 Failure of any device of component in the circuit.

6.2.2.4 Loss of exhaust to the gas isolation box.

6.2.2.5 Gas leak detection.

6.2.2.6 Gas isolation box access door open.

6.2.2.7 Toxic gas high delivery line pressure signal from the gas source.

6.2.3 Shutoff, Internal Gas Supply System - Failure detection shutoff for a toolwith an internal supply system should be as follows:

6.2.3.1 Shutoff is a system shutdown that closes the cylinder valve andthe high pressure valve.

6.2.3.2 A system shutdown circuit opens upon

• All of applicable items in section 6.2 of this appendix

• Loss of cylinder gas compartment exhaust.

• Cylinder gas compartment door open, unless the tool isinterlocked to shut down gases to gain access to the gascompartment or if the system complies with section 10.1 ofthis guide.

• Toxic gas high delivery pressure, unless componentsexposed are rated for 1.5X cylinder pressure.

• Actuation of gas detector alarm when requested by the end-user.

6.2.4 Shutoff, Liquid and Vapor Dopant System - Failure detection shutoff fora tool with a liquid or vapor dopant system should be as follows:

6.2.4.1 Shutoff is a system shutdown which closes the carrier gassupply valve or liquid pump and the delivery valve.

6.2.4.2 A system shutdown circuit opens upon:

• All of applicable items in section 6.2 of this appendix

• Loss of liquid source cabinet exhaust.

• Liquid source cabinet door open, unless the systemcomplies with section 10.1 of this guide.


115 Appendix C


• Actuation of liquid leak detection. The system complies withsection 10.1 of this guide.

6.2.5 Manual Reset - The interlock circuit should remain open until manuallyreset.

6.2.6 Alarm and Monitoring - Provisions for both a local alarm and a remotecentral monitoring system should be provided.

7. Vacuum Pumps7.1 The vacuum pump should be approved by the vendor for the process gases

used.7.2 Dry pumps are preferred. Wet pumps should use an oil compatible with the

process gases used.

7.2.1 For oxygen or other reactive gases, a perfluorinated oil isrecommended.

7.2.2 Connections should be provided for sealed oil changing carts.

7.3 Vacuum piping should be compatible with the gases contained. Metallic piping isrecommended for flammable and pyrophoric gases.

7.4 Where residues may collect, the vacuum piping should be accessible forinspection and cleaning

7.5 Vacuum pumps handling highly toxic gases or vapors with NFPA health,flammability or reactivity rating of 3 or 4 should be nitrogen purged with purgeflow monitoring and interlocking of all branches of the nitrogen lines.

7.6 Isolation of cryo pumps from process chamber before the introduction of toxic,flammable, or pyrophoric gases is recommended.

8. Flammable Gas/Vapor Recommendations(NFPA: Flammability = 3 or 4)8.1 General Recommendations

8.1.1 All applicable Toxic Gas recommendations in section 5 should be met.

8.1.2 Flammable gases and vapors should be isolated from oxidizers andsources of ignition.

8.1.3 Electrical components within the equipment gas panel enclosure and inany space with flammables under pressure should comply with one ofthe following:

8.1.3.1 Be designed according to the National Electric Code, Articles500 and 501, meeting Class I, Division 2, Group B, C, or Drequirements, or

8.1.3.2 Be intrinsically safe according to NFPA 493, or

8.1.3.3 Be rendered safe by a combination of items 1 and 3 or 2 and 3below:


Appendix C 116


1. A monitored exhaust to drop power to the affected spacesand shut off gases on loss of exhaust.

2. Nitrogen purged enclosures according to NFPA 496.Nitrogen purge flow should be monitored to drop power tothe affected spaces and shut off gases on loss of flow.

3. Flammable gas leak detection to drop power to the affectedspaces and shut off gases on sensing 20% of the LFL.

8.2 Introduction of Flammable Gas/Vapor

8.2.1 The system should be designed with the capability to

8.2.1.1 Purge air or oxygen or other oxidizer from the tool by a fixedpurge control program, or

8.2.1.2 Ensure that the ignition temperature for the gas is exceeded andthat excess oxygen is available to guarantee completecombustion.

