ASTM D5543-94(2005)
(Test Method)Standard Test Methods for Low-Level Dissolved Oxygen in Water
Standard Test Methods for Low-Level Dissolved Oxygen in Water
SIGNIFICANCE AND USE
Dissolved oxygen is detrimental in certain boiler and steam cycles because it may accelerate corrosion. Concentrations above 10 μg/L are unacceptable in many high-pressure boiler systems. The efficiency of dissolved oxygen removal from boiler feedwater by chemical or mechanical means, or both, is determined by measuring the concentration before and after the process. The measurement is also made to check for air leakage into the boiler system.
The oxygen treatment method for boiler corrosion reduction requires injection of oxygen into the boiler feedwater. The resulting oxygen level is monitored for control purposes.
SCOPE
1.1 These test methods cover the determination of low-level (∧lt;100 [mu]g/L) dissolved oxygen in thermal-cycle steam condensate, deaerated boiler feedwater, boiler water, and deaerated deionized water. The following test methods are included: Range, mg/L Sections Test Method A--Color Comparator Test 0 to 100 8 to 17 Method Using Self-Filling Glass Ampoules Test Method B--Instrument Test Method 0 to 100 18 to 26 Using Self-Filling Glass Ampoules
1.2 These test methods may be applicable to electronic-grade, pharmaceutical-grade, and other high-purity waters, although these were not addressed in the collaborative study.
1.3 Test Method A is a colorimetric procedure applicable to dissolved oxygen in water in the range from 0 to 100 [mu]g/L.
1.4 Test Method B is an instrumented colorimetric procedure applicable to dissolved oxygen in water in the range from 0 to 100 [mu]g/L.
1.5 It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.
1.6 The values stated in SI units are to be regarded as the standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation:D 5543–94 (Reapproved 2005)
Standard Test Methods for
Low-Level Dissolved Oxygen in Water
This standard is issued under the fixed designation D 5543; 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 D 1192 Specification for Equipment for Sampling Water
and Steam in Closed Conduits
1.1 These test methods cover the determination of low-level
D 1193 Specification for Reagent Water
(<100µ g/L) dissolved oxygen in thermal-cycle steam conden-
D 2777 Practice for Determination of Precision and Bias of
sate, deaerated boiler feedwater, boiler water, and deaerated
Applicable Methods of Committee D19 on Water
deionized water. The following test methods are included:
D 3370 Practices for SamplingWater from Closed Conduits
Range, µg/L Sections
Test Method A—Color Comparator Test 0to100 8to17
3. Terminology
Method Using Self-Filling Glass
Ampoules
3.1 Definitions—For definitions of terms used in these test
Test Method B—Instrument Test Method 0 to 100 18 to 26
methods, refer to Terminology D 1129.
Using Self-Filling Glass Ampoules
1.2 These test methods may be applicable to electronic-
4. Significance and Use
grade, pharmaceutical-grade, and other high-purity waters,
4.1 Dissolved oxygen is detrimental in certain boiler and
although these were not addressed in the collaborative study.
steam cycles because it may accelerate corrosion. Concentra-
1.3 Test MethodAis a colorimetric procedure applicable to
tions above 10 µg/L are unacceptable in many high-pressure
dissolved oxygen in water in the range from 0 to 100 µg/L.
boiler systems. The efficiency of dissolved oxygen removal
1.4 Test Method B is an instrumented colorimetric proce-
from boiler feedwater by chemical or mechanical means, or
dure applicable to dissolved oxygen in water in the range from
both, is determined by measuring the concentration before and
0 to 100 µg/L.
after the process. The measurement is also made to check for
1.5 It is the user’s responsibility to ensure the validity of
air leakage into the boiler system.
these test methods for waters of untested matrices.
