ASTM G93-03(2011)
(Practice)Standard Practice for Cleaning Methods and Cleanliness Levels for Material and Equipment Used in Oxygen-Enriched Environments
Standard Practice for Cleaning Methods and Cleanliness Levels for Material and Equipment Used in Oxygen-Enriched Environments
SIGNIFICANCE AND USE
The purpose of this practice is to furnish qualified technical personnel with pertinent information for the selection of cleaning methods for cleaning materials and equipment to be used in oxygen-enriched environments. This practice furnishes qualified technical personnel with guidance in the specification of oxygen system cleanliness needs. It does not actually specify cleanliness levels.
Insufficient cleanliness of components used in oxygen systems can result in the ignition of contaminants or components by a variety of mechanisms such as particle, mechanical, or pneumatic impact. These mechanisms are explained in detail in Guide G88.
Adequate contamination control in oxygen systems is imperative to minimize hazards and component failures that can result from contamination. Contamination must also be minimized to ensure an acceptable product purity.
Removal of contaminants from materials and components depends on system configuration, materials of construction, and type and quantity of contaminant.
Examples of cleaning procedures contained herein may be followed or specified for those materials, components, and equipment indicated. The general cleaning text can be used to establish cleaning procedures for materials, components, equipment, and applications not addressed in detail. See Guide G127 for discussion of cleaning agent and procedure selection.
SCOPE
1.1 This practice covers the selection of methods and apparatus for cleaning materials and equipment intended for service in oxygen-enriched environments. Contamination problems encountered in the use of enriched air, mixtures of oxygen with other gases, or any other oxidizing gas may be solved by the same cleaning procedures applicable to most metallic and nonmetallic materials and equipment. Cleaning examples for some specific materials, components, and equipment, and the cleaning methods for particular applications, are given in the appendices.
1.2 This practice includes levels of cleanliness used for various applications and the methods used to obtain and verify these levels.
1.3 This practice applies to chemical-, solvent-, and aqueous-based processes.
1.4 This practice describes nonmandatory material for choosing the required levels of cleanliness for systems exposed to oxygen or oxygen-enriched atmospheres.
1.5 This practice proposes a practical range of cleanliness levels that will satisfy most system needs, but it does not deal in quantitative detail with the many conditions that might demand greater cleanliness or that might allow greater contamination levels to exist. Furthermore, it does not propose specific ways to measure or monitor these levels from among the available methods.
1.6 The values stated in both inch-pound and SI units are to be regarded separately as the standard unit. The values given in parentheses are for information only.
1.7 This standard does not purport to address all of the safety concerns, if any, associated 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. Federal, state and local safety and disposal regulations concerning the particular hazardous materials, reagents, operations, and equipment being used should be reviewed by the user. The user is encouraged to obtain the Material Safety Data Sheet (MSDS) from the manufacturer for any material incorporated into a cleaning process. Specific cautions are given in Section 8.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:G93 −03 (Reapproved 2011)
Standard Practice for
Cleaning Methods and Cleanliness Levels for Material and
Equipment Used in Oxygen-Enriched Environments
ThisstandardisissuedunderthefixeddesignationG93;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope local safety and disposal regulations concerning the particular
hazardousmaterials,reagents,operations,andequipmentbeing
1.1 This practice covers the selection of methods and
used should be reviewed by the user.The user is encouraged to
apparatus for cleaning materials and equipment intended for
obtain the Material Safety Data Sheet (MSDS) from the
service in oxygen-enriched environments. Contamination
manufacturer for any material incorporated into a cleaning
problems encountered in the use of enriched air, mixtures of
process. Specific cautions are given in Section 8.
oxygen with other gases, or any other oxidizing gas may be
solved by the same cleaning procedures applicable to most
2. Referenced Documents
metallic and nonmetallic materials and equipment. Cleaning
2.1 ASTM Standards:
examples for some specific materials, components, and
A380 Practice for Cleaning, Descaling, and Passivation of
equipment, and the cleaning methods for particular
Stainless Steel Parts, Equipment, and Systems
applications, are given in the appendices.