8.2.2 Chambers within the tool where combustion of the gas is possible shouldbe designed to contain the maximum reaction pressure possible or haveadequate explosion relief.

8.2.3 Flammable gas discharges from the tool should meet one of thefollowing criteria:

8.2.3.1 Diluted with an inert gas to below 20% of the LFL beforedischarge into the exhaust system; the inert gas flow must beinterlocked as in section 8.5, Pyrophoric Gas. (Exception:Hydrogen may be diluted to 5% in nitrogen before discharge.)

8.2.3.2 Ignited by an approved burn-off unit containing a sensing unitthat ensures automatic shutoff of flammable gas and inert gaspurge on loss of ignition temperature.

9. Pyrophoric GasesThis section applies to tools using detonable pyrophorics: >2% silane (disilane).

9.1 All applicable recommendations of section 5, Toxic Gas, should be met, exceptthat exhaust air flow within all enclosures containing silane under pressureshould exceed 100 lfm at all potential leak sites. Potential leak sites should belocated in a free-flowing, non-baffled air stream and should be accessible forexhaust air flow measurement.

9.2 Silane should be diluted in nitrogen to 2% before discharge into an exhaust airstream, or an approved, monitored burn-off system should be provided. Nitrogensupply to vacuum eductors should be sequenced and interlocked to purgeair/oxygen from the vent line before venting silane.

9.3 Where monitored burn-off systems are not installed, temperatures should besensed at the point of connection to the facilities exhaust duct and at the point ofmixing with dilution air if these points are separated. When temperatures exceed25% above normal maximum operating temperatures, the interlock circuitshould be opened and the alarm circuit closed to the local alarm and the remotecentral monitoring system.


117 Appendix C


9.4 Vacuum pumps should be nitrogen purged according to the manufacturer’srecommendations. Purge gas flow should be monitored to shut off Silane flow ifinsufficient.

9.5 Vacuum pump discharges should be nitrogen diluted to 2% silane beforedischarge to the exhaust system.

9.5.1 This dilution level should be provided for all systems running atmaximum flow and be interlocked.

9.5.2 Provide flow restrictors in all purge/bypass lines to ensure silane dilutionto <2%.

9.5.3 Pump discharge lines should be accessible for regular inspection forbuildup of reaction residues.

9.6 Vacuum tools should be protected against accumulation of silane in the processchamber.

9.6.1 After silane shutoff, but before venting, a leak-check sequence shouldbe performed to determine silane valve leak-through.

9.6.2 If leak-through is detected, the tool should be interlocked to remainunder vacuum until corrective action is taken.

10. Oxidizer Gas Recommendations (NFPA Oxidizer)10.1 Oxidizer gases should be isolated from flammable and pyrophoric gases.

10.2 Gas flows should be interlocked to controls such as purge, pressure/vacuum, ortemperature sensing to prevent flow unless safe reaction conditions are present.

11. Corrosive Gas Recommendations11.1 Corrosive gas recommendations are covered, in general, in section 5 of this

appendix.

11.2 Corrosive gas eductor vent discharges in the gas isolation box should becontinuously purged to preclude moisture.


Appendix C 118


Symbols Legend

Symbols and Abbreviations

MFC

LFC

ICV

PT

IPT

MASS FLOW CONTROLLER

LIQUID FLOW CONTROLLER

INJECTION CONTROL VALVE

PRESSURE TRANSDUCER

INDICATING PRESSURE TRANSDUCER

FILTERNO----NORMALLY OPENNC----NORMALLY CLOSEDCOM---COMMONHP----HIGH PRESSURELP----LOW PRESSUREOPT---OPTIONAL

PRESSURE REGULATOR

Documents

Sematech Safety Guide -- Silane