ASTM F1394-92(1999)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F 1394 – 92 (Reapproved 1999)
Standard Test Method for
Determination of Particle Contribution from Gas Distribution
System Valves
This standard is issued under the fixed designation F 1394; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Semiconductor clean rooms are serviced by high-purity gas distribution systems. This test method
presentsaprocedurethatmaybeappliedfortheevaluationofoneormorecomponentsconsideredfor
use in such systems.
1. Scope short lengths of tubing) to compare, with statistical signifi-
cance, to the data generated from the spool piece. For this
1.1 This test method covers gas distribution system compo-
reason, this test method cannot reliably support comparisons
nents intended for installation into a high-purity gas distribu-
between these types of components.
tion system.
1.3.1.2 If detection or classification of particles, or both, in
1.1.1 This test method describes a procedure designed to
the size range of laser particle counter (LPC) technology is of
draw statistically significant comparisons of particulate gen-
interest, an LPC can be utilized for testing components. Flow
eration performance of valves tested under aggressive condi-
rates,testtimes,samplingapparatus,anddataanalysisoutlined
tions.
in this test method do not apply for use with an LPC. Because
1.1.2 This test method is not intended as a methodology for
ofthesevariations,datafromCNCsarenotcomparabletodata
monitoring on-going particle performance once a particular
from LPCs.
valve has been tested.
1.3.2 This test method specifies flow and mechanical stress
1.2 Thistestmethodutilizesacondensationnucleuscounter
conditions in excess of those considered typical. These condi-
(CNC) applied to in-line gas valves typically used in semicon-
tions should not exceed those recommended by the manufac-
ductor applications. It applies to automatic and manual valves
turer. Actual performance under normal operating conditions
of various types (such as diaphragms or bellows), 6.3 through
may vary.
1 1
12.7-mm ( ⁄4 through ⁄2-in.) size. For applications of this test
1.3.3 The test method is limited to nitrogen or clean dry air.
method to larger valves, see the table in the appendix.
1 Performance with other gases may vary.
1.2.1 Valves larger than 12.7 mm ( ⁄2 in.) can be tested by
1.3.4 This test method is intended for use by operators who
this methodology. The test stand must be sized accordingly.
1 understand the use of the apparatus at a level equivalent to six
Components larger than 12.7 mm ( ⁄2 in.) should be tested
months of experience.
while maintaining a Reynolds number of 20000 to 21000.
1 1.3.5 The appropriate particle counter manufacturer’s oper-
This is the Reynolds number for 12.7-mm ( ⁄2-in.) components
ating and maintenance manuals should be consulted when
tested at a velocity of 30.5 m/s (100 ft/s).
using this test method.
1.3 Limitations:
1.4 The values stated in SI units are to be regarded as the
1.3.1 This test method is applicable to total particle count
standard. The inch-pound units given in parentheses are for
greater than the minimum detection limit (MDL) of the
information only.
condensation nucleus particle counter and does not consider
1.5 This standard does not purport to address all of the
classifying data into various size ranges.
safety concerns, if any, associated with its use. It is the
1.3.1.1 It is questionable whether significant data can be
responsibility of the user of this standard to establish appro-
generated from nondynamic components (such as fittings and
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific hazard
This test method is under the jurisdiction of ASTM Committee F-1 on
statements are given in Section 6, Hazards.
Electronics and is the direct responsibility of Subcommittee F01.10 on Processing
Environments.
Current edition approved May 15, 1992. Published July 1992.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 1394 – 92 (1999)
2. Referenced Documents velocity is specified to maintain a Reynolds number of 20000
to 21000 (see the table in the appendix).
2.1 ASTM Standards:
3.2 Abbreviations:Abbreviation:
FED-STD-209D Federal Standard Clean Room and Work
3.2.1 LPC—laser particle counter.
Station Requirements, Controlled Environment
3. Terminology
4. Significance and Use
3.1 Definitions of Terms Specific to This Standard:
4.1 The purpose of this test method is to define a procedure
3.1.1 background counts—counts contributed by the test
for testing components intended for installation into a high-
apparatus (including counter electrical noise) with the spool
purity gas distribution system. Application of this test method
piece in place of the test object.
isexpectedtoyieldcomparabledataamongcomponentstested
3.1.2 condensation nucleus counter (CNC)—lightscattering
for the purposes of qualification for this installation.
instrument that detects particles in a gaseous stream by
4.2 Background Testing—Thistestmethodusesbackground
condensing supersaturated vapor upon the particles.
testing to ensure that the system is not contributing particles
3.1.3 control product—sample component that gives con-
abovealow,acceptablelevel.Thisensuresthatcountsseenare
sistent, stabilized counts at or below the expected counts from
from the test device, not from a contaminated system. The
the test components. The product is run periodically in accor-
techniques used to obtain background counts do not produce
dance with the test protocol to ensure that the system is not
conditions identical to the conditions existing when a test
contributing particles significantly different from expected
device is in place. It is recommended that the control products
levels.
be run periodically to see that they give consistent results.
