By Joshua Johnson, Meridian Fire and Security
One of the largest maintenance issues that associations can face is corrosion of their current fire sprinkler system. Microbiologically Induced Corrosion (MIC) is only one of several types of corrosion found in wet and dry sprinkler systems. MIC can involve different types of bacteria that colonize on the internal surfaces of sprinkler systems and cause highly localized corrosion, resulting in the common "pinhole" leak. To mitigate the risks associated with potential leakage or even flooding of corroded systems, the need to conduct periodic internal assessments of water-based fire protection system piping is imperative and mandated to comply with the National Fire Protection Association (NFPA) standards.
The traditional method of conducting an internal inspection of a sprinkler pipe involves draining the system, opening the piping and associated fittings, and physically looking inside, in order to take pictures and samples of any organic growth. This can be time consuming, costly, and potentially disruptive to owners/tenants due to the labor involved and the smells immitted from the opened pipe. For larger facilities or buildings with multiple systems, this can ultimately equate to days or even weeks where the system will be down. However, there are alternatives available that are less invasive for conducting these assessments such as ultrasound or ultrasonic technology.
Ultrasonic/ultrasound technology is available as an alternative and is a less-disruptive testing protocol. The sprinkler industry has used two forms of this technology for years with good results. One method is Pulse Echo ultrasonic technology. This measures the remaining wall thickness by bouncing a straight beam signal through the pipe, and off the back wall. The accuracy of this measurement is down to 1/1000th of an inch. The other ultrasonic option is Guided Wrap Wave, which sends a wave signal around the circumference of the pipe, creating a signature. This is then compared against the signature of a pipe in perfect condition. Discrepancies between the two measurements (signature of pipe in perfect condition and Guided Wrap Wave signature) can indicate a number of issues, such as corrosion, ice plugs and other changes.
Utilizing these methods of testing also allows the inspection team the ability to test numerous parts of the pipe in numerous locations on each riser without having to shut down the system at all. It is very thorough and effective in identifying if there are any problem spots internally and can rectify and evaluate the results instantaneously. If there is a problem spot detected, the inspection team alerts property manager/maintenance personnel of the findings, and then will attempt to schedule a time to open up the pipe and go through a more hands on investigation as detailed in Chapter 14 of NFPA 25. An inspection team, upon approval from management, will take numerous pictures at this point and investigate with a telescopic flashlight. The team will clear any obstructions from the branch line or other areas and continue with further testing.
Ultimately, if real corrosion has occurred, there is no substitute for manually opening and replacing the pipe. The problem is in identifying where to do that, and ultrasonic testing is an efficient and cost-effective way to identify the spots that are prone to problems. It is one of the reasons many companies are seeking out and researching this new technology in order to provide the best overall value to their customers. Associations that are sensitive to disturbances for their owners or who have a substantial potential for water damage, such as high-rise associations, would benefit from this technology.
One of the primary goals of a successful management team is to provide effective life safety. As part of this effort, these teams utilize building and fire codes to establish a threshold of acceptable compliance to protect their occupants. These codes are continuously being changed and updated to reflect new technologies and trends (such as sonic testing), as well as lessons learned from historical events. This burden on management teams poses a distinct challenge of not only being aware of the adoption of new codes, but also understanding how the changes in these codes directly effects and impacts both current and future occupants. In order to combat these adversities, it is important to be familiar with individual buildings and the codes that apply to them, periodically check NFPA websites for periodic updates, and being involved with local authorities having jurisdiction.
Joshua Johnson has worked at Meridian Fire and Security for 15 years and holds a NICET 3 Certification in Fire Alarm Systems and holds inspectors’ licenses in both Colorado and Nebraska. Meridian Fire & Security specializes in the design, engineering, development, supply, installation and service of integrated fire and life safety systems.
