1、Institute of Environmental Sciences and Technology IEST-STD-CC1246E Contamination Control Division Standard 1246E Product Cleanliness Levels Applications, Requirements, and Determination Arlington Place One 2340 S. Arlington Heights Road, Suite 620 Arlington Heights, IL 60005-4510 Phone: (847) 981-0
2、100 Fax: (847) 981-4130 E-mail: informationiest.org Web: www.iest.org 2 IEST 2013 All rights reserved Institute of Environmental Sciences and Technology IEST-STD-CC1246E This Standard is published by the Institute of Environmental Sciences and Technology to advance the technical and engineering scie
3、nces. Use of this document is entirely voluntary, and determination of its applicability and suitabil-ity for any particular use is solely the responsibility of the user. Use of this Recommended Practice does not imply any warranty or endorsement by IEST. This Standard was prepared by and is under t
4、he jurisdiction of Working Group 901 of the IEST Contamination Con-trol Division. Copyright 2013 by the Institute of Environmental Sciences and Technology First printing, February 2013 ISBN 978-1-937280-08-6 PROPOSAL FOR IMPROVEMENT: The Working Groups of the Institute of Environmental Sciences and
5、Tech-nology are continually working on improvements to their Recommended Practices and Reference Documents. Sug-gestions from users of these documents are welcome. If you have a suggestion regarding this document, please use the online Proposal for Improvement form found on the IEST website at www.i
6、est.org. Institute of Environmental Sciences and Technology Arlington Place One 2340 S. Arlington Heights Road, Suite 620 Arlington Heights, IL 60005-4510 Phone: (847) 981-0100 Fax: (847) 981-4130 E-mail: informationiest.org Web: www.iest.org IEST 2013 All rights reserved Institute of Environmental
7、Sciences and Technology IEST-STD-CC1246E 3 Product Cleanliness Levels Applications, Requirements, and Determination IEST-STD-CC1246E CONTENTS HISTORICAL BACKGROUND .4 SECTION 1 SCOPE AND LIMITATIONS 5 2 REFERENCES AND APPLICABLE DOCUMENTS .5 3 TERMS AND DEFINITIONS 6 4 BACKGROUND AND PURPOSE 7 5 CLE
8、ANLINESS REQUIREMENTS 7 6 MEASUREMENT OF CLEANLINESS . 11 7 STATISTICAL ANALYSIS AND REPORTING OF DATA 12 8 PROTECTION . 14 9 INSPECTION 14 10 BIBLIOGRAPHY . 14 11 ADDITIONAL RESOURCES . 14 FIGURE 1 PARTICLE SIZE DISTRIBUTION ON A LOGLOG2 SCALE 8 2 FORMAT AND EXAMPLE FOR SPECIFYING PRODUCT CLEANLINE
9、SS LEVELS 10 TABLE 1 PARTICULATE CLEANLINESS LEVELS .8 2 NONVOLATILE RESIDUE CLEANLINESS LEVELS .9 3 SAMPLING AND MEASUREMENT TECHNIQUES FOR SURFACES, LIQUIDS, AND GASES 11 4 STUDENTS t FACTOR FOR 95% CONFIDENCE LIMIT . 13 A1 PARTICLE FALLOUT CLEANLINESS LEVELS 15 A2 PARTICLE FALLOUT CLEANLINESS LEV
10、EL PLUS INITIAL PARTICLE CLEANLINESS LEVEL 15 B1 CALCULATING PARTICLE PERCENT AREA COVERAGE . 16 D1 VISIBLY CLEAN CRITERIA . 19 ANNEX A PARTICLE FALLOUT SPECIFICATION 15 B PERCENT AREA COVERAGE OF PARTICLES . 16 C OTHER PARTICLE COUNT SPECIFICATIONS . 18 D VISIBLY CLEAN . 19 4 IEST 2013 All rights r
11、eserved Institute of Environmental Sciences and Technology IEST-STD-CC1246E HISTORICAL BACKGROUND The establishment of contamination control practices became a necessity with the advent of World War II and the ensuing mechanical wartime innovations. Two of the wartime inventions requiring high level
12、s of cleanliness were the Norden bombsight and the first navigational gyroscopes. Particles in the range of 20 to 50 m would cause the bombsight and the gyroscope to malfunction. Further degrees of refinement in equipment created the need for great-er control of product cleanliness and ambient condi
13、tions. In 1956 the US government acquired an inertial guidance system containing two floating gyros. The suspension system was highly dependent on contaminant-free fluid. It was observed that contamination one-half the size of cigarette smoke particles could compromise the system, indi-cating the de
14、gree of cleanliness control necessary in the development of that system. Major improvements in the area of industrial contamination control and air filtration occurred during the late 1950s and early 1960s. The development of improved techniques occurred as a result of manufacturing advances and the
15、 introduction of extremely sophisticated electronic, electromechanical, electro-optical, and hydraulic equipment. These devices required major improvements in cleanliness levels because the presence of microscopic particles could result in the malfunction of a device, an entire system, or even the m
16、ission. With the technological advancements that have followed, requirements for higher degrees of cleanliness have forced contamination control efforts to keep pace through new developments and applications. The greatest impetus for stricter requirements for contamination control has come from the
