ASTM C871-95(2000)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C 871 – 95 (Reapproved 2000)
Standard Test Methods for
Chemical Analysis of Thermal Insulation Materials for
Leachable Chloride, Fluoride, Silicate, and Sodium Ions
This standard is issued under the fixed designation C 871; 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 3.2.1 Amperometric-coulometric titration test method.
3.2.2 Titrimetric test method.
1.1 These test methods cover laboratory procedures for the
3.2.3 Specific ion electrode test method.
determination of water-leachable chloride, fluoride, silicate,
3.3 Analysis for Fluoride:
and sodium ions in thermal insulation materials in the parts per
3.3.1 Specific ion electrode test method.
million range.
3.3.2 SPADNS colorimetric test method.
1.2 Selection of one of the test methods listed for each of the
3.4 Analysis for Silicate:
ionic determinations required should be made on the basis of
3.4.1 Atomic absorption spectrophotometry test method.
laboratory capability and availability of the required equip-
3.4.2 Colorimetric test methods—AWWA Methods 4500-Si
ment.
D and 4500-Si E.
1.3 This standard does not purport to address all of the
3.5 Analysis for Sodium:
safety concerns, if any, associated with its use. It is the
3.5.1 Flame photometric test method
responsibility of the user of this standard to establish appro-
Test Methods D 1428.
priate safety and health practices and determine the applica-
3.5.2 Atomic absorption spectrophotometry test method.
bility of regulatory limitations prior to use.
3.5.3 Ross Sodium Ion-Sensitive electrode.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 It has been demonstrated that chlorides, when deposited
C 692 Test Method for Evaluating the Influence of Thermal
and concentrated on the surface of austenitic stainless steel, can
Insulations on the External Stress Corrosion Cracking
contribute to external stress corrosion cracking (ESCC).
Tendency of Austenitic Steel
Analysis for fluoride has been covered because Test Methods
C 795 Specification for Thermal Insulation for Use in Con-
C 871 is the “source document” for other standards that require
tact with Austenitic Stainless Steel
testing for leachable fluoride ions.
D 1428 Test Methods for Sodium and Potassium in Water
3 4.2 Testing has shown that, using the methodology of Test
and Water-Formed Deposits by Flame Photometry
Method C 692, neither fluoride nor iodide nor bromide initiates
2.2 AWWA Standards:
4 ESCC in the manner that can be demonstrated with chloride.
4500-Si D Molybdosilicate Method for Silica
After being exposed to 1500 mg/kg fluoride for 60 days with
4500-Si E Heteropoly Blue Method for Silica
no cracking, a change to 1500 mg/kg chloride resulted in
3. Summary of Test Methods
cracking in 3 days, as required by the metal qualification
procedure in Test Method C 692. Similar tests with iodide and
3.1 Insulation specimens are leached for 30 min in boiling
bromide showed that these ions do not promote ESCC as does
water. Tests to determine quantitatively chloride, fluoride,
chloride.
silicate, and sodium ions are performed on aliquots of the
4.3 Chlorides (and fluorides) may be constituents of the
filtered leachate solution.
insulating material or of the environment, or both. Moisture in
3.2 Analysis for Chloride:
the insulation or from the environment can cause chlorides
(and fluorides) to migrate through the insulation and concen-
trate at the hot stainless steel surface.
These test methods are under the jurisdiction of ASTM Committee C-16 on
Thermal Insulation and are the direct responsibility of Subcommittee C16.31 on
Chemical and Physical Properties.
Current edition approved June 15, 1995. Published August 1995. Originally
published as C 871 – 77. Last previous edition C 871 – 94. Available from VWR Scientific, Box 39396, Denver, CO 80239.
2 6
Annual Book of ASTM Standards, Vol 04.06. Dana, A. W., Jr., “Stress-Corrosion Cracking of Insulated Austenitic Stainless
Annual Book of ASTM Standards, Vol 11.01. Steel,” ASTM Bulletin No. 225, October 1957, pp. 46–52.
4 7
Standard Methods for the Examination of Water and Wastewater, 17th Edition, Insulation Materials, Testing, and Applications, ASTM STP 1030, ASTM, 1990,
American Public Health Association, Washington, DC, 1989. pp. 688–698.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 871
4.4 The presence of sodium and silicate ions in the insula- 7.1.3 Each sample should be placed in a suitable container,
tion has been found to inhibit external stress corrosion cracking protected from contamination, and oven dried at 230 6 10°F
caused by chloride (and fluoride) ions, whether such ions come (1006 5°C) to a constant weight (60.1 g) or overnight.
from the insulation itself or from external sources. Further-
8. Extraction Technique
more, if the ratio of sodium and silicate ions to chloride (and
fluoride) ions is in a certain proportion in the insulation,
8.1 Apparatus:
external stress corrosion cracking as a result of the presence of
8.1.1 Electronic Balance, capable of weighing to 2000 g
chloride (and fluoride) in the insulation will be prevented or at
with readability to the nearest 0.1 g.
least mitigated (see also Specification C 795).