D1193 Specification for Reagent Water
1.2 This practice includes levels of cleanliness used for
E312 Practice for Description and Selection of Conditions
various applications and the methods used to obtain and verify
for Photographing Specimens Using Analog (Film) Cam-
these levels.
eras and Digital Still Cameras (DSC)
1.3 This practice applies to chemical-, solvent-, and E1235 Test Method for Gravimetric Determination of Non-
aqueous-based processes.
volatile Residue (NVR) in Environmentally Controlled
Areas for Spacecraft
1.4 This practice describes nonmandatory material for
E2042 Practice for Cleaning and Maintaining Controlled
choosingtherequiredlevelsofcleanlinessforsystemsexposed
Areas and Clean Rooms
to oxygen or oxygen-enriched atmospheres.
F312 Test Methods for Microscopical Sizing and Counting
1.5 This practice proposes a practical range of cleanliness
Particles from Aerospace Fluids on Membrane Filters
levels that will satisfy most system needs, but it does not deal
F331 Test Method for Nonvolatile Residue of Solvent Ex-
in quantitative detail with the many conditions that might
tract from Aerospace Components (Using Flash Evapora-
demand greater cleanliness or that might allow greater con-
tor)
tamination levels to exist. Furthermore, it does not propose
G63 Guide for Evaluating Nonmetallic Materials for Oxy-
specific ways to measure or monitor these levels from among
gen Service
the available methods.
G88 Guide for Designing Systems for Oxygen Service
1.6 The values stated in both inch-pound and SI units are to G121 Practice for Preparation of Contaminated Test Cou-
beregardedseparatelyasthestandardunit.Thevaluesgivenin pons for the Evaluation of Cleaning Agents
parentheses are for information only. G122 Test Method for Evaluating the Effectiveness of
Cleaning Agents
1.7 This standard does not purport to address all of the
G125 Test Method for Measuring Liquid and Solid Material
safety concerns, if any, associated with its use. It is the
Fire Limits in Gaseous Oxidants
responsibility of the user of this standard to establish appro-
G127 Guide for the Selection of Cleaning Agents for Oxy-
priate safety and health practices and determine the applica-
gen Systems
bility of regulatory limitations prior to use. Federal, state and
G128 Guide for Control of Hazards and Risks in Oxygen
Enriched Systems
This practice is under the jurisdiction of ASTM Committee G04 on Compat-
ibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is the
direct responsibility of Subcommittee G04.02 on Recommended Practices. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2011. Published April 2011. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1987. Last previous edition approved in 2003 as G93 – 03e01. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0093-03R11. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G93−03 (2011)
G131 Practice for Cleaning of Materials and Components by or experience, know how to apply physical and chemical
Ultrasonic Techniques principles involved in the reactions between oxidants and other
G136 Practice for Determination of Soluble Residual Con- metals.
taminants in Materials by Ultrasonic Extraction
3.2 Definitions of Terms Specific to This Standard:
G144 Test Method for Determination of Residual Contami-
3.2.1 cleanliness, n—the degree to which an oxygen system
nation of Materials and Components by Total Carbon
is free of contaminant.
Analysis Using a HighTemperature CombustionAnalyzer
3.2.2 fibers, n—particulate matter with a length of 100 µm
2.2 CGA Documents:
or greater, and a length-to-width ratio of 10 to 1 or greater.
CGA Pamphlet G-4.1 Cleaning Equipment for Oxygen Ser-
3.2.3 particulate,n—ageneraltermusedtodescribeafinely
vice
divided solid of organic or inorganic matter.
CGA Pamphlet G-4.4 Industrial Practices for Gaseous Oxy-
3.2.3.1 Discussion—These solids are usually reported as the
gen Transmission and Distribution Piping Systems
amount of contaminant by the population of a specific microm-
2.3 SAE Document:
eter size. See methods described in Methods F312 orARP598
ARP598 The Determination of Particulate Contamination in
for particle size and population determination.
