1、Designation: G 93 03e1Standard Practice forCleaning Methods and Cleanliness Levels for Material andEquipment Used in Oxygen-Enriched Environments1This standard is issued under the fixed designation G 93; the number immediately following the designation indicates the year of originaladoption or, in t
2、he case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTESection 8.3.7 was corrected editorially in July 2004.1. Scope1.1 This practice covers the
3、selection of methods andapparatus for cleaning materials and equipment intended forservice in oxygen-enriched environments. Contaminationproblems encountered in the use of enriched air, mixtures ofoxygen with other gases, or any other oxidizing gas may besolved by the same cleaning procedures applic
4、able to mostmetallic and nonmetallic materials and equipment. Cleaningexamples for some specific materials, components, and equip-ment, and the cleaning methods for particular applications, aregiven in the appendices.1.2 This practice includes levels of cleanliness used forvarious applications and t
5、he methods used to obtain and verifythese levels.1.3 This practice applies to chemical-, solvent-, andaqueous-based processes.1.4 This practice describes nonmandatory material forchoosing the required levels of cleanliness for systems exposedto oxygen or oxygen-enriched atmospheres.1.5 This practice
6、 proposes a practical range of cleanlinesslevels that will satisfy most system needs, but it does not dealin quantitative detail with the many conditions that mightdemand greater cleanliness or that might allow greater con-tamination levels to exist. Furthermore, it does not proposespecific ways to
7、measure or monitor these levels from amongthe available methods.1.6 The values stated in both inch-pound and SI units are tobe regarded separately as the standard unit. The values given inparentheses are for information only.1.7 This standard does not purport to address all of thesafety concerns, if
8、 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. Federal, state andlocal safety and disposal regulations concerning the particularhazardou
9、s materials, reagents, operations, and equipment beingused should be reviewed by the user. The user is encouraged toobtain the Material Safety Data Sheet (MSDS) from themanufacturer for any material incorporated into a cleaningprocess. Specific cautions are given in Section 8.2. Referenced Documents
10、2.1 ASTM Standards:2A 380 Practice for Cleaning, Descaling, and Passivation ofStainless Steel Parts, Equipment, and SystemsD 1193 Specification for Reagent WaterE 312 Practice for Description and Selection of Conditionsfor Photographing SpecimensE 1235 Test Method for Gravimetric Determination of No
11、n-volatile Residue (NVR) in Environmentally ControlledAreas for SpacecraftE 2042 Practice for Cleaning and Maintaining ControlledAreas and Clean RoomsF 312 Test Methods for Microscopical Sizing and CountingParticles from Aerospace Fluids on Membrane FiltersF 331 Test Method for Nonvolatile Residue o
12、f SolventExtract from Aerospace Components (Using Flash Evapo-rator)G63 Guide for Evaluating Nonmetallic Materials for Oxy-gen ServiceG88 Guide for Designing Systems for Oxygen ServiceG 121 Practice for Preparation of Contaminated Test Cou-pons for the Evaluation of Cleaning AgentsG 122 Test Method
13、for Evaluating the Effectiveness ofCleaning AgentsG 125 Test Method for Measuring Liquid and Solid Mate-rial Fire Limits in Gaseous OxidantsG 127 Guide for the Selection of Cleaning Agents forOxygen SystemsG 128 Guide for Control of Hazards and Risks in OxygenEnriched Systems1This practice is under
14、the jurisdiction of ASTM Committee G04 on Compat-ibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is thedirect responsibility of Subcommittee G04.02 on Recommended Practices.Current edition approved Nov. 1, 2003. Published December 2003. Originallyapproved in 1987. Last previo
15、us edition approved in 1996 as G 93 96.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM Intern
16、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.G 131 Practice for Cleaning of Materials and ComponentsBy Ultrasonic TechniquesG 136 Practice for Determination of Soluble Residual Con-taminants in Materials by Ultrasonic ExtractionG 144 Test Method for De
17、termination of Residual Contami-nation of Materials and Components by Total CarbonAnalysis Using a High-Temperature Combustion Analyzer2.2 CGA Documents:CGA Pamphlet G-4.1 Cleaning Equipment for OxygenService3CGA Pamphlet G-4.4 Industrial Practices for Gaseous Oxy-gen Transmission and Distribution P
18、iping Systems32.3 SAE Document:ARP 598 The Determination of Particulate Contaminationin Liquids by the Particle Count Method42.4 ISO Document:ISO 14644-1 Cleanrooms and Associated ControlledEnvironmentsPart 1: Classification of Air Cleanliness53. Terminology3.1 Definitions:3.1.1 contaminant, nunwant