8.1.2 Blender, Osterizer with jar-top thread preferred.
8.1.3 Beaker, 1-L stainless or Pyrex.
5. Reagents 10
8.1.4 Filter, Buchner with suitable filter paper.
5.1 Purity of Reagents—Reagent grade chemicals shall be 8.2 Using a closed-top blender, such as a 1-qt Mason jar
used in all tests. Unless otherwise indicated, it is intended that
with Osterizer blender blades, blend exactly 20.0 g of sample
all reagents shall conform to the specifications of the Commit- in approximately 400 mL of DI or distilled water for 30 s.
tee on Analytical Reagents of the American Chemical Society,
While most materials blend to a homogeneous mixture in 30 s,
where such specifications are available. Other grades may be some very hard materials may require 60 s or more.
used, provided it is first ascertained that the reagent is of
8.3 Quantitatively transfer the mixture to a tared 1-L stain-
sufficiently high purity to permit its use without lessening the less steel or Pyrex beaker, rinsing with distilled or DI water.
accuracy of the determination.
8.4 Bring to boiling and maintain at the boiling point for 30
5.2 Purity of Water— Distilled or deionized water (DI), 6 5 min.
having maximum conductivity of 2.5 μS/cm and containing
8.5 Remove from heat, and cool in a cold water bath to
less than 0.1 ppm of chloride ions shall be used in all tests. ambient temperature.
8.6 Remove water from the outside of the beaker and place
6. Sampling
on a balance. Add DI (or distilled) water to bring amount of
6.1 With low-chloride insulating materials, wear clean poly-
water up to exactly 500.0 mL (g).
ethylene gloves while taking and handling the sample to avoid 8.7 Stir mixture until it is uniform and filter through filter
chloride contamination from perspiration. Do not use gloves
paper to get a clear filtrate. If not clear after the first filtration,
made from chloride-containing compounds such as neoprene refilter through a finer filter paper. The first 100 to 200 mL of
or saran, or materials with metallic chlorides in their formula-
filtrate should be used to rinse the receiving flask and Solution
tions. Prior to use, rinse gloves twice, drain, and air-dry in a
A bottle. Complete this filtration by putting this filtrate in the
clean, halide-free environment. Store clean gloves in a closed bottle labeled Solution A. Since the relationship between solids
container or envelope.
and liquid has been established, it is not necessary to filter all
6.2 Materials with more than 25 ppm chloride may be of the extract. DO NOT WASH THE FILTER CAKE!
handled with clean, dry hands with no significant contamina-
8.8 Calculate the Gravimetric Conversion Factor (GCF) by
tion. dividing the weight of the water by the weight of the sample.
In the ideal case, this is 500/20 = 25. If weights are not exactly
7. Test Specimen
as prescribed, a correct GCF must be calculated and used.
7.1 Apparatus and tools used for special preparation and
8.9 With calsil it has been shown that it is not necessary to
leaching shall be clean and free of chlorides, fluorides, sili- pulverize the thin chips called for in 7.1.1. Equivalent results
cates, sodium, and acidic or alkaline materials that might affect
are obtained, and a lengthy filtration step is avoided, by
the chemical test. Distilled water must be used in all tests extracting the unpulverized chips.
unless deionized water has been shown to be adequate.
9. Test Procedures
7.1.1 For molded insulation, use a band saw or equivalent,
making several cuts through the entire cross section of each
9.1 Chloride Determination—One of the following test
piece of insulation to be tested. Each specimen shall be
methods shall be used on a fresh aliquot from Solution A:
representative of the entire cross section of the piece, except
9.1.1 Amperometric-Coulometric Titration Test Method—
that metal screen, or expanded metal used as a supportive
Use an apparatus in which direct current between a pair of
facing shall not be included. It is recommended that thin wafers
1 1
of material be cut between ⁄16 and ⁄8 in. (1.6 and 3.2 mm)
thick. Cut enough material for two 20-g samples.
