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Appendix 1

Federal Standard 209D

FEDERAL STANDARD

CLEAN ROOM AND WORK STATION

REQUIREMENTS, CONTROLLED ENVIRONMENT

This standard is approved by the Commissioner, Federal Supply Service, General Services Administration, for the use of all Federal Agencies.

308

1.

1.1

1.2

2.

3.

3.1

3.2

3.3

3.4

3.4.1

3.4.2

3.4.3

3.5

3.6

3.7

3.8

3.9

3.10

3.11

Federal Standard 209D 309

CONTENTS

SCOPE AND LIMITATIONS

scope

Limitations

REFERENCED DOCUMENT

DEFINITIONS •

Airborne particulate cleanliness class

Calibration

Clean zone

Cleanroom

AS-built cleanroom (facility)

At-rest cleanroom (facility)

Operational cleanroom (facility)

Unidirectional airflow

Nonunidirectional airflow

Condensation nucleus counter

Optical particle counter

Particle

Particle size

Particle concentration

page

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

3

3

310 Appendix 1

3.12

3.13

4.

4.1

4.2

4.3

4.4

4.5

4.6

5.

Student's t distribution

Upper confidence limit

AIRBORNE PARTICULATE CLEANLINESS CLASSES

Determination of class limits •..

Table I. Class limits in particles per cubic

foot of size equal to or greater than particle

sizes shown (micrometers)

Particle sizes measured to determine Classes

100 and greater . • • .

Particle sizes measured to determine Classes

less than 100 ...

Figure 1. Class limits in particles per cubic

foot of size equal to or greater than particle

sizes shown t

Classification by measurement at other

particle sizes

Provision for alternative airborne particulate

cleanliness classes

3

3

3

3

• • 4

• • • 4

• • 4

• • 5

• • 6

• 6

Particle counts for the determination of cleanliness

classes . • 6

VERIFICATION AND MONITORING OF AIRBORNE PARTICULATE

CLEANLINESS CLASSES . • . . • 7

I I

5.1

5.1.1

5.1.2

5.1.2.1

5.1.2.2

5.1. 3

5.1.3.1

5.1.3.2

5.1.3.3

5.1.3.4

5.1.3.5

5.1.4

5.2

5.2.1

5.2.2


Verification of airborne particulate

cleanliness classes

Frequency •

Environmental test conditions

Conditions of test

Environmental and use parameters

Particle counting

Sample locations and number - unidirectional

airflow ••••••••••

Sample locations and number - nonunidirectional

airflow ••••

Sample location restrictions .•

Sample volume and sampling time

Table II. Minimum volume per sample in cubic

feet for the air cleanliness class and measured

particle size shown

Sample volume at other classes or particle sizes

Interpretation of the data ••

Monitoring of airborne particulate cleanliness

Moni tori ng plan

Particle counting

III

7

7

7

7

7

7

• • 7

8

8

8

9

9

9

9

10

10

312 Appendix 1

5.3 Methods and equipment for measuring airborne

particle concentration •••••

5.3.1

5.3.2

5.3.3

5.3.3.1

5.3.3.2

5.3.3.3

5.3.4

5.4

5.4.1

5.4.1.1

5.4.1.2

5.4.1.3

5.4.1.4

5.4.1.5

5.4.1.6

6.

7.

8.

Counting particles 5 micrometers and larger

Counting particles 0.1 micrometer and larger

Limitations of particle counting methods

Optical particle counters

Microscopic evaluation

Upper limits.

Calibration of particle counting

instrumentation

Statistical analysis

Acceptance criteria

Average particle concentration

Mean of the averages

Standard deviation

Standard error •

upper confidence limit (UCL)

Table III. UCL factor for 95% upper control limit

Sample calculation

CHANGES

CONFLICT WITH REFERENCED SPECIFICATIONS

FEDERAL AGENCY INTERESTS

IV

10

11

11

11

11

11

11

12

12

12

12

13

13

13

13

13

14

14

14

14

A10.

A20.

A30.

A40.

A50.

A60.

A70.

ABO.

A90.

B10.

B20.

B30.

B40.

B50.

B60.

B70.


APPENDIX A

PARTICLE MONITORING - MANUAL COUNTING AND SIZING METHODS

Scope

Summary of method

Equipment

preparation of equipment

Sampling •

Microscope calibration

Microscopic counting and sizing of particles

Reporting

Factors affecting precision and accuracy

APPENDIX B

OPERATION OF OPTICAL PARTICLE COUNTERS

Scope . . . Applicable references

Summary of method

Apparatus and related documentation

preparations for sampling and counting

Counting procedure

Reporting

v

15

15

15

17

19

20

22

24

24

25

25

26

26

29

31

31

314 Appendix 1

CIO.

C20.

010.

020.

030.

EIO.

E20.

E20.1

E20.2

E20.3

E20.4

APPENDIX C

STATISTICAL ANALYSIS

Sample calculation

Conclusion •••.

APPENDIX 0

SOURCES OF SUPPLEMENTAL INFORMATION

Scope

Source references

Document references

APPENDIX E

GLOSSARY

Scope

List of terms

Isokinetic ••

Isotropic particles

Membrane filters

Reynolds number

VI

32

33

34

34

35

41

41

41

41

41

41


1. Scope and limitations.

1.1 Scope. This document establishes standard classes of air cleanllness for airborne particulate levels in cleanrooms and clean zones. It prescribes methods for class verification and monitoring of air cleanliness. It also addresses certain other factors, but only as they affect control of airborne particulate contamination.

1.2 Limitations. The requirements of this document do not apply to equlpment or supplies for use within cleanrooms or clean zones. Except for size classification and population, this document is not intended to characterize the physical, chemical, radiological, or viable nature of airborne particulate contamination. No definitive relationship between airborne particulate cleanliness classifications and the level of viable airborne particles has been established. In addition to the need for a clean air supply monitored for total particulate contamination and meeting established limits, special requirements are necessary for monitoring and controlling microbial contamination.

2. Referenced document.

For further information on Student's t, see: Johnson, Norman L. and Leone, Fred C., Statistics and Experimental Design in Engineering and the Physical Sciences, volume I (New York, London, Sydney: John Wlley & Sons, Inc., 1964).

3. Definitions.

3.1 Airborne particulate cleanliness class. The statistically allowable number of particles equal to or larger than 0.5 micrometer in size per cubic foot of air.

3.2 Calibration. Comparison of a measurement standard or instrument of unknown accuracy with another standard or instrument of known accuracy to detect, correlate, report, or eliminate by adjustment any variation in the accuracy of the unknown standard or instrument.

316 Appendix 1

3.3 Clean zone. A defined space in which the concentration of airborne particles is controlled to specified limits.

3.4 Cleanroom. A room in which the concentration of airborne particles IS controlled to specified limits.

3.4.1 As-built cleanroom (facility). A cleanroom (facility) that is complete and ready for operation, with all services connected and functional, bu~ without production equipment or personnel within the facility.

3.4.2 At-rest cleanroom (facility). A cleanroom (facility) that is complete and has the production equipment installed and operating, but without personnel within the facility.

3.4.3 of era tiona 1 cleanroom (facility). A cleanroom (facility) in norma operation with all services functioning and with production equipment and personnel present and performing their normal work functions in the facility.

3.5 Unidirectional airflow. (commonly known as laminar flow) Air flowIng in a sIngle pass in a single direction through a cleanroom or clean zone with generally parallel streamlines.

3.6 Nonunidirectional airflow. (commonly known as turbulent flow) AIrflow which does not meet the definition of unidirectional airflow by having either multiple pass circulating characteristics or a nonparallel flow direction.

3.7 Condensation nucleus counter. An instrument for counting small airborne partIcles, approxImately 0.01 micrometer and larger, by optically detecting droplets formed by condensation of a vapor upon the small particles.

3.8 optical particle counter. A light-scattering instrument with display and/or recordIng means to count a~d size discrete particles in air.

3.9 Particle. A solid or liquid object generally between 0.001 and 1000 micrometers in size.

2


3.10 particle size. The apparent maximum linear dimension of the particle in the plane of observation as observed with an optical microscope, or the equivalent diameter of a particle detected by automatic instrumentation. The equivalent diameter is the diameter of a reference sphere having known properties and producing the same response in the sensing instrument as the particle being measured.

3.11 Particle concentration. The number of individual particles per unit volume of air.

3.12 Student's t distribution. The distribution:

t = [(population mean) - (sample mean)l/[standard error)

obtained from sampling a Gaussian ("normal") distribution. (Available in -tables in statistics texts.)

3.13 Upper confidence limit (UCL). An upper limit of the estimate of the mean, calculated in such a way that in a given percentage of cases (here, 95%) the upper limit of the estimate would be more than the true mean, if the means were sampled from a Gaussian ("normal") distribution.

4. Airborne particulate cleanliness classes.

4.1 Determination of class limits. Airborne particulate cleanliness classes listed in Table I shall be determined as follows:

3

318 Appendix 1

TABLE

Class limits in particles per cubic foot of size equal to or greater than particle sizes shown (micrometers)

Measured Particle Size (Micrometers)

Class 0.1 0.2 0.3 0.5

1 35 7.5 3 1 10 350 75 30 10

100 NA. 750 300 100 1,000 NA. NA. NA. 1,000

10,000 NA. NA. NA. 10,000

5.0

NA. NA. NA.

7 70

100,000 NA·. NA. NA. 100,000 700

(NA. - not applicable)

a The class limit particle concentrations shown in Table I and Figure 1 are defined for class purposes only and do not necessarily represent the size distribution to be found in any particular situation.

4.2 Particle sizes measured to determine Classes 100 and greater. Airborne partlculate cleanllness classes shall be determined by measurement at anyone of the particle sizes listed for the class in Table I. The class is considered met if the measured particle concentration is within the limits specified, at anyone of the particle sizes shown in Table I, as determined by the statistical analysis of Paragraph 5.4.

4.3 Particle sizes measured to determine Classes less than 100. Airborne partlculate cleanliness classes shall be determlned by measureme~t at one or more of the particle sizes in Table I, as specified , and determined by the statistical analysis of Paragraph 5.4.

lWhen the terms "as specified" or "shall be specified" are used without further reference, the degree of control needed to meet requirements will be specified by the user or contracting agency.

4

.... 0 0 .... ~ .Q :> u .. Q) Q.

11\ .91 ~ .... .. 0 Q.

100000

/0000

/000

100

10

0.1 0.01


~7. I\~ ....

R3

C(- "" I~

I\~ r\

97. .... 0

• ~ C(- \~ 1\ ~ .... \~ \<J) \"~ 1\

:7\S'j .... IS'

.... 0 '\.

""- ~ -...

\« \ \ :7\S'j

IS' ....

1'\

~

0.1 10

Part/c/e slze (mIcrometers)

Figure 1. Class limits in particles per cubic foot of size equal to or greater than particle sizes shown*

*The class limit particle concentrations shown on Table I and Figure 1 are defined for class purposes only and do not necessarily represent the size distribution to be found in any particular situation.

5

320 Appendix 1

4.4 Classification by measurement at other particle sizes. A classification of air cleanliness by measurement at particle sizes other than those specified herein may be performed with the following limitation: Particle counts may be interpolated between points but under no conditions may counts be extrapolated beyond the end points of Table I or Figure 1. The particle count limit for the next larger particle size in Table I must not be exceeded.

4.5 provision for alternative airborne sarticulate cleanliness classes. Classes other than those state in Table I (for example, 50, 300, 50,000, etc.) may be defined where special conditions dictate their use. Such classes will be defined by the intercept point on the 0.5-micrometer line in Figure 1, with a curve parallel to the established curves. Any curves that are used for these other classifications shall not be extrapolated to indicate concentrations for particles outside the following limi ts:

(a) Classes greater than 1,000 shall be determined by rneasureme~t at either 0.5 or 5 micrometers, as specified •

(b) Classes greater than 10 and less than 1,000 shall be determined by measuremen~ at 0.2, 0.3, or 0.5 micrometer, as specified.