4.2 The oxygen treatment method for boiler corrosion
1.6 The values stated in SI units are to be regarded as the
reduction requires injection of oxygen into the boiler feedwa-
standard.
ter. The resulting oxygen level is monitored for control
1.7 This standard does not purport to address all of the
purposes.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Reagents
priate safety and health practices and determine the applica-
5.1 This test method does not require the preparation of any
bility of regulatory limitations prior to use.
reagents.All the necessary analytical reagents are provided by
the manufacturer in sealed ampoules.
2. Referenced Documents
5.2 Purity of Water—Unless otherwise indicated, references
2.1 ASTM Standards:
to water shall be understood to mean reagent water as defined
D 1066 Practice for Sampling Steam
by Type II of Specification D 1193.
D 1129 Terminology Relating to Water
6. Precautions
6.1 Users must exercise caution by using finger cots, in
These test methods are under the jurisdiction of ASTM Committee D19 on
accordance with the manufacturer’s instructions, when han-
Water and are the direct responsibility of Subcommittee D19.03 on Sampling of
Water and Water-Formed Deposits, Analysis of Water for Power Generation and
dling the mixing of sample and reagent in the glass ampoules.
Process Use, On-Line Water Analysis, and Surveillance of Water.
Current edition approved Jan. 1, 2005. Published January 2005.
7. Sampling
Originally approved in 1994. Last previous edition approved in 1999 as
e1
7.1 Sampling is the most critical part of any dissolved
D 5543 – 94 (1999) .
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
oxygen test. The sample stream must be completely leak-free,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Withdrawn.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5543–94 (2005)
since even the smallest leak can elevate the oxygen level in the 10.4 The following interferences occur in the presence of
sample and cause large errors in the results. New or intermit- 2200 mg/L boron present as boric acid: (1) at pH levels below
tentlyusedsamplingsystemsmustbepurgedforaminimumof pH 6, recovery can be as low as 80 %; ( 2) added hydrogen
4 h. Sample streams that are used routinely may require only a peroxide at a concentration of 0.1 mg/L yields a positive
few minutes of purging. interference of 10 µg/L dissolved oxygen; and ( 3) added
7.2 Collect the samples in accordance with Practices hydrogen peroxide in a concentration range from 0.5 to 650
D 1066 and D 3370 and Specification D 1192. mg/L yields a positive interference of 20 to 25 µg/L.
7.3 With water under pressure, connect a tube of inert
NOTE 1—Measurements of 0 to 100 µg/L of dissolved oxygen are
material to the inlet and extend the tube outlet to the bottom of
unaffectedbythepresenceof2200mg/LboronpresentasboricacidatpH
the sample bottle or tube. Use stainless steel, Type 304 or 316,
6 and above in the absence of hydrogen peroxide.
or glass tubing with short neoprene connections. Do not use
10.5 Benzoquinone, an oxidation product of hydroquinone,
copper tubing, long sections of neoprene tubing, or other types
interferes with this test method. One hundred micrograms per
of elastomeric polymeric materials. If the water being sampled
litreofbenzoquinonemayappearas33µg/Ldissolvedoxygen.
is above room temperature, the sample line shall contain a
10.6 Reducing agents such as hydrazine and sulfite do not
suitable cooling coil to cool it to approximate room tempera-
interfere at 5-mg/L (ppm) levels in the sample.
ture.
10.7 Ampoules must be protected from light to prevent
darkening. Follow the manufacturer’s storage recommenda-
TEST METHOD A—COLOR COMPARATOR TEST
tions.
METHOD USING SELF-FILLING GLASS AMPOULES
10.8 Colorcomparatortubesmustbeprotectedfromlightto
8. Scope
prevent fading. Follow the manufacturer’s storage recommen-
dations.
8.1 This test method covers the rapid, routine determination
of dissolved oxygen in steam condensate, deaerated boiler
11. Apparatus
feedwater, and deaerated deionized water. Color comparators
allow the estimation of concentrations ranging from 0 to 100 11.1 Color Comparator,for0,2,4,6,8,12,16,and20µg/L
µg/L (ppb) oxygen. (ppb) of oxygen.
