The State of Sprinklers: MIC, Recalls and New NFPA Standards

CONSULTING-SPECIFYING ENGINEER (CSE): Central Sprinkler's recall of 5 million Omega sprinklers, the recall of dry-pendant sprinklers and now o-ring replacements in glass-bulb and solder-link sprinklers potentially affecting 35 million in- stalled sprinklers brings into question sprinkler reliability.

By Barbara Horwitz, Associate Editor October 1, 2002

CONSULTING-SPECIFYING ENGINEER (CSE): Central Sprinkler’s recall of 5 million Omega sprinklers, the recall of dry-pendant sprinklers and now o-ring replacements in glass-bulb and solder-link sprinklers potentially affecting 35 million in- stalled sprinklers brings into question sprinkler reliability. Are manufacturers sufficiently addressing this crucial issue? In what ways?

HANKINS: Unfortunately, the response by manufacturers has been mostly reactive in that identified problems are corrected as they arise. But th
e more fundamental issue is that competitive pressures have resulted in a wide variety of cost-cutting methods whose long-term impacts have not been considered or are difficult to predict. It is not beyond the realm of possibility that the next “problem sprinkler” is on the market today.

PRYMAK: It’s important to note that manufacturers are unable to control the atmospheres into which sprinklers are placed, as well as the microbes that may be present in water supplies to the sprinklers. Sprinklers in some locations are exposed to environments that were never anticipated during the product design and laboratory approval process.

BELLAMY: The real measure of integrity for the industry is not in what problems are discovered, but how the industry reacts to such problems. F
or example, I think the proposed replacement program for the affected sprinklers represents the first crucial step to limiting industry impact.

PRYMAK: It is also important to keep in mind that over their 100-plus year history, fire sprinklers have a tremendous record of reliability. Central Sprinkler’s voluntary replacement program was prompted, in large part, by testing data that o-ring sealed sprinklers are not as resilient as belleville-sealed sprinklers and degrade much more quickly than originally anticipated. The program was launched to address this issue proactively.

In addition, sprinkler manufacturers recently funded a long-term study to look for ways to improve the functionality and reliability of sprinklers. In
a related issue, the National Fire Protection Association recently adopted a 10-year standard for dry sprinklers based, in large part, on Underwriters Laboratories test data that showed all manufacturers’ dry pendant models experienced performance degradation over a much shorter time frame than previously realized. Over time, this amended standard will enhance the reliability of dry pendant sprinklers by accelerating the replacement cycle.

CSE: On the subject of NFPA, the recent release of an updated NFPA 13 includes a number of new technological requirements, such as minimum timing standards for water delivery on a dry-pipe system. In your opinion, what kind of an impact will some of these changes have on the industry and on the way fire-protection systems are designed?

PRYMAK: The recent change to NFPA 13 is an excellent example of technological change that improves the industry. The use of a calculation program during the preliminary system design and bid phase allows the system designer to improve the system by comparing performance when using different sizes or types of sprinklers and pipe, or different layouts.

BELLAMY: This will reduce the guess work typically involved with designing the system to accomplish the required water delivery time and will reduce the potential for costly installation changes at the end of a project.

SCHULTZ: In my opinion, the biggest change in NFPA 13 is the new requirements addressing solid shelving. But another important change that
appears to be occurring is a recognition of the need for the owner to assume responsibility for the system at various points. For example, there is now a requirement that the owner provide a certificate to the contractor outlining the intended use of the building. This includes building materials and the maximum storage height.

The document must also include a preliminary building plan, design concepts necessary to perform the layout, detail of the sprinkler system and any special knowledge of the water supply, including known environmental conditions that might be responsible for microbiologically influenced corrosion (MIC).

CSE: Is MIC a real and active threat to sprinkler/ fire-protection safety, or is it something that has received undue hype? If it is a real issue, how is it being addressed?

HANKINS: MIC is a very real problem that affects both the reliability and longevity of sprinkler systems. As in so many areas of the fire protection industry, the response has been a reactive one. While corrective action is taken when MIC is found, there is not a widespread, concerted effort to look for it.

PRYMAK: While MIC is a concern, experience also has shown that such corrosion is not present in all water supplies and tends to surface within a given water service.

Steel pipe manufacturers are addressing the problem, and at least one manufacturer has developed an anti-MIC interior coating that is now standard on its sprinkler-pipe offering. Studies have shown that when present, MIC attacks various points within the system, often finding small occlusions or irregularities that may be present in the pipe wall. In time, the corrosion finds its way through the wall.

BELLAMY: Since the specific number of MIC cases causing a problem is very low, when compared to the total number of sprinkler system installations, MIC has received some degree of undue hype. However, in those cases where MIC has been found to be the contributor to corrosion problems, the problem is very real. As a result, the application of simple deterministic criteria should be utilized to determine the highest risk potentials.

SCHULTZ: I sometimes wonder if ordinary corrosion is being classified as MIC. It appears that MIC is being identified when premature failure of pipe occurs. Hopefully, the National Fire Sprinkler Association and the American Fire Sprinkler Association will use the data obtained during their annual inspection to get a true handle on the problem.

CSE: How long, exactly, has MIC been a problem?