(c) Classes less than 10 shall be determined by measurement at one or more of. the following particle yizes: 0.1, 0.2, 0.3, or 0.5 micrometer, as specified.

4.6 Particle counts for the determination of cleanliness classes. To determIne an aIrborne partIculate cleanlIness clas., particle counts shall be made in accordance with Section 5.


6


5. Verification and monitoring of airborne particulate cleanl1ness classes.

5.1 Verification of airborne particulate cleanliness classes. The a1rborne part1culate cleanl1ness class as defined 1n Section 4 shall be verified for a cleanroom or clean zone by measurement of airborne particle concentration under the following conditions.

5.1.1 Frequency. Verification tests shall be perfoimed· initially and at periodic intervals, or as specified .

5.1.2 Environmental test conditions. Verification of air cleanliness class shall be ~etermined by particle concentration measurement under specified operating conditions.

5.1.2.1 Conditio~s of test. The conditions of test of the cleanroom or clean zone shall be recorded as "aI-built," "atrest," "operational," or as otherwise specified.

5.1.2.2 Environmental and use environmenta an use parameters 0 zone shall be recorded. These conditions of measurement may include (but are not limited to) air velocity, air volume change rate, room air pressure, makeup air volume, unidirectional airflow parallelism, temperature, humidity, vibration, equipment, and personnel activity.

5.1.3 particle counting. Particle counting shall be performed using a method spec1f1ed in paragraph 5.3 for verification of all classifications of cleanrooms and clean zones.

5.1.3.1 Sam Ie locations and number - unidirectional airflow. For unidirect10nal a1r low, the clean zone 1S 1dent1 Ie y an entrance and an exit plane perpendicular to the airflow. The entrance plane shall be immediately upstream of the work activity


7

322 Appendix 1

area within the clean zone. The minimum number of sample locations required for classification of a clean zone shall be the lesser of (a) the area of the entrance plane (in square feet) divided by 25, or (b) the area of the entrance plane (in square feet) divided by the square root of the airborne particulate cleanliness class designation.

5.1.3.2 Sample locations and number - nonunidirectional airflow. For nonunidirectlonal airflow, the number of sample lOCatIOns shall be uniformly spaced horizontally, and as specified vertically, throughout the clean zone, except as limited by equipment within the clean zone. The minimum number of sample locations shall be equal to the square feet of floor area of the clean zone divided by the square root of the airborne particulate cleanliness class designation.

5.1.3.3 Sample location restrictions. No fewer than two locations shall be sampled for any clean zone. The number of sample locations shall be uniformly spaced throughout the clean zone except as limited by equipment within the clean zone. At least one sample shall be taken at each of the sampling locations specified in paragraph 5.1.3.1 or 5.1.3.2. A total of at least five samples shall be taken. More than one sample may be taken at each location and different numbers of samples may be taken at different locations.

5.1.3.4 Sample volume and sampling time. Table II lists the minimum volume per sample for varIOUS airborne particulate cleanliness classes and measured particle sizes. The sample time is calculated by dividing the sample volume by the sample flow rate. A larger sample volume will improve the precision of the concentration measurements, decreasing the amount of variation between samples; however, the volume should not be so large as to render the sample time impractical. The particle concentration shall be reported in terms of particles per cubic foot of air regardless of the sample volume size. The sample volume size shall also be reported.


8


TABLE II

Minimum volume per sample in cubic feet for the air cleanliness class and measured particle size shown

Measured Particle Size (Micrometers)

Class 0.1 0.2 0.3 0.5

1 0.6 3.0 7.0 20.0 10 0.1 0.3 0.7 2.0

100 NA. 0.1 0.1 0.2 1,000 NA. NA. NA. 0.1

10,000 NA. NA. NA. 0.1 100,000 NA. NA. NA. 0.1

INA. - not applicable)

5.0

NA. NA. NA.

3.0 0.3 0.3

5.1.3.5 Sample volume at other classes or particle sizes. Sample volume for other classes or partIcle sizes not specified herein shall be the same as that specified for the next lower class or particle size.

5.1.4 Interpretation of the data. A statistical evaluation of particle concentratIon measurement data shall be performed according to paragraph 5.4 to verify the airborne particulate cleanliness class level.

5.2 Monitorin of airborne particulate cleanliness. After verifIcatIon, 1 speci Ie , t e aIrborne particu ate cleanliness shall be monitored during operations. Monitoring shall consist of particle concentration measurements. Other environmental parameters as suggeste1 in Paragraph 5.1.2.2 may also be monitored as specified to indicate trends in airborne particulate cleanliness.

IWhen the terms "as specified" or "shall be specified" are used without further reference, the degree of control needed to meet requirements will be specified by the user or contracting agency.

9

324 Appendix 1

5.2.1 Monitorin£ plan. A monitoring plan shall be established based on the aIr orne particulate cleanliness class and the degree of cleanliness control necessary for work activity or product protection. The monitoring plan shall specify frequency, operating conditions, the method of counting particles, the locations, number, and volume of samples, and some method for interpretation of the sample data.

5.2.2 Particle counting. Particle counting shall be perfor~ed using one of the test methods in Paragraph 5.3, as specified • Particle concentration measurements shall be taken at locations throughout the clean zone or where the cleanliness level is particularly critical or where the higher particle concentration levels are found during verification testing. The air shall be sampled as it reaches the clean zone.

5.3 Methods and equipment for measuring airborne aarticle concentrat10n. The method and equIpment to be use for measuring the airborne particle concentration shall be selected on the basis of the particle size of interest. The following methods are suitable for class verification anq monitoring of air cleanliness unless otherwise specified. Other particle counting methods and equipment may be used if demonstrated to have accuracy and 2r!peatability equal to or better than the methods listed below '


2For example, for particle size approximately 0.01 micrometer in diameter and larger, a condensation nucleus counter, which optically detects particles which have been grown by condensation of a supersaturated vapor, may be used. The counter must detect single particles.

3For monitoring purposes only, evaluation of particles by sedimentation methods may be carried out by allowing the particles to deposit on the surface of an appropriate medium and then counting them using optical microscopy.

10


5.3.1 Counting particles 5 micrometers and larger. For particle sizes 5 micrometers and larger, a manual sizing and counting method or an optical particle counting instrument shall be used. The manual sizing and counting method shall be in accordance with Appendix A, and the optical particle counting instrument shall be in accordance with Appendix B.

5.3.2 Counting particles 0.1 micrometer and lar~er. For particle Sizes 0.1 micrometer and larger, an optical particle counting instrument shall be used in accordance with Appendix B. The instrument must count single particles. Only information obtained with a periodically calibrated and properly maintained particle counter shall be used in conducting airborne particle concentration measurements. Particle size data shall be reported in terms of equivalent diameter as calibrated against reference standard particles.

5.3.3 Limitations of particle counting methods.

5.l.3.l Optical particle counters. optical particle counters with unlike geometry or different operating principles may give different results when counting the same particles. Even recently calibrated instruments of like design may show differences in measurement results when sampling the same air. Caution should be used when comparing measurements from different instruments.

5.3.3.2 Microscopic evaluation. Since the microscopically measured Size of a particle is the apparent longest linear dimension, and the size of particles measured by optical particle counters is based upon the diameter of a reference particle, microscopic counts will generally differ from counts obtained by optical particle counters.

5.3.3.3 ueper limits. Particle counters shall not be used to count particle concentrations or particle sizes greater than the upper limits specified by the manufacturer.

11

326 Appendix 1

5.3.4 Calibration of particle counting instrumentation. All instruments shall be callbrated agalnst known reference standards at regular intervals as specifiedl • Parameters which may need calibration include, but are not limited to, air flow rate and particle size.

5.4 Statistical analysis. The collection and analysis of airborne partlcle concentration data for verification of an airborne particulate cleanliness class shall be performed in accordance with the following requirements. This statistical analysis deals only with random errors (lack of precision), not errors of a nonrandom nature ("bias"), such as erroneous calibration.

5.4.1 Acceptance criteria. The c1eanroom or clean zone shall meet the acceptance crlterla for an airborne particulate cleanliness class if 1) the average of the particle concentrations (see Table I) measured at each location falls at or below the class limit, and 2) the mean of these averages falls at or below the class limit with a 95% confidence limit. The confidence limit shall be based on a one-tailed Student's t distribution, as follows.

5.4.1.1 Average particle concentration. The average particle concentration (A) at a location is the sum of the individual sample particle counts (C.) divided by the number of samples taken at the location (N)! as shown in Equation (5-1). If only one sample is taken, the average particle concentration is the same as the particle count measured.

A (5-1)

1When the terms "as specified" or "shall be specified" are used without further reference, the degree of control needed to meet the requirements will be specified by the user or contracting agency.

12


5.4.1.2 Hean of the averages. The mean of the averages (H) is the sum of the individual averages (Ai) divided by the number of locations (L), as shown in Equation (5-2). All locations are weighted equally, regardless of the number of samples taken.

( 5-2)

5.4.1.3 Standard deviation. The standard deviation (SO) of the averages is the square root of the sum of the squares of differences between eaSh of the individual averages and the mean of the averages (Ai-H) divided by the number of locations (L) minus one, as shown in Equation (5-3).

SO (AI - H) 2 + (A 2 - H) 2 + ••• + (AL _ H) 2

L - 1

( 5-3)

5.4.1.4 Standard error. The standard error (SE) of the mean of the averages (H) IS determined by dividing the standard deviation (SO) by the square root of the number of locations, as shown in Equation (5-4).

SE = SOl ~ (5-4)

5.4.1.5 Upper confidence limit (UCL). The 95% UCL of the mean of averages (H) is determIned by adding to the mean the appropriate UCL factor (see Table III for UCL factor) times the standard error (SE), as shown in Equation (5-5).

UCL = H + (UCL Factor x SE) (5-5)

TABLE III

UCL factor for 95% upper control limit

No. of locatlons(L) 95% UCL factor

13

328 Appendix 1

5.4.1.6 sample calculation. A sample calculation is shown in Appendix C.

6. Changes. When a Federal agency considers that this standard does not provide for its essential needs, written request for changing or adding to the standard, supported by adequate justification, shall be sent to the Administration. This justification shall explain wherein the standard does not provide for,esssential needs. The request shall be sent to the General Services Administration, Federal Supply Service, Engineering Division, 819 Taylor Street, Fort Worth, TX 76102. The Administration will determine the appropriate action to be taken and will notify the agency.

7. s ecifications. Where the reqUIrements state In t IS stan ar con llct with any requirement in a referenced specification, the requirements of this standard shall apply. The nature of conflict between the standard and the referenced specification shall be submitted in duplicate to the General Services Administration, Federal Supply Service, Engineering Division, 819 Taylor Street, Fort Worth, TX 76102.

8. Federal agency interests.

Department of Commerce Department of Defense, Office of the Assistant Secretary

of Defense (Installations and Logistics) Army Navy Air Force

Department of Energy Department of Health and Human Services Department of Transportation General Services Administration National Aeronautics and Space Administration Nuclear Regulatory Commission

14


APPENDIX A

PARTICLE MONITORING - MANUAL COUNTING AND SIZING METHODS

AIO. Scope. This appendix describes procedures for determining airborne particulate contamination levels of particles 5 micrometers and greater in size in cleanrooms and clean zones by a membrane filtration and particle count method.

A20. Summary of method.

A20.1 Description of the basic method. At the sampling point, air is passed through a membrane filter using a vacuum to effect the filtration. The air flow rate is controlled by means of a limiting orifice or an air flowmeter, and the total volume of air sampled is controlled by the sampling time. The membrane filter is examined microscopically, using a high-intensity oblique incident light source, to determine the number of particles 5 micrometers and greater collected from the air sample.

A20.2 Alternatives to optical microscopy. Image analysis or projectlon mlcroscopy can replace dlrect optical microscopy for sizing and counting, provided that the accuracy and reproducibility are equal to or better than those of the direct optical microscopic method.

A20.3 Acceptable sampling procedures. There are two acceptable procedures for thls method as descrlbed herein: (a) Aerosol Monitor Method, and (b) Open Filter Holder Method. They differ primarily in the apparatus used and in the time required for performance.

