ASTM G131-96

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: G 131 – 96
Standard Practice for
Cleaning of Materials and Components by Ultrasonic
Techniques
This standard is issued under the fixed designation G 131; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This practice covers a procedure for the cleaning of 3.1 Definitions of Terms Specific to This Standard:
materials and components used in systems requiring a high 3.1.1 contaminant (contamination), n—unwanted molecular
level of cleanliness, such as oxygen, by ultrasonic techniques. and particulate matter that could affect or degrade the perfor-
1.2 This practice may be used for cleaning small parts, mance of the components upon which they reside.
components, softgoods, etc. 3.1.2 contaminate, v—a process of applying a contaminant.
1.3 The values stated in SI units are standard. 3.1.3 control coupon (witness coupon), n—a coupon made
1.4 This standard does not purport to address all of the from the same material and prepared in exactly the same way
safety concerns, if any, associated with its use. It is the as the test coupons, which is used to verify the validity of the
responsibility of the user of this standard to establish appro- method or part thereof.
priate safety and health practices and determine the applica- 3.1.3.1 Discussion—In this practice, the control coupon will
bility of regulatory limitations prior to use. Specific precau- be contaminated in the same manner as the test coupons and
tionary statements are given in Note 1. will be subjected to the identical cleaning procedure.
3.1.4 degas, v—the process of removing gases from a
2. Referenced Documents
liquid.
2.1 ASTM Standards: 3.1.5 nonvolatile residue (NVR), n—residual molecular and
D 1193 Specification for Reagent Water
particulate matter remaining following the filtration and con-
E 1235 Practices for Gravimetric Determination of Non- trolled evaporation of a solvent containing contaminants.
volatile Residue (NVR) in Environmentally Controlled
3.1.6 particle (particulate contaminant), n—a piece of mat-
Areas for Spacecraft ter in a solid state with observable length, width, and thickness.
F 311 Practice for Processing Aerospace Liquid Samples for
3.1.6.1 Discussion—The size of a particle is usually defined
Particulate Contamination Analysis Using Membrane Fil- by its greatest dimension and is specified in micrometres.
ters
4. Summary of Practice
F 324 Test Method for Nonvolatile Residue of Volatile
Cleaning Solvents Using the Solvent Purity Meter 4.1 A part, material or component is placed in a container
F 331 Test Method for Nonvolatile Residue of Halogenated containing the cleaning agent. This container is then placed in
Solvent Extract from Aerospace Components (Using Ro- an ultrasonic cleaner and treated for a given period of time at
tary Flash Evaporator) the recommended temperature for the cleaning agent. This
G 121 Practice for the Preparation of Contaminated Cou- results in a solution if the contaminant is soluble in the test
pons for the Evaluation of Cleaning Agents fluid or a emulsion if the contaminant is not soluble in the test
G 122 Test Method to Evaluate the Effectiveness of Clean- fluid. The cleaning solution combined with the rinse solutions
ing Agents may then be analyzed for particulate, NVR, or total carbon
(TC).
4.1.1 In the case of aqueous based agents, the parts are
rinsed after the removal from the cleaning bath and ultrasoni-
cally cleaned in reagent water to provide a solution for TC
This practice is under the jurisdiction of ASTM Committee G-4 on Compat-
analysis using G TC.
ibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is the
4.1.2 In the case of solvent based agents, the parts are rinsed
direct responsibility of Subcommittee G04.02 on Recommended Practices.
with fresh solvent, which is collected and combined with the
Current edition approved March 10, 1996. Published August 1996. Originally
published as G 131 – 95. Last previous edition G 131 – 95. solvent used in the cleaning process, and the NVR determined
Annual Book of ASTM Standards, Vol 11.01.
using Practice E 1235, Test Method F 324, or Test Method
Annual Book of ASTM Standards, Vol 15.03.
F 331, as appropriate.
Annual Book of ASTM Standards, Vol 10.05.
4.1.3 Particulate analyses may be performed by filtering the
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
G 131
final cleaning solution. The particles captured by the filter are high purity to permit its use without lessening the accuracy of
then counted using Test Method F 311. the determination. Detergents used shall be identified by
manufacturer and name (registered trademark, if any).
