ASTM G93-96
(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
SCOPE
1.1 This practice covers the selection of methods and apparatus for the cleaning of 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 described in detail in the appendix.
1.2 This guide does not include levels of cleanliness necessary for various applications and materials. These sections are currently under development and will be included in a future revision.
1.3 This standard does not purport to address all of the safety problems, 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 Sheets (MSDS) from the manufacturer for any material incorporated into a cleaning process. Specific cautions are given in Section 8.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
Designation: G 93 – 96
Standard Practice for
Cleaning Methods and Cleanliness Levels for Material and
Equipment Used in Oxygen-Enriched Environments
ThisstandardisissuedunderthefixeddesignationG93;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This practice covers the selection of methods and
responsibility of the user of this standard to establish appro-
apparatusforthecleaningofmaterialsandequipmentintended
priate safety and health practices and determine the applica-
for service in oxygen-enriched environments. Contamination
bility of regulatory limitations prior to use. Federal, state and
problems encountered in the use of enriched air, mixtures of
local safety and disposal regulations concerning the particular
oxygen with other gases, or any other oxidizing gas may be
hazardousmaterials,reagents,operations,andequipmentbeing
solved by the same cleaning procedures applicable to most
usedshouldbereviewedbytheuser.Theuserisencouragedto
metallic and nonmetallic materials and equipment. Cleaning
obtain the Material Safety Data Sheets (MSDS) from the
examples for some specific materials, components, and equip-
manufacturer for any material incorporated into a cleaning
ment, and the cleaning methods for particular applications, are
process. Specific cautions are given in Section 8.
described in detail in the appendix.
1.2 This practice includes levels of cleanliness used for
2. Referenced Documents
various applications and the methods used to obtain and verify
2.1 ASTM Standards:
these levels.
A380 Practice for Cleaning, Descaling, and Passivation of
1.3 This practice discourages the use of chlorinated fluoro-
Stainless Steel Parts, Equipment, and Systems
carbon solvents in cleaning operations and encourages the use
D1193 Specification for Reagent Water
of alternate methods. A substitute method for the use of
E312 Practice for Description and Selection of Conditions
solvents in the verification methods is in development and will
for Photographing Specimens
be issued as a separate standard.
E1235 TestMethodforGravimetricDeterminationofNon-
1.4 This practice describes nonmandatory material for
volatile Residue (NVR) in Environmentally Controlled
choosingtherequiredlevelsofcleanlinessforsystemsexposed
Areas for Spacecraft
to oxygen or oxygen-enriched atmospheres.
F312 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 Halogenated
in quantitative detail with the many conditions that might
Solvent Extract from Aerospace Components (Using Ro-
demandgreatercleanlinessorthatmightallowgreaterlevelsof
tary Flash Evaporator)
contamination to be present. 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
NOTE 1—Althoughthispracticehasbeenfoundapplicableforassisting
G121 Practice for Preparation of Contaminated Test Cou-
qualified technical personnel to establish necessary cleanliness levels, 6
pons for the Evaluation of Cleaning Agents
each system is unique and departures from these suggestions may be
G122 Test Method for Evaluating the Effectiveness of
warranted.
Cleaning Agents
1.6 The values stated in both inch-pound and SI units are to
G125 Test Method for Measuring Liquid and Solid Mate-
be regarded separately as the standard. The values given in 6
rial Fire Limits in Gaseous Oxidants
parentheses are for information only.
1 2
This practice is under the jurisdiction of ASTM Committee G-4 on Compat- Annual Book of ASTM Standards, Vol 01.03.
ibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is the Annual Book of ASTM Standards, Vol 11.01.
direct responsibility of Subcommittee G04.02 on Recommended Practices. Annual Book of ASTM Standards, Vol 06.01.
Current edition approved April 10, 1996. Published August 1996. Originally Annual Book of ASTM Standards, Vol 15.03.