A30. Equipment.

A30.1 Equipment common to both methods.

A30.1.1 Microscope. Binocular microscope with ocular-objective combinations for 100X to 250X magnifications. These combinations are chosen such that the ultimate smallest division of the ocular reticle, at the highest magnification, is less than or equal to 5 micrometers. The latter objective should have a numerical aperture of at least 0.25.

A30.1.2 Ocular micrometer scale: 5- or la-millimeter linear scale with 100 divisions, dependent upon ocular-objective combinations, or micrometer eyepiece with movable scale.

15

330 Appendix 1

A30.l.3 Stage micrometer: standard 0.01- to O.l-millimeter-perdivision scale.

A30.1.4 External microscope illuminator.

A30.l.s Vacuum pump capable of maintaining a vacuum of 500 torr while pumping at a rate of at least 1 cubic foot per minute.

A30.1.6 Electrical timer or timing device. 60-minute range.

A30.1.7 Flowmeter or limiting orifice calibrated with the vacuum pump. filter holder. and filter to collect a sample of sufficient volume. See Paragraph AsO.l.

A30.1.B Manual tally counter.

A30.l.9 Filter storage holders for membrane filters after sampling; Petri plates o~ Petri slides with covers.

A30.l.l0 Rinse fluid: purified water prefiltered to 0.45 to 1.2 micrometers.

A30.l.1l Forceps: flat. with unser rated tips.

A30.2 Equipment for aerosol monitor method.

A30.2.1 Aerosol monitors: dark. O.B-micrometer mean pore size. with imprinted grid.

A30.2.2 Aerosol adapter.

A30.3 Equipment for open filter holder method.

A30.~.1 Filter holder: aerosol. open type.

A30.3.2 Membrane filter: dark. O.B-micrometer or smaller pore size, with imprinted grid.

A30.3.3 Membrane filters: white (for evaluating dark particles). O.B-micrometer or smaller pore size. with imprinted grid.

A30.4 Optional equipment.

A30.4.1 Image analyzer.

16


A30.4.2 projection microscope and screen.

A40. preparation of equipment.

A40.1 preparation for both methods.

A40.1.1 All equipment preparation should be performed within a clean zone having an airborne particulate cleanliness class equal to or less than that of the clean zone to be monitored.

A40.1.2 All equipment should be maintained at maximum cleanliness and should be stored with protective covers, cases, or other suitable enclosures when not in use in a location having an airborne particulate cleanliness class equal to or less than that of the clean zone of lowest class number where sampling is performed.

A40.1.3 Personnel performing sampling, sizing, and counting operations should be equipped with garments consistent with the airborne particulate cleanliness class of the clean zone being monitored.

A40.1.4 Thoroughly rinse with purified water all internal surfaces of the Petri slide holders or Petri plates used to hold the exposed membranes for counting. Rinse in cascading action, as with the membrane holders. After rinsing, leave the lid open in a unidirectional airflow clean zone until the interior surfaces are dry.

A40.2 preparation for aerosol monitor method.

A40.2.1 Establish a filter background count in the following manner. Where the manufacturer of aerosol monitors has indicated an average background count for a package of monitors (in the particle size ranges of concern), examine and establish the average background count for 5% of the filters in the package. If the average background count determined is equal to or less than the manufacturer's indication, use the indication as the background count for all filters in the package. If the determined count is higher than the manufacturer's indication, or if there is no such indication, establish a background count for each filter used.

17

332 Appendix 1

A40.2.2 Background counts for individual filters are determined by following the microscopic procedures of paragraph A70.

A40.2.3 After the background count has been established, package the aerosol monitors in a particle-free container or place into their appropriate sampling devices and transport them to the sampling location.

A40.2.4 Except for purposes.of making background counts, aerosol monitors should be opened only when in the sampling location or the counting area.

A40.3 preparation for open filter holder method.

A40.3.l Disassemble the filter holder and wash in liquid soap and water. After washing, rinse and store in the unidirectional airflow clean zone until dry. (00 NOT WIPE DRY.) Deionized water or distilled water are the rinse media of choice.

A40.3.2 After the filter holder is completely dry, mount a membrane filter in the filter holder, with the grid exposed. After mounting the membrane filter, invert the filter holder assembly and thoroughly flush the filter surface area and exposed filter holder parts with purified water using a cascade rinsing action, starting at the top and progressing to the bottom of the filter face. Place in the unidirectional airflow clean zone and allow to dry.

A40.3.3 Establish a filter background count for each membrane filter to be used by following the procedures of Paragraph A70.

A40.3.4 After the interior surfaces of the filter storage holders are dry, apply a small piece of double-sided cellophane tape or stopcock grease to the bottom surface.

A40.3.5 After the fi Iter holder and membrane ar.e clean and dry, package them in a particle-free container.

A40.3.6 Transport the prepared filter holder, with membrane filter and vacuum source, to the sampling location. 00 NOT EXPOSE THE FILTER SURFACE UNTIL THE APPARATUS IS ASSEMBLED AND READY FOR SAMPLING.

18


ASO. sampli ng.

ASO.l Sampling orientation and flow. For unidirectional airflow cleanrooms and clean zones, the aerosol monitor or filter holder should be oriented to face into the airflow. For nonunidirectional airflow cleanrooms and clean zones, orient the aerosol monitor or filter holder s~ that the opening faces upward, unless otherwise specified. Airflow into the filter should be adjusted to be isokinetic for unidirectional airflow. For nonunidirectional airflow, the airflow into the filter should be adjusted to be 0.2S cubic foot per minute for a 2S-millimeter filter or 1 cubic foot per minute for a 47-millimeter filter. The minimum sample volume should be 10 cubic feet for Class 1000 and 1 cubic foot for Class 10,000 and greater.

ASO.2 Sampling by aerosol monitor method.

ASO.2.1 At the sampling location, attach the aerosol monitor to the aerosol adapter and the adapter to the vacuum source. Have in line either a limiting orifice or a flowmeter. Isolate the va·cuum pump exhaust from the area being sampled, as it may be a source of extraneous airborne contamination.

ASO.2.2 Adjust the flowmeter, if used, for the flow rate at the operating vacuum pressure where it is used.

ASO.2.3 Connect a timer to ~he vacuum pump power source.

ASO.2.4 Remove the bottom plug from the aerosol monitor and attach it to the free end of the aerosol adapter. position the aerosol monitor as required, pry off the top portion of the aerosol monitor, and store it in a clean location.

ASO.2.S Turn on the pump, adjust the flowmeter, and operate for a time which will provide the required sample at the chosen flow rate.


19

334 Appendix 1

ASO.2.6 When the sampling time has elapsed, release the vacuum, replace the top portion of the aerosol monitor, and remove the aerosol monitor from the aerosol adapter. The bottom plug need not be replaced. Identify the aerosol monitor with a sample identification tag. Transport the aerosol monitor to a counting area which should be a clean zone of airborne particulate cleanliness class at least equal to that of the clean zone sampled.

ASO.3 Sampling by open filter holder method.

ASO.3.1 When in the sampling area, place the filter holder in position. with the aid of vacuum tubing, connect the filter holder to the vacuum train which includes the filter holder, either a limiting orifice or a flowmeter, and a source of vacuum (vented outside the sampling area or filtered to prevent contamination of the area sampled).

ASO.3.2 Adjust the flowmeter, if used, for the flow rate at the operating vacuum pressure where it is used.

ASO.3.3 Remove the protective cover from the membrane filter holder and turn on the vacuum source. Turn on the pump, adjust the flowmeter, and operate for a time which provides the required sample at the chosen flow rate.

ASO.3.4 At the. end of the sampling period, turn off the vacuum source and carefully re-cover the filter holder with a precleaned cover. Return the covered sample filter holder to the counting area, which should be a clean zone of airborne particulate cleanliness class at least equal to that of the clean zone sampled.

A60. Microscope calibration.

A60.l IF CALIBRATION OF THE MICROSCOPE HAS BEEN PERFORMED PREVIOUSLY BY THE OPERATOR, OMIT THIS SECTION.

A60.2 Place the stage micrometer on the mechanical stage; focus and adjust the light to give an even and full illumination in the field of view.

A60.3 Verify that the proper eyepiece and objective combination is in place to provide total magnification equal to lOOX to 250X, as required.

20


A60.4 Assure that the microscope is properly focused by focusing each eyepiece to achieve a sharp stage micrometer image.

A60.5 If an image analyzer or projection microscope is used, perform a similar calibration.

A60.6 using the entire length of the ocular reticle scale, record the number of stage micrometer divisions the eyepiece reticle covers.

(a) Compute the ocular micrometer scale calibration for a particular magnification by the formula:

Micrometers per ocular scale division =

(No. of Stage Micrometer Div.) x (Size of One Stage Micrometer Div.) (No. of Eyepiece Divisions)

Example:

At 100X: 100 eyepiece divisions equals 100 stage divisions, each 5.0 micrometers in length.

Thus: Micrometers/Eyepiece Division

(100 Divisions) x (5.0 Micrometers) 5.0 Micrometers

(100 Divisions)

(b) Calculate the number of linear divisions required to measure each range.

Example:

At 100X: each eyepiece division equals 5 micrometers, so for a 16- to 20-micrometer range, 3 to 4 divisions would be examined.

Note: If the microscope is equipped with a zoom adjustment, this may be employed to adjust the calibration to the nearest integer (X micrometers/division, instead of X.Y micrometers/division), provided the adjustment is noted in the calculations.

NOTE: A CHANGE IN INTERPUPILLARY DISTANCE BETWEEN OPERATORS CHANG~ FOCAL DISTANCE, HENCE CALIBRATION.

21

336 Appendix 1

A70. Microscopic counting and sizing of particles.

A70.1 In the clean zone where the particles upon the membrane filters are counted and sized, remove the membrane filter from the aerosol monitor or the open filter holder with unser rated flat forceps.

A70.2 place the membrane filter, grid side up, in a precleaned Petri slide holder or Petri ~late, allowing the filter to adhere to the sticky surface of the storage holder. Tightly seal the carrier to prevent contamination of the sample filter.

A70.3 The microscope should be clean so as not to add particulate contamination to the sample. Carefully place the covered Petri slide or Petri plate on the microscope stage and adjust the angle and focus of the illuminator to provide optimum particle definition at the magnification used for counting. Use an oblique lighting angle of 10 to 20 degrees to cast a shadow of the particle, thereby effectively separating the particle image from the filter background.

A70.4 Select a field size so that there are no more than about 50 particles larger than 5 micrometers in the field. Optional fields are: a grid square1 a rectangle defined by the width of a grid square and the calibrated length of the ocular micrometer scale1 a rectangle defined by the width of the grid square and a portion of the length of the ocular micrometer scale.

A70.5 Estimate the number of particles in the greater-than-5-micrometer range over the effective filtering area by scanning one unit area of the field size selected. If the total number of particles in this range is estimated to be less than 500, count the number of particles in this range over the entire effective filtering area. If the Dumber is greater, the counting procedure in paragraph A70.8.1 applies.

A70.6 In scanning for particles, manipulate the stage so that particles to be counted pass under the ocular scale. Only the maximum dimension of the particle is regarded as significant. The eyepiece containing the ocular micrometer may be rotated to accommodate specific particles, if necessary.

22


A70.7 using a manual tally counter, record all particles in the selected field that are equal to or exceed the dimension as indicated by the ocular micrometer scale. Record the number of particles in each field counted, in order to establish uniformity of distribution and to have a record of the number of fields counted.

A70.8 statistical particle counting.

A70.8.l When the estimated number of particles over the effective filtering area exceeds 500, the method entails the selection of a unit area for statistical counting, counting all particles in the unit area, and then similarly counting additional unit areas until the following statistical requirement is met:

F x N > 500

where:

F number of grid squares or unit areas counted, and

N total number of particles counted in F areas.

A70.8.2 Calculate the t~tal number of particles on the filter as follows:

A P N x

n x a

where:

P = total number of particles of a size range on the filter.

