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
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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
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-
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
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.
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 ADJE0595.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
E595 − 15 (2021)
3.1.2 total mass loss, TML—total mass of material out- 4.3 After the specimen has been weighed to determine the
gassed from a specimen that is maintained at a specified TML, the WVR can be determined, if desired, as follows: the
constant temperature and operating pressure for a specified specimenisstoredfor24hat23°Cand50%relativehumidity
time. TML is calculated from the mass of the specimen as topermitsorptionofwatervapor.Thespecimenmassafterthis
measured before and after the test and is expressed as a exposure is determined. From these results and the specimen
percentage of the initial specimen mass. mass determined after vacuum exposure, the percentage WVR
is obtained.
3.1.3 water vapor regained, WVR—the mass of the water
vapor regained by the specimen after the optional recondition-
4.4 Twoorthreeemptyspecimenchambersintheheaterbar
ing step. WVR is calculated from the differences in the
and collector plates on the cold bar, selected for each test at
specimen mass determined after the test for TML and CVCM
random, can be used as controls to ensure that uniform
and again after exposure to a 50% relative humidity atmo-
cleaning procedures have been followed after each test.
sphere at 23°C for 24 h. WVR is expressed as a percentage of
4.5 Atypicaltestapparatuscanhave24specimenchambers
the initial specimen mass.
with 24 associated collector plates so that a number of
specimens of different types can be tested each time the
4. Summary of Test Method
foregoing operations are conducted. Three specimen compart-
4.1 This microvolatile condensable system was developed
mentscanserveascontrolsandthreecanbeusedforeachtype
from an earlier system for determination of macrovolatile
of material being tested. The total time required for specimens
condensables that required much larger samples and a longer
requiring no prior preparation is approximately 4 days. The
test.
equipment should be calibrated at least once a year by using
previously tested materials as test specimens. The reference
4.2 Thetestspecimenisexposedto23°Cand50%relative
humidity for 24 h in a preformed, degreased container (boat) sample should be selected from materials that had a narrow
range of TML and VCM results when tested originally.
that has been weighed. After this exposure, the boat and
specimen are weighed and put in one of the specimen com-
4.6 The apparatus may be oriented in any direction as long
partments in a copper heating bar that is part of the test
as the configuration shown in Fig. 1 is maintained and bulk
apparatus. The copper heating bar can accommodate a number
material does not fall from the sample holder nor obstruct the
ofspecimensforsimultaneoustesting.Thevacuumchamberin
gas-exit hole.The dimensions for critical components given in
which the heating bar and other parts of the test apparatus are
Fig. 2 and Table 1 are provided so that apparatus constructed
placed is then sealed and evacuated to a vacuum of at least
for the purpose of this test may provide uniform and compa-
−3 −5
7×10 Pa (5×10 torr).The heating bar is used to raise the
rable results.
specimen compartment temperature to 125°C. This causes
vapor from the heated specimen to stream from the hole in the
5. Significance and Use
specimen compartment. A portion of the vapor passes into a
5.1 This test method evaluates, under carefully controlled
collector chamber in which some vapor condenses on a
conditions, the changes in the mass of a test specimen on
previously-weighedandindependentlytemperature-controlled,
exposure under vacuum to a temperature of 125°C and the
chromium-plated collector plate that is maintained at 25°C.
mass of those products that leave the specimen and condense
Each specimen compartment has a corresponding collector
on a collector at a temperature of 25°C.
chamber that is isolated from the others by a compartmented
separator plate to prevent cross contamination.After 24 h, the
test apparatus is cooled and the vacuum chamber is repressur-
izedwithadry,inertgas.Thespecimenandthecollectorplates
are weighed. From these results and the specimen mass
determined before the vacuum exposure, the percentage TML
and percentage CVCM are obtained. Normally, the reported
values are an average of the percentages obtained from three
samples of the same material.
NOTE2—Itisalsopossibletoconductinfraredandotheranalyticaltests
on the condensates in conjunction with mass-loss tests. Sodium chloride
flats may be used for infrared analysis. These flats are nominally 24 mm
(1in.)indiameterby3.2mm(0.125in.)thickandaresupportededgewise
inametalholderthatfitsintothecollectorplatereceptacle.Oncompletion
of the test, the flats are placed into an infrared salt flat holder for
examination by an infrared spectrophotometer.As an alternative method,
the condensate may be dissolved from the metallic collector, the solvent
evaporated, and the residue deposited on a salt flat for infrared tests.
Sodium chloride flats shall not be used for CVCM determinations.
Muraca,R.F.,andWhittick,J.S.,“PolymersforSpacecraftApplications.”SRI
Project ASD-5046, NASA CR-89557, N67-40270, Stanford Research Institute, FIG. 1 Schematic of Critical Portion of Test Apparatus (Section
September 1967. A-A of Fig. 2)
E595 − 15 (2021)
FIG. 2 Critical Portion of Test Apparatus (See Table 1 for Dimensions)
5.2 The 24 h test time does not represent actual outgassing operating temperature in service. If expected operating tem-
from years of operation, so a higher test temperature shorter peratures exceed 65 to 70°C the test temperature should be
timewasselectedtoallowmaterialcomparisonswithnointent increased.Itissuggestedthattesttemperaturebeatleast30°C
to predict actual outgassing in service. The test temperature of higherthanexpectedmaximumservicetemperatureinorderto
125°C was assumed to be significantly above the expected provide material comparisons for TML and CVCM.