3.1.3.1 Discussion—The control product may have to be
These control products should be the lowest particle release
changed periodically if its performance degrades with testing.
products. They will be additional proof that the system is not
Between tests, the control product must be bagged in accor-
contributing excess particles during the static, dynamic, or
dancewiththeoriginalmanufacturer’spackagingandstoredin
impact portions of the test.
acleanmanner.Thecontrolproductisusedtoallowthesystem
4.3 This test method can be used for testing lengths of
toconsiderthedisruptioncausedbytheactivationofanyvalve
tubing. The flow criteria will be identical to that indicated for
under test, such as significant fluctuations in flow, pressure,
valves.Atubing test would only include the static background,
turbulence, and vibration.
the impact background, and the static and impact portions of
3.1.4 dynamic test—test performed to determine particle
themethod.Adynamicportioncouldbeaddedbyactuatingthe
contribution as a result of valve actuation.
upstream pneumatic valve (PV1), thus creating a flow surge to
3.1.5 impact test—test performed to determine particle
the test length of tubing.
contribution as a result of mechanical shock while the compo-
nent is in the fully open position.
5. Apparatus
3.1.6 sampling time—thetimeincrementoverwhichcounts
5.1 Test Gas—Clean, dry nitrogen or air is to be used
are recorded.
(minimum dryness−40°C (−40°F) dew point at 689 kPa gage
3.1.7 sample flow rate—the volumetric flow rate drawn by
pressure (100 psig) and <10 ppm total hydrocarbons).
thecounterforparticledetection.Thecountermaydrawhigher
5.2 Filters—Electronicsgradefiltersarerequiredtoprovide
flow for other purposes (for example, sheath gas).
88particle-free” test gas. Each filter must be no more than 10%
3.1.8 spool piece—anullcomponentconsistingofastraight
penetrationinaccordancewithmanufacturer’sspecificationsto
piece of electropolished tubing and appropriate fittings used in
0.02 µm particles and have a pressure drop of less than 6.89
place of the test component to establish the baseline.
kPa at 0.00471 m /s at 689 kPa gage pressure (1 psi at 10
3.1.9 standard conditions—101.3 kPa, 20°C (14.73 psia,
standardft /minat100psiginlet).Thefiltermustbecapableof
68°F).
passinglessthan70particles$0.02µm/m (2particles$0.02
3.1.10 static test—a test performed on an as-received com-
µm/ft ) of test gas under test conditions.
ponent in the fully open position. This test establishes particu-
5.3 Pressure Regulator—A high-purity electronics grade
late contribution by the valve to the counting system.
pressure regulator is required to maintain system test pressure.
3.1.11 test duration—total time required to complete the
5.4 Pressure Gage—A high-purity electronics grade pres-
test procedure.
sure transducer or gage is required to monitor system test
3.1.12 test flow rate—volumetric flow at test pressure and
pressure.
temperature.
5.5 Low-Flow Control Device—A high-purity electronics
3.1.13 test pressure—pressure immediately downstream of
grade 0 to 0.00472 m /s flow control device is required for
the test component.
1 3 1
testing 6.3, 9.5, and 12.7-mm ( ⁄4 , ⁄8 and ⁄2-in.) components.
3.1.14 test velocity—the average velocity of the test gas in
5.6 High-Flow Control Device—A high-purity electronics
the outlet tube of the test valve (volumetric flow at ambient
grade0to0.0142m flowcontroldeviceisrequiredfortesting
pressure and temperature divided by the internal cross-
19, 25.1 and 50.8-mm ( ⁄4 , 1 and 2-in.) components.
sectional area of the valve outlet). In this test method, the test
5.7 Tubing—High-purity electronics grade, electropolished
12.7-mm ( ⁄2-in.) 316-L tubing is required. Larger diameter
tubing is required for testing components larger than 12.7 mm
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. ( ⁄2 in.).
F 1394 – 92 (1999)
5.8 Sampler—Thesampleristobeconstructedaccordingto used for particle counting. Test durations in this test method
the drawing (see Fig. 1) and calculations shown in 8. The have been established based on a sampling flow rate of
sampler collects gas from the stream exiting the test device, standard 0.0236 L/s.
where the sample is near-isokinetic in design.