(When a background count is obtained, subtract this from the P value after calculation, but prior to dividing by sample volume.)

N total number of particles counted in n unit areas.

n = number of unit areas counted.

a = unit area in square millimeters.

A = effective total filter area in square millimeters.

23

338 Appendix 1

A80. Reporting.

A80.l Subtract the background count for a filter from the total count obtained for the filter in accordance with Paragraph A70.

A80.2 Results should be expressed for each size range of specific interest, including S-micrometer particles, in particles per cubic foot of sample by dividing the number of particles, P, by the sample volume (V).

Particles per cubic foot = Plv

A80.3 Final results are expressed in particles per cubic foot of sampled air,S micrometers and greater.

A90. Factors affecting precision and accuracy.

A90.l The precision and accuracy of this method can be no higher than the sum total of the variables. In order to minimize the variables attributable to an operator, a trained microscopist technician is required. Variables of equipment are recognized by the experienced operator, thus further reducing possible error. The operator should have adequate basic training in microscopy and the techniques of particle sizing and counting.

A90.2 For training personnel, low- to medium-concentration specimens may be prepared on a grid filter and preserved between microslides as standards for a given laboratory. Standard counting specimens are available for this purpose.

A90.3 Accuracy for a sampling location can be increased by increasing the number of samples taken and processed at that sampling location.

A90.4 Accuracy for a sampling location can be increased by increasing the volume of air per sample and by increasing the time of sampling.

A90.S Accuracy can be increased by establishing and using background counts for filters.

24


APPENDIX B

OPERATION OF OPTICAL PARTICLE COUNTERS

BlO. Scope.

BlO.l Application. Optical particle counters provide data on airborne particle concentration and size distribution on a nearreal-time basis. This appendix describes methods for the operation, use, and testing of optical particle counters used to satisfy requirements of this Federal Standard. Guidelines are given which should aid in standardization of optical airborne particle monitoring procedures for defining air cleanliness.

B10.2 Limitations. Particle size data are referenced to the particle system used to calibrate the optical particle counter; however, differences in optical, electronic, and sam~le handling systems among the various optical particle counters may contribute to variations in counting results. Care must be exercised in attempting to compare data from samples which vary significantly in particle composition or shape from the calibration base. variations may also occur between instruments using particle sensing systems with different operating parameters. These effects should be recognized and minimized by using standardized methods for counter calibration and operation.

BlO.3 ersonnel. Individuals performing the procedures descrlbe ereln soul be trained in the use of the optical particle counter and understand its operation, capabilities, and limitations.

B20. Applicable references.

B20. 1 ASTM F 328 Determining Counting and Sizing Accuracy of an Airborne Particle Counter Using Near-Monodisperse Spherical Particulc~e Materials.

B20.2 ASTM F 649 Secondary Calibration of Airborne Particle Counter Using Comparison Procedures, American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.

25

340 Appendix 1

820.3 IES-RP-CC-013 Recommended Practice for Equipment Calibration or Validation Procedures, Institute of Environmental Sciences, 940 East Northwest Highway, Mt. Prospect, IL 60056.

830. Summary of method.

830.1 Calibration. primary calibration of optical particle counters is performed with spherical isotropic particles of refractive index 1.6. Secondary calibration may be performed with atmospheric particles for correlation with a reference particle counter. In addition, stable operation should be assured by standardizing against internal references built into the counter or by other approved methods.

830.2 Operation. The air to be classified is sampled at a known flow rate from the sample point or points of concern. Particles contained in the sampled air pass through the sensing zone of the optical particle counter and produce a signal which is related to particle size. An electronic discriminator circuit sorts and counts the pulses in relation to particle size and displays or prints out the particle count in the sample volume.

840. Apparatus and related documentation.

840.1 Optical particle counting system. The optical particle counting system may lnclude a recorder or printer; alternatively, data may be transmitted to a remote location for additional processing and computing.

840.2 Sample air. flow system. The sample air flow system consists of an lntake tube, a sensing chamber, an air flow metering or control system, and an exhaust system. The exhaust system may consist of either a built-in vacuum source or an external vacuum supply with a separate flow control element for the optical particle counter in use. If a built-in vacuum source is used, and the optical particle counter is to be used where the exhaust air could affect either the particle c_oun.ts being measured or operations in the cleanroom or clean zone, then the exhaust should be suitably filtered.

26


B40.3 Sensing system. The sensing system of the 9ptical particle counter IS formed by intersecting the sample air flow with a fixed sensing volume of such dimension so that the probability of more than one particle being present at any time (the coincidence error) is less than 5'. The signal produced from each particle passage through the sensing volume is received and processed by the electronic system in real time. The instrument should be designed to maintain its stated accuracy despite variations in the specified operating line voltage and ambient temperature. The operating line voltage and temperature ranges should be specified.

B40.4 Electronic system. The electronic system includes a pulse analyzer and counter, along with a system for registering particle counts in relation to particle size.

B40.4.l The pulse analyzer may operate in either one or both of two modes: (1) in response to all particles within discrete size ranges, or (2) in response to all particles larger than the predetermined lower threshold size limit(s). Air cleanliness classification data, however, should be reported in terms of mode (2). Particle size ranges or limits may be either selectable or fixed.

B40.4.2 The c~unting circuits during a known time interval may accumulate information generated by the pulse analyzer in response to particle passages. Pulse count accumulation in one or more size ranges may be provided.

B40.4.3 For determination of the airborne particulate cleanliness class, the counting circuit is allowed to accumulate data for a preset time interval before reporting. The time interval is selected to yield a known sample volume, so that particle concentration can be readily calculated.

B40.4.4 The registering system indicates the number of particles or the particle coftcentration with respect to the selected particle size range(s) or size limit(s). counts may be recorded or displayed on the optical particle counter, or may be transmitted to a remote location for recording, display, or computer processing.

27

342 Appendix 1

B40.5 Calibration. An internal secondary calibration system or a means of ensurIng stability should be provided in the instrument. The internal secondary calibration system should be capable of validation with respect to primary calibration in accordance with the methods of ASTM F 328 and ASTM F 649. The secondary calibration system is used for checking the sizing and counting stability of the optical particle counter and to provide a stable reference for any necessary sensitivity adjustment of the instrument.

B40.6 Documentation. Instructions which should be supplied with the instrument by the manufacturer include:

(a) Brief description of the operating principles of the instrument.

(b) Description of major components.

(c) Environmental conditions (ambient temperature, relative humidity, and pressure) and line voltage range required for stable operation.

(d) Particle size and concentration ranges for accurate measurement.

(e) suggested maintenance procedure and recommended intervals for routine maintenance.

(f) operating procedure for particle counting and sizing.

(g) Secondary calibration procedure (where applicable).

(h) primary calibration procedure (a factory primary calibration facility should be available for calibration of the counter upon customer request), and field primary calibration capability and procedures.

(i) Suggested intervals for primary calibration.

28


B50. preparations for sampling and counting. The procedures described in the following paragraphs should be performed or verified before the optical particle counter is used for determination of airborne particulate cleanliness classes. Each of the procedures has its own requirements regarding frequency interval.

B50.l Primary calibration. Particle sizing and air sample volume requIre primary calIbration. The comments in the following paragraphs are intended as a general guideline for primary calibration to be considered in interpreting ASTM F 328, ASTM F 649, or IES-RP-CC-013. Deviations may be necessary to achieve a specific objective. It is, however, the duty of the manufacturer to include in the operating instructions a description of the appropriate primary calibration method for the optical particle counter.

B50.l.l Particle sizing. Primary calibration of the particle sizing function of the optical particle counter is carried out by registering the response of the counter to a monodisperse homogeneous and isotropic controlled aerosol containing predominantly spherical particles of known size and refractive index, and by adjusting the calibration control until the correct sizing response is obtained. Thereafter, the internal secondary calibration system is adjusted, if necessary, for correct response to the reference aerosol. Nonspherical particles may be used for primary calibration for specific applications. In these cases, the particle size is defined in terms of an appropriate dimension for the reference particles. Means of generating the reference particles has been extensively described in the literature L.

850.1.2 Air sample volume. The air sample volume is calibrated by measuring the flow rate and the duration of the sampling

lFor instance, Liu, B.Y.H., "Methods for Generating Monodisperse Aerosols." 1967. Publication '104, Particle Technology Laboratory, Department of Mechanical Engineering, University of Minnesota.

29

344 Appendix 1

interva1 2 • To avoid erroneous readings, equipment used for this measurement should not introduce an additional static pressure drop to the optical particle counter flow system. All flow measurements should be referenced to ambienl conditions of temperature and pressure or as otherwise specified.

B50.2 Sampling setup.

B50.2.1 Sample location. 'In-place sample locations and orientation of the sample inlet tube should be established in accordance with Section 5 of this standard.

B50.2.2 Extension of sample inlet tube. Any extension of the sample inlet tube may affect the sampling results. The effects may be of little significance for particles in the size range from approximately 0.1 to 1 micrometer for sample tube extensions up to approximately 30 meters. Outside of this range, extensions of the sample inlet tube are used only if no other method is possible for sample acquisition. The sample tube extensions should be configured to maintain the sample flow Reynolds number in the range from 5,000 to 10,000 and the sample residence time in the extension below 5 seconds; no radius of curvature below 10 centimeters should be used. Where air sampling requires data on particles larger than 3 micrometers in diameter, no extension tube longer than 3 meters should be used.

B50.2.3 Particle counter exhaust air. The particle counter should be located and used so that air vented does not contaminate the sample or clean zone. The exhaust air should be filtered to a level consistent with the ambient airborne particulate cleanliness class or else vented outside of the cleanroom.

B50.3 Field calibration procedure. Perform secondary calibratlon or standardlzatlon (If applicable) in accordance with the manufacturer's instructions.

2See Baker, W.C. and pouchot, J.F., "The Measurement of Gas Flow Part I," 1983, Journal of Air Pollution Control Association, January, Vol. 33, No.1 and Baker, W.C. and Pouchot, J.F., "The Measurement of Gas Flow Part II," 1983, Journal of Air pollution Control Association, February, Vol. 33, No.2.

30


B50.4 Zero count check. The absence of spurious counts is verified by a zero count check, as described in the following paragraphs.

B50.4.l Place an appropriate filter on the counter sample inlet tube to prevent the passage of particles larger than the smallest size particle the counter can count.

B50.4.2 Turn on the sample air flow system; adjust for the specified sample air flow rate, if necessary.

B50.4.3 Turn on the counting circuits.

B50.4.4 verify that the instrument reads zero counts for particles 0.5 micrometer and larger. If counts are registered, permit the counter to purge itself with the filter in place until a zero count level is reached.

B50.4.5 For counters capable of detecting particles smaller than 0.5 micrometer, zero counts may not be achievable for the smallest particles detectable. For such instruments, a tare concentration less than 10% of the airborne particulate cleanliness class concentration of such smaller particles (e.g., 0.1, 0.2, 0.3' micrometer) should be achieved.

B60. Counting procedure.

B60.1 Perform the field (secondary) calibration and zero count check, in accordance with Paragraphs B50.3 and B50.4.

B60.2 Check and adjust to the specified air flow rate (if applicable) •

B60.3 Turn on the counting circuits, if necessary; read and record the particle count displayed for the particle size(s) of interest.

B70. Reporting.

B70.l Record the particle size range(s), the volume of air sampled, the particle count, the time, and the sample pOint location.

B70.2 Report particle count data in terms of the number of particles per cubic foot of air sampled.

31

346 Appendix 1

APPENDIX C

STATISTICAL ANALYSIS

C10. Sample calculation. The data and calculations presented in the following paragraphs are intended to serve as a working example, illustrating the statistical procedures involved in eetermination of acceptance criteria for cleanrooms and clean zones. The data and calculations are based upon a l-cubic-foot sample volume and testing at 0.3-micrometer measured particle size for Class 10. (Note: Table 1 indicates that the UCL is to be less than or equal to 30 particles per cubic foot 0.3 micrometer and larger to meet Class 10.)