1 6
published as G93–87. Last previous edition G93–88 (1993)´ . Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
G93–96
G127 Guide for the Selection of Cleaning Agents for 4. Summary of Practice
Oxygen Systems
4.1 General methods, apparatus, and reagents for cleaning
G128 Guide for the Control of Hazards and Risks in
materials and equipment used in oxygen-enriched environ-
Oxygen Systems
ments are described in this practice. Exact procedures are not
G131 Practice for Cleaning of Materials and Components
given since they are dependent upon the type of contaminants
By Ultrasonic Techniques
and materials to be cleaned, cleaning agents used, and the
G136 Practice for Determination of Soluble Residual Con-
degree of cleanliness required. Methods may be used individu-
taminants In Materials By Ultrasonic Extraction
ally, or may be combined or repeated to achieve the desired
2.2 CGA Documents:
results. Examples of cleaning procedures that have been used
CGAPamphlet G-4.4 Industrial Practices for Gaseous Oxy-
successfullyforspecificmaterials,components,andequipment
gen Transmission and Distribution
in selected applications are described in detail as a supplement
CGA Pamphlet G-4.1 Cleaning Equipment for Oxygen
to the general text.An index of the specific materials, compo-
Service
nents, equipment, and applications covered in these examples
2.3 SAE Document:
is given in Table 1.
ARP 598 The Determination of Particulate Contamination
4.2 For the purpose of this practice, both solid and fluid
in Liquids by the Particle Count Method
contaminants have been subclassed into three categories:
2.4 Federal Standard:
organics, inorganics, and particulates. The definition of each
FED-STD-209 Clean Room and Work Station Require-
category is given in Section 3.Alist of common contaminants
ments, Controlled Environments
is given in Table 2, and their approximate size is shown
graphically in Fig. 1.
3. Terminology
4.3 Cleanliness specifications that have been used in the
3.1 Definitions:
past are identified, levels of cleanliness that can be achieved
3.1.1 oxygen compatibility, n—the ability of a substance to
are listed along with the factors that suggest what the upper
coexist with both oxygen and a potential source(s) of ignition
limits of contamination in these systems might be, and the
withintheacceptableriskparameteroftheuser(atanexpected
practical difficulties in adopting and achieving adequately
pressure and temperature) (Guide G128G128).
clean systems are reviewed.
3.2 Definitions of Terms Specific to This Standard:
5. Significance and Use
3.2.1 cleanliness, n—the degree of success in preventing
contamination from being present in an oxygen system. Clean- 5.1 The purpose of this practice is to furnish qualified
liness and contamination are inverse properties: increasing technicalpersonnelwithpertinentinformationfortheselection
cleanliness implies decreasing contamination. of cleaning methods for the cleaning of materials and equip-
3.2.2 contaminant, n—a foreign or unwanted substance that ment to be used in oxygen-enriched environments. This prac-
can have deleterious effects on system operation, life, or tice furnishes qualified technical personnel with guidance in
reliability. the specification of oxygen system cleanliness needs. It does
3.2.3 contamination, n—the amount of material (that typi- not purport to actually specify a cleanliness.
callyisnotoxygencompatible)inasystemthatisnotintended 5.2 Insufficient cleanliness of components used in oxygen
to be there. Contamination and cleanliness are inverse proper- systems can result in the ignition of contaminants or compo-
ties: increasing cleanliness implies decreasing contamination. nents by a variety of mechanisms such as particle impact,
3.2.4 emulsion, n—a liquid consisting of two or more mechanical or pneumatic impact. These mechanisms are ex-
immiscibleliquids,atleastoneofwhich,asminuteglobules,is plained in detail in Guide G63G63.
dispersed uniformly throughout the other. 5.3 Adequate contamination control in oxygen systems is
3.2.5 fibers, n—particulate matter with a length of 100 mm imperative to minimize hazards and component failures as a
or greater, and a length-to-width ratio of 10 to 1 or greater. result of contamination. Contamination must also be mini-
mized to ensure an acceptable product purity.
3.2.6 nonmetallics, n—organicandinorganicmaterialssuch
as ceramics, glasses, polymers, rubber, cloth, wood, and paper 5.4 Removal of contamination from materials and compo-
products. nents is dependent on system configuration, materials of
3.2.7 particulate, n—a general term used to describe a construction, and type and quantity of contaminant.
finely divided solid of organic or inorganic matter, including 5.5 Examples of cleaning procedures contained herein may
metals. These solids are usually reported as the amount of be followed or specified for those materials, components, and
contaminant by the population of a specific micrometer size. equipment indicated. The general cleaning text can be used to
SeemethodsdescribedinMethodsF312F312orARP598for establish cleaning procedures for materials, components,
particle size and population determination. equipment, and applications not addressed in detail. See Guide
G127G127 for discussion of cleaning agent and procedure
selection.
