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The MICKit(tm)FPS can be used to test for microbes important in MIC of fire protection system piping. 


Testing For and Treating MIC

Monitor For MIC to Help Prevent Long-Term Effects

by Daniel H. Pope, Ph.D.

President, Bioindustrial Technologies, Inc.

Editor's Note: This is not intended to be an endorsement of any particular product or manufacturer. However, the number of questions we received regarding the article "Microbiologically Influenced Corrosion," which appeared in the July 1997 issue of Sprinkler Age, prompted us to provide additional information on testing for MIC.

What is MIC?

MIC is microbiologically influenced corrosion. Simply put, MIC is corrosion influenced by the activities of bacteria. MIC results in the formation of deposits (nodules) and subsequent severe under-deposit pitting. This can lead to blockage of pipes and rapid failure of the fire protection system (FPS) piping. It has recently been recognized that MIC in FPS is a problem throughout North America. Many different types of materials (e.g., steel and copper) and systems (e.g., wet and dry) are affected.

Testing for MIC in Your FPS

The MICkit™ FPS was developed by Bioindustrial Technologies, Inc. (BTI) to test for microbes important in MIC of fire protection system piping. Like BTI's other test kits, it is designed to be used by field personnel on-site. Rapid processing of the samples into the MICkit FPS is critical in obtaining accurate information about MIC-type bacteria. The MICkit FPS is used to enumerate viable bacteria of the following categories:

Aerobic bacteria: BTI-AERO media grows general aerobic bacteria (bacteria that require oxygen to live). Aerobes are very important in forming biofilms and nodules, with resulting biofouling (slime formation) and microbiologically influenced corrosion (MIC) in aerobic systems.

Acid-producing bacteria: BTI-APB media grows acid-producing bacteria (APB), which are microorganisms capable of producing organic acids. Organic acids are an important factor in biofouling and microbiologically influenced corrosion (MIC).

Sulfate-reducing bacteria: BTI-SRB media grows more types of sulfate-reducing bacteria (SRB) more rapidly than API RP-38. SRBs are strictly anaerobic bacteria which are an important factor in biofouling and microbiologically influenced corrosion (MIC).

Iron-related bacteria: BTI-IRB media grows iron-related bacteria (IRB) which are capable of precipitating iron through a variety of metabolic processes. These bacteria are responsible for forming nodules and deposits on surfaces (i.e., pipes).

Low nutrient bacteria: BTI-LNB media grows bacteria from samples containing low levels of organic foodstuffs (e.g., potable water, well water, demineralized water, condensates, etc.). These low nutrient bacteria (LNB) are aerobic bacteria that are very important in the processes of biofouling and MIC in systems using such water (i.e., FPS).

It is also important to determine the basic chemistry of the water being used in the system. Residual chlorine, hardness, and pH are important chemical parameters that should be measured. BTI also provides a kit for such tests.

Monitoring Your FPS for MIC

Responses to the July 1997 article about MIC indicated the problem can be found in a variety of U.S. regions and in different types of fire sprinkler system piping. Therefore, monitoring your piping for MIC can be important to your system's integrity no matter where you are located.

Monitoring for MIC in your fire protection system piping should include analysis of source water and water from several points in the system. If possible, examine the inside of one or more sections of pipe for the presence of nodules and bacteria. Monitoring should be done routinely since conditions can change over time.

What If You Have MIC?

The interior of the FPS must first be cleaned to remove existing deposits and other debris. Treatment with a biocide without prior cleaning will not stop existing MIC sites from continuing to corrode.

After cleaning the FPS, all water entering the system must be treated to kill microbes entering the FPS. Tests of the success of cleaning and treatment should be done routinely.

 

NOTE: For more Information, contact Bioindustrial Technologies, Inc. (BTI); at phone 800-798-4650 or Fax: 512-863-8097; Address: 40105 Industrial Park Circle, Georgetown, TX 78626; E-mail: bti_@hotmail.com or basic information guide available at: http://www.io.com/~bti/

 



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