5. Significance and Use
7.3 Purity of Water—The water used shall meet the require-
5.1 This practice is suitable for the removal of contaminants ments of Specification D 1193, Type II.
found on materials, parts, and components used in systems
8. Procedure
requiring a high level of cleanliness, such as oxygen. Parts
8.1 Sample Preparation:
shall have been precleaned to remove visible contaminants
8.1.1 If cleanliness verification is to be performed on control
prior to using this procedure. Softgoods such as seals and valve
or test coupons, prepare the coupons in accordance with
seats may be cleaned without precleaning.
Practice G 121.
5.2 This procedure may also be used as the cleanliness
8.1.2 If cleanliness verification is to be performed on small
verification technique for coupons used during cleaning effec-
parts, measure the total surface area (S) in square centimetres
tiveness tests as in Test Method G 122.
or the mass in grams, or both, as applicable, to the nearest tenth
5.3 The cleaning efficiency has been shown to vary with the
of a milligram (M1). Record the surface area (S) and mass
frequency and power density of the ultrasonic unit. Low
(M1).
frequencies in the 20 to 25 kilohertz range have been found to
8.2 Preliminary Procedure:
damage soft metals such as aluminum and silver. Therefore, the
8.2.1 If a cleaning agent is being used that requires dilution
specifications of the unit and the frequencies available must be
or special preparation, carefully follow the manufacturer’s
considered in order to optimize the cleaning conditions without
instructions. Use Type II water to prepare the aqueous cleaning
damaging the parts.
agent solutions or as the actual cleaning agent.
6. Apparatus
NOTE 3—It has been found that many common hydrocarbon based
6.1 Ultrasonic Cleaner, with an operating frequency range
lubricants are effectively removed to acceptable levels using Type II water
at 50 to 55°C. More difficult to remove contaminants, such as fluorinated
between 25 and 90 kHz, a typical power range between 10 and
or silicone based lubricants, have typically been found to require the use
25 W/L, and a temperature controlled bath capable of main-
of surface active agents. Use Practice G 122 to evaluate the cleaning
taining a temperature between ambient and 70°C with an
effectiveness of the proposed cleaning agent.
accuracy of 2°C.
8.2.2 Fill the ultrasonic bath to the level specified by the
6.2 Parts Pans, stainless steel container with volumes
manufacturer with water. Place the support bracket in the
between 1 and 4 L.
ultrasonic bath, heat the ultrasonic bath to the desired tempera-
6.3 Bracket, stainless steel device capable of supporting the
ture, and degas the water for 10 min.
parts pans in the ultrasonic bath.
8.2.3 Clean the stainless steel sample parts pan to be used.
NOTE 1—The bracket should be designed to hang in the ultrasonic bath
Conduct the sampling procedure using the selected cleaning
without contact with the bottom.
agent without parts to verify the cleanliness of the parts pan.
Use the same sampling and analysis procedures that will be
7. Reagents
used on the actual parts. Determine the contamination level of
7.1 Solvents such as the following may be used: tetrachlo-
the parts pan, the blank value (B), which shall be less than the
roethylene (perchloroethylene), trichloroethylene, methylene
allowable contamination level for the items being cleaned or
chloride, and perfluorinated carbon fluids.
extracted. If the contamination level of the parts pan is greater
NOTE 2—Warning: Solvents such as tetrachloroethylene (perchloroet-
than that specified for the parts, reclean the parts pan until the
hylene), trichloroethylene, and methylene chloride have relative low
contamination level is less than the allowable contamination
threshold limit values and the user should refer to appropriate safe
specified for the parts.
handling procedures, particularly in open tanks. Many solvents are not
8.3 Cleaning Procedure:
considered to be compatible with oxygen and must be completely
8.3.1 Place the material or part(s) being cleaned in the
removed from cleaned components prior to the use of these components
in oxygen systems. The preferred method of removal shall be determined stainless steel parts pan.
by the user.
