1、Designation: F 327 78 (Reapproved 2000)Standard Practice forSampling Gas Blow Down Systems and Components forParticulate Contamination by Automatic Particle MonitorMethod1This standard is issued under the fixed designation F 327; the number immediately following the designation indicates the year of
2、original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes how to connect, prepare, andsample
3、 pressurized gas systems (having up to 0.75-in. (19.1-mm) diameter lines) for particulate contamination by using anautomatic monitor.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport
4、 to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For hazard state-ments, see Section 5.2. Termino
5、logy2.1 Definitions:2.1.1 downstream terminal pointthe point in a gas systemfrom which gas is fed into a further system or component,usually the designated “sample port.”2.1.2 filtered gas systema gas system that is equippedwith required filtration devices to furnish gas that is suitablyclean for th
6、e intended application.2.1.3 purgeto flush a gas supply system or componentwith a regulated flow of gas.2.1.4 sample portthe designated point in a gas system orcomponent from which a representative gas sample may betaken.3. Summary of Practice3.1 The pressurized gas system or component and theappara
7、tus are prepared in accordance with the requirements ofthe users sample analysis procedure. The sensing unit of theautomatic particle monitor is connected to the designatedsample port which is under purge condition. The systemflow-rate is adjusted to the sample flow rate requirement. Allthe gas pass
8、ing through the sensing unit is monitored forparticulate contamination until the required sample volume hasbeen analyzed.4. Apparatus4.1 Automatic Monitor, with sensor that sizes and counts allentering fluid in accordance with the users requirements forpressure, flow, temperature, and accuracy.4.2 F
9、iltered Gas SystemSee Fig. 1.4.3 Stop Watch or Timer, with a + 1, 0-s resolution.4.4 Miscellaneous Fittings, as needed for sampling pointadaption, cleaned and packaged within system contaminationrequirements.4.5 Connecting Lines, cleaned and packaged within systemcontamination requirements.4.6 Flowm
10、eter, calibrated for the sample port fluid, flow,and temperature requirements.5. Hazards5.1 Personnel must stand clear of exiting gas.5.2 Ear protection must be used when gas flow approachessonic velocity.5.3 All lines and associated system components must beconnected and operated within the require
11、ments of recognizedsafety codes.6. Procedure6.1 Establish a minimum continuous purge pressure of 1psig (6.89 kPa) gage or 0.1 ft3/min (2.83 dm3/min), flow fromthe filtered gas pressure supply.6.2 Connect one end of a suitable connecting line to thepurge outlet of 6.1, and then connect the other end
12、to the inletof the component or system to be sampled.NOTE 1If the system to be sampled is already connected to the filteredgas pressure supply, then establish the purge as noted in 6.1.6.3 Connect a suitable connecting line from the sample portto the inlet of the automatic monitor sensing device. (W
13、hen nosample port is designated, use the down-stream terminal pointfrom which purge gas is flowing.)6.4 Increase the purge to one of the following:6.4.1 0.3-ft3/min (8.49-dm3/min) flow,6.4.2 5-psig (34.5-kPa) gage pressure, or6.4.3 5 % of system operating pressure when this pressure is1This practice
14、 is under the jurisdiction of ASTM Committee E21 on SpaceSimulation and Applications of Space Technology and is the direct responsibility ofSubcommittee E21.05 on Contamination.Current edition approved Aug. 25, 1978. Published October 1978. Originallypublished as F 327 72. Last previous edition F 32
15、7 72.1Copyright ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.less than 5-psig (34.5-kPa) gage.6.5 Surge Pressure Cleaning:6.5.1 Quickly increase the continuous purge pressure for a5-s duration, three times at 1-min intervals in accordance withone of the following:6.5.
16、1.1 To 100-psig (689.5-kPa) gage pressure,6.5.1.2 To 4.0-ft3/min (113.2-dm3/min) flow,6.5.1.3 70 % of system operating pressure when this oper-ating pressure is below 100 psig (689.5 kPa) gage.6.5.1.4 In accord with a given system operation require-ment, but not to exceed the rated pressure of the s
17、ensing unit.6.5.2 Reduce the purge pressure to the level in 6.4 after eachsurge pressure application of 6.5.1 (that is during 1-mininterval).6.6 Connect a flowmeter to the outlet of the automaticmonitor sensor and adjust the flow versus time to achieve arequired sample volume within the capability o
18、f the sensor.Remove the flowmeter after adjusting the flow.6.7 Set automatic monitor display to zero.6.8 Simultaneously begin automatic particulate counting,sizing and timing of volumetric flow.6.9 Record particulate contamination counts on the monitordisplay for the required sample volume.6.10 Adju
19、st the continuous purge to the level in 6.4.6.11 Evaluate results and if requirements of contaminationlevels are acceptable, disconnect the monitor and secure thesystem in accordance with the users requirements.6.12 If results are rejected, repeat 6.5-6.12.7. Precision7.1 Each testing agency has the
20、 responsibility of judging theacceptability of its own results. The precision of the results isa function of the procedures (Note 2), facilities utilized, as wellas compliance to the recommended industry state-of-the-artpractices in cleanliness. Reproducible analysis determinationsby different users
21、 can be achieved only with identical facilitiesand trained conscientious personnel.NOTE 2Every effort should be made to eliminate outside contamina-tion during operations.The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connect
22、ionwith any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any suchpatent rights, and the risk of infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsibl
23、e technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a
24、 meeting of the responsibletechnical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make yourviews known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM, 100 Barr Harbor Drive, PO Box C70
25、0, West Conshohocken, PA 19428-2959, United States.Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website (www.astm.org).FIG. 1 Filtered Gas SystemF 3272