8.2 This test method was tested in steam condensate, 11.2 Color Comparator, for 0, 5, 10, 15, 20, 25, 30, and 40
deaerated boiler feedwater, and deaerated deionized water. It is µg/L (ppb) of oxygen.
the user’s responsibility to ensure the validity of the test 11.3 Color Comparator, for 0, 10, 20, 30, 40, 60, 80, and
method for waters of untested matrices. 100 µg/L (ppb) of oxygen.
11.4 Sampling Tube. See Fig. 1.
9. Summary of Test Method
9.1 The tip of a partially evacuated sealed ampoule is 12. Reagents and Materials
broken while submerged in a flowing water sample. The
12.1 Sealed, evacuated glass ampoules containing oxygen-
sample is drawn into the ampoule where it reacts instanta-
sensitive indicator.
neously with the oxygen-sensitive indicator to produce a
reddish violet color whose intensity is proportional to the
concentration of dissolved oxygen.
10. Interferences
10.1 Color, turbidity, and oxidizing impurities interfere in
this test method to yield high results. If the sample is colored
or turbid or contains oxidizing impurities, the amount of
interference that may be contributed by such effects must be
determined independently prior to using this test method.
10.2 Easily reduced metal ions may interfere in this test
method to cause high results. For example, 100 µg/L (ppb) Cu
+2 may appear as 5 µg/L(ppb) dissolved oxygen, and 100 µg/L
+3
Fe may appear as 7 µg/L dissolved oxygen. However, less
+2 +3
than 50 µg/L Cu or Fe cause less than 1-µg/L interference.
10.3 Hydrogen peroxide alone in concentrations up to 200
µg/L does not affect the measurement of 1.5 µg/L of dissolved
oxygen.Above 200 µg/Lhydrogen peroxide, there is a positive
interference of 3.3 µg/L dissolved oxygen per 100 µg/L excess
over 200 µg/L hydrogen peroxide.
Spokes, G. N., Dissolved Oxygen in Water Measurement and Standardization,
EPRI PWR Plant Chemists’ Meeting, San Diego, CA, Nov. 17–20, 1992. Copies FIG. 1 Sampling Tube for Use with Ampoules to Measure
obtainable from CHEMetrics Inc., Route 28, Calverton, VA 22016. Dissolved Oxygen in a Flowing Water Sample
D 5543–94 (2005)
13. Sampling determine the level of dissolved oxygen in the sample. Place
the ampoule in the center (empty) tube of the comparator, with
13.1 Attach the feedwater source to the plastic sampling
theflatenddownward.Directthetopofthecomparatortoward
tube as described in 7.3. Clamps may be attached to the tube to
a source of bright, white light while viewing from the bottom.
hold it vertical, or it can be attached to a vertical rod or pipe
Hold the comparator in a nearly horizontal position, and rotate
above a sink, drain, or bucket.
it until the color standard below thc ampoule shows the closest
match. Complete this color matching procedure in less than 30
14. Calibration and Standardization
s after snapping the tip in the sample.
14.1 No calibration is required.
NOTE 5—The color intensity may continue to increase after the rapid
NOTE 2—The color comparator standards are precalibrated by the
initial color reaction. However, it is the initial color reaction that is
manufacturer for measurement of dissolved oxygen in water.
complete within 30 s, and to which the system calibrations apply.
14.2 A dissolved-oxygen-in-water standard may be gener-
15.4.1 Find the analytical result from the concentration
ated by following the procedures given in Appendix X1.
value of the closest matching color standard as designated on
the comparator label. Estimate the concentration to within a
15. Procedure
half color standard interval.
15.1 Insert the ampoule into the sampling device, with the
pointed end down. Allow the sample to flow at least 5 min.