19、ed molecular or particulatematter that could adversely affect or degrade the operation, life,or reliability of the systems or components upon which itresides.3.1.2 contamination, n(1) the amount of unwanted mo-lecular or particulate matter in a system; (2) the process orcondition of being contaminat
20、ed.3.1.2.1 DiscussionContamination and cleanliness are op-posing properties; increasing cleanliness implies decreasingcontamination.3.1.3 direct oxygen service, nservice in contact withoxygen-enriched atmosphere during normal operation.3.1.3.1 DiscussionExamples are oxygen compressor pis-ton rings o
21、r control valve seats.3.1.4 nonmetal, nany material other than a metal, non-polymeric alloy, or any composite in which the metalliccomponent is not the most easily ignited component and forwhich the individual constituents cannot be evaluated indepen-dently, including ceramics (such as glass), synth
22、etic polymers(such as most rubbers, thermoplastics, and thermosets), andnatural polymers (such as naturally occurring rubber, wood,and cloth). Nonmetallic is the adjective use of this term.3.1.5 oxygen compatibility (also oxidant compatibility),nthe ability of a substance to coexist with both oxygen
23、 anda potential source(s) of ignition at an expected pressure andtemperature with a magnitude of risk acceptable to the user.3.1.6 qualified technical personnel, npersons such asengineers and chemists who, by virtue of education, training,or experience, know how to apply physical and chemicalprincip
24、les involved in the reactions between oxidants and othermetals.3.2 Definitions of Terms Specific to This Standard:3.2.1 cleanliness, nthe degree to which an oxygen systemis free of contaminant.3.2.2 fibers, nparticulate matter with a length of 100 mor greater, and a length-to-width ratio of 10 to 1
25、or greater.3.2.3 particulate, na general term used to describe afinely divided solid of organic or inorganic matter.3.2.3.1 DiscussionThese solids are usually reported as theamount of contaminant by the population of a specific mi-crometer size. See methods described in Methods F 312 orARP 598 for p
26、article size and population determination.4. Summary of Practice4.1 General methods, apparatus, and reagents for cleaningmaterials and equipment used in oxygen-enriched environ-ments are described in this practice. Exact procedures are notgiven because they depend on the contaminant type andmaterial
27、 to be cleaned, cleaning agent used, and degree ofcleanliness required. Methods may be used individually, ormay be combined or repeated to achieve the desired results.Examples of cleaning procedures that have been successfullyused for specific materials, components, and equipment inselected applicat
28、ions are described in the appendices. An indexof the specific materials, components, equipment, and applica-tions covered in these examples is given in Table X1.1.4.2 For the purpose of this practice, both solid and fluidcontaminants have been subclassed into three categories:organics, inorganics, a
29、nd particulates. A list of common con-tamination levels is given in Table 1.4.3 Cleanliness specifications that have been used in thepast are identified, levels of cleanliness that can be achievedare listed along with factors that suggest potential upper limitsfor allowable system contamination, and
30、 the practical difficul-ties in adopting and achieving adequately clean systems arereviewed. Cleanliness specifications used by suppliers andmanufacturers often differ; it is therefore important to commu-nicate and agree upon which specification is to be used for agiven system and to adhere to the m
31、ost conservative measures.5. Significance and Use5.1 The purpose of this practice is to furnish qualifiedtechnical personnel with pertinent information for the selectionof cleaning methods for cleaning materials and equipment to beused in oxygen-enriched environments. This practice furnishesqualifie
32、d technical personnel with guidance in the specificationof oxygen system cleanliness needs. It does not actuallyspecify cleanliness levels.3Available from Compressed Gas Association (CGA), 1725 Jefferson DavisHwy., Suite 1004, Arlington, VA 22202-4102.4Available from Society of Automotive Engineers
33、(SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001.5Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland.TABLE 1 Oil Film Contamination Level SpecificationsConcentration,mg/m2(mg/ft2)Source0.14 (0.013) 1967 Navy Stan
34、dard per Presti and DeSimone (6)10.8 (1) NASA KSC 123 per Report MTB 306-71 (7)16.1 (1.5) Recommended by Presti and DeSimone (6)43.1 (4) Air Force 1950s value per LeSuer (8)75.3 (7) Recommended by Walde (9)108 (10 mg/ft2or per item) Union Carbide Guideline (10,4)50-100 (4.6 to 9.3) Compressed Gas As
