How often do I need to test for corrosion and/or MIC?
The 2017 edition of the National Fire Protection Association (NFPA 25) “Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems,” addresses the requirements for investigating possible corrosion and other possible pipe obstructions in water based systems in Chapter 14, Internal Piping Condition and Obstruction Investigation. NFPA standards can be purchased and viewed online at http://www.nfpa.org/codes-and-standards. Note the minimum required inspection frequency for internal pipe conditions is 5 years but can be extended provided a risk assessment is performed. Also, note that the code does require that microbiologically influenced corrosion (MIC) be tested for should any investigation find tubercles or slime.
How do I deal with corrosion in my system?
NFPA 13 “Standard for the Installation of Sprinkler Systems” does not allow the use of additives or chemicals to stop leaks according to Chapter 4 General requirements under Section 4.4 except for the use of biocides and other chemicals approved for the prevention and mitigation of MIC as long as they do not impact the performance of the fire sprinkler system (A.4.4). Nitrogen or other approved gas is allowed in sprinkler systems where air is used to charge, maintain, or supervise the system according to Section 4.5.
For more information about corrosion and how it specifically impacts fire sprinkler systems, FM Global published the Property Loss Prevention Data Sheet 2-1 in October of 2016 titled, “Corrosion in Automatic Sprinkler Systems.” This document is available for free at www.fmglobal.com/research-and-resources/fm-global-data-sheets. The data sheet provides recommendations for the prevention and control of corrosion in fire sprinkler systems as well as background information on various issues. MIC, for example, is addressed in Section 3.7 where they talk about the chemistry of MIC, how responsible it is for corrosion issues, and how to deal with it. Specifically, FM Global states, “In many cases, the presence of MIC-related bacteria may exert some influence on corrosion in fire protection systems, but not as a major contributor. Therefore, it is necessary to evaluate all corrosion parameters before determining the causes of corrosion.” They discuss the need to evaluate chemical, microbiological, metallurgical, and operational data to get a true picture of what is going on. Also, note in Section 3.7.5 that “chemical treatment to mitigate MIC is not recommended.” Replacement of affected piping sections is recommended.
More publications on corrosion in fire sprinkler systems are available online through governing bodies as well as commercial entities. Presentations at conventions such as NFPA, AFSA, and NFSA are also great sources of information. It is important to stay up to date with the latest information since evaluation and treatment methods can change as our understanding of how these systems are affected by corrosion and react to treatment methods increases.
What companies can help me with my corrosion issues?
Dyne currently does not offer any corrosion assessment services. There are a variety of other companies, however, that can specifically help with your corrosion issues including the following:
Does Dyne recommend any of these laboratories?
Dyne does not currently recommend any particular corrosion assessment company. We do suggest you review the information on corrosion and MIC before making a decision as companies can have different approaches to assessing and dealing with your specific issue. The use of nitrogen versus chemical treatments specifically can vary from company to company.
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