1、Designation: G127 15Standard Guide for theSelection of Cleaning Agents for Oxygen-Enriched Systems1This standard is issued under the fixed designation G127; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The purpose of this guide is to establish a procedure toselect cleaning agents, both solvents and water-baseddetergents, for oxygen-
3、enriched systems. This includeslaboratory-scale tests for cleaning effectiveness, materialscompatibility, and oxygen compatibility.1.2 The effectiveness of a particular cleaning agent dependsupon the method by which it is used, the nature and type of thecontaminants, and the characteristics of the a
4、rticle beingcleaned, such as size, shape, and material. Final evaluation ofthe cleaning agent should include testing of actual products andproduction processes.1.3 Different cleaning agents may be required for differentcleaning activities, such as aqueous ultrasonic cleaning, spraycleaning, hand wip
5、ing, and flushing of oxygen lines in fieldapplications.1.4 This standard does not purport 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
6、 of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D471 Test Method for Rubber PropertyEffect of LiquidsD543 Practices for Evaluating the Resistance of Plastics toChemical ReagentsD1193 Specification for Reagent WaterD1460 Test Method for Rubber PropertyChange inLengt
7、h During Liquid ImmersionD2512 Test Method for Compatibility of Materials withLiquid Oxygen (Impact Sensitivity Threshold and Pass-Fail Techniques)D2863 Test Method for Measuring the Minimum OxygenConcentration to Support Candle-Like Combustion ofPlastics (Oxygen Index)D4809 Test Method for Heat of
8、Combustion of LiquidHydrocarbon Fuels by Bomb Calorimeter (PrecisionMethod)F483 Practice for Total Immersion Corrosion Test for Air-craft Maintenance ChemicalsG5 Reference Test Method for Making PotentiodynamicAnodic Polarization MeasurementsG31 Guide for Laboratory Immersion Corrosion Testing ofMet
9、alsG59 Test Method for Conducting Potentiodynamic Polariza-tion Resistance MeasurementsG63 Guide for Evaluating Nonmetallic Materials for Oxy-gen ServiceG72 Test Method for Autogenous Ignition Temperature ofLiquids and Solids in a High-Pressure Oxygen-EnrichedEnvironmentG74 Test Method for Ignition
10、Sensitivity of NonmetallicMaterials and Components by Gaseous Fluid ImpactG86 Test Method for Determining Ignition Sensitivity ofMaterials to Mechanical Impact in Ambient Liquid Oxy-gen and Pressurized Liquid and Gaseous Oxygen Envi-ronmentsG93 Practice for Cleaning Methods and Cleanliness Levelsfor
11、 Material and Equipment Used in Oxygen-EnrichedEnvironmentsG94 Guide for Evaluating Metals for Oxygen ServiceG121 Practice for Preparation of Contaminated Test Cou-pons for the Evaluation of Cleaning AgentsG122 Test Method for Evaluating the Effectiveness ofCleaning Agents2.2 CGA Document:CGA Pamphl
12、et G-4.1 Cleaning Equipment for Oxygen Ser-vice2.3 Other ASTM Documents:MNL36 Safe Use of Oxygen and Oxygen Systems: Hand-book for Design, Operation, and Maintenance23. Significance and Use3.1 The purpose of this guide is to provide information thatmay be considered when selecting and qualifying a c
13、leaningagent for oxygen-enriched systems.1This guide is under the jurisdiction of ASTM Committee G04 on Compatibilityand Sensitivity of Materials in Oxygen Enriched Atmospheres and is the directresponsibility of Subcommittee G04.02 on Recommended Practices.Current edition approved Oct. 1, 2015. Publ
14、ished October 2015. Originallyapproved in 1995. Last previous edition approved in 2008 as G127 95 (2008).DOI: 10.1520/G0127-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
15、, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Insufficient cleanliness can result in the ignition ofcontaminants or components by a variety of mechanisms.Therefor
16、e, an acceptable level of contamination for eachcondition of use in oxygen-enriched service should be defined.The acceptable level of contamination may depend on variousfactors, such as:3.2.1 The nature and type of the contaminants,3.2.2 The location and degree of contamination,3.2.3 The type of sub
17、strate material,3.2.4 The configuration and end use of the equipment or partto be cleaned, and3.2.5 The operating parameters of the oxygen-enrichedsystem (pressure, temperature, phase, concentration, fluidvelocity, etc.).4. Selection of Cleaning Agent4.1 Before a specific cleaning agent is selected
