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SEMI S14-0704 © SEMI 2000, 2004 8 APPENDIX 1 RISK ASSESSMENT CRITERIA NOTICE : The material in this appendix is an o fficial part of SEMI S14 and was approve d by full letter ballot procedures on September 3, 1999 b y th…

SEMI S14-0704 © SEMI 2000, 2004 7

• limiting their energy, and

• separating them from combustible materials of

construction and from flammable and combustible

process chemicals. Separation may be by distance

or by barriers.

7.3.3 Equipment in which flammable liquids or gases

are used should be assessed to determine if additional

precautions (e.g., purging) in the electrical design are

necessary.

NOTE 23: NFPA 497 and EN 1127-1 are among the

documents that provide methods for making this assessment.

7.4 Oxidizers

7.4.1 Reducing the quantities or pressures of oxidizing

process chemicals may reduce the fire risk.

7.4.2 The fire risks of oxidizing process chemicals may

also be reduced by limiting those factors described in

Section 6.

7.5 Exhaust, Enclosures and Barriers

7.5.1 Mechanical exhaust may reduce the risk of

damage to the facility, other equipment, or other

portions of the same equipment by limiting the spread

of combustion and decomposition products. The

mechanical exhaust could be provided by the

equipment or by the facility.

7.5.2 Enclosures and barriers within the equipment

may reduce the fire risk by separating the fuels and

oxidizers from each other and from potential sources of

ignition.

7.5.3 These design features may also limit the spread

of fire, reducing both the loss of equipment and the

emission of combustion and decomposition products.

8 Related Documents

8.1 SEMI Standard

SEMI S11 — Environmental, Safety, and Health

Guidelines for Semiconductor Manufacturing Equip-

ment Minienvironments

8.2 NFPA Documents

National Fire Protection Association: NFPA 70 —

National Electric Code (NEC)

National Fire Protection Association: NFPA 318 —

Standard for Protection of Cleanrooms

National Fire Protection Association: NFPA 496 —

Standard for Purged and Pressurized Enclosures for

Electrical Equipment

National Fire Protection Association: NFPA 497 —

Recommended Practice for the Classification of

Flammable Liquids, Gases, or Vapors and of

Hazardous (Classified) Locations for Electrical

Installations in Chemical Process Areas

8.3 CEN/CENELEC Standards

EN 1127-1 — Explosive Atmosphere – Explosion

prevention and protection – Part 1 Basic concepts and

methodology

8.4 Other Documents

Building Officials and Code Administrators (BOCA)

NBC: National Building Code

Factory Mutual System Data Sheet 7-7

, Semiconductor

Fabrication Facilities

International Conference of Building Officials (ICBO)

UBC: Uniform Building Code

International Fire Code Institute

, UFC: Uniform Fire

Code

International SEMATECH

, Process Compatibility

Parameters for Wet Bench Plastic Materials

(Technology Transfer # 98123623A)

Southern Building Code Congress International

(SBCCI)

, SBC: Standard Building: Code

4 European Committee for Standardization (CEN)/European

Committee for Electrotechnical Standardization (CENELEC), Central

Secretariat: rue de Stassart 35, B-1050 Brussels Belgium

5 Building Officials & Code Administrators International, Inc., 4051

West Flossmoor Road, Country Club Hills, IL 60477

6 Factory Mutual, 1301 Atwood Ave. P.O. Box 7500 Johnston R.I.

02919, website: www.fmglobal.com

7 ICBO, 5360 South Workman Mill Rd., Whittier, CA 90601

8 International Fire Code Institute, 5360 South Workman Mill Rd.,

Whittier, CA 90601

9 SEMATECH, 2706 Montopolis Drive, Austin, TX, website:

www.sematech.org

10 SBCCI, 900 Montclair Rd, Birmingham, AL 35213-1206

SEMI S14-0704 © SEMI 2000, 2004 8

APPENDIX 1

RISK ASSESSMENT CRITERIA

NOTICE: The material in this appendix is an official part of SEMI S14 and was approved by full letter ballot procedures on

September 3, 1999 by the North American Regional Standards Committee.

A1-1 The risk assessment should be performed for each identified fire hazard using the method provided in SEMI

S10 and the following definitions of Likelihood and Severity Groupings and Risk Categories.

NOTE A1-1: Unlike SEMI S10, in which the tables are provided only as examples, this document defines the Severity,

Likelihood, and Risk to be used herein.

A1-2 Severity

A1-2.1 The Severity Groupings are given in Table A1-1.

Table A1-1 Severity Groupings

Severity Group

Equipment Physical

Damage

Equipment Loss

of Use

Facility Loss of

Use (Minimum

Times)

Environmental and Real Property

Contamination

1 Catastrophic Loss of entire piece of

equipment

One year One week Lasting facility or environmental

impact

2 Severe Loss of major

subsystem

One month One day Temporary facility or environmental

impact

3 Moderate Loss of minor

subsystem

One week One shift Limited to the equipment, but

requiring more than routine cleanup

4 Minor Non-serious

equipment loss

One day Less than one

shift

Requiring routine cleanup but not

external reporting

A1-2.2 The Severity should be assigned for each of the columns for which information is available.

A1-2.3 The most severe Group assigned should be used in determining the risk.

A1-2.4 Each of the Severities should be reported.

A1-2.5 Contamination is by release of materials that were used in the equipment or by combustion or thermal

degradation byproducts.

A1-2.6 To be included in the assessment, a foreseen occurrence must be unplanned and include a loss.

A1-2.7 Losses exclude the performance of the design function of protective devices, such as fuses.

A1-2.8 The scope of the assessment in this document is limited to the consequences of fire.

A1-2.9 The Equipment Loss of Use time is the downtime, as defined in SEMI E10, resulting from the fire incident.

A1-3 Likelihood

A1-3.1 The Likelihood Groupings are given in Table A1-2.

Table A1-2 Likelihood Groupings

Likelihood Group Expected Frequency (% of Systems per Year)

A Frequent More than 1%

B Likely More than 0.2% but not more than 1%

C Possible More than 0.04%, but not more than 0.2%

D Rare More than 0.02%, but not more than 0.04%

E Unlikely Not more than 0.02%

A1-3.2 “System” refers to the equipment as configured and offered by the supplier.

A1-4 Risk

A1-4.1 The Risk should be calculated based on the Severity and Likelihood assigned above and the Risk Categories

defined in Table A1-3.

Table A1-3 Risk Categories

Likelihood

Severity A B C D E

1 Critical Critical High Medium Low

2 Critical High Medium Low Low

3 High Medium Low Low Slight

4 Medium Low Low Slight Slight

A1-4.2 The Risks are to be reported in total for the equipment as offered for sale. (e.g., if the equipment being

evaluated is a cluster tool, the risks should be reported by the system integrator for the assembled tool, not the

individual modules.)

NOTE A1-2: Although the risks for cluster tools should be reported for the assembled tool, the modules are not necessarily

contiguous and this may bear on the risk.

NOTE A1-3: The Risks of components or subsystems may be increased or decreased by their integration into the equipment

being assessed.