PRYMAK: Findings show that the MIC problem is not a new one, but that in the old, thicker-walled, Schedule 40 systems, the microbes may have actually ‘died out’ prior to penetrating the pipe wall. The new generation of both Schedule-10 pipe and engineered lightwall pipe are thinner, so there is less material through which the microbes must penetrate.

In fact, the entire industry has been made aware of the MIC problem because the corrosion in these lighter-walled materials succeeds in causing the system piping to leak. However, testing has also confirmed that the MIC problem is a factor that contributes to the deterioration of o-rings in sprinklers. With respect to sprinklers, the problem is the opposite of the leakage experienced with pipe in that the sprinklers may require elevated pressures to operate. This situation is being addressed by the elimination of o-ring seals and the use of belleville seals in the sprinkler waterway.

CSE: Earlier, NFPA was brought up in the context of re-addressing existing standards. This begs the question, is the occupancy hazard classification system that the industry has been using for the past 30 years or so still up to date, or is it time to re-evaluate?

HANKINS: The Light, Ordinary and Extra Hazard classification scheme used in NFPA 13 has been continually modified to address changes in building occupancies. Also, specific guidance for occupancies that fall outside the scope of the scheme is regularly added to NFPA standards. To that extent, it is quite up-to-date.

PRYMAK: The classifications in today’s code have been expanded to recognize fire loading and variations in storage, packaging and storage arrangements. The result is reflected in the loss rates for such occupancies. Overall, the NFPA code-making body has done a remarkable job modifying the old codes and reclassifying many of the standard occupancies and commodities, as well as recognizing changes that are required for the ever-increasing plastics and packaging materials markets and the hazards that they represent.

SCHULTZ: I disagree. The occupancy classification method was developed 30 years ago and needs to be addressed. As we move into more and more performance-based design projects, it is time to look at true fuel loads and fire growth rates. Although NFPA 13 has placed the examples of occupancy classifications in the appendix, the industry continues to turn to the back of the book and look for a classification. For example, a parking garage is classified as an Ordinary Hazard Group 1 occupancy, but with the introduction of more and more plastics in cars, the question becomes does a parking garage remain a Group 1 occupancy?

CSE: Speaking of performance-based design, in your opinion, will the ever-improving k-factor in sprinkler heads and other developments in sprinkler technology have any impact on the acceptance and adoption of performance-based design in more jurisdictions?

BELLAMY: The ever-improving k-factors will not directly impact the application of performance-based design. However, the advent of such sprinkler technology as the development of methodologies to characterize the size and trajectory of water droplets, along with the suppression algorithms and computational fluid dynamics programs, can allow for performance-based design applications. These technological advances, coupled with comparative full-scale test data, can allow for continued development of specific performance-based design application tools and standards allowing for more widespread acceptance.

SCHULTZ: Although building codes and the architectural community may welcome performance-based design, the sprinkler industry still remains at the point where things are looked at in black and white. Although sprinklers are a necessary component of a total performance-based design approach, in the near future, the design of a sprinkler system will not be based on a performance-based design approach. It will take time before performance-based design finds its way into sprinkler design.

To Share or Not to Share

The trend toward privately funded product testing could be harming the sprinkler industry because companies aren’t so quick to share this costly and critical information.

“Sharing sprinkler technology is very similar to asking Coca-Cola to share its soft drink formulation,” says Thomas Prymak, vice president of marketing for Tyco Fire Products, Lansdale, Pa.

Manufacturers bear the expense of product research and development, manufacturing and marketing, he adds. And the cost of full-scale fire tests can range from the mid-six figures to well over $1 million.

“The lack of sharing product knowledge and test data can be viewed by some as not being in the best interest of the industry,” Prymak says. “On the other hand, if a manufacturer is willing to make the investment, that manufacturer should enjoy the economic rewards that are associated without having to share the data.”

But Tracey Bellamy, P.E., vice president of engineering with TVA Fire & Life Safety Inc., Atlanta, sees more harm than good in withholding product test results.

“Private testing of sprinklers results in a fragmented knowledge of sprinkler performance, which can result in duplication of efforts and also disallow complete evaluations of all available data in developing potential solutions.”

Although, in many cases, the results of successful testing make their way to the industry by way of proposed changes to design standards, data from unsuccessful tests is more closely held, according to Bellamy.

“Lack of access to these unsuccessful tests and those successful tests that are not released to the public domain represent a real disadvantage to the industry,” he says.

Despite proprietary product development, Prymak notes that manufacturers have been willing to share data, whether through coalitions or mutually funded independent test laboratories. The National Fire Protection Association also aids in getting information out, adds Joe Hankins, industry leader, manufacturing & storage with FM Global, Johnston, R.I.


Tracey D. Bellamy, P.E., Vice President of Engineering TVA Fire & Life Safety, Inc., Atlanta

Joe Hankins, Industry Leader, Manufacturing & Storage FM Global, Johnston, R.I.

Thomas N. Prymak, Vice President of Marketing Tyco Fire Products, Lansdale, Pa.

Gerald R. Schultz, P.E., Principal, Chicago office The FPI Consortium, Inc., Downers Grove, Ill.