5.9 Upstream Adaptor—The upstream adaptor piece con-
6. Hazards
nects 12.7-mm ( ⁄2-in.) tubing to the test device. For 12.7-mm
6.1 Exhaust from the CNC may contain toxic or flammable
( ⁄2-in.)testdevices,theadaptorisasimpleface-sealconnector.
vapors, or both. Make sure that it is properly vented.
For 6.3-mm ( ⁄4-in.) test devices, the adaptor is a smooth
6.2 This test method is to be conducted at a normal indoor
1 1
transition between 6.3 and 12.7-mm ( ⁄4 and ⁄2-in.) face-seal
temperature of between 18°C (64°F) and 26°C (78°F). Envi-
connections.
ronmentaltemperaturewithinthisrangeisnotexpectedtohave
5.10 Downstream Adaptor—The downstream adaptor piece
any measurable effect on particle detection.
connects 12.7-mm ( ⁄2-in.) tubing of the sampler to the test
6.3 Test apparatus shall be enclosed in a Class 100 environ-
device. For 12.7-mm ( ⁄2-in.) test devices, the adaptor is a
ment (in accordance with FED-STD-209D). If a clean hood is
simple face seal connector. For 6.3-mm ( ⁄4-in.) test devices,
used, locate the hood within a clean environment. Use proce-
the adaptor is a tapered cone between 6.3 and 12.7-mm ( ⁄4 in.
dures necessary to maintain Class 100 when handling test
and ⁄2-in.) face-seal connections.
apparatus and test component.
5.11 Spool Pieces—Spoolpiecesshallbethesamediameter
6.4 Take care to protect the test apparatus from excessive
as the fittings on the test piece and be 15 cm (6 in.) in length.
vibration. For example, vacuum pumps and compressors shall
The spool piece is to be installed in the system in place of the
be isolated from the system.
test device while obtaining background counts for the system.
5.12 Fittings—Use face seal connectors or compression
7. Sampling
fittings depending on test component end connections.
7.1 Theaveragevelocityofgasflowingthroughthesampler
5.13 Gaskets—Use tetrafluoroethylene (TFE) or nylon gas-
shall approximate the average velocity in the tubing in which
kets for attaching the test device and adapter pieces. New
the sampler is inserted. The sample flow rate used to calculate
gaskets should be used for each new connection. The use of
the sampler diameter is the total flow drawn by the counter.A
TFEgasketsisrecommendedinordertominimizetheparticles
−4 3
typical CNC counter draws 0.472 310 standard m /s (0.1
that may be generated by installation of the test piece.
3 −4 3
standard ft /min) of which only 0.236 310 standard m /s is
5.14 Mechanical Shock Device—A weight dropped on the
used for sampling.
test device is used to provide mechanical shock. Drawing and
7.2 Gradual expansion to atmospheric pressure is used for
component specifications are shown in Section 7.
sampling.Avoidcriticalorificeexpansionduetoitscomplexity
5.15 Instrumentation—A CNC capable of detecting par-
and potential maintenance problems.
ticles as small as 0.02 µm with counting efficiency of 50%
−4 3 7.3 Thetipofthesamplingprobeshouldhavea30°taperon
(1) with a sample flow rate of 0.2363 10 m /s, is to be
the outside diameter.
7.4 The pick-off point shall be centered within the flow
stream.
7.5 The pick-off point should be approximately 15 diam-
eters of the primary flow tube upstream or downstream of any
The boldface numbers in parentheses refer to a list of references at the end of
the text.
connection.
7.6 There is enough volume in the exhaust portion of the
sampler to supply the CNC for 1 min. This volume represents
60 times the volume that will be drawn by the CNC while the
valve is closed during the dynamic testing.
7.7 Nominal sample tube diameters have been calculated
and matrixed in the table in the appendix. In most cases, these
approximate the actual diameters needed for isokinetic sam-
pling,sothatstandardtubesizescanbeused.Understaticflow
conditions the sampler size is within 50% of the size required
to achieve isokinetic sampling. For particles of interest < 0.5
µm, Hinds and Fissan (2, 3) indicate that any likely isokinetic
sampling biases are insignificant. During dynamic testing,
isokinetic sampling is compromised regardless of the sample
tube size.
7.7.1 To establish isokinetic sampling condition (refer to
Fig. 2 and (4)):
V 5 V (1)
1 2
1 3 1
Q 5 AV (2)
FIG. 1 Sampling Device for Testing ⁄4 , ⁄8 , and ⁄2 in.
(6.3, 9.5, and 12.7 mm) Valves
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