Liquids by the Particle Count Method
2.4 ISO Document:
4. Summary of Practice
ISO 14644-1 Cleanrooms and Associated Controlled
4.1 General methods, apparatus, and reagents for cleaning
Environments—Part 1: Classification of Air Cleanliness
materials and equipment used in oxygen-enriched environ-
3. Terminology ments are described in this practice. Exact procedures are not
given because they depend on the contaminant type and
3.1 Definitions:
material to be cleaned, cleaning agent used, and degree of
3.1.1 contaminant, n—unwanted molecular or particulate
cleanliness required. Methods may be used individually, or
matterthatcouldadverselyaffectordegradetheoperation,life,
may be combined or repeated to achieve the desired results.
or reliability of the systems or components upon which it
Examples of cleaning procedures that have been successfully
resides.
used for specific materials, components, and equipment in
3.1.2 contamination, n—(1) the amount of unwanted mo-
selected applications are described in the appendices.An index
lecular or particulate matter in a system; (2) the process or
of the specific materials, components, equipment, and applica-
condition of being contaminated.
tions covered in these examples is given in Table X1.1.
3.1.2.1 Discussion—Contamination and cleanliness are op-
4.2 For the purpose of this practice, both solid and fluid
posing properties; increasing cleanliness implies decreasing
contaminants have been subclassed into three categories:
contamination.
organics, inorganics, and particulates. A list of common con-
3.1.3 direct oxygen service, n—service in contact with
tamination levels is given in Table 1.
oxygen-enriched atmosphere during normal operation.
4.3 Cleanliness specifications that have been used in the
3.1.3.1 Discussion—Examples are oxygen compressor pis-
past are identified, levels of cleanliness that can be achieved
ton rings or control valve seats.
are listed along with factors that suggest potential upper limits
3.1.4 nonmetal, n—any material other than a metal, non-
for allowable system contamination, and the practical difficul-
polymeric alloy, or any composite in which the metallic
ties in adopting and achieving adequately clean systems are
component is not the most easily ignited component and for
reviewed. Cleanliness specifications used by suppliers and
which the individual constituents cannot be evaluated
manufacturers often differ; it is therefore important to commu-
independently, including ceramics (such as glass), synthetic
nicate and agree upon which specification is to be used for a
polymers (such as most rubbers, thermoplastics, and
given system and to adhere to the most conservative measures.
thermosets), and natural polymers (such as naturally occurring
rubber, wood, and cloth). Nonmetallic is the adjective use of
5. Significance and Use
this term.
5.1 The purpose of this practice is to furnish qualified
3.1.5 oxygen compatibility (also oxidant compatibility),
technical personnel with pertinent information for the selection
n—the ability of a substance to coexist with both oxygen and
ofcleaningmethodsforcleaningmaterialsandequipmenttobe
a potential source(s) of ignition at an expected pressure and
temperature with a magnitude of risk acceptable to the user.
TABLE 1 Oil Film Contamination Level Specifications
3.1.6 qualified technical personnel, n—persons such as
Concentration,
Source
engineers and chemists who, by virtue of education, training, 2 2
mg/m (mg/ft )
0.14 (0.013) 1967 Navy Standard per Presti and DeSimone (6)
10.8 (1) NASA KSC 123 per Report MTB 306-71 (7)
Available from Compressed Gas Association (CGA), 4221 Walney Rd., 5th
16.1 (1.5) Recommended by Presti and DeSimone (6)
Floor, Chantilly, VA 20151-2923, http://www.cganet.com.
43.1 (4) Air Force 1950s value per LeSuer (8)
Available from SAE International (SAE), 400 Commonwealth Dr.,Warrendale,
75.3 (7) Recommended by Walde (9)
PA 15096-0001, http://www.sae.org.
108 (10 mg/ft or per item) Union Carbide Guideline (10,4)
Available from International Organization for Standardization (ISO), 1, ch. de
50-100 (4.6 to 9.3) Compressed Gas Association Pamphlet G-4.8 (3)
la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:// 500 (47.5) Compressed Gas Association Pamphlet G-4.1 (5)
www.iso.ch.
