ASTM D4940-15(2020)

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:D4940 −15 (Reapproved 2020)
Standard Test Method for
Conductimetric Analysis of Water Soluble Ionic
Contamination of Blast Cleaning Abrasives
This standard is issued under the fixed designation D4940; 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.
1. Scope 2.2 Other Standard:
ISO 11127-6Preparation of Steel Substrates beforeApplica-
1.1 This test method describes a procedure for assessing
tion of Paints and Related Products - Test Methods for
blast cleaning abrasives for the presence of conductive-
Non-Metallic Blast CleaningAbrasives - Part 6: Determi-
potential, ionic contaminants by determining the total concen-
nation of Water-Soluble Contaminants by Conductivity
trationofwatersolubleconductivespeciesusingaconductivity
Measurement
test.
2.3 SSPC: The Society for Protective Coatings:
1.2 This test method does not identify the ionic species
SSPC-AB 1Mineral and Slag Abrasives
present nor provide quantitative results on each species.
SSPC-AB 2Cleanliness of Recycled Ferrous MetallicAbra-
sive
1.3 This test method is based on a volume comparison
among abrasives of similar sizes. A volume comparison is SSPC-AB 3Ferrous Metallic Abrasive
SSPC-AB 4Recyclable Encapsulated Abrasive Media
more closely related to surface area of the abrasives than is a
weight comparison.
3. Summary of Test Method
1.4 The values stated in SI units are to be regarded as
3.1 Abrasive and pure water are combined into a slurry that
standard. No other units of measurement are included in this
is stirred to leach the soluble salts from the abrasive. This
standard.
slurry is filtered and conductance of the filtrate is measured.
1.5 This standard does not purport to address all of the
The conductivity, which is related to the concentration of
safety concerns, if any, associated with its use. It is the
soluble ionic materials contaminating the abrasive, is calcu-
responsibility of the user of this standard to establish appro-
lated from the conductance and the cell constant.
priate safety, health, and environmental practices and deter-
4. Significance and Use
mine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accor-
4.1 Abrasive media may contain ionic contamination natu-
dance with internationally recognized principles on standard-
rally (for example, beach sand), from manufacturing (quench-
ization established in the Decision on Principles for the
ingwithcontaminatedwater),transportation,storageoruse(in
Development of International Standards, Guides and Recom-
the case of abrasive that is reused). Ionic contamination on the
mendations issued by the World Trade Organization Technical
abrasive may transfer to the surface during abrasive blast
Barriers to Trade (TBT) Committee.
cleaning, resulting in potential osmotic blistering, accelerated
underfilm corrosion and premature coating failure.
2. Referenced Documents
4.2 This test method describes a shop/field procedure for
2.1 ASTM Standards:
assessing the level of conductive species on an abrasive.
D1193Specification for Reagent Water
4.3 Abrasive standards published by SSPC (AB) and ISO
E832Specification for Laboratory Filter Papers
11126 provide tolerance levels for water soluble contaminants
of the abrasive.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
5. Apparatus
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.46 on Industrial Protective Coatings.
5.1 Conductivity Bridge and Cell—Any commercial con-
Current edition approved Feb. 1, 2020. Published February 2020. Originally
ductivity bridge and conductivity cell typically having a range
ɛ1
approved in 1989. Last previous edition approved in 2015 as D4940–15 . DOI:
10.1520/D4940-15R20.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 4th Floor, New York, NY 10036, http://www.ansi.org.
Standards volume information, refer to the standard’s Document Summary page on Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor,
the ASTM website. Pittsburgh, PA 15222-4656, http://www.sspc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4940−15 (2020)
of at least 5 µmho/cm to 10000 µmho⁄cm with built-in 6.3 Potassium Chloride (KCl or 0.02 N KCl solution).
temperature compensation is satisfactory. A dip-type, pipet-
7. Sampling
type, or cup-type cell may be used.
7.1 Sampling shall be as follows unless otherwise agreed
5.2 Filter Paper, conforming to Specification E832,Type 1,
upon between the purchaser and the seller. Take two 1-L
Class C, to keep silt from fouling the surfaces of the conduc-
samples of abrasive at random from different packages of each
tivity cell.
lot, batch, day’s pack, or other unit of production in the
NOTE 1—ISO 11127-6 is another method for assessing the level of
soluble salt contamination present in an abrasive. It differs from this test shipment. When no markings distinguishing between units of
method in two major areas:
production appear, take samples from the different packages in
(1)TheISOmethodusesaweighttovolumeratiobetweentheabrasive
the ratio of two samples for each 5000 kg, except that for
and the fluid (deionized water) used to extract soluble salts from the
shipments of less than 5000 kg, take two samples. Test the
abrasive. The ASTM method allows a user to measure a loose packed
samples separately.
volumeofabrasiveandmixthatabrasivewithanequalvolumeofreagent
water. The ISO method is well suited to use in a laboratory setting but is
poorly suited to use in the field. TheASTM method is well suited for use
8. Calibration and Standardization
in the field or laboratory.
8.1 Determination of Cell Constant:
(2)The ISO method reports the effect of the level of extracted salts in
terms of milliSiemens/m, whereas this test method uses µmho/cm. The 8.1.1 The conductivity cell will come with a predetermined
ISO method uses strict SI units, this test method reports using SI
constant. This constant should be checked periodically, one
compliant units.
method being as follows:
Method to Method Comparison:
8.1.1.1 Prepare a standard solution such as a 0.0005 N
The reader is warned that it is difficult to make direct comparisons
solution of KCl by diluting a 0.02 N KCl solution with water
between the results of these two different methods of analysis.
Weight/Volume versus Volume/Volume Method Considerations: or by dissolving 0.0372 g of KCl (weighed after heating for 1
In the ASTM Method the weight of the abrasive is not known; this
h at 105°C) in water, followed by dilution to 1 L. Cool and
makes it impossible to assess the ratio between conductivity values
measure the conductance at 25°C as described in Section 9.
determined using this test method procedure and those determined using
Calculate the cell constant, K , as follows:
the ISO 11127-6 procedure.
Comparisons Betw
...