ASTM D5543-94(2005)

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.

1.1 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:

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.