CIO.l Tabulation of particle count data.

PartIcle Counts (C i ) Total No. (~ CAl (A.) of Tot 1 AveiagE

Location 1 2 3 4 5 Samples (N) Count Counts

A 15 NR NR NR NR 1 15 15.00 B 33 24 9 15 NR 4 81 20.25 C 18 3 12 24 NR 4 57 14.25 D 39 18 9 33 6 5 105 21.00 E 0 27 6 0 NR 4 33 8.25

(NR - no reading taken)

C10.2 Mean of averages .(M).

M (Equation 5-2)

M = (15.00 + 20.25 + 14.25 + 21.00 + 8.25)/5 = 15.75

L (Number of sample locations)

32


C10.3 standard deviation of averages (SO). (Equation 5-3)

SO • ~ ('1 - M,' • (A2 - M)2 + ••• + (AL _ M)2

L - 1

SO

SO = 5.17

[(15.00-15.75)2 + (20.25-15.75)2 + (14.25-15.75)2 +

(21.00-15.75)2 + (8.25-15.75)2] I [5-1]

CIO.4 Standard error of mean of averages (SE).

SE SO/.,;-r;-- (Equation 5-4)

SE = 5.171 v-s- = 2.31

C10.5 upper 95% confidence limit (UCL).

For 5 locations, UCL factor 2.1

UCL M + (UCL Factor x SE) (Equation 5-5)

UCL 15.75 + (2.1 x 2.31) = 20.6

C20. Conclusion. Since the upper 95% confidence limit (UCL) is less than 30 and all location average particle concentrations (Ai) were less than 30, the above data meet the acceptance criteria for Class 10, although some of the individual particle counts were above 30.

33

348 Appendix 1

APPENDIX D

SOURCES OF SUPPLEMENTAL INFORMATION

D10. Scope. The purpose of this appendix is to list references for supplemental information which may provide instruction or guidance in the preparation of documents related to the design, acquisition, testing, operation, and maintenance of cleanrooms and clean zones. This listing of sources and documents emphasizes that information contained in such sources is not part of this standard and is not mandatory for compliance with this standard. .

D20.

D20.1

D20.2

D20.3

D20.4

020.5

020.6

020.7

020.8

D20.9

020.10

Source references.

AFWP - Headquarters, AFLC/OAPD, Wright-patterson AFB, OH 45433

AFWR - Warner Robins ALO/MMEDT, Robins AFB, GA 31098

ANSI - American National Standards Institute, 1430 Broadway, New York, NY 10018

ASH RAE - American Society of Heating, Refrigerating, and Air-Conditioning Engineers, 1791 Tullie Circle Northeast, Atlanta, GA 30329

ASME - American Society of Mechanical Engineers, 345 East 47th Street, New York, NY 10017

ASTM - American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103

DOE - Nuclear Standards Management Center, Oak Ridge National Laboratory, Building 9204.1, Room 321, MS/IO, P. O. Box Y, Oak Ridge, TN 37830

IES - Institute of Environmental Sciences, 940 East Northwest Highway, Mount Prospect, IL 60056

MSFC - Marshall Space Flight Center, NASA, Marshall Space Flight Center, AL 35812

NPFC - The Naval Publications and Forms Center, 5801 Tabor Avenue, Philadelphia, PA 19120

34

020.11

020.12

020.13

030.

030.1

030.2

030.3

030.4


NRC - u.s. Nuclear Regulatory Commission, Attn: Director, Division of Document Control, P-130A, Washington, DC 20555

NSF - National Sanitation Foundation, 3465 Plymouth Road, P. O. Box 1468, Ann Arbor, MI 48106

NTIS - National Technical Information Service, u.S. Department of Commerce, 5285 Port Royal Road, springfield, VA 22161

Document references.

Document No. Title

Abstract

Document No. Title

Abstract

Document No. Title

Abstract

Document No. Title

AFM 88-4 Chapter 5 Source AFWP & AFWR Criteria for Air Force Clean Facility Design and Construction Prescribes criteria for the design and construction of Air Force clean facilities. It specifies the real property standards for meeting the requirements of Air Force T.O. 00-25-203.

T.O. 00-25-203 Source AFWP & AFWR Contamination Control of Aerospace Facilities, u.S. Air Force This document specifies cleanroom design, operating, and test procedures. It also includes recommended cleanliness levels for typical operations.

ASH RAE Std. 52-76 Source ASHRAE Method of Testing Air-Cleaning Devices Used in General Ventilation for Removing Particulate Matter This standard defines unified test procedures and apparatus for evaluating filters with efficiencies below that of HEPA filters.

F 25 Source ASTM Standard Method for Sizing and Counting Airborne Particulate Contamination in Clean Rooms and Other Dust-ControJled Areas Designed for Electronic and Similar Applications

35

350 Appendix 1

030.5

030.6

030.7

030.8

Abstract

Document No. Title

Abstract

Document No. Title

Abstract

Document No. Title

Abstract

Document No. Title

Abstract

Procedures are given for membrane filter sampling and microscope counting in clean areas.

F 50 Source ASTM Standard Practice for Continuous Sizing and Counting of Airborne Particles in Dust-Controlled Areas Using Instruments Based upon Light scattering principles Methods are given for sampling, particle counting, and data evaluation using light-scattering particle counters in cleanrooms.

F 91 Source ASTM Standard Recommended Practice for Testing for Leaks in the Filters Associated with Laminar Flow Clean Rooms and Clean Work Stations by the Use of a Condensation Nuclei Detector Provides a method of testing the integrity of HEPA filter installations in laminar flow cleanrooms and clean work stations.

F 328 Source ASTM Standard Practice for Determining counting and Sizing Accuracy of an Airborne Particle Counter Using Near-Monodisperse Spherical Particulate Materials counting and sizing accuracy determination procedures are given for certifying operation of an optical airborne particle counter.

F 649 Source ASTM Standard Practice for Secondary Calibration of Airborne Particle Counter Using Comparison Procedures Procedures are given for fine-.tuning the response of an airborne particle counter to match that of a standard

36

030.9 Document No. Title

Abstract

030.10 Document No.

030.11

030.12

Title • Abstract

Document No. Title Abstract



instrument for defining atmospheric dust, following calibration with monodisperse latex particles.

F 661 Source ASTM Standard Practice for Particle Count and Size Distribution Measurements in Batch Samples for Filter Evaluation using an optical Particle Counter Procedures are given for sample handling, sample evaluation, and particle count and size analysis in batch samples for use in an optical single particle counter. The method is directed at samples obtained in filter testing, but can be used for any samples.

IES-RP-CC-002 Source IES Laminar Flow Clean Air Devices Covers definitions, procedures for evaluating performance, and major requirements of laminar flow clean air devices. Sixteen test and performance criteria are considered.

I ES-RP-CC-OOI source IES HEPA Filters Recommends basic provisions for HEPA filters for use in clean air devices and cleanrooms. Five levels of performance and two grades of construction are included.

IES-RP-CC-006 Source IES Testing Clean Rooms Describes test methods for characterizing the performance of cleanrooms. Performance tests are recommended for three types of cleanrooms at three operational phases.

37

352 Appendix 1

D30.l3

D30.l4

D30.l5

D30.l6

D30.l7

D30.l8

Document No. Title

Abstract

Document No. Title

Abstract

Document No. Title

Abstract


Document No. Title

Abstract

Document No. Title

IES-RP-CC-013 Source IES Recommended practice for Equipment Calibration or validation Procedures This Recommended Practice covers definitions and procedures for calibrating instruments used for testing cleanrooms and clean air devices, and for determining intervals of calibration.

NAB 5340.2 Source MSFC NASA Standards for Clean Rooms and Work Stations for the Microbially Controlled Environment Establishes standard classes of air conditions (both total particles and viable particles) within cleanrooms and clean work stations for the microbially controlled environment.

IES-CC-009 Source IES Compendium of Standards, Practices, Methods and Similar Documents Relating to Contamination Control Listing of documents.

MIL-STD-45622 Source NPFC Calibration systems Requirements Prescribes requirements for establishment and maintenance of a calibration system used to control the accuracy of measuring and test equipment.

MIL-F-5l068 Source NPFC Military Specification: Filter, particulate, High-Efficiency, Fire Resistant Covers design, construction, and performance of HEPA filters in six sizes and seven types.

MIL-F-5l079 Source NPFC Military Specification: Filter Medium, Fire-Resistant, High-Efficiency

38

030.19

030.20

030.21

030.22

030.23

Abstract

Document No. Title

Abstract

Document No. Title

Abstract





Provides requirements and test methods for determining compliance for one grade of HEPA filter medium.

MIL-F-S1477 Source NPFC Military Specification: Filters, Particulate, High-Efficiency, Fire Resistant, Biological Use Covers general requirements for particulate filters for use in air cleaning or air filtration systems involving chemical, carcinogenic, radiogenic, or hazardous biological particles.

NE: F3-41 Source DOE In-place Testing of HEPA Filter Systems by the Single-Particle, Particle-Size Spectrometer Method Procedures are described for in-place testing of single and tandem HEPA filter installations with DOP challenge and an optical particle counter with sensitivity to 0.1 micrometer.

NASA SP-S04S Source NTIS Contamination Control principles Broad overview and guidelines to those designing or planning cleanroom facilities.

NASA SP-S074 Source NTIS Clean Room Technology Considerable information on history, need, nature, and type of cleanrooms with details of cleanroom environment and operation.

NASA SP-S076 Source NTIS Contamination Control Handbook Extensive detail on contaminants and their control and cleaning methods.

39

354 Appendix 1

030.24

030.25

030.26

030.27

Document No. Title

Abstract

Document No. Title

Abstract

Document No. Title

Abstract

Document No. Title

Abstract

F 24 Source ASTM Measuring and Counting particulate Contamination on Surfaces A method for size distribution analysis of particulate contamination, 5 micrometers and larger, either on, or washed from, surfaces of small electronic device components.

F 51 Source ASTM Sizing and Counting Particulate Contaminant In and On Clean Room Garments A membrane filter/microscope method for determining detachable particulate contaminants, 5 micrometers and larger, on cleanroom garments.

MIL-HDBK-406 Source NPFC Contamination Control Technology -Cleaning Materials for Precision Precleaning and Use in Clean Rooms and Clean Work Stations Extensive information on selection and use of cleaning materials developed by DOD.

MIL-HDBK-407 Source NPFC Contamination Control Technology -Precision Cleaning Methods and Procedures Extensive information on cleaning methods used by the military services for gross and precision cleaning of work processed under controlled environment conditions.

40


APPENDIX E

GLOSSARY

ElO. Scope. This appendix lists terms used in the other appendixes, for which further explanation in the context of such use may benefit the user.

E20. List of terms.

E20.l Isokinetic. A term describing a condition of sampling, in which the veloclty of gas into the sampling device (at the opening or face of the inlet) has the same velocity rate and direction as the ambient atmosphere being sampled.

E20.2 Isotropic particles. Particles with equal, uniform physical and chemical properties along all axes.

E20.3 Membrane filter. Porous membrane composed of pure and biologically lnert cellulose esters, polyethylene, or other materials through which the air stream is passed for the purposes of filtration.

E20.4 Reynolds number. A dimensionless number which is significant in the design of a model of any system in which the effect of viscosity is important in controlling the velocities or the flow pattern of a fluid: equal to the density of a fluid times its velocity, times a characteristic length, divided by the fluid viscosity.

41

356

Appendix 2

Simplified Cleanroom Certification Procedure

Simplified Cleanroom Certification Procedure 357

Page 1 of 3 Arizona State University

Cleanroom Monitoring/Certification Procedure

Originator: Edward J. Bawolek 9/13/89 Revision:1/1/90

OBJECTIVE

To describe a procedure which can be employed to certify or routinely monitor a cleanroom or cleanroom area in accordance with Federal Standard 2090.

