ASTM E595-15(2021)
(Test Method)Standard Test Method for Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in a Vacuum Environment
Standard Test Method for Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in a Vacuum Environment
SIGNIFICANCE AND USE
5.1 This test method evaluates, under carefully controlled conditions, the changes in the mass of a test specimen on exposure under vacuum to a temperature of 125 °C and the mass of those products that leave the specimen and condense on a collector at a temperature of 25 °C.
5.2 The 24 h test time does not represent actual outgassing from years of operation, so a higher test temperature shorter time was selected to allow material comparisons with no intent to predict actual outgassing in service. The test temperature of 125 °C was assumed to be significantly above the expected operating temperature in service. If expected operating temperatures exceed 65 to 70 °C the test temperature should be increased. It is suggested that test temperature be at least 30 °C higher than expected maximum service temperature in order to provide material comparisons for TML and CVCM.
5.3 Comparisons of material outgassing properties are valid at 125 °C sample temperature and 25°C collector temperature only. Samples tested at other temperatures may be compared only with other materials which were tested at that same temperature.
5.4 The measurements of the collected volatile condensable material are also comparable and valid only for similar collector geometry and surfaces at 25 °C. Samples have been tested at sample temperatures from 50 to 400 °C and at collector temperatures from 1 to 30 °C by this test technique. Data taken at nonstandard conditions must be clearly identified and should not be compared with samples tested at 125 °C sample temperature and 25 °C collector temperature.
5.5 The simulation of the vacuum of space in this test method does not require that the pressure be as low as that encountered in interplanetary flight (for example, 10−12 Pa (10−14 torr)). It is sufficient that the pressure be low enough that the mean free path of gas molecules be long in comparison to chamber dimensions.
5.6 This method of screening materials is considered a conservativ...
SCOPE
1.1 This test method covers a screening technique to determine volatile content of materials when exposed to a vacuum environment. Two parameters are measured: total mass loss (TML) and collected volatile condensable materials (CVCM). An additional parameter, the amount of water vapor regained (WVR), can also be obtained after completion of exposures and measurements required for TML and CVCM.
1.2 This test method describes the test apparatus and related operating procedures for evaluating the mass loss of materials being subjected to 125 °C at less than 7 × 10−3 Pa (5 × 10−5 torr) for 24 h. The overall mass loss can be classified into noncondensables and condensables. The latter are characterized herein as being capable of condensing on a collector at a temperature of 25°C.
Note 1: Unless otherwise noted, the tolerance on 25 and 125 °C is ±1 °C and on 23 °C is ±2 °C. The tolerance on relative humidity is ±5 %.
1.3 Many types of organic, polymeric, and inorganic materials can be tested. These include polymer potting compounds, foams, elastomers, films, tapes, insulations, shrink tubings, adhesives, coatings, fabrics, tie cords, and lubricants. The materials may be tested in the “as-received” condition or prepared for test by various curing specifications.
1.4 This test method is primarily a screening technique for materials and is not necessarily valid for computing actual contamination on a system or component because of differences in configuration, temperatures, and material processing.
1.5 The criteria used for the acceptance and rejection of materials shall be determined by the user and based upon specific component and system requirements. Historically, TML of 1.00 % and CVCM of 0.10 % have been used as screening levels for rejection of spacecraft materials.
1.6 The use of materials that are deemed acceptable in accordance with this test method does not ensure that the system or component will rem...
General Information
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E595 − 15 (Reapproved 2021)
Standard Test Method for
Total Mass Loss and Collected Volatile Condensable
1
Materials from Outgassing in a Vacuum Environment
This standard is issued under the fixed designation E595; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 1.6 The use of materials that are deemed acceptable in
accordance with this test method does not ensure that the
1.1 This test method covers a screening technique to deter-
system or component will remain uncontaminated. Therefore,
mine volatile content of materials when exposed to a vacuum
subsequent functional, developmental, and qualification tests
environment. Two parameters are measured: total mass loss
should be used, as necessary, to ensure that the material’s
(TML) and collected volatile condensable materials (CVCM).
performance is satisfactory.
An additional parameter, the amount of water vapor regained
1.7 This standard does not purport to address all of the
(WVR), can also be obtained after completion of exposures
safety concerns, if any, associated with its use. It is the
and measurements required for TML and CVCM.
responsibility of the user of this standard to establish appro-
1.2 Thistestmethoddescribesthetestapparatusandrelated
priate safety, health, and environmental practices and deter-
operating procedures for evaluating the mass loss of materials
−3 mine the applicability of regulatory limitations prior to use.
being subjected to 125 °C at less than 7 × 10 Pa
1.8 This international standard was developed in accor-
−5
(5×10 torr) for 24 h.The overall mass loss can be classified
dance with internationally recognized principles on standard-
into noncondensables and condensables. The latter are charac-
ization established in the Decision on Principles for the
terized herein as being capable of condensing on a collector at
Development of International Standards, Guides and Recom-
a temperature of 25°C.
mendations issued by the World Trade Organization Technical
NOTE 1—Unless otherwise noted, the tolerance on 25 and 125°C is
Barriers to Trade (TBT) Committee.
61°C and on 23°C is 62°C. The tolerance on relative humidity is
65%.
2. Referenced Documents
1.3 Many types of organic, polymeric, and inorganic mate-
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2.1 ASTM Standards:
rials can be tested. These include polymer potting compounds,
E177Practice for Use of the Terms Precision and Bias in
foams, elastomers, films, tapes, insulations, shrink tubings,
ASTM Test Methods
adhesives, coatings, fabrics, tie cords, and lubricants. The
2.2 ASTM Adjuncts:
materials may be tested in the “as-received” condition or
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Micro VCM Detailed Drawings
prepared for test by various curing specifications.
1.4 This test method is primarily a screening technique for
3. Terminology
materials and is not necessarily valid for computing actual
3.1 Definitions:
contamination on a system or component because of differ-
3.1.1 collected volatile condensable material, CVCM—the
ences in configuration, temperatures, and material processing.
quantity of outgassed matter from a test specimen that con-
1.5 The criteria used for the acceptance and rejection of
denses on a collector maintained at a specific constant tem-
materials shall be determined by the user and based upon
perature for a specified time. CVCM is expressed as a
specific component and system requirements. Historically,
percentage of the initial specimen mass and is calculated from
TML of 1.00% and CVCM of 0.10% have been used as
thecondensatemassdeterminedfromthedifferenceinmassof
screening levels for rejection of spacecraft materials.
the collector plate before and after the test.
1 2
This test method is under the jurisdiction of ASTM Committee E21 on Space For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Simulation andApplications of SpaceTechnology and is the direct responsibility of contactASTM Customer Service at service@astm.org. ForAnnual Book ofASTM
Subcommittee E21.05 on Contamination. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2021. Published May 2021. Originally the ASTM website.
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approved in 1977. Last previous edition approved in 2015 as E595–15. DOI: Available fromASTM International, 100 Barr Harbor Dr., PO Box C700,West
10.1520/E0595-15R21. Conshohocken, PA 19428–2959. Order Adjunct ADJE05
...
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