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.
1. 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.
2. Referenced Documents
D1066 Practice for Sampling Steam
D1129 Terminology Relating to Water
D1192 Specification for Equipment for Sampling Water and Steam in Closed Conduits
D1193 Specification for Reagent Water
D2777 Practice for Determination of Precision and Bias of Applicable Methods of Committee D19 on Water
D3370 Practices for Sampling Water from Closed Conduits
Index Terms
Ampoules; Bichromatic instrument; Boiler; Boiler feedwater; Color comparator method; Colorimetric analysis-water; Dissolved oxygen (DO); Glass ampoules; Instrumental measurement-water; Oxygen demand-water; Rhodazine D; Steam; Steam condensate; low-Level dissolved oxygen-water, test,; Ampoules; Bichromatic instrument; Boiler feedwater; Color comparator method; Colorimetric analysis; Dissolved oxygen (DO); Oxygen; Rhodazine D; Steam; Steam condensate; low-level (∧lt;100 [mu]g/L) dissolved oxygen (DO)-water, test; ICS Number Code 13.060.50
DOI: 10.1520/D5543-94R05
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Citing ASTM Standards
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