35、sociation Pamphlet G-4.8 (3)500 (47.5) Compressed Gas Association Pamphlet G-4.1 (5)G9303e125.2 Insufficient cleanliness of components used in oxygensystems can result in the ignition of contaminants or compo-nents by a variety of mechanisms such as particle, mechanical,or pneumatic impact. These me
36、chanisms are explained in detailin Guide G88.5.3 Adequate contamination control in oxygen systems isimperative to minimize hazards and component failures thatcan result from contamination. Contamination must also beminimized to ensure an acceptable product purity.5.4 Removal of contaminants from mat
37、erials and compo-nents depends on system configuration, materials of construc-tion, and type and quantity of contaminant.5.5 Examples of cleaning procedures contained herein maybe followed or specified for those materials, components, andequipment indicated. The general cleaning text can be used toe
38、stablish cleaning procedures for materials, components,equipment, and applications not addressed in detail. See GuideG 127 for discussion of cleaning agent and procedure selection.6. Interferences6.1 Disassembly:6.1.1 It is imperative that oxygen systems be cleaned asindividual components or piece p
39、arts, preferably before assem-bly. Assembled systems must be disassembled for cleaning ifconstruction permits. Flushing an assembled system can de-posit and concentrate contaminants in stagnant areas. Nonvola-tile cleaning agents may remain in trapped spaces and laterreact with oxygen. Cleaning solu
40、tions may degrade nonmetalsin an assembly. Caustic and acid cleaning solutions may causecrevice corrosion in assemblies.6.1.2 Manufactured products (that is, valves, regulators, andpumps) should be cleaned preferably by the manufacturerbefore final assembly and test. All tests should be structured t
41、oprevent recontamination. The part must then be packaged inoxygen-compatible materials (see 12.1) and identified to pro-tect it from contamination in transit and storage. The purchasershould approve the cleaning procedure and packaging to assurethat they satisfy system requirements. Some purchasers
42、mayrequire the product manufacturer to certify cleanliness leveland oxygen compatibility of all component materials.6.1.3 Manufactured products cleaned by the purchaser mustbe disassembled for cleaning if construction permits. Thepurchaser should follow the manufacturers instructions fordisassembly,
43、 inspection for damage, reassembly, and testing.6.2 Cleaners:6.2.1 Mechanical cleaning methods such as abrasive blast-ing, tumbling, grinding, and wire brushing are very aggressiveand should be avoided on finished machined articles. Suchmethods can damage sealing surfaces, remove protectivecoatings,
44、 and work-harden metals. Sensitive surfaces must beprotected before mechanical cleaning methods are applied.6.2.2 Chemical cleaners, both acid and caustic, can damagemetal parts if not neutralized upon completion of cleaning.Corrosion, embrittlement, or other surface modifications arepotentially har
45、mful side effects of chemical cleaning agents.Crevice corrosion can occur and sealing surfaces can be etchedenough to destroy the finish necessary to seal the part. See TestMethod G 122 and Guide G 127 for methods used to evaluatecleaners for use on various materials used in oxygen service.6.2.3 Sol
46、vent cleaning solutions often damage plastics andelastomers. The manufacturer should be consulted or sampleparts should be tested to ensure that the solvent is not harmfulto the item being cleaned.6.3 Lubricants:6.3.1 Mechanical components are normally assembled withlubricants on seals, threads, and
47、 moving surfaces. The manu-facturer should be consulted to determine the kind of lubricantoriginally used on the article to ensure that the cleaningsolutions and methods selected are effective in removing thelubricant and will not damage the component.6.3.2 Oxygen-compatible lubricants should be sel
48、ected inaccordance with Guide G63. The component manufacturershould also be consulted to ensure that the selected lubricantprovides adequate lubrication for component performance.Oxygen-compatible lubricants often have markedly differentlubricating properties from conventional lubricants.6.4 Environ
49、ment and Assembly Requirements:6.4.1 Equipment intended for oxygen service must behandled carefully during all phases of a cleaning procedure.The environment should be clean and dust-free. Nearby grind-ing, welding, and sanding should be prohibited. Parts shouldnot be allowed to stand in the open unprotected after they havebeen cleaned. Care should be taken to avoid contamination byoil deposits from rotating machinery or oil aerosols in the air.Do not touch part surfaces that will be in direct oxygen serviceexcept with clean gloves or handling devices.6.4.2 In some ca
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