17、microelectronics industry. The advent of solid-state electronics and integrated circuits made it possible to produce chips containing hundreds of thousands of dis-crete devices, each consisting of multiple component parts with specific functions, totaling perhaps millions of such components per chip
18、. Without the innovations in contamination control, the advances in low-cost computers, com-munications, and a myriad of other uses of microelectronics would not have been possible. The development of cleanliness standards for critical components was the direct result of satisfying the need for comm
19、on terminology and standardization. In 1962 a military standard was created to establish guidelines and re-quirements for the specification of cleanliness levels essential to product reliability and quality. This document, known as MIL-STD-1246, has been updated periodically in order to keep current
20、 with technological advances. Its history is summarized as follows: MIL-STD-1246 (MI) 19 December 1962 MIL-STD-1246A 18 August 1967 MIL-STD-1246B 4 September 1987 MIL-STD-1246C 11 April 1994 IEST-STD-CC1246D January 2002 The 1246C version was prepared for the US Army Missile Command by the Contamina
21、tion Control Division of the Institute of Environmental Sciences and Technology (IEST). In 1997, the U.S. Army commissioned IEST to revise and adapt this military standard as an industry standard. Its usefulness today extends far beyond military applications. This document is the resulting industry
22、standard. IEST 2013 All rights reserved Institute of Environmental Sciences and Technology IEST-STD-CC1246E 5 Institute of Environmental Sciences and Technology Contamination Control Division Standard 1246E Product Cleanliness Levels Applications, Requirements, and Determination IEST-STD-CC1246E 1 S
23、COPE AND LIMITATIONS 1.1 Scope This standard provides methods for specifying and determining product cleanliness levels for contamina-tion-critical products. The emphasis is on contami-nants that can impact product performance. 1.2 Use The requirements set forth in this standard are not required for
24、 all products but are intended for use in procurement and design contracts for those items where contamination control limits for parts, compo-nents, or fluids are necessary to ensure reliability and performance. 1.3 Safety This standard does not purport to address the safety problems that may be as
25、sociated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4 Contamination Control Program This standard no longer provides information con-cerning the cre
26、ation of a contamination control pro-gram. Refer to ASTM E1548, Standard Practice for Preparation of Aerospace Contamination Control Plans, for this information. 2 REFERENCES AND APPLICABLE DOCUMENTS The following documents are incorporated into this Standard to the extent specified herein. Unless o
27、ther-wise specified, the latest revision shall apply. In the event of a conflict between the text of this document and the references cited herein, the text of this docu-ment takes precedence. No content in this document, however, supersedes applicable laws and regulations unless specific exemption
28、has been obtained. 2.1 American Society for Testing and Materials (ASTM) E1216: Standard Practice for Sampling for Particu-late Contamination by Tape Lift E1234: Standard Practice for Handling, Transport-ing, and Installing Nonvolatile Residue (NVR) Sam-ple Plates Used in Environmentally Controlled
29、Areas for Spacecraft E1235: Standard Test Method for Gravimetric De-termination of Nonvolatile Residue (NVR) in Envi-ronmentally Controlled Areas for Spacecraft E1548: Standard Practice for Preparation of Aero-space Contamination Control Plans F25: Standard Test Method for Sizing and Counting Airbor
30、ne Particulate Contamination in Cleanrooms and Other Dust-Controlled Areas 6 IEST 2013 All rights reserved Institute of Environmental Sciences and Technology IEST-STD-CC1246E F50: Standard Practice for Continuous Sizing and Counting of Airborne Particles in Dust-Controlled Areas and Clean Rooms Usin
31、g Instruments Capable of Detecting Single Sub-Micrometre and Larger Particles F51: Standard Test Method for Sizing and Counting Particulate Contaminants in and on Clean Room Garments F302: Standard Practice for Field Sampling of Aero-space Fluids in Containers F303: Standard Practices for Sampling f
32、or Particles in Aerospace Fluids and Components F307: Standard Practice for Sampling Pressurized Gas for Gas Analysis F310: Standard Practice for Sampling Cryogenic Aerospace Fluids F311: Standard Practice for Processing Aerospace Liquid Samples for Particulate Contamination Analy-sis Using Membrane
33、 Filters F312: Standard Test Methods for Microscopical Siz-ing and Counting Particles from Aerospace Fluids on Membrane Filters F327: Standard Practice for Sampling Gas Blow Down Systems and Components for Particulate Con-tamination by Automatic Particle Monitor Method F331: Standard Test Method for