SCOPE

This method meets the requirements of Fed. Std. 209D, but is not all-inclusive. Significant deviations from this procedure are possible which still meet the requirements of the standard. This method is designed to be a convenient subset of the standard. This procedure does not specify safe operating procedures for c1eanroom equipment and personnel. This procedure does not cover calibration of the optical particle counter.

EQUIPMENT/MATERIALS

1. Optical particle counter with 0.5 um detection capability. (0.3 um capability required for Class 10 and Class 1 measurements.)

2. Data sheet. 3. Statistical Calculator

PROCEDURE

1. Fill out Steps 1 through 6 of the attached worksheet to determine the number of air samples required, the particle size to be measured, and the sample volume.

2. Space the sample locations as uniformly as possible throughout the clean area to be measured. Avoid direct interference with operating equipment. Do not attempt to move equipment to enable sampling a location. When taking a sample, set the sample intake at a height which approximates the working surfaces of the room. The sample tube should be perpendicular to the airflow (this typically means the sample tube should be oriented horizontally at approx. 40" above floor) .

3. Set the particle counter to the appropriate particle size and sample volume. Take THREE measurements at each sample location. Record the data on the data sheet.

4. Use the COMMENTS area on the data sheet to record activity in the sample area (at-rest, operational, maintenance, etc.).

5. Follow the mathematical analysis in steps 7 through 13 on the worksheet to determine whether the cleanroom is in statistical control.

6. Report the results to appropriate facilities personnel and file the worksheet and datasheet for future reference.

358 Appendix 2

SAMPLING

1. Write the area of the clean work space here: A

2. Write the Class number of the clean work space here:

3. Check the appropriate box for the type of airflow:

a. Unidirectional (Laminar)

C

b. Nonunidirectional (Turbulent)

4. Determine the divisor, D, from the following table:

CLASS (Line 2)

Unidirectional Flow (Box 3a Checked)

Nonunidirectional Flow (Box 3b Checked)

100,000 10,000 1,000

100 10

1

316 100

31. 6 25 25 25

Write the divisor here: D

316 100 31.6 10 3.1 1

5. Determine the number of sample --------locations, L, by dividing A L = A / D = (from Line 1) by D (from Line 4): --------

(If L is less than 2, write 2 in the box.) This is the number of locations you must test in the clean room. At each location, THREE air samples will be taken.

6. Determine the particle size to be measured, the air sample volume, and the class limit from the following table:

CLASS (Line 2)

100,000 10,000 1,000

100 10

1

Particle Size P (um)

0.5 0.5 0.5 0.5 0.3 0.3

Air Sample Volume V (ft A 3)

0.1 0.1 0.1 0.2 0.7 7.0

6a. Write the particle size, P here: P

6b. Write the air sample volume, V here: V

6c. Write the class limit, Cl here: Cl

Class Limit Cl

100,000 10,000

1,000 100

30 3

(um)

E. J. Bawolek 9/13/89 Revision: 1/1/90

Simplified Cleanroom Certification Procedure 359

7. Are any of the numbers in Column 4 LARGER than Cl, (from Line 6c)?

8.

9.

10.

a. NO b. YES I

-a. If you checked NO, then STOP!! The cleanroom meets thestatistical control criteria and no further work is necessary!

b. If you checked YES, proceed with the following statistical analysis to determine if room is in control:

Take the mean, M, of the numbers in Col 4: M (Use a statistical calculator) --------

--------Take the Standard Deviation, SD of Col 4: SD (Use a statistical calculator) --------

--------Calculate the Standard Error by dividing SE SD / L SD (from Line 10) by L (from Line 5) : --------

11. Determine F, the Upper Control Limit Factor from the following table:

I L I 2 3 4 5-6 7-9 I 10-16 I 17-29 I >29

I F I 6.3 2.9 2.4 2.1 1.9 1.8 1.7 I 1.65

Write the value for F here: F

12. Determine the UCL by multiplying F (from Line 11) by SE (from Line 10) and adding this result to M (from Line 8).

Write the UCL here: UCL = (SE * F) + M =

13. Compare UCL (from Line 12) with Cl (from Line 6c). Check the appropriate box:

a. UCL greater than Cl: Clean room is lOUT OF CONTROL I (UCL > Cl)

b. UCL less than Cl: Clean room is I IN CONTROL I (UCL < Cl)

E. J. Bawolek 9/13/89 Revision: 1/1/90

360 Appendix 2

DATA SHEET

Date: Particle Size: Room or Bay Identification: Air Sample volume:

I Colli Col 2 I Col 3 II Col 4* I ITime I Location IComments I Sample 1 I Sample 2 I Sample 3 I I Sample I I I I I Result I Result I Result I I Average I

II II

----------------------------------~-----------------------------------I I I I I I II I I I I I I I II I

I . I

II II

II II

II II

II II

II II

II II

II II

II II

II II

II II

II II

II II

II II

* Col 4 = (COL 1 + Col 2 + Col 3) I 3

Appendix 3

Program and Sample Output

361

362 Appendix 3

10 CLS 211 COLOR 2,11 39 INPUT nAIR DUMPED, (cfml ";Fs 411 INPUT "CLEANROOM EXHAUST, (cfml" ;F3 59 Fl z F3+Fs 69 PRINT "MAKE-UP AIR, (cfml" ;Fl 79 INPUT "MAKE-UP PARTICLE DENSITY, C/ft A 31"; Pl 89 INPUT "PREFILTER EFFICIENCY, (%I n;EFl 99 El-(11l9-EF11/199 11l1l INPUT nCLEANROOM AIRFLOW, (cfmln; F2 110 IF F2<Fl THEN GOTO 359 120 PM=109*Fl/F2 139 PRINT '" MAKEUP AIRn;PM 140 INPUT nHEPA FILTER EFFICIENCY, (%In;EF2 150 E2-(199-EF21/100 160 INPUT "CLEANROOM FLOOR AREA, (ft A 21";FA 170 INPUT "CLEANROOM HEIGHT, (ftl" ;HT 189 V-FA*HT 190 INPUT "CLEANROOM PARTICLE GENERATION, C/ft A 3-minl" ;G0 289 P41=G0*V*(1-F3/F21 219 P42=Fl*Pl*El*E2 220 P43=(F2-F31-(F2-Fll*E2 230 P4-(P41+P421/P43 240 P2Pl=(F2-Fll*P4*E2 250 P2P-(P42+P2P1I/F2 260 PRINT "------------------------------------------------------------------270 PRINT "PARTICLE DENSITY AT CEILING, C/ft A 3 I"; P2P 280 PRINT "PARTICLE DENSITY AT FLOOR, (/ft A 31";P4 290 PRINT "AVERAGE PARTICLE DENSITY IN CLEANROOM, C/ft A 31"; (P2P+P41/2 399 PRINT "AIRCHANGES C/minl" ;F2/V 310 PRINT "AVERAGE AIR VELOCITY, (fpml" ;F2/FA 329 PRINT "' HEPA REQUIRED"; «F2/FAI/90)*100 330 PRINT ,,------------------------------------------------------------------" 349 GOTO 311 350 PRINT "CLEANROOM AIRFLOW TOO LOW" 368 GOTO 11118

AIR DUMPED, (cfm)? 0 CLEANROOM EXHAUST, (cfm)? 25000 MAKE-UP AIR, (cfm) 25000

Program and Sample Output 363

MAKE-UP PARTICLE DENSITY, (/ft'3)? 1000000 PREFILTER EFFICIENCY, (%)? 95 CLEAN ROOM AIRFLOW, (cfm)? 120000 % MAKEUP AIR "20.83333 HEPA FILTER EFFICIENCY, (%)? 99.97 CLEANROOM FLOOR AREA, (ft'2)? 4000 CLEANROOM HEIGHT, (ft)? 10 CLEANROOM PARTICLE GENERATION, (/ft'3-min)? 500

PARTICLE DENSITY AT CEILING, (/ft'3) 3.165404 PARTICLE DENSITY AT FLOOR,(/ft'3) 170.6651 AVERAGE PARTICLE DENSITY IN CLEANROOM, (/ft'3) 86.91524 AIRCHANGES (/min) 3 AVERAGE AIR VELOCITY, (fpm) 30 % HEPA REQUIRED 33.33334

AIR DUMPED, (cfm)? 45000 CLEANROOM EXHAUST, (cfm)? 25000 MAKE-UP AIR, (cfm) 70000 MAKE-UP PARTICLE DENSITY, (/ft'3)? 1000000 PREFILTER EFFICIENCY, (%)? 95 CLEANROOM AIRFLOW, (cfm)? 360000 % MAKEUP AIR 19.44445 HEPA FILTER EFFICIENCY, (%)? 99.9997 CLEANROOM FLOOR AREA, (ft'2)? 4000 CLEANROOM HEIGHT, (ft)? 10 CLEANROOM PARTICLE GENERATION, (/ft'3-min)? 100 ------------------------------------------------------------------PARTICLE DENSITY AT CEILING, (/ft'3) 2.895483E-02 PARTICLE DENSITY AT FLOOR,(/ft'3) 11.14223 AVERAGE PARTICLE DENSITY IN CLEANROOM, (/ft'3) 5.585591 AIRCHANGES (/min) 9 AVERAGE AIR VELOCITY, (fpm) 90 % HEPA REQUIRED 100 ------------------------------------------------------------------AIR DUMPED, (cfm)?

Index

Absolute filters, 175 Absorption, 169-170,254-255,257 Acceptable risk, 194 Acid bath, 155 Acid rain, 166 Acids, 258 Acrylic shields, 273 Activated charcoal, 62, 169 Active mounts, 141 Acute toxicity, 255 Aerospace industry, 6, 21-22 Aftershave, 14 Air-blowing, 73 Airborne particulates. See Particulates Air conditioning, 42, 115, 116, 205, 287 Air control. See also Air handling systems

and fans, 118-120 feedback, 122 parameters, 120-121 systems, 120-124 types of, 121-124

Air delivery, 80-82 Air filtration, 58-66

basic theory, 58-61 contamination reduction techniques,

62-64 efficiimcy, 64-65 and fire protection, 150 gas and vapor removal, 61-62 practical problems, 64-66 prefiltration, 115

Airflow, 66-70, 340 laminar or undirectional, 67-70, 121 pressurization, 70 turbulent, 66-67, 119, 133, 137 vortices, 66-67

Air handling systems, 111-118,289 configurations, 112-114 and fire protection, 150 heating and cooling, 115-116 humidity control, 116-118

prefiltration, 115 Air pressure, 26, 48, 70, 121 Air recirculation, 113-114, 143, 152 Air return, 82-83, 99 Air showers, 240, 241 Air supply, 95-97 Air velocity, 26, 48, 121 Aluminum, 51, 53 American Conference of Governmental

Industrial Hygienists (ACGIH), 30, 195, 268

Ammonia, 145 Ammonium chlOride, 208-209 Anions, 171 Anodization, 53 Antimony, 259 Antiperspirants, 14 Apparel, 57-58, 211-240, 248

advanced suit concepts, 234-235 changing procedures, 236-238 changing room layout, 235 facemasks, 219, 224-228, 249 garment materials, 211-218 garment storage and monitoring, 235-

236 gloves and skin coatings, 219-224,

237,272,275,281 laundering of, 217, 219, 231-233 and particulate dispersion, 229-231 protective, 272-273, 275, 280-281,

283 static control, 233-234 suit styles, 218-219, 230 use of, 235-240

Aquifers, 159 Aramid, 174 Area monitoring, 43-44, 269-270 Argon, 189, 190, 301 Aromatics, 258 Arsenic, 23, 260 Arsine, 260

365

366 Index

Asphyxiants, 261 Atomic absorption, 177 Automatic control systems, 46 Automation, 304--306 Axial flow fans, 118

