MIC Remediation Prevention
You may have heard the term “MIC” used to describe corrosion issues in fire sprinkler systems. MIC, which stands for microbiologically influenced corrosion, is a very specific type of corrosion caused by the combination of bacteria and oxygen. Without testing your Fire Sprinkler systems for MIC, there is really know way to tell how long your system will last or how long until it needs to be replaced. Is it functioning properly right now? Metro Fire and Safety will perform an inspection and test to determine if your fire sprinkler system has bacteria corrosion problems. At that time, they can also treat the corrosion by your choice of mechanical cleaning, flushing, killing of the microbes on the interior wall of the pipe or chemical treatment of the water. What you need to know about MIC:
- What is MIC?
What is “MIC”?
MIC is the acronym for Microbiologically Influenced Corrosion. This particular mode of corrosion is the reaction of microbes causing or influencing other types of corrosion process’s, usually in metallic materials.
- What causes MIC?
What causes MIC?
A combination of bacterial microbes, water, oxygen, nutrients, and metal, causes MIC. These bacteria are omnipresent in the environment and in the piping materials. Microbial growth will occur when all of these conditions are present. When all the nutrients, such as oxygen, have been consumed the microbes may become dormant. When the nutrients are replenished, the microbial growth resumes. Replenishment of nutrients happens when new oxygenated water is introduced to the fire sprinkler system. This process can happen when: flow testing happens, draining and refilling the system, leaks in the piping, periodic filling or tripping the dry system.
- Why is MIC a problem?
Why is MIC a problem?
Consumption of the metal pipe occurs as the MIC bacterium grows. Tubercle’s are formed and pitting of the pipe takes place. The pipe walls then become compromised and the flow characteristics of the pipe become degraded.
- Example of Multiple Bacteria's Present
Example of Multiple Bacteria’s Present
- How do you Test for MIC?
How do you Test for MIC?
A simple test is performed. Using a “back-pak” test kit, a water sample can be taken from the pipe and tested. The nine day test period can determine what bacteria, or bacteria’s, are present in the pipe. This is the least expensive method and the least obtrusive method as well. With this test kit can essentially determine if the bacteria are present, what type of bacteria is present, what damage the bacteria is known for, and potentially how bad the problem is.
- Why should MIC testing be done?
Why should MIC testing be done?
NFPA 25 “Standard for the Inspection, Testing, and Maintenance of Water- Based Fire Protection Systems” requires an obstruction investigation every 5 years, or when there is evidence of rust, foreign debris, pinhole leaks, or a loss in flow pressure. The NFPA 25 requires that if “tubercles” are found or slimes and debris are observed, they shall be tested for MIC. (NFPA 25 2014 section 220.127.116.11).
- Can dry systems have issues with MIC?
MIC is almost always more prevalent in dry systems. After a dry system has been flushed, tripped, or had its 3 year full trip test, some water remains in the fitting edges, low points of the system, and of course the drops. The MIC bacteria find these conditions favorable, due to the high amounts of trapped oxygen and small to moderate pools of stagnate water.
All dry system use an air compressor to fill and monitor the dry side of the system. Most compressor’s however do not use a water separator or desiccant tower to remove the water vapor created by compressing the air. This potentially can and will fill the system over time with water vapor, which over a period of time will accumulate to water. This process attributes to the growth of MIC by providing a fa
vorable condition in the system piping for MIC to flourish.
- What steps can be taken if MIC is found?
What steps can be taken if MIC is found?
The early detection of MIC has proved to be significant in the treatment of MIC. Treatment can vary from mechanical cleaning, flushing, killing of the microbes on the interior wall of the pipe, chemical treatment of the water. If the MIC problem has reached a level where the pipe has been compromised, either by pin hole leaks, or significant thinning of the pipe wall, the pipes must be replaced. This can be expensive and disruptive to the building operations. Inspection’s done with a video bore scope at every 5 year cycle required by NFPA 25, is the best defense a building owner can take for progressively fighting the battle against MIC.
- How can Metro Safety and Fire provide you with a MIC solution?
How can Metro Safety and Fire provide you with a MIC solution?
Metro Safety and Fire test for MIC using a “Back-Pac” test kit. This test kit will test for all MIC causing bacteria, and will essentially determine how significant the MIC problem is. We also provide 5 year internal inspection for all systems using two different methods. The first method is visually inspecting the pipe per NFPA 25, at several different locations in the system, and providing an analysis with picture documentation. The second method is using a video bore scope on systems where opening up the pipe can be difficult or disruptive to the customer.