Standard Practice for Quantitative Accelerated Laboratory Evaluation of Extraction Solutions Containing Ions Leached from Thermal Insulation on Aqueous Corrosion of Metals
|Publication Date:||1 May 2019|
|ICS Code (Corrosion of metals):||77.060|
This practice covers procedures for a quantitative accelerated laboratory evaluation of the influence of extraction solutions containing ions leached from thermal insulation on the aqueous corrosion of metals. The primary intent of the practice is for use with thermal insulation and associated materials that contribute to, or alternatively inhibit, the aqueous corrosion of different types and grades of metals due to soluble ions that are leached by water from within the insulation. The quantitative evaluation criteria are Mass Loss Corrosion Rate (MLCR) expressed in mils per year determined from the weight loss due to corrosion of exposed metal coupons after they are cleaned.
This practice cannot cover all possible field conditions that contribute to aqueous corrosion. The intent is to provide an accelerated means to obtain a non-subjective numeric value for judging the potential contribution to the corrosion of metals that can come from ions contained in thermal insulation materials or other experimental solutions. The calculated numeric value is the mass loss corrosion rate. This calculation is based on general corrosion spread equally over the test duration and the exposed area of the experimental cells created for the test. Corrosion found in field situations and this accelerated test also involves pitting and edge effects and the rate changes over time.
The insulation extraction solutions prepared for use in the test can be altered by the addition of corrosive ions to the solutions to simulate contamination from an external source. Ions expected to provide corrosion inhibition can be added to investigate their inhibitory effect.
Prepared laboratory ionic solutions are used as reference solutions and controls, to provide a means of calibration and comparison.2
Other liquids can be tested for their potential corrosiveness including cooling tower water, boiler feed, and chemical stocks. Added chemical inhibitors or protective coatings applied to the metal can also be evaluated using the general guidelines of the practice.
The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
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.
2 The Uncertainty Test data have been moved to Appendix X4 because they are based on data obtained using laboratory fabricated old style test coupons. The precision and bias section, using the current practice of purchased test coupons, replaces this uncertainty data. The Uncertainty Test data is preserved (for historical purposes).