18、for testing,the following attributes should be considered.4.1.1 Toxicity,4.1.2 Carcinogenicity,4.1.3 Stability and recyclability,4.1.4 Waste disposal,4.1.5 Environmental impacts and associated regulatory re-strictions (ozone depletion potential, global warming potential,volatile organic compound con
19、tribution to ground level ozone,etc.),4.1.6 Inertness (flammability and combustibility),4.1.7 Corrosivity and compatibility with metallic and non-metallic engineering materials,4.1.8 Availability and technical support from supplier,4.1.9 Cost effectiveness, and4.1.10 Compliance with local, state and
20、 federal regulations.4.2 It is desirable that the cleaning agent could be applied bya variety of methods, such as wiping, immersion, spraying, etc.Consequently, the cleaning agent manufacturers instructionsfor applying the cleaner should be considered.5. Selection of Substrate Materials5.1 Substrate
21、 materials used for cleaning effectiveness andcompatibility tests should be representative of those used in theend application, including both the parts to be cleaned and thecleaning system itself.5.2 Metallic Materials:5.2.1 Metallic materials commonly used in oxygen-enrichedsystems are listed in G
22、uide G94 and Handbook MNL36.5.2.2 Materials compatability tests should include thosemetals used in the oxygen-enriched system that are expected tocome in contact with the candidate cleaning agent. As aminimum, alloys representative of each family of metals usedin the system should be tested. The all
23、oy and finish expected tobe used in the oxygen-enriched system that is most susceptibleto corrosion within the metal family should be tested.5.3 Nonmetallic Materials:5.3.1 Nonmetallic materials commonly used in oxygen-enriched systems are discussed in Guide G63 and HandbookMNL36.5.3.2 Materials com
24、patibility tests should include thosenonmetallic materials used in the oxygen-enriched system thatare expected to come in contact with the candidate cleaningagent. As a minimum, materials representative of each familyof these nonmetals should be tested.6. Cleaning Effectiveness Tests6.1 Selection of
25、 Test Contaminants:6.1.1 Numerous contaminants encountered in oxygen-enriched systems that could result from manufacturing,assembly, fabrication, and construction processes are listed inPractice G93. Typical contaminant types include:6.1.1.1 Hydrocarbon oils and greases (mineral oil, hydraulicfluids
26、, lubricants, water-displacing compounds),6.1.1.2 Fluorinated fluids and greases,6.1.1.3 Inks,6.1.1.4 Machine cutting oils (hydrocarbon- or water-based),6.1.1.5 Carbon deposits,6.1.1.6 Silicone oils and greases,6.1.1.7 Phosphate esters (fire-resistant hydraulic fluids),6.1.1.8 Waxes,6.1.1.9 Dye pene
27、trants,6.1.1.10 Chlorotrifluoroethylene based oils and greases,6.1.1.11 Pariculate (sand, metal shavings, fibers, etc.), and6.1.1.12 Tape residue.NOTE 1Some contaminants are more difficult to remove after aging orexposure to heat. Selection of a cleaning agent should consider removalefficiency for b
28、oth the type and condition of contaminants typicallyencountered at the facility.6.1.2 Among typical contaminants, hydrocarbons are theprime candidates for the test protocol. When dealing with othercontaminants, the user should attempt to classify the type ofcontamination expected on the equipment to
29、 be cleaned.6.1.3 As a preliminary test, mineral oil or a mixture ofcommon cutting oils may be used as a contaminant. It may becarried in a suitable volatile solvent as a means to introduce itinto a system. In addition, vacuum pump oil, or a compressoroil are suggested as contaminants for the evalua
30、tion program.In a more refined test at later stages, fluorinated oils/greases,dye penetrants, or a mixture of as many contaminants asnecessary may be prepared in a suitable solvent. Eventually,actual contaminants encountered on an engineering componentor system for oxygen-enriched service should be
31、evaluated forremoval efficiency.6.2 Test Methods:6.2.1 A suggested starting level of contamination is 1000mg/m2. This is a hydrocarbon level that is consistent withcontamination levels associated with final cleaning and it istwice the acceptable level specified for oxygen service in CGApamphlet G-4.
