1、Designation: G 127 95 (Reapproved 2000)Standard Guide for theSelection of Cleaning Agents for Oxygen Systems1This standard is issued under the fixed designation G 127; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 The purpose of this guide is to establish a procedure toselect cleaning agents, both solvents and water-based deter-gent
3、s, for oxygen service. This includes of laboratory-scaletests for cleaning effectiveness, materials compatibility andoxygen 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 o
4、f the article beingcleaned, such as size, shape, and material. Final evaluation ofthe cleaning agent should include testing of actual products andproduction processes.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
5、the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 471 Test Method for Rubber PropertyEffect of Liq-uids2D 543 Test Method for Resistance of Plastics to Ch
6、emicalReagents3D 1193 Specification for Reagent Water4D 1460 Test Method for Rubber PropertyChange inLength During Liquid Immersion2D 2512 Test Method for Compatibility of Materials withLiquid Oxygen (Impact Sensitivity Threshold and Pass-Fail Techniques)5D 2863 Test Method for Measuring the Minimum
7、 OxygenConcentration to Support Candle-like Combustion of Plas-tics (Oxygen Index)6D 2934 Practice for Rubber SealsCompatibility with Ser-vice Fluids7D 4809 Test Method for Heat of Combustion of LiquidHydrocarbon Fuels by Bomb Calorimeter (IntermediatePrecision Method)8G 5 Reference Test Method for
8、Making Potentiostatic andPotentiodynamic Anodic Polarization Measurements9G 31 Practice for Laboratory Immersion Corrosion Testingof Metals9G 59 Practice for Conducting Potentiodynamic PolarizationResistance Measurements9G 63 Guide for Evaluating Nonmetallic Materials for Oxy-gen Service10G 72 Test
9、Method for Autogenous Ignition Temperature ofLiquids and Solids in a High-Pressure Oxygen-EnrichedEnvironment10G 74 Test Method for Ignition Sensitivity of Materials toGaseous Fluid Impact10G 93 Practice for Cleaning Methods for Material andEquipment Used in Oxygen-Enriched Environments10G 94 Guide
10、for Evaluating Metals for Oxygen Service10G 121 Practice for Preparation of Contaminated Test Cou-pons for the Evaluation of Cleaning Agents10G 122 Test Method to Evaluate the Effectiveness of Clean-ing Agents102.2 CGA Document:CGA Pamphlet G-4.1 Cleaning Equipment for OxygenService3. Significance a
11、nd Use3.1 The purpose of this guide is to provide information thatmay be considered when selecting and qualifying a cleaningagent for an oxygen system.3.2 Insufficient cleanliness can result in the ignition ofcontaminants or components by a variety of mechanisms.Therefore, an acceptable level of con
12、tamination for eachcondition of use in oxygen service should be defined. Theacceptable 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 substrate material,3.2.4 The configuratio
13、n and end use of the equipment or partto be cleaned, and1This guide is under the jurisdiction of ASTM Committee G4 on Compatibilityand Sensitivity of Materials in Oxygen Enriched Atmospheres and is the directresponsibility of Subcommittee G04.02 on Recommended Practices.Current edition approved June
14、 15, 1995. Published May 1996.2Annual Book of ASTM Standards, Vol 09.01.3Annual Book of ASTM Standards, Vol 08.01.4Annual Book of ASTM Standards, Vol 11.01.5Annual Book of ASTM Standards, Vol 15.03.6Annual Book of ASTM Standards, Vol 08.02.7Annual Book of ASTM Standards, Vol 09.02.8Annual Book of AS
15、TM Standards, Vol 05.03.9Annual Book of ASTM Standards, Vol 03.02.10Annual Book of ASTM Standards, Vol 14.04.1Copyright ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.3.2.5 The operating parameters of the oxygen system (pres-sure, temperature, phase, concentration, flui
16、d velocity, etc.).4. Selection of Cleaning Agent4.1 Before a specific cleaning agent is selected for testing,the following attributes should be considered.4.1.1 Toxicity,4.1.2 Carcinogenicity,4.1.3 Recyclability,4.1.4 Waste disposal,4.1.5 Ozone depletion,4.1.6 Inertness (flammability and combustibil
17、ity),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 federal regulations.4.2 It is desirable that the cleaning agent could be applied b
18、ya variety of methods, such as wiping, immersion, spraying, etc.Consequently, the cleaning agent manufacturers instructionsfor applying the cleaner shall be considered.5. Selection of Substrate Materials5.1 Substrate materials used for cleaning effectiveness andcompatibility tests should be represen
19、tative of those used in theend application.5.2 Metallic Materials:5.2.1 Metallic materials commonly used in oxygen systemsare listed in Guide G 94.5.2.2 Alloys representative of numerous applications inoxygen systems and suitable for inclusion in a test protocol areas follows:5.2.2.1 304 stainless s