Bacteria, 9, 22, 66, 167, 168, 176 Bag filters, 115 Ball valves, 183 Barium, 259-260 Basements, 103 Bases, 258 Basic Codes, 142 Bellows effect, 230 Bellows valve, 193 Belts, 15 Benzene, 258 Beryllium, 259-260 Bimetal element, 47 Biocides, 177, 183-184 Biomedics, 22-23 Body salts, 39 Bonnet hair dryer, 240, 244, 245 Booties, 235, 237 Boric acid, 258 Boron gases, 260 Bottled chemicals, 200-202 Break-tip tube detectors, 45 Bright light inspection system, 32 Brushes, 75 Bubble pointing, 183 Building codes, 142-145 BUilding materials. See Construction

materials BUilding techniques, 57-58 Bunny suits, 219, 230, 235, 237 Burning, 253

Cabinets, 196-197, 274, 286, 287, 288 Cadmium, 259 California, 266 Carbon-based fly ash, 12 Carbon dioxide, 78 Carbon monoxide, 12, 154 Carcionogens, 257 Cascades, 179, 182 Cations, 170-171 Ceilings

construction materials, 55-57 perforated, 81-82 suspended, 56-57

T -bar supports, 104 Cellosolve, 257-258 Centrifugal fans, 118, 284 C-frames, 83 CGA (Compressed Gas Association)

fitting, 191, 285 Changing room, 235 Channeling, 271 Charcoal, 62, 169 Charge induction, 207 Chemicals, wet. See Wet chemicals Chemical vapors, 54 Chemical warfare, 59 Chemopolishing, 189 Chlorinated fluorocarbons (CFCs), 160-

161,258 Chlorinated hydrocarbons, 223 ChlOrine, 43-44, 174, 177, 184 Chlorine diOxide, 184 Chronic toxicity, 255 Clean Air act, 159 Cleaning

of cleanrooms, 248-249 of particulates, 73-74 solvent, 75-76 techniques, 72-76 technology, 76-79

Clean maintenance tent (CMT), 303-304 Cleanrooms. See also Controlled

environment advanced concepts, 294-296 apparel for. See Apparel bringing items in, 71-72 class, 28-29, 104-110

determining requirements, 104-106 lower, middle, and upper, 105-107 models, 107-110

cleaning of, 248-249 creating clean areas, 49-79 design of, 153-154 Federal Standard 209D, 27-29, 30,

32, 308-355 layout, 80-110 miscellaneous applications, 6-7 modular, 89-90 monitoring. See Monitoring need for, 1-2 parameters, 25-26 program and sample output, 361-363 safety practices. See Safety Simplified certification procedure, 356-

360 as systems, 307

technology, 1-8 tunnel, 90-97

Clean Water Act, 159 Clothing. See Apparel Cobalt, 259 Codes. See Building codes; Fire codes Colorimetry, 177 Combustion, 253 Compact disks (CDs), 22 CompreSSion fitting, 190 Computer modeling, 154 Condensation nuclei counters (CNC) , 34 Construction materials, 49-58

basic properties, 49-50 ceilings, 55-57 combustible, 149-150 floors, 54-55, 56 walls, 50-54

Contamination. See also Decontamination; specific contaminants

of apparel. See Apparel identification, 37-40 microcontamination. See

Microcontamination pathway, 25 and personnel, 211-251 recirculation of contaminants, 152-155 reduction techniques, 62-64. See also

specific techniques and filters water, 20-21 world, 1

Contamination Control Coordinator (CCC),247

Continuous transfer technique, 299 Controlled environment, 2, 25-48

future of, 293-307 miscellaneous detection methods, 35-

37 monitOring, 40-46 parameter measurement, 32-46 performance considerations, 25-27 performance standards, 27-31

Copper pipes, 188 Copper smelting, 12 Corona discharge, 36, 62 Corona grids, 126 Corridors, 143-144, 147 Corrosivity, 254 Cosmetics, 14,39,244 Cotton, 212 Cross contamination, 22 Cross-flow air, 83

Index 367

Cross zoning, 41 Crust, Earth's 132-133 CWS (Chemical Warfare Service) filter,

59 Cyanide, gas, 261

Dacron, 212, 219 Decontamination

bringing items into c1eanroom, 71-72 cleaning techniques, 72-76 of equipment and material, 70-79 new cleaning technologies, 76-79

Deionization, 170-172, 177-181 Deodorants, 14 Dessicant, 117 Dew point, 116 Diaphragm valve, 193 Diatom, 165 Diffusion badge collectors, 44 Distillation, 169 Drains, 147 Dry-ice snow, 77-78,207 Ducts, 80-81, 83, 101, 114, 119-120,

143, 146-147, 150, 151 Dust, 37, 245-246 Dynamic air balancing, 26

Electrets, 62-64, 78-79, 207 Electrical panels, 276 Electrical wiring, 143 Electricity, 265, 277 Electrodialysis, 170 Electromigration, 18 Electron beam lithography, 101 Electron microscopy, 33 Electrons, 33, 36 Electropolishing, 189 Electrostatic discharge (ESD), 125 Electrostatic field, 207 Electrostatic filter ((ESF), 62-63 Emergencies, 147-148, 160, 201, 205,

263,266-267,278-280,289 Emergency planning and Community

Right-to-Know Act, 160 Enamel, 53, 54 Enclosed transfer systems, 296-304 Energy dispersive x-ray analysis (EDXA),

38 Engineering controls, 269-270, 283-287 Environment, 159

368 Index

Environmental Protection Agency (EPA), 159-161,199,290

Episodic monitoring, 45 Equipment

decontamination, 70-79 Integration, 101-103 layout, 139-140,273-276 maintenance safety, 276-278 particle monitoring, 329-330 process, 101-104 sensitive, 140-141 services, 103-104 vibration, 19

ERT (Emergency Response Team), 279 Esters, 258 Etching, 3 Evacuation, 267,279 Excess flow control provisions, 145 Exhausted vertical workstations, 85 Exhaust stacks, 154 Exhaust systems, 146-147,284,287 Exits, 143-144 Exposure monitOring, 268-271 External industrial sources, 12-13 External natural sources, 11-12 Extractables, 206 Eye protection, 273, 274

Facemasks, 219, 224-228, 249 Failure mode-effect, 281 Fans,83-85,118-120,284 Fasteners, 219 Fault-tree, 281 Federal Standard 2090, 27-29, 30, 32,

308-355 Fetotoxin, 257 Fiberglass, 181 Filter leakage, 270-271 Filtration. See Air filtration; Gases,

filtration; Water, filtration Fire codes, 142-143, 145-148, 287 Fire extinguishers, 150-151 Fire insurance, 148-149, 155 Fire Officers Committee of Great Britain

(FOC),l48 Fire prevention, 256 FIre protection

recirculation of contaminants, 152-155 smoke removal, 155-157 standards, 143 systems, 148-151 and water supply, 151

Rame ionization, 177 Harne photometry, 43 Flammability, 253, 265 Roors

construction materials, 54-55, 56 isolation of, 137-139 noncombustible, 143 perforated, 55 raised, 99-100, 103, 138 structural, 100

Ruorescence, 39-40 Ruorescent powders, 76 Ruorescent seeding technique, 77 Ruorescent silicone grease, 76 Ruorinated hydrocarbons, 12 Ruorinated liqUids, 75 Ryash,12 Fossil fuels, 12 Freeze-thaw cycles, 11 Freon, 12, 75,160-161,258 Frequencies, 134-135 Fungi, 9, 66 Furnaces, 19, 102, 103

Gallium, 259 Galvanization, 54 Garments. See Apparel Gas chromatography, 43, 45, 204 Gases, 186-199.

bulk storage and distribution, 186-190 cabinets, 196-197,286,287,288 categories, 285 as contamination source, 9, 10, 12-13,

15 cylinder use, 190-193, 196-197,287,

288 detection of hazardous, 197-199 filtration, 193 hydride,43,I96 monitoring and cleaning, 145-146,

193-194, 197 pipework, 188-190, 194, 196 removal, 61-62 safety aspects, 194-197, 287-289 standards,30-31 tOxic,43-46,195-196,260-261,286 and transfer systems, 300-302

Gastrointestinal tract, 254-255 Gears, 15 Geology, 136 Germane, 260 Glass, 54

Gloves, 219-224, 237, 272, 275, 281 Glycerol, 208-209 Glycol ethers, 257 Gold, 259 GORE-TEX, 217-218, 232 Gowning, 57, 235-236, 246 Great Britain, 148 Groundwater, 159

Hair, 237, 240, 244 Halogenated hydrocarbons, 258 Handoff,297 Harmonics, 134 Hazard Communication Law, 158, 265 Hazardous materials

and fire codes, 145-147 gas detection, 197-199 hazardous production materials

(HPMs), 30, 252-261 effects of common, 257-261 handling, 282-291 properties of, 253-261 safety controls, 282-287

legislation, 157-161 piping and tubing to transport, 144 storage of, 144

Health, 23-24 Heating, 115-116 Heat transfer, 115 Helmke Drum, 232 HEPA (high efficiency particulate air)

filter, 59-62, 65-69, 81-83, 85-90, 93,95,97-98,101,103,104,106-108, 110, 114-115, 120, 152, 155, 156,200,248,271,289,296,300, 304

Herringbone weaves, 212, 218 Hexamethyl disilizane (HMOS), 258 High-volume sampling, 46 Holes, 50, 51, 58 Honeycombed aluminum, 51 Horizontal laminar flow (HLF), 83, 100-

101 Horizontal workstations, 85 Hot furnace processes, 19 House gases, 187 House nitrogen, 188 HPMs. See Hazardous materials Humidity, 26, 47, 116-118, 120, 152 Hydride gases, 43, 196 HydroflUOriC acid, 162, 259 Hydrogel, 223

Index 369

Hydrogen, 40-41,45,261 Hydrogen peroxide, 184, 259 Hydrogen sulfide, 12 Hydroxyl ions, 171

IDLH (immediately dangerous to life and health), 256

Indium, 259 Infrared spectroscopy, 176-177 Inorganic substances, 8-9, 40, 164-166 In-situ proceSSing, 306 Intercoms, 102 International Association of Fire Chiefs,

148 Iodine, 177, 184 Ionizers, 126-127 Ions, mobile, 20

Jumpsuits, 57, 219. See also Bunny suits

Keratin, 14

La Calhene system, 298-299 Laminar flow cabinets (LFCs), 83-87,

90,97 Laminates, 51 Lasers, 33-34, 37, 73, 265 Lead, 259 Leakage, 270-271,288 Leaking Underground Storage Tank

(LUST) legislation, 159 Legislation, 157-161 lighting, 104 light-scattering techniques, 33-35, 193,

302 linewidth, 4 linoleum, 55 liquefied gases, 187 liquid carbon dioxide, 78 liqUid chemicals. See Wet chemicals liqUids. See also Ultrapure water; Water

contamination in, 10-11 flUOrinated, 75 high pressure, 73 organic, 257 particles in, 176, 185

lithography, 3, 17-19, 101, 120, 131-132, 140

370 Index

Local Emergency Planning Committees (LEPCs), 160

Local toxicity, 255 Local undirectional flow, 83--89 Lower explosive limit (LEL), 253, 285 Lower flammable limit (LFL), 253 LSI (Large Scale Integration), 3, 4, 107 Lubrication, 15 Lungs, 255

Machinery, 134 Magma, 132 Magnetic disk industry, 22 Magnetic levitation, 300 Maintenance, 276-278, 290, 303 Male reproductive system (MRS) toxin,

257 Management, 246, 264 Manganese oxide, 54 Manufacturing yield. See Yield Mass spectroscopy, 193 Mass spring system, 207 Material Safety Data Sheet (MSDS), 158,

160,265,287 Mechanical breakdown, 21-22 Metal coatings, 22 Metal hydrides, 260 Metals, 259 Methane, 12 Microchemical analysis, 38 Microcontamination, 8-24, 105

by improper work practices, 17 by plant equipment and facilities, 14-

16 by plant personnel, 13-14 by production materials and processes,

16-17 control for solid surfaces, 206-208 effects of, 17-24 general practices, 247-248 sources of, 11-17 types of, 8-11

Micro-organisms, 167-169 Microscopy, 32-33, 37, 325, 329, 334-

336 Mineral salts, 20 Mixed flow rooms, 80--83 MLD (minimal lethal dose), 256 Models, mathematical, 107-110 Modular c1eanrooms, 89-90 Mold, 66 Molecular beam epitaxy (MBE), 301