One such apparatus found acceptable is the 10-speed Osterizer, manufactured
by the Oster Division, Sunbeam Corporation in Milwaukee, WI 53217. While Oster
7.1.2 Blanket fibrous materials may be cut into strips across
manufactures several models, all use the “jar-top thread” on the blade assembly,
the entire width of the blanket using clean, dry scissors.
making it possible to use a 1-qt Mason jar for the pulverization step of the
procedure.
Whatman 41, GF-A, or other filter paper is suitable for this purpose and
Reagent Chemicals, American Chemical Society Specifications, American commercially available.
Chemical Society, Washington, DC. For suggestions on the testing of reagents not Bowman, R. L., Cotlove, E., Trantham, H. V., “An Instrument and Method for
listed by the American Chemical Society, see Analar Standards for Laboratory Automatic, Rapid, Accurate, and Sensitive Titration of Chloride in Biologic
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia Samples,” Journal of Laboratory and Clinical Medicine, Vol 51, 1958, pp. 461–468.
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, An apparatus found acceptable is the Aminco-Cotlove Chloride Titrator, manufac-
MD. tured by American Instrument Co., Silver Springs, MD 20907.
C 871
silver electrodes causes electrochemical oxidation of the anode color produced becomes progressively lighter or different in
and produces silver ions at a constant rate. When all of the hue, depending on the reagent used.
chloride ions have combined with silver ions, the appearance 9.3 Silicate Determination—One of the following test meth-
of free silver ions causes an abrupt increase in current between ods shall be used on a fresh aliquot from Solution A. If
a pair of indicator electrodes. Because silver ions are generated Solution A is cloudy, it shall be refiltered through a 0.45-μm
at a constant rate, the amount used to precipitate the chloride millipore filter before use.
ions is proportional to the elapsed time. Hence, the chloride 9.3.1 Atomic Absorption Spectrophotometry Test Method—
content of the titration solution can be determined. Since the Atomize an aliquot from Solution A by means of a nitrous
coulometric titrator would not discriminate between chloride, oxide-acetylene flame. The absorption by the silicon atoms of
bromide, and iodide—all would test as chloride—in some radiation being emitted by a silicon hollow cathode lamp
cases it may be necessary to differentiate between the halides to source provides a measure of the amount of silicon present in
show chloride only, since the others have not been shown to the solution, using an atomic absorption spectrophotometer.
cause stress corrosion cracking in austenitic stainless steel. A 9.3.2 Colorimetric Test Method—This test method covers
chloride-sensitive electrode detects chloride only. the determination of soluble silica (SiO ) by the molybdosili-
9.1.2 Titrimetric Test Method —Add dilute mercuric ni- cate colorimetric procedure. In this test method, ammonium
trate solution to an acidified aliquot in the presence of molybdate at low pH reacts with soluble silicate or phosphate
diphenylcarbazone indicator. At the mercury-chloride equiva- to produce heteropoly acids. Oxalic acid is used to destroy the
lence point, a blue-violet, mercury-diphenylcarbazone com- molybdophosphoric acid but not the molybdosilicic acid. The
plex forms, which is proportional in intensity to the excess of intensity of the yellow molybdosilicate complex follows Beers
mercury ion present. The titrimetric procedure is independent law. This test method is an adaption of AWWA Methods 4500-
of practically all common interferences. Si D and 4500-Si E. If phosphates are not present as contami-
9.1.3 Specific Ion Electrode Test Method—The chloride- nants, the oxalic acid may be omitted to obtain a more stable
sensitive electrode consists of silver halide/silver sulfide mem- molybdosilicate complex.
branes bonded into the tip of an epoxy electrode body. When 9.3.2.1 Reagents:
the membrane is in contact with a chloride solution, silver ions (1) 10 % Ammonium Molybdate—Dissolve 10.0 g of
dissolve from the membrane surface and the electrode develops (NH ) Mo O ·4H O in distilled water, bringing final volume
6 7 24 2
a potential due to the silver ion concentration. This concentra- to 100.0 mL.
tion is in turn determined by the sample chloride ion concen- (2) Hydrochloric Acid—Dilute 125 mL of concentrated HCl
tration. This potential is measured against a constant reference to 500 mL to make 1:3.
potential with a digital pH/mV meter or specific ion meter. (3) Oxalic Acid—Dissolve 7.5 g of H C O ·2HOin
2 2 4 2
Operation and use should follow manufacturer’s recommended distilled water to make 100.0 mL.
procedures, especially noting any corrections for interferences (4) Silica—Prepare a standard silica solution from pure
to determinations. The chloride-sensitive electrode is not sodium metasilicate or from “Dilut-it” or equivalent concen-
reliable for chloride levels below 2 ppm in Solut
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