20、teel,5.2.2.2 Aluminum alloy 6061 (or 5051),5.2.2.3 Carbon steel 1018,5.2.2.4 Admiralty brass CDA 443,115.2.2.5 Monel 400,5.2.2.6 4130X low alloy steel,5.2.2.7 Inconel 718,5.2.2.8 Copper,5.2.2.9 Tin-bronze, and5.2.2.10 Cobalt alloy 188.5.3 Nonmetallic Materials:5.3.1 Nonmetallic materials commonly us
21、ed in oxygenservice are discussed in Guide G 63.5.3.2 Nonmetallic materials representative of numerous ap-plications in oxygen systems and suitable for inclusion in a testprotocol are as follows:5.3.2.1 Ethylene Propylene Rubber (EPDM),5.3.2.2 Perfluoroelastomer (KalrezR, ChemrazR),5.3.2.3 PCTFE, Po
22、lychlorotrifluoroethylene (Kel-FR),5.3.2.4 Chloroprene Rubber (Neoprene),5.3.2.5 Polyamid Polymer (Nylon),5.3.2.6 PTFE, Polytetrafluoroethylene (TeflonR), and5.3.2.7 Fluoroelastomer (VitonRA, Fluorel).6. Cleaning Effectiveness Tests6.1 Selection of Test Contaminants:6.1.1 Numerous contaminants encou
23、ntered in oxygen sys-tems that could result from manufacturing, assembly, fabrica-tion, and construction processes are listed in Practice G 93.Typical contaminants include:6.1.1.1 Hydrocarbon oils and greases,6.1.1.2 Fluorinated fluids and greases,6.1.1.3 Inks,6.1.1.4 Machine cutting oils,6.1.1.5 Ca
24、rbon deposits,6.1.1.6 Silicone oils and greases,6.1.1.7 Phosphate esters,6.1.1.8 Waxes,6.1.1.9 Dye penetrants,6.1.1.10 Chlorotrifluoroethylene based oils and greases.6.1.2 Among typical contaminants, hydrocarbons are theprime candidates for the test protocol. When dealing with othercontaminants, the
25、 user should attempt to classify the type ofcontamination expected on the equipment to be cleaned.6.1.3 As a preliminary test, a mixture of common cuttingoils may be used as a contaminant. It may be carried in asuitable volatile solvent as a means to introduce it into asystem. In addition, vacuum pu
26、mp oil, or a compressor oil aresuggested as contaminants for the evaluation program. In amore refined test at later stages, fluorinated oils/greases, dyepenetrants, or a mixture of as many contaminants as necessarymay be prepared in a suitable solvent. Eventually, actualcontaminants encountered on a
27、n engineering component orsystem for oxygen service shall be evaluated for removalefficiency.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 acce
28、ptable level specified for oxygen service in CGApamphlet G.4.1. Heavily contaminated surfaces with levels inexcess of 1000 mg/m2must be precleaned using more aggres-sive cleaning agents with mechanical scrubbing (PracticeG 93). Precleaning is not a cleaning step with which this guideis concerned.6.2
29、.2 Contaminants may be applied to the specimens by anyof the means specified in Practice G 121.6.2.3 The cleaning effectiveness of a cleaning agent shall beevaluated using the test method outlined in Test Method G 122.6.2.4 A test basis shall be established for each contaminatedsample by using an ac
30、ceptable solvent as a control cleaningagent.7. Material Compatibility Tests7.1 If a cleaning agents ability to remove the selectedcontamination is deemed promising, additional testing (seeSections 8.2 and 8.3) should be performed to evaluate itscompatibility with the oxygen systems.7.2 Metallic Mate
31、rials:7.2.1 Significant corrosion damage may occur during clean-ing operations. Corrosion rates may be affected by temperature,contaminants, degree of aeration, concentration and presence11Available from the Copper Development Association, 405 Lexington Ave,New York, NY 10017.G 1272of residual stres
32、s (see Note 1). To avoid this, assessmentsshould be made of the corrosion severity of cleaning environ-ments for the engineering materials of interest. Weight gain-loss measurements can be performed as per Practice G 31.Where applicable, Test Method G 5 can be applied (see Note2).7.2.2 The electroch
33、emical technique of potentiodynamicpolarization resistance (Practice G 59) can be used to deter-mine the corrosion rate of conductive cleaning agents on metalsubstrates. The corrosion rate (in mils per year, mpy) should bedetermined using the solution parameters which would be usedin actual cleaning
34、 practices. The cleaning solution may betested: (1) as-is; (2) deaerated; (3) aerated. It is recommended,however, that the corrosion test be performed under as-isconditions in order to simulate the actual cleaning process. ThepH and conductivity of the cleaning agent should be measuredboth before an
35、d after the corrosion test. If these property valueschange, the test is considered invalid. A separate experimentshould be performed.NOTE 1The presence of residual stresses may promote stress corro-sion cracking in susceptible materials. Information in the technicalliterature on corrosion rates and
36、stress corrosion cracking may be used inevaluating corrosion susceptibility. Further testing, as outlined later in thisguide, may be necessary.NOTE 2In order to reflect the actual material property, samples forcorrosion tests should not be wet ground with 600-grit SiC papers toexpose fresh surface.
