As a companion document to MR21525, this Technical Report provides results, review and commentary on many investigations of HSC and includes important literature data, references, background information, service experience and related standards that were utilized in the development of the AMPP MR21525. Most of the information in this Technical Report covers findings from HSC field experience and HSC data from brine/CP exposure tests or from other cathodic charging experiments. It is important to note, in the use of MR21525 and in the review of data contained herein, that HSC can also be induced from hydrogenating environments and conditions other than from just from CP exposure alone. A non-exhaustive list of such conditions is presented later in this Technical Report.
This report explains different types of corrosion phenomena and contributing factors of corrosion that can occur in fire protection systems (FPS), such as water corrosivity, MIC, trapped air (wet systems), residual water (dry systems), and pipe weld corrosion. The basis for selection of corrosion mitigation strategies for corrosion mitigation and management of FPS are also discussed.
Corrosion that results in pipe leakage or obstruction is the most significant issue for owners of water-based FPS or fire sprinkler systems, in terms of both cost and system reliability. Corrosion damage/products and mineral deposits can impair the effectiveness of sprinkler systems, leaving facilities vulnerable to uncontrolled fire loss even though they are equipped with fire protection systems. This report describes practices that have been successful in mitigating FPS corrosion.