Monitoring area, 43-44, 269-270 chlOrine, 42 controlled environment, 40-46 episodic, 45 exposure, 268-271 Federal Standard 2090, 323-324,

329-338 gases, 43-46, 145-146, 193-194,

197 hydrogen, 41 smoke, 41 vapor, 42 velometers, 42

Monjreal Protocol, 160 Moon, 133 MSI (Medium Scale Integration), 3, 4,

107 Multiple point monitors, 43 Mutagens, 257, 258 MVfR (moisture vapor transmission rate),

218

National Aeronautics and Space Administration (NASA), 50, 51, 52

National Electrical code, 276 National Fire Protection Association

(NFPA), 142-143, 148,254,256 National Institute for Occupational Safety

and Health (NIOSH), 30 Natural frequency, 135 Neutralization, 286 NFPA. See National Fire Protection

Association Nickel, 259 Nitric acid, 259 Nitrogen, 126, 179, 187, 188, 189, 194,

285,301 Nitrogen-blowing, 73 Nitrogen oxides, 260 Nominal filters, 175 Nuclear materials, 59

Oasis Project, 299 Occupational Safety and Health

Administration (OSHA), 31, 158, 195,199,265,268,288

Oils, 73 Optical scanning systems, 33 Organics scavengers, 171 Organic substances, 8-9, 40, 167

O-rings, 183 OSHA. See Occupational Safety and

Health Administration Osmotic pressure, 172 Outgassing, 51-52 Oxidizers, 258 Oxygen, 187 Ozone, 12, 160, 260 Ozone/water/ultrasonic system, 76-77

Packed valves, 192 Packless valves, 193 Paints, 15,51-53 Paper tape systems, 43 Particulates

airborne, 9-10, 34, 315, 317, 323, 324

air filtration, 58-66 analysis, 38 and apparel, 229-231 cleaning techniques, 73-74 dust, 37, 245-246 Federal Standard 209D, 315-326,

329-345 in gases, 193-194 in liqUids, 176, 185 materials, 8-9 parameter measurements, 32-35 in process chemicals, 202-203 on sensitive solid surfaces, 206-207 and smoking, 227-228 standards, 27-30 in vacuum systems, 302-303 water filtration, 174-175

Passive elements, 141 Pellicle, 19 PELs. See Permissible Exposure Limits Perfluoroalkoxy (PFA), 180-181 Perforated ceilings, 81--82 Perforated floors, 55 Permissible Exposure Limits (PEls), 31,

43,195,256,268,286 Personnel

apparel. See Apparel motivation and training, 240, 242-247 safety. See Safety stress, 249-250

Pharmaceuticals, 22-23 Phosphine, 196,260,286 Phosphoric acid, 258 Photoelectric effect, 35-36 Photoionization, 43

Index 371

Photolithography, 17, 44, 132, 258 Physical examinations, 283 Piping, 144-145, 168, 180, 185, 188-

190,194,196,200 Pistons, 15 Planar technology, 4 Plant isolation, 140 Plant layout, 139-140 Plants (vegetation), 11, 137 Plasma etching system, 101 Plastics, 51 Plates in the crust, 133 Platinum, 259 Plenum, 81, 82, 98-100, 103, 114, 120 Point defects, 6, 105 Pollen, 11 Polyester, 218, 219 Polymers, 170-171, 180-181 Polyolefin, 217 Polypropylene, 156 Polystyrene, foam, 51 Polysulfone, 174 Polytetrafluoroethylene (PTFE), 61, 180-

181,200,202,217-219,234 Polyvinyl chloride (PVC), 156, 180-181 Polyvinylidene fluoride (PVDF), 180-181 Popper fasteners, 219 Potassium chloride, 39, 226-227 Precipitates, 54 Premanufacturing notice (PMN), 158 Pressure regulator, 192 Printed circuit boards (PCBs), 3 Printed wiring boards (PWBs), 3-4 Procedural controls, 269, 270 Product reliability. See Reliability PTFE. See Polytetrafluoroethylene Pyrogens, 167 Pyrophoric materials, 253

Radiation, 265 Radioactive material, 265 Reactivity, 253-254 Reliability

circuit, 17-21 product, 1-2 in semiconductor processing, 5-6

Residual gas analyzer (RGA), 302 Resins, 170-171 Resistance element, 47 Resistivity measurement, 175 Resonant frequency, 135

372 Index

Resource Conservation and Recovery Act (RCRA) , 159

Retrofit systems, 89-90 Reverse osmosis (RO), 172-174, 184-

185 Reverse osmosis/deionization systems,

177-181, 182 materials, 180-181 point of use, 179-180 pretreatment section, 177 storage tanks, 179 typical configuration, 177-179

"Right to Know" law, 158 Robotics, 304-306 Rocketry,21 Rod and tube element, 47 Rotary pumps, 285 Rotating machinery, 15

Safety, 252-292. See also Hazardous materials

cleanroom practices, 261-280 emergencies, 278-280 equipment layout, 273-276 exposure monitoring, 268-271 of gases, 194-197, 287-289 general practices, 272-273 maintenance, 276-278 personal protection systems, 281-282 protective clothing, 272-273, 275,

280-281,283 regulations, 262-263 and solid process materials, 208, 210 and static charge, 125 team, 261-262 training, 263-268 waste disposal, 290-291 of wet chemicals, 289-290

Salt, 152 Salt water, 11 Satellite Building Concept (SBC), 140 Scale inhibitor, 177 Scale modeling, 154 Scanning electron microscopy, 33 Scattering theory, 33-34 Scrubbing, 286 Sealants, 50, 51-53 Sealed bellows, 47 Semiconductor industry, 131

area monitoring, 269-270 and enclosed transfer systems, 296-

298,300

gases in, 187, 198,287-288 history, 2-3 integration, 3-5 manufacturing, 21 optical scanning systems, 33 retrofit systems, 90 and robotics, 304-306 and sodium, 166 technology, 2-6 training, 246, 266 and Uniform Rre Code Article 51, 145 and wet chemicals, 162, 290 yield and reliability in processing, 5-6

Semipermeable membrane, 170 Service chase, 92-95, 103 Service COrridors, 144, 147 Sewing, 218 Sheet steel, 54 Shoes, 238-240. See also Booties Short term exposure limit (STEL), 31 Showers, emergency, 274 Significant new use rule (SNUR), 158 Silica, 11, 260 Silicon, 11,23 Silicon dioxide, 34, 165, 260 Silicone grease, 52-53, 76 Silicone rubber sealants, 52-53 Silicon gases, 261 Silicon wafers, 16,270,281 Silver, 259 Site selection, 135-136 Shln, 13-14, 19,254-255 Shln coatings, 219-224 Smoke detectors, 41, 143, 156 Smoke removal, 155-157 Smohlng, 227-228 Sodium, 166 Sodium bisulfite, 174 Sodium chlOride, 165 Sodium hydroxide, 259 Soft walls, 51 Soils, 159 Solid process materials, 208, 210 Solid surfaces, 206-208 Solvent cleaning 75-76 Soot, 12 Southern Codes, 142 Spin-bake system, 37 Spittle, 227 Spot VLF (vertical laminar flow), 85-90,

97-98,107 Sprinkler systems, 104, 151, 155, 157 SSI (Small Scale Integration), 3, 4

Stainless steel, 54, 188 Standard Mechanical Interface (SMIF)

system, 297-300 State Emergency Response Commissions,

160 Static charge, 124-128

effects of, 124-125 measurement of, 126 miscellaneous reduction means, 127-

128 reduction by ionizers, 126-127 safety aspect, 125 sources and detection, 125-126

Static control, 233-234 Steam spray, 117 Steel,54 Steel cylinders, 190 Stibine, 260 Storage, 144, 150, 159,201,235-236,

277,285 Stress, worker, 249-250 Strychnine, 268 Sulfur dioxide, 12 Sulfuric acid, 177, 205, 259 Superfund Amendments and

Reauthorization Act (SARA), 160 Suspended ceilings, 56-57 Suspended material, 164 Synthetics, 212, 233 Systemic toxicity, 255

Tacky mats, 238-239 Taffeta weaves, 212, 218 Tantalum, 259 T -bar supports, 104 Temperature, 26, 46-47, 114, 116, 120 Tenting, 98 T eratogens, 257 Thermal processing, 306 Thermophoresis, 208 Threads, 212, 218 Threshold Limit Values (TLVs), 30-31,

43,195-199,256,268,285 Tides, 133 Time weighted average (TWA), 23, 31 Tin, 259 TLVs. See Threshold Limit Values Total dissolved solids (TDS), 164, 166 Total VLF (vertical laminar flow), 97-

100,106 TOxicity,254-255 TOxicology, 195,254-257,268

Index 373

Toxic substances. See Hazardous materials; specific substances

Toxic Substances Control Act (TOSCA), 158

Trenches, 137 Trichloroethane (TCA), 258 Trichloroethylene (TCE), 258 Trolleys, 300 Trucks, 133-134, 137 Tubing, 144 Tunnel c1eanrooms, 90-97

air supply and zoning, 95-97 layout, 90-92 service chase configurations, 92-95

Turbidity, 164 TV cameras, 246-247 Tyvek, 57, 217-219

ULPA (ultra low particulate/penetration air) filter, 61

ULSI (Ultra Large Scale Integration), 3, 4 Ultra-high vacuum (UHV) environment,

301 Ultrapure water, 162-185

biocides, 183-184 changeovers, 182 deionization, 170-172 detergent in, 76 filtration, 174-175 measurement techniques, 175-177 need for, 162-163 operational considerations, 181-184 pUrification techniques, 169-181 redrculation, 181-182 reverse osmosis, 172-174 as solvent, 117

Ultraviolet light, 35-36 Ultraviolet rays, 13 Underwear, 229, 237 Uniform Codes, 142 Uniform Fire Code Article 51, 145 Upper explosive limit (UEL), 253 Upper flammable limit (UFL), 253 U-tube,48

Vacuum pumps, 285 Vacuum systems, 15, 73, 277, 301-302,

303 Valves, 21, 183, 192-193,282 Vapors

chemical, 54

374 Index

Vapors (Cont.) as contamination source, 9, 10, 12-13,

22 monitors, 42, 45 removal,61-62 standards, 30-31

VCO fittings, 190 VCR fittings, 190, 192 Velometers,42 Venillation, 143,284-285 Vents, 82 Vertical workstations, 85 VHSIC (Very High Speed Integrated

Circuits), 3 Vibration, 15, 130-141

effects of, 130-132 in equipment, 19 external sources, 132-134 internal engineering, 140 internal sources, 134-135 practices, 141 reducing, 136-137 and site selection, 135-136 steady-state vertical, 132 and structure, 136-140

Vinyl, 50--51, 55, 56, 68 Viruses,22 VLSI (Very Large Scale Integration), 3, 4 Voltage ionizer, 126 Voltage-switching techniques, 127 Vortices, 66-67

Wall materials, 50--54 Waste disposal, 290-291 Water

constituents of raw, 163-169 contamination, 20-21

ffitration, 174-175, 185 for fire protection, 151 inorganic materials, 164-166 micro-organisms, 167-169 organic materials, 167 purification techniques, 169-181 sources of, 163-164 ultrapure. See Ultrapure water vapor, 193-194

Weaves, 212-217 Weirs. See Cascades Welding, 190 Wet-and-dry bulb thermometer, 47 Wet benches, 156, 157, 179 Wet chemicals, 199-206

bottle chemical use, 200-202 bulk storage and distribution, 199-20 monitoring and cleaning, 202-205 safety of, 289-290 spill control, 205-206

Wetting, 286 Winds,137 Wipers, 74-75 Work function, 35 Work practices, 240-250 Workstations, 85, 145-147

Yield bust phenomenon, 153 circuit, 17-21 manufacturing, 1-2 product, 105 in semiconductor processing, 5-6

Yttrium, 259-260

Zero pressure stackhead, 284 Zinc, 54