37、The surface roughness of test samples should beeither in compliance with that recommended in Practice G 121, or, ifpossible, commensurate with that of the actual engineering components.7.3 Nonmetallic Materials:7.3.1 When exposed to the cleaning agent under actual useconditions of temperature, time,
38、 concentration etc., some of thenonmetallics are susceptible to degradation and may experi-ence physical, mechanical, chemical and possibly thermalproperty changes. These changes are typically characterized byswelling, distortion, cracking, crazing, blistering, embrittle-ment and decomposition tempe
39、rature shift. To evaluate thecompatibility of cleaning agents with nonmetallic materials,refer to Test Methods D 471, D 543, D 1460, and PracticeD 2934.7.3.2 Corrosion rates of less than 63.5 micrometer per year(2.5 mpy) are usually desirable. However, to avoid setting upunduly conservative criteria
40、 which may eliminate potentialcleaning agents, estimation of corrosion rate can be madebased upon realistic, total accumulated contact time of thecleaner with a component or system throughout its service life.The rate of corrosion should be determined based upon themaximum allowable dimensional vari
41、ations of the componentor system.8. Residue Analysis8.1 Although CFC-based cleaning solvents pose ozone-depleting potential they usually have a fast evaporation rateand do not leave measurable quantities of non-volatile residuesafter complete evaporation. On the other hand, non-CFC basedcleaning age
42、nts, especially water-based detergents, exhibit amuch slower evaporation rate. Moreover, they often leave asignificant amount of residue after complete drying of thesurfaces. If residues are not reduced to acceptable levels, theyare susceptible to ignition or combustion, or both, duringoxygen servic
43、e, which may lead to a fire. As a result, a wateror solvent rinsing, after final cleaning by non-CFC basedcleaning agents is sometimes an essential step in the water-based detergent cleaning process.8.2 A quantitative determination of the cleaning agentsrinsability can be made by assessing the amoun
44、t of residueremaining after complete drying. This assessment can beaccomplished by weight measurement using the proceduresdescribed in 8.2.1, 8.2.2 and 8.2.3. When the amount of residueis low and cannot be accurately determined by weight mea-surement, the residue may be extracted by flushing, rinsin
45、g, orimmersing in a low-residue solvent, such as Type II reagentwater (Specification D 1193). The rinsing solvent can beexamined by analytical methods such as UV spectroscopy, totalorganic carbon analysis, ion chromatography, high perfor-mance liquid chromatography, etc.8.2.1 A fixed quantity of the
46、 cleaning solution is prepared inthe concentration to be used in actual cleaning operations,weighed, and placed in beakers. The solution is completelydried and the remaining residue is weighed to determine theweight percent residue. See Note 3.8.2.2 A fixed quantity of the cleaning solution is prepa
47、red inthe concentration to be used in actual cleaning operations, andplaced in a beaker of known mass. The solution is emptied,leaving the walls of the beaker wetted with the solution. Thebeaker is then allowed to dry and the weight of the residue isdetermined. See Note 3.8.2.3 A test, similar to 8.
48、2.2, is performed with the excep-tion that the recommended number of water or solvent rinsesare performed before the amount of residue is determined. Thesame procedures can be used with metal coupons chosen torepresent typical materials used in the system or components tobe cleaned.NOTE 3A sufficien
49、t quantity of solution ranging from 100 to 1000 mLmay be required in order to yield satisfactory statistical confidence.8.3 Oxygen Compatibility Test:8.3.1 The following methods may be used to evaluate theoxygen compatibility of the residues: an oxygen impact test perTest Method D 2512, an oxygen index test per Test MethodD 2863, a heat of combustion test per Test Method D 4809, anautoignition temperature test per Test Method G 72, and apneumatic impact test per Test Method G 74.9. Keywords9.1 chlorofluorocarbon; cleaning; compatibility; contami-nant; detergent; non-volatile resid
