Fire sprinkler systems are rather robust piping networks. This robustness makes them valuable as a fire suppressant measure and a key component of workplace fire safety. However, because they are made of pipes, which are subject to corrosion, sprinkler systems have many potential failure points. Corroded pipes can have some serious consequences, such as:
- Impairment due to loss of pipe integrity, clogging of pipes or clogging of sprinklers
- Functional deterioration resulting in the unintended release of fire protection water
- Design failure due to deterioration of the internal pipe caused by friction.
Corrosion can occur both inside and outside pipe surfaces; however, this blog will focus on internal corrosion issues and some measures to help offset those issues. One common form of internal corrosion is microbiologically influenced corrosion (MIC). MIC can be responsible for:
- Metal pitting
- Internal scale or build up from mineral deposits
- Pinhole leaks, usually where pipe wall is less than schedule 40
While scale build up can be good for starving a microbe community and protecting the interior of pipes from pitting and pinhole leaks, it can present its own set of problems. If not kept in check, scale can clog test connections, potentially rendering sprinkler heads useless.
Maintenance of fire sprinkler systems is essential for reducing the risks associated with corrosion. While there is no ideal method to avoid a re-occurrence of internal pipe corrosion, companies can work with their sprinkler contractor to review available methods and select the method they consider most appropriate.
Four available methods to help avoid corrosion include:
- Install pipe less affected by MIC. This involves biostatic pipe coating.
- Treat all water entering the system. Identify the type of microbe affecting the system, and select a chemical treatment effective at eliminating the microbe.
- Provide a monitoring system. This method allows deterioration to reoccur; however, early awareness can trigger further maintenance before the system becomes unreliable.
- Provide nitrogen to pressurize dry or pre-action systems. This can be a costly solution, but it is potentially the most effective.