8.3.2 Pour a measured amount of the cleaning agent into the
stainless steel cleaning pan sufficient to cover the parts. Cover
7.2 Purity of Reagents—Reagent grade chemicals shall be
the parts pan with aluminum foil or a stainless steel lid, place
used in all tests. Unless otherwise indicated, it is intended that
the parts pan in the bracket in the ultrasonic bath, adjust the
all reagents conform to the specifications of the Committee on
water level in the bath such that it is above the cleaning agent
Analytical Reagents of the American Chemical Society where
level in the parts pan, and allow the cleaning agent and bath
such specifications are available. Other grades may be used,
temperature to equilibrate to the desired cleaning temperature.
provided it is first ascertained that the reagent is of sufficiently
Alternatively, preheat the parts pan and cleaning agent prior to
the placement of the materials or parts into the parts pan. Then
cover the parts pan with foil and place into the bracket in the
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
bath and allow the cleaning agent to equilibrate to the
listed by the American Chemical Society, see Analar Standards for Laboratory
temperature of the bath.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
8.3.2.1 Cleaning agent to parts surface area ratio shall not
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
2 2
MD. exceed 1000 mL/0.1 m ; the preferred ratio is 500 mL/0.1 m .
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
G 131
8.3.3 Clean the parts in the ultrasonic bath for 10 min. If an 8.5.3 Wash the parts pan and parts with 500 mL of Type II
aqueous detergent or surfactant solution was used for cleaning, water in three roughly equal portions and combine with the
thoroughly rinse the parts with Type II water and then perform Type II water from 8.5.2.
the ultrasonic procedure with fresh Type II water. Perform the 8.5.4 Use the combined volumes of water from 8.5.3 to
sampling procedure as soon as possible within a maximum
determine the TC of the sample using G TC.
time limit of 120 min after turning off the ultrasonic cleaner.
8.4 Sampling Procedure for Solvent Cleaned Parts: 9. Report
8.4.1 Remove the parts pan from the ultrasonic bath and
9.1 Report the following information:
remove the cover. Swirl the parts pan to mix the solvent.
9.1.1 Identification of the part or material being cleaned
8.4.2 After swirling, quickly decant the solvent from the
(including tradename, part number, serial number, proper
parts pan.
chemical name, ASTM designation, lot number, batch number,
8.4.3 Wash the parts pan and parts with 500 mL of fresh
and manufacturer),
solvent in three roughly equal portions and combine with the
9.1.2 Cleaning reagent,
solvent decanted from 8.4.2. Determine the particulate con-
9.1.3 Cleaning time,
tamination analysis using Practice F 311. Use the filtrate from
9.1.4 Cleaning temperature,
the particulate analysis as the sample for NVR analysis.
9.1.5 Frequency of the ultrasonic bath, kHz,
8.4.4 Determine and record the mass (M ) of the nonvolatile
9.1.6 Power density of the ultrasonic cleaner, W/L,
residue in milligrams to the nearest tenth of a milligram using
9.1.7 Volume of cleaning reagent used,
Practice E 1235, Test Methods F 324, or F 331. Ensure that the
9.1.8 Mass (M1) of parts cleaned, g, and
reported NVR is adjusted to subtract the NVR of an equivalent
9.1.9 Surface area, cm , and
volume of “blank” solvent.
9.1.10 Mass (M2) of thr NVR, g.
8.5 Sampling procedure for aqueous cleaned materials and
parts.
10. Keywords
8.5.1 Remove the parts pan from the ultrasonic bath and
remove the cover. Swirl the parts pan to mix the Type II water. 10.1 cleaning; contamination; contaminant; nonvolatile
8.5.2 After swirling, quickly decant the Type II water from residue; NVR; oxygen systems; TC; total carbon; ultrasonic
the parts pan. cleaning
APPENDIX
(Nonmandatory Information)
X1. SELECTION OF ULTRASONIC BATHS
X1.1 Introduction—This appendix describes technical in- X1.2.2.3 Number Per Load or Per Unit of Time—parts per
formation useful in the selection of ultrasonic baths for rack or basket, parts per hour.
aqueous extraction and cleaning applications. The following X1.2.2.4 Complexity—holes, blind holes, internal surfaces,
information was graciously provided by Blackstone Ultrason- hems, etc.
ics and is reprinted here with their permission. X1.2.2.5 Ratio of Part Surface Area to Part Size—Solid
cube versus typical heat exchanger.
X1.2 Designing an immersible ultrasonic transducer system
X1.2.3 The Contaminant Being Removed:
requires that several factors be taken into account. Each case is
X1.2.3.1 Removal Diffıculty—Light oil versus buffing com-
individual. The following list will give the reader some idea of
pound.
the parameters that should be defined. Later, each will be
X1.2.3.2 Thickness of Buildup—Holes plugged solid versus
considered as to its effect on the design of the system.
surface coat.
X1.2.1 The Tank:
X1.2.3.3 Sol
...