Microbiologically Influenced Corrosion Remediation and Mitigation in Fire Protection Systems. At what risk to public health and the environment?

By: Doug Chartier, WHI USA, Inc.
Copyright©2004
Published in FPC Magazine June 2004

MIC causing bacteria seem to be everywhere. It has recently been reported that, evidence of their presence and by-products are even seen on Mars. It is now known that MIC causing bacteria are present, to some degree, in almost all of our potable and municipal water supplies. It is a worldwide problem & the effects are experienced and paid for by all of us, in many ways.

MIC causing bacteria presence first became of concern in the fire protection industry in 1998. A nursing home in Iowa was exposed to a malfunction in their sprinkler system, when tripped by a fire. The NFPA, in updated versions of Codes 13 & 25, quickly addressed this problem. MIC committees were formed & continue on to the date of this article.

We have now identified the problem. The question is, “Are we approaching Remediation & Mitigation in the proper way?”

The Future

It is estimated that the fire sprinkler market will continue to grow in the United States with 35 to 40 million sprinklers installed annually & on a worldwide basis, approximately 70 million . It may be assumed that MIC bacterium infection will also increase, endangering life & property around the world.

MIC bacteria have been reported to be extremely aggressive with corrosion rates recorded as high as 20 – 100 MPY (mils per year) ! This makes the integrity of 4-inch schedule-40 pipe, suspect to failure within one year. Never mind, the risk to the popular thin-walled pipe (schedule-10). Neither are long-term assets if MIC is Identified & not controlled.

Biocides

MIC is found in many industries & has been a lengthy problem in Oil & Gas, Water Treatment, Textiles, Nuclear, Pulp & Paper & numerous other industries where water usage is part of the process. How have these industries confronted the MIC problem? They have the most experience combating MIC in the workplace.

Biocides are commonly used in these industries to combat MIC & have recently been adopted by the fire sprinkler industry for mitigation of MIC. There are several problems with using biocides in fire sprinkler systems, which protect people & property:

• The EPA defines “Biocides” as, “A diverse group of poisonous substance including preservatives, insecticides, disinfectants and pesticides used for the control of organisms that are harmful to human or animal health or that cause damage to natural or manufactured products.”The EPA requires that biocides be registered. This does not make them less poisonous, but allows the chemicals to be used under certain guidelines. Should we be using such methods in fire protection systems, to protect the public at large? The industries that have historically used biocides have very little– if any, public exposure. Therefore, there are only a few reported instances when the public has been exposed to biocides in these industrial processes.What happens when a fire sprinkler system is tripped in a crowded retail store or nursing home? Do we really want to atomize dangerous biocides in the air and possibly be inhaled by people, exiting the building?
• The fire sprinkler industry must look at this high-risk procedure differently than other industries. The threat to the public is too high, as is the liability & the possibility of litigation. Biocides are also adverse to our environment, contaminating our land, streams, lakes & seas. Use of them; follows property owners and managers (liability) in Environmental Remediation of real estate and facilities.
• MIC bacterium become “immune” to biocides when used over a period of time. Thus creating immunity to the exact bacterium species we are trying to kill. Their action is to mutate, so they are not affected by that certain biocide much the same way antibiotics become ineffective, if used too often. Biocides must be rotated on a regular scheduled basis to be effective. Eventually, the bacterium become immune to all of the available biocides and ineffective in killing the MIC bacterium creating, “Super-Bacterium”.

Coatings:

Another philosophy to mitigate MIC is more palatable: Coat the internal diameter of the piping or tubing so bacterium cannot attach to start a colony formation (biofilm). This idea has been proven a viable option. Why try to kill all the MIC causing bacteria when you can protect the piping, tubing & fabricated product. We are trying to control corrosion and protect our assets, in an environmentally friendly manner. After all, it is well known that biocides are Ineffective and hazardo us.

Let us look at the various kinds of coatings. Not all coatings are created equally.