G93−03 (2011)
used in oxygen-enriched environments. This practice furnishes 6.2.2 Chemical cleaners, both acid and caustic, can damage
qualified technical personnel with guidance in the specification metal parts if not neutralized upon completion of cleaning.
of oxygen system cleanliness needs. It does not actually Corrosion, embrittlement, or other surface modifications are
specify cleanliness levels. potentially harmful side effects of chemical cleaning agents.
Crevice corrosion can occur and sealing surfaces can be etched
5.2 Insufficient cleanliness of components used in oxygen
enough to destroy the finish necessary to seal the part. SeeTest
systems can result in the ignition of contaminants or compo-
Method G122 and Guide G127 for methods used to evaluate
nents by a variety of mechanisms such as particle, mechanical,
cleaners for use on various materials used in oxygen service.
orpneumaticimpact.Thesemechanismsareexplainedindetail
6.2.3 Solvent cleaning solutions often damage plastics and
in Guide G88.
elastomers. The manufacturer should be consulted or sample
5.3 Adequate contamination control in oxygen systems is
parts should be tested to ensure that the solvent is not harmful
imperative to minimize hazards and component failures that
to the item being cleaned.
can result from contamination. Contamination must also be
6.3 Lubricants:
minimized to ensure an acceptable product purity.
6.3.1 Mechanical components are normally assembled with
5.4 Removal of contaminants from materials and compo-
lubricants on seals, threads, and moving surfaces. The manu-
nents depends on system configuration, materials of
facturer should be consulted to determine the kind of lubricant
construction, and type and quantity of contaminant.
originally used on the article to ensure that the cleaning
solutions and methods selected are effective in removing the
5.5 Examples of cleaning procedures contained herein may
lubricant and will not damage the component.
be followed or specified for those materials, components, and
6.3.2 Oxygen-compatible lubricants should be selected in
equipment indicated. The general cleaning text can be used to
accordance with Guide G63. The component manufacturer
establish cleaning procedures for materials, components,
should also be consulted to ensure that the selected lubricant
equipment, and applications not addressed in detail. See Guide
provides adequate lubrication for component performance.
G127 for discussion of cleaning agent and procedure selection.
Oxygen-compatible lubricants often have markedly different
lubricating properties from conventional lubricants.
6. Interferences
6.4 Environment and Assembly Requirements:
6.1 Disassembly:
6.4.1 Equipment intended for oxygen service must be
6.1.1 It is imperative that oxygen systems be cleaned as
handled carefully during all phases of a cleaning procedure.
individual components or piece parts, preferably before assem-
The environment should be clean and dust-free. Nearby
bly. Assembled systems must be disassembled for cleaning if
grinding, welding, and sanding should be prohibited. Parts
construction permits. Flushing an assembled system can de-
should not be allowed to stand in the open unprotected after
posit and concentrate contaminants in stagnant areas. Nonvola-
they have been cleaned. Care should be taken to avoid
tile cleaning agents may remain in trapped spaces and later
contamination by oil deposits from rotating machinery or oil
react with oxygen. Cleaning solutions may degrade nonmetals
aerosols in the air. Do not touch part surfaces that will be in
in an assembly. Caustic and acid cleaning solutions may cause
direct oxygen service except with clean gloves or handling
crevice corrosion in assemblies.
devices.
6.1.2 Manufactured products (that is, valves, regulators, and
6.4.2 In some cases, laminar-flow clean rooms may be
pumps) should be cleaned preferably by the manufacturer
necessary in which the entire room is purged with filtered air.
before final assembly and test.All tests should be structured to
In horizontal flow clean rooms, parts are cleaned and verified
prevent recontamination. The part must then be packaged in
in a sequence in which successive cleaning operations are at
oxygen-compatible materials (see 12.1) and identified to pro-
locations progressively closer to the filtered air source so that
tect it from contamination in transit and storage.The purchaser
the part an
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