E595 − 15 (2021)
TABLE 1 Test Apparatus Dimensions (See Fig. 2)
Letter mm Tolerance in. Tolerance Notes
A B
A 6.3 ±0.1 0.250 ±0.005 diameter
A B
B 11.1 ±0.1 0.438 ±0.005 diameter
A B
C 33.0 ±0.1 1.300 ±0.005 diameter
AC
D 13.45 ±0.10 0.531 ±0.005
AC
E 12.7 ±0.10 0.500 ±0.005
AC
F 0.65 ±0.10 0.026 ±0.005
C
G 9.65 ±0.3 0.380 ±0.01
A
H 0.75 ±0.10 0.030 ±0.05 stock size
A
J 12.7 ±0.3 0.500 ±0.010
1 1
K 1.6 ±0.8 ⁄16 ± ⁄32
7 1
L 8.0 ±0.8 ⁄16 ± ⁄32
M 16.0 ±0.1 0.625 ±0.005 cover plate must fit snugly
5 1
N 16.0 ±0.8 ⁄8 ± ⁄32
1 1
P 32.0 ±0.8 1 ⁄4 ± ⁄32
Q 50.0 ±0.8 2 ± ⁄32
R 25.5 ±0.8 1 ± ⁄32
S 0.4 ±0.3 0.015 ±0.010 half stock thickness
1 1
T 12.0 ±0.8 ⁄2 ± ⁄32
U 25.5 ±0.8 1 ± ⁄32
V 25.5 ±0.8 1 ± ⁄32
W 50.0 ±0.8 2 ± ⁄32
1 1
X 6.0 ±0.8 ⁄4 ± ⁄32
Y 25.0 ±0.8 1 ± ⁄32
1 1
Z 1.6 ±0.8 ⁄16 ± ⁄32 radius, typical
A
Critical dimensions that must be maintained for test results to be comparable.
B
Diameters must be concentric to ±0.1 mm (±0.005 in.) for test results to be comparable.
C
Dimensionsincludeplatingthickness.Satisfactorysurfaceshavebeenproducedbymakingsubstratesurfacefinish,1.6-µmRMS(63-µin.RMS),highlypolished,plated
with electroless nickel, 0.0127 mm (0.0005 in.) thick, and finished with electroplated chromium, 0.0051 mm (0.0002 in.) thick.
5.3 Comparisons of material outgassing properties are valid 5.8 Alternatively, all specimens may be put into open glass
at 125°C sample temperature and 25°C collector temperature vials during the 24-h temperature and humidity conditioning.
only. Samples tested at other temperatures may be compared Thevialsmustbecappedbeforeremovalfromtheconditioning
only with other materials which were tested at that same chamber. Each specimen must be weighed within 2 min after
temperature. opening the vial to minimize the loss or absorption of water
vaporwhileexposedtoanuncontrolledhumidityenvironment.
5.4 The measurements of the collected volatile condensable
While control of humidity is not necessary at this point, the
material are also comparable and valid only for similar
temperaturefortheweighingshouldbecontrolledat23°C,the
collector geometry and surfaces at 25°C. Samples have been
same temperature prescribed for the 24-h storage test.
tested at sample temperatures from 50 to 400°C and at
collector temperatures from 1 to 30°C by this test technique.
6. Apparatus
Datatakenatnonstandardconditionsmustbeclearlyidentified
and should not be compared with samples tested at 125°C
6.1 The apparatus used in the determination of TML and
sample temperature and 25°C collector temperature.
CVCM typically contains two resistance-heated copper bars.
Generally, each bar is 650 mm (25.5 in.) in length with a
5.5 The simulation of the vacuum of space in this test
25-mm (1-in.) square cross section and contains twelve speci-
method does not require that the pressure be as low as that
−12
men chambers. The open section of each specimen chamber
encountered in interplanetary flight (for example, 10 Pa
−14
allows vapors from the specimen to pass through a hole into a
(10 torr)). It is sufficient that the pressure be low enough that
collector chamber where it impinges on a removable
the mean free path of gas molecules be long in comparison to
chromium-plated collector plate maintained at 25°C through-
chamber dimensions.
out the test. (See Figs. 1 and 2.) Variations in test apparatus
5.6 This method of screening materials is considered a
configurations are acceptable if critical dimensions are main-
conservative one because maximum operating temperatures in
tained as prescribed in Table 1.
service are assumed not to exceed 50 to 60°C for most
6.2 Typically, a total of 24 specimen chambers is used for
applications. It is possible that a few materials will have
testing during a 24-h vacuum operation; 3 of the chambers are
acceptable properties at the i
...
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