ASTM G121-98(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:G121–98(Reapproved2004)
Standard Practice for
Preparation of Contaminated Test Coupons for the
Evaluation of Cleaning Agents
This standard is issued under the fixed designation G121; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Fluids and Components
F312 Test Methods for Microscopical Sizing and Counting
1.1 This practice describes the procedure for the preparation
Particles from Aerospace Fluids on Membrane Filters
of single- and double-sided contaminated metallic test coupons
F324 Test Method for Nonvolatile Residue of Volatile
for the evaluation of cleaning agents. It is applicable for the
Cleaning Solvents Using the Solvent Purity Meter
evaluation of cleaning agents proposed for the cleaning of
F331 Test Method for Nonvolatile Residue of Solvent
oxygen-enriched systems and components. It also is applicable
Extract from Aerospace Components (Using Flash Evapo-
to other systems where contamination is a concern.
rator)
1.2 Several classes of contaminants most likely to be found
G63 Guide for Evaluating Nonmetallic Materials for Oxy-
in oxygen-enriched systems and components are identified.
gen Service
However, if the user of this practice has identified contami-
G94 Guide for Evaluating Metals for Oxygen Service
nants not included in these classes, such identified contami-
2.2 ANSI Standard:
nants may be substituted for the preparation of the test
B46.1 Surface Texture (Surface Roughness, Waviness, and
coupons.
Lay)
1.3 Preparation of nonmetallic substrates is not addressed,
although similar methodology may be used. Solvent and
3. Terminology
cleaning agent compatibility with the nonmetallic substrate
3.1 Definitions:
should be verified prior to the preparation of the test coupons.
3.1.1 contaminant, n—unwanted molecular and particulate
Typical nonmetallic materials utilized in oxygen systems are
matter that could affect or degrade the performance of the
contained in Guide G63.
components upon which they reside.
1.4 This practice may involve hazardous materials, opera-
3.1.2 contamination, n—a process of contaminating.
tions, and equipment. This practice does not purport to address
3.1.3 surface roughness, R , n—the arithmetic average de-
a
all of the safety concerns associated with its use. It is the
viation of the surface profile from the centerline, normally
responsibility of whomever uses this practice to consult and
reported in micrometres.
establish appropriate safety and health practices and deter-
3.1.4 nonvolatile residue (NVR), n—residual molecular and
mine the applicability of regulatory limitations prior to use.
particulate matter remaining following the filtration of a
2. Referenced Documents solventcontainingcontaminantsandevaporationofthesolvent
2 at a specified temperature.
2.1 ASTM Standards:
3.1.5 particle (particulate contaminant), n—a piece of mat-
D1193 Specification for Reagent Water
terinasolidstatewithobservablelength,width,andthickness.
E1235 Test Method for Gravimetric Determination of Non-
3.1.5.1 Discussion—The size of a particle is usually defined
volatile Residue (NVR) in Environmentally Controlled
by its great dimension and is specified in micrometres.
Areas for Spacecraft
3.1.6 molecular contaminant (nonparticulate contamina-
F303 Practices for Sampling for Particles in Aerospace
tion), n—the molecular contaminant may be in a gaseous,
liquid, or solid state.
3.1.6.1 Discussion—It may be uniformly or nonuniformly
This practice is under the jurisdiction of ASTM Committee G04 on Compat-
distributed, or be in the form of droplets. Molecular contami-
ibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is the
nants account for most of the NVR.
direct responsibility of Subcommittee G04.02 on Recommended Practices.
Current edition approved Sept. 1, 2004. Published September 2004. Originally
3.1.7 blank, n—the contamination level of the fluid when
approved in 1993. Last previous edition approved in 1998 as G121 – 98. DOI:
the test coupon is omitted.
10.1520/G0121-98R04.
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contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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G121–98 (2004)
3.1.7.1 Discussion—Sometimes referred to as “back-
ground” level.