34、 Nonvolatile Residue of Solvent Extract from Aerospace Components (Us-ing Flash Evaporator) F1094: Standard Test Methods for Microbiological Monitoring of Water Used for Processing Electron and Microelectronic Devices by Direct Pressure Tap Sampling Valve and by the Presterilized Plastic Bag Method
35、2.2 Society of Automotive Engineers International (SAE) AS 598: Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems ARP 743: Procedure for the Determination of Par-ticulate Contamination of Air in Dust Controlled Spaces by the Particle Count Method 2.3 Sour
36、ces and addresses ASTM American Society for Testing and Materials 100 Barr Harbor Drive West Conshohocken, PA 19428-2959 USA Phone: 610-832-9500 www.astm.org SAE SAE International 400 Commonwealth Drive Warrendale, PA 15096-0001 USA Phone: 724-776-4841 Fax: 724-776-0790 www.sae.org 3 TERMS AND DEFIN
37、ITIONS cleanliness level a) A designation indicating the maximum amount of contamination allowed per unit of area or volume, or on the defined surface of a component. b) The measured extent of contamination. contaminant A specific type of contamination. contamination Unwanted material. contamination
38、 control Any organized action taken to maintain the level of contamination at or below a specified acceptable level. demonstrated equivalence The condition in which a method of measurement has passed a series of tests to show that the method produces results equivalent to those of a standard measure
39、ment. micrometer (m) A unit of measurement equal to one-millionth (10-6) of a meter, or approximately thirty-nine millionths (0.000039) of an inch (or, 25 micrometers is approx-imately 0.001 inch). nonvolatile residue (NVR) Material remaining after evaporation of a liquid. Units are determined by th
40、e test method used. particle fallout level The particle size distribution on a surface attributable to fallout from the ambient environment. particle percent area coverage (PAC) The fraction of a surface that is covered by particles, reported as total particle projected area divided by total surface
41、 area. particle size The apparent maximum linear dimension of a particle in the plane of observation, as observed with an opti-cal microscope, or the equivalent diameter of a parti-cle detected by automatic instrumentation. The equivalent diameter is the diameter of a reference sphere having known p
42、roperties and producing the same response in the sensing instrument as the parti-cle being measured. IEST 2013 All rights reserved Institute of Environmental Sciences and Technology IEST-STD-CC1246E 7 particle sizing bins A bin for recording particles counts within a speci-fied size range. point of
43、contact A designated individual in an organization who has the responsibility for assuring that contractual con-tamination control requirements are met. This posi-tion serves as a focal point for all activities concern-ing contamination control. significant surface Any surface of an item or product
44、that is required to meet established cleanliness level requirements. visibly clean Examination of a surface for the absence of contami-nation (particles or molecular films) using specified lighting (illuminance and angle), viewing distance, and normal or corrected vision. 4 BACKGROUND AND PURPOSE Th
45、is standard provides mutually agreed-upon limits for defining significant surface cleanliness and liquid cleanliness with respect to particles and molecular residue. The standard has been modified to include alternative cleanliness level designations that are better suited to accommodate user-specif
46、ic applications. These modifications are included in informative annexes at the end of the document. 5 CLEANLINESS REQUIREMENTS 5.1 Contamination control responsibility The responsibility for selecting or determining spe-cific product cleanliness levels rests with the engi-neering organization initi
47、ally responsible for the product that is to be produced or processed. The re-sponsibility for achieving and maintaining product cleanliness rests with the organization responsible for processing or producing the product from the design and related specification requirements. The responsi-bility for
48、a continuing contamination control effort rests with a designated point of contact, as defined herein, who has the authority to verify that the prod-uct meets design and specification requirements. The engineering organization should also determine the appropriate environment to perform the cleaning
49、. 5.2 Cleanliness levels Use of cleanliness levels provides a basis for specify-ing and determining conformance to cleanliness re-quirements. Unless otherwise specified, cleanliness levels shall be expressed in terms of maximum amounts per unit measure (area, volume, mass), such as particles per 0.1 m2. Use of a particular unit of measure does not imply that the measurements are to be taken over this extent, but rather that the quanti-fied amount is to be normalized and expressed in the units sh