Conventional coatings group

This group is most familiar to all of us. We see them every day from the paint on our car & house, to tar coatings on pipelines. They create a “Physical Barrier” to chemical corrosion, such as oxygen-cell corrosion and the formation of Rust.

Do they protect from MIC causing bacterium? Not very well. These coatings usually have a polymeric basis and form a coating, which is susceptible to micro-cracking (from film shrinkage) allowing MIC bacteria an entrance to start forming corrosive colonies underneath. This affects the integrity of the iron by honeycombing the pipe walls, like swiss cheese. Thus, giving a false sense of protection, sometimes not evident to the naked eye. These are obviously not a good choice for MIC protection.

Permanent biostatic coatings

This group is a definite improvement over conventional coatings. They are coatings which contain molecules that ward off MIC bacterium attachment and colony formations. They are a good solution for various applications. However, they do have some drawbacks when used in fire protection systems:

Most fire protection systems are fabricated on site. They contain many components & only the coated part of the system will be protected from MIC. In fact the new welds, threads, sprinkler heads and valves will experience an accelerated MIC problem. This is due to the bacterium competing for a place of attachment on limited surface area. The MPY (mils / year) corrosion rate, on these uncoated components, may exceed corrosion rates of a completely unprotected FPS system. FPS system life can be extremely shortened. There are also environmental concerns with many of these coatings.

Dynamic biostatic coatings

This is a classification of coatings, which is relatively new. They may be applied on FPS pipe, tubing or other components. Once a product is coated with the dynamic biostatic coating, it is put into service and becomes part of the overall FPS system. These coatings are somewhat water soluble. When a fire sprinkler system is filled with water, some of the coating becomes soluble and the molecules become of equal concentration throughout the system (by a process called ionic-diffusion).

The dynamic coatings are attracted to the component’s surface with a chemical reaction, which bonds the coating to all uncoated metallic surface areas. Thus coating the entire fabricated system. Coating concentration can be measured, in the sprinkler system water. When the concentration becomes low; a maintenance canister can be added to boost the level. They are environmentally friendly, non-regulated & non-hazardous to people, land or bodies of water. The level of dynamic biostatic coating must be maintained, Periodically (Usually Once-year).

WHI USA, Inc. has recently been awarded a U.S. Patent on a dynamic biostatic coating (U.S. # 6,517,617). We have developed this product for fire sprinkler systems to be non-hazardous, environmentally friendly, economical, & convenient to use. We call this product “Par-Guard” and more information is available on our website Par-Guard.com. You may also call (303.257.1978) or e-mail ( Info@Par-Guard.com ) for information as to how it may apply to your MIC problem.

In summation, it is the author’s belief that a good part of the solution to MIC in fire protection systems is the employment of “Dynamic Biostatic Coatings” to ward off the attachment of MIC bacterium and colony formation. We believe “Par-Guard” is the solution for MIC control in FPS. One thing is certain: We must widen our spectrum in the remediation & mitigation of MIC in FPS. The public and the environment are currently at a very unnecessary risk.

Doug Chartier President/CEO of WHI USA, Inc.

Doug has been involved in MIC for 24 years & is a “Hands On” Field Chemist. Starting in the Oilfield as a Researcher for a Fracturing & Acidizing Corporation, Doug is the co-author of various patents. He was recently awarded a US Patent on a dynamic biostatic coating for FPS titled, “FPS MIC remediation & mitigation methods and apparatus #6,517,617”. He has worked in a variety of industries where MIC corrosion is a problem: Oil & Gas, FPS, Cooling Towers, Nuclear, Pulp & Paper, Concrete, Metal Stock, Tubing & Pipe Manufacturing & Water Treatment Facilities. Doug was educated at Adams State College, Colorado State University & University of Colorado. He is well versed in both chemistry & biology. Doug is a member of the NFPA & ACS (American Chemical Society).