32、1. Heavily contaminated surfaces with levels inexcess of 1000 mg/m2must be precleaned using more aggres-sive cleaning agents with mechanical scrubbing (PracticeG93). Precleaning is not a cleaning step with which this guideis concerned.6.2.2 Contaminants may be applied to the specimens by anyof the m
33、eans specified in Practice G121.6.2.3 The cleaning effectiveness of a cleaning agent may beevaluated using the test method outlined in Test Method G122.G127 1526.2.4 A test basis should be established for each contami-nated sample by using an acceptable solvent as a controlcleaning agent.7. Material
34、 Compatibility Tests7.1 If a cleaning agents ability to remove the selectedcontamination is deemed promising, additional testing (seeSections 8.2.2 and 8.3) should be performed to evaluate itscompatibility with the oxygen-enriched systems.7.2 Metallic Materials:7.2.1 Significant corrosion damage may
35、 occur during clean-ing operations. Corrosion rates may be affected by temperature,contaminants, degree of aeration, concentration and presenceof residual stress (see Note 2). To avoid this, assessmentsshould be made of the corrosion severity of cleaning environ-ments for the engineering materials o
36、f interest. Weight gain-loss measurements can be performed as per Practice F483 orG31. Where applicable, Test Method G5 can be applied (seeNote 3).7.2.2 The electrochemical technique of potentiodynamicpolarization resistance (Practice G59) can be used to determinethe corrosion rate of conductive cle
37、aning agents on metalsubstrates. The corrosion rate (in mils per year, mpy) should bedetermined using the solution parameters which would be usedin actual cleaning practices. The cleaning solution may betested: (1) as is; (2) aerated; or (3) de-aerated. It isrecommended, however, that the corrosion
38、test be performedunder as-is conditions in order to simulate the actual cleaningprocess. The pH and conductivity of the cleaning agent shouldbe measured both before and after the corrosion test. If thesevalues change, the test is considered invalid. A separateexperiment should be performed.7.2.3 Cor
39、rosion rates of less than 32.5 micrometre per year(0.0025 in. per year) are usually desirable. However, to avoidsetting up unduly conservative criteria that may eliminatepotential cleaning agents, estimation of corrosion rate can bemade based upon realistic, total accumulated contact time ofthe clea
40、ner with a component or system throughout its servicelife. The rate of corrosion should be determined based upon themaximum allowable dimensional variations of the componentor system.NOTE 2The presence of residual stresses may promote stress corro-sion cracking in susceptible materials. Information
41、in the technicalliterature on corrosion rates and stress corrosion cracking may be used inevaluating corrosion susceptibility. Further testing, as outlined later in thisguide, may be necessary.NOTE 3In order to reflect the actual material property, samples forcorrosion tests should not be wet ground
42、 with 600-grit SiC papers toexpose fresh surface. The surface roughness of test samples should beeither in compliance with that recommended in Practice G121,or,ifpossible, commensurate with that of the actual engineering components.7.3 Nonmetallic Materials:7.3.1 When exposed to the cleaning agent u
43、nder actual useconditions of temperature, time, concentration etc., somenonmetallics are susceptible to degradation and may experi-ence physical, mechanical, and chemical changes. Physical andmechanical changes can be reversible or irreversible, whilechemical changes are generally irreversible. Depe
44、nding on thematerial-solvent pair, these changes can be characterized byswelling, distortion, weight gain or loss, cracking, crazing,blistering, embrittlement, decomposition temperature shift, orleaching of additives and low-molecular-weight species (e.g.unreacted monomer, catalyst residues). To eva
45、luate the com-patibility of cleaning agents with nonmetallic materials, referto Test Methods D471, D543, and D1460. These test methodsmay not include a pass/fail criterion for each material property.Therefore, an engineering evaluation that considers whetherany identified material property changes a
46、re acceptable in theapplication should be performed. Some of these materialproperty changes can influence the oxygen compatibility of thenonmetallic material. If the influence of a material propertychange on oxygen compatibility is uncertain, the oxygencompatibility testing discussed in Guide G63 sh
47、ould be per-formed on the nonmetallic material (pre- and post-exposure tothe cleaning solution and process) to support this evaluation.7.3.2 Weight loss, shrinkage, cracking, crazing, blistering,or embrittlement are evidence that the cleaning agent isreacting with or leaching materials from the nonm
48、etal and istherefore incompatible.7.3.3 Swelling and weight gain may indicate that the non-metal is absorbing some of the cleaning agent during exposure.Some slight swelling and weight gain may be acceptable if thecleaning agent does not adversely affect oxygen compatibilityor component function. Th
49、e drying method and length ofdrying time used in the test should be representative of theexpected user cleaning process.NOTE 4Return to original dimensions after drying is indicative of atotally reversible solvent absorption/desorption process with no effect onproperties or oxygen compatibility.WarningProlonged exposure to solvents can result in time-dependent absorption and desorption processes, and lead toerroneous conclusions based on weight and dimensions alone.7.3.4 Cleaning agents that are effective at removinghydrocarbon, halocarbon, perhalogenated, or silicone conta