3.1.8 control coupon (witness coupon), n—a coupon made
from the same material as the test coupons, but in this test
method is not coated with the contaminant.
4. Summary of Practice
4.1 A solution of the contaminant is applied to either one
side or both sides of the precleaned test coupons and dried
under standard conditions. The amount of contaminant on the
test coupons is determined. Nonmetallic material test coupons
used as inserts, seats, seals, etc. may also be prepared by this
procedure and are evaluated in the as-used condition.
4.2 Three methods of coupon preparation are provided:
Method A, NVR sample, single side
Method B, NVR sample, double side
Method C, NVR and particulate sample
5. Significance and Use
5.1 This practice will be suitable to direct the preparation of
test coupons with a known amount of contaminant on the
surface. A standard test coupon is described and a list of
contaminants that have typically been found in oxygen-
enriched systems and components is provided.
5.2 These coupons shall be used in the evaluation of
FIG. 1 Standard Test Coupon
cleaning agents for oxygen-enriched systems and components.
This will permit direct comparison within and between test
fluorinated aerospace fluids and greases,
facilities.
petroleum based oils and greases,
5.3 Materials used in other fluid handling systems such as
ester based oils and greases,
nitrogen,helium,hydrogen,gasoline,etc.mayalsobeprepared
phosphate esters,
for evaluation by this practice.
waxes,
chlorotrifluoroethylene based oils and greases,
6. Apparatus
inks,
6.1 Test Coupon—Metal panels of the same material as the
cutting oils, and
component part to be cleaned. Other alloys that may be used if
dye penetrants.
the specific alloy is unknown are included in Guide G94. The
7.2 Solvent-reagentgradeusedtopreparestandardsolutions
coupon configuration is shown in Fig. 1.
of contaminants which may include the following: 2-propanol,
NOTE 1—Thesurfacefinishofthetestcouponshouldbethesameasthe
2-butanone, hexane, Type II reagent water, or better, in
part to be cleaned.
accordance with Specification D1193, and perfluorinated car-
6.2 Balance-Range to a minimum of 50 g with an 0.1-mg
bon fluids.
accuracy capable of weighing to 60.1 mg.
NOTE 2—Warning: Solvents such as 2-propanol hexane and
6.3 Oven-Convection, capable of maintaining 50°C 6 5°C.
2-butanone are highly flammable. The reader should refer to appropriate
6.4 Spray Applicator—Capable to apply an even coat of
safe handling procedures.
contaminant; i.e., an artist’s airbrush, perfume atomizer, or a
7.3 Desiccant—e.g., silica gel.
spray device such as that used with window or tile cleaners has
7.4 Particulate contaminant—fine (0- to 80-µm), or coarse
been found to apply an even coating of the contaminant in a
(0- to 200-µm) dusts available commercially.
controlled manner.
6.5 Other standard equipment such as a vacuum filtration
8. Procedure
system, solvent resistant filters, gloves, laboratory glassware,
8.1 Coupon Preparation
syringes, pipettes, desiccator, laboratory tongs, tweezers, and
8.1.1 The test coupons shall be numbered and precleaned
wire.
prior to use; record the number. Determine the surface rough-
ness, R , of representative coupons of each alloy being
a
7. Reagents
evaluated per ANSI B 46.1 and record. Determine the surface
7.1 Contaminant materials-general classes of materials that
area to be contaminated (S) of each of the test coupons and
have typically been found in oxygen-enriched systems and
components as a result of the manufacturing, assembly, fabri-
cation, and construction processes include:
Dusts of varying particle sizes are available from the AC Spark Plug Division
silicone oils and greases, of General Motors, 1300-T N. Dort Hwy., Flint, MI 48556.
G121–98 (2004)
on the test coupon. It is recommended that the test coupons be air dried
record. Attach a handling wire through the hole at the top of
until no traces of a liquid phase are visible.
each of the test coupons. The preclean procedure shall be
performed in an ultrasonic cleaner with the coupons immersed
8.2.4 Test coupons s
...