Available from Compressed Gas Association, 1235 Jefferson Davis Highway,
6. Interferences
Arlington, VA 22202.
Available from Society of Automotive Engineers, 400 Commonwealth Drive,
6.1 Disassembly:
Warrendale, PA 15096.
6.1.1 It is imperative that oxygen systems be cleaned as
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. individual articles, preferably prior to assembly. Assembled
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
G93–96
TABLE 1 Surface Cleanliness Tests
Name of Test Test Method Characteristics or Limitations
Visual Examination with the unaided eye or with a microscope. Subjective but widely used; most effective with particulate matter,
least effective with invisible films; use of a highly trained
microscopist increases the validity of test results.
Tissue paper or white Surface is rubbed with a piece of white tissue paper or a white Limited to visible soils, insensitive qualitative test.
cloth. Grease or soot is observable.
cloth
Water break Normally applied after last clean water rinse. Any break in A qualitative test for hydrophobic soils; contaminates in the water
continuity or receding water film is observed as water drains off lessen sensitivity; use of deionized water and a trained inspector
the part. may increase sensitivity to one-molecular thickness of
contaminant.
−5 2
Gravimetric A test piece is weighed before and after cleaning, or the soil Results show good sensitivity (5 3 10 gm/cm ), but are more
remaining from the evaporated cleaning solvent is weighed. indicative of the effectiveness of the cleaning method than surface
cleanliness.
Ferrocyanide paper Paper is immersed in a solution of NaCl, K Fe(CN) and Limited to ferrous metals and laboratory tests.
3 6
k Fe(CN) in water and dried. Paper is moistened and placed on
4 6
metal surface, then removed and rinsed in clear water. Clear
areas on the paper are caused by soil on the metal.
Copper dip Cleaned metal panels are dipped in an acid copper surface Adherence, continuity, and appearance of copper flash indicate
(copper flash) solution. part cleanliness before the test. Limited to ferrous metals; requires
an experienced operator.
Solvent ring A drop of solvent is repeatedly deposited and picked up from the Enables subsequent identification of soil by infrared
test surface. It is finally deposited on a quartz or glass slide and spectrophotometry, assumes use of a high purity solvent.
dried. If contamination is present, a ring will be formed on the
slide.
Solvent After each cleaning step, used solvent is filtered through Commonly used indirect method which assumes part cleanliness if
membrane filters and examined for levels of particulate the solvent no longer removes contamination.
contamination. NVR is also monitored. Deionized water rinses are
monitored for resistivity if ionic cleaners are used.
Atomizer Surface is cleaned and dried. Water is applied as a spray with an Sensitive but only for hydrophobic soils; results affected by spray
atomizer. The droplet pattern with the advancing contact angle is time, nozzle-to-part distance, atomizer air pressure and ambient
observed to determine surface cleanliness. temperature; applicable to small cross-sectional areas with
stainless steel or gold. Surface must be smooth and free of
wettable detergent films.
Contact angle A light beam is directed into a water droplet on the test surface. Effective only on nonwetting hydrophobic contaminants.
The angle of the reflected beam indicates the contact angle or
angle of incidence. Greater contact angles indicate larger amounts
of contamination.
Ring test A droplet of water on a surface tension ring tester is repeatedly Must be performed by a trained operator to be repeatable; a
lowered to contact the test surface. The number of contacts, or measure of surface wettability.
B-number, indicates surface cleanliness.
TABLE 2 Examples of Oil Film Specifications
facturer prior to final assembly and test. All tests should be
Concentration, mg/m
structured to prevent recontamination. The part must then be
Source
(mg/ft )
packaged in oxygen-compatible materials (see 12.1) and iden-
0.14 (0.013) 1967 Navy Standard per Presti and DiSimone
tified to protect it from contamination in transit and storage.
(6)
The purchaser should approve the cleaning procedure and
10.8 (1) NASA KSC 123 per Report MTB 306-71 (7)
16.1 (1.5) Recommended by Presti and DiSimone (6) packaging t
...
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