16. Calculation
A15-min wait time may be necessary to achieve the best
16.1 The dissolved oxygen content of the sample is the
accuracy for samples with below 20 µg/Lof dissolved oxygen.
value obtained in 15.4. Use the average of the two resulting
15.2 Gently press the ampoule toward the wall of the
values if two ampoules are used.
sampling tube to snap off the tip, and remove thc ampoule,
keeping the tip down, immediately after filling is complete. 5
17. Precision and Bias
15.3 Usingaprotectiverubberfingercot,placeafingerover
17.1 The overall precision and bias of this test method
the broken tip. (Warning—glass may be sharp.) Invert the
cannot be determined by round-robin testing because of the
ampoule several times to mix the contents, allowing the bubble
instability of shipping solutions.
to travel from end to end each time. Wipe all liquid from the
17.2 This test method was evaluated for single-operator
exterior of the ampoule.
precision by eight laboratories, with a total of 15 operators
NOTE 3—A small bubble of inert gas will remain in the ampoule to
running a total of 200 samples in triplicate. The collaborative
facilitate mixing.
test data were obtained on the samples available at the
NOTE 4—Due to the possibility of air leaking in during this step, it is
laboratory site locations. These data may not apply for other
advisable to run tests in duplicate. It should be noted, however, that some
matrices.
variation in observed concentrations may be due to changes in system
17.2.1 The single-operator precision, S , of this test method
conditions. o
was found to be dependent on the ampoule type and to be
15.4 Use the color comparator as illustrated in Fig. 2 to
partly dependent on the dissolved oxygen content of the
sample. The data are summarized in the tables that follow.
17.2.1.1 Thedatainthefollowingtablewereobtainedusing
0 to 20-µg/L (ppb) range ampoules and comparators. A total
of 66 samples was measured in triplicate by a total of 15
operators in 8 laboratories:
Range, µg/L (ppb) 0 to 0.9 1 to 4.9 5 to 9.9 10 to 14.9 15 to 20
S 0.20 1.6 2.5 1.4 3.2
o
17.2.1.2 Thedatainthefollowingtablewereobtainedusing
0 to 40-µg/L (ppb) range ampoules and comparators. A total
Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR: D19–1153.
CHEMetrics Catalog No. K7511 kits or R7511 ampoule with a C7511
comparator The sole source of supply of the apparatus known to the committee at
this time is CHEMetrics, 4295 Catlett Road, Calverton, VA20138. If you are aware
of alternative suppliers, please provide this information to ASTM International
Headquarters.Your comments will receive careful consideration at a meeting of the
responsible technical committee , which you may attend.
CHEMetrics Catalog No. K7540 kits or R7540 ampoule with C7540 compara-
tor. If you are aware of alternative suppliers, please provide this information to
FIG. 2 Use of the Comparator—Test Method A ASTM International Headquarters.
D 5543–94 (2005)
of 78 samples was measured in triplicate by a total of 14 22. Reagents and Materials
operators in 7 laboratories:
22.1 Sealed, evacuated glass ampoules containing oxygen-
Range, µg/L (ppb) 0 to 1.9 2 to 9.9 10 to 19.9 20 to 29.9 30 to 40
sensitive indicator.
S 0.15 1.4 2.8 2.7 2.2
o
23. Sampling
17.2.1.3 Thedatainthefollowingtablewereobtainedusing
0 to 100-ppb range ampoules and comparators. A total of 56 23.1 Attach the feedwater source to the plastic sampling
tube in accordance with 7.3. Clamps may be attached to the
samples was measured in triplicate by a total of 10 operators in
6 laboratories. tube to hold it vertical, or it can be attached to a vertical rod or
pipe above a sink, drain, or bucket.
Range, µg/L (ppb) 0 to 4.9 5 to 19.9 20 to 39.9 40 to 59.9 60 to 100
S 0.95 1.1 1.4 5.3 2.9
o
24. Calibration and Standardization
17.3 Eight independent laboratories (and a total of fifteen
24.1 Nocalibrationisrequired.Acalibrationcheckampoule
operators) participated in this study. Precision testing for this
is provided by the manufacturer.
test method conforms to Practice D 2777.
24.2 A dissolved-
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