Microbiologically Influenced Corrosion (MIC) poses as a threat to fire protection systems, particularly dry pipe sprinkler systems. If left untreated, MIC can compromise pipe integrity, reduce system reliability, and lead to premature failure, often without obvious warning signs.

Flushing dry systems is essential when MIC is present, helping preserve the integrity and reliability of your fire protection infrastructure.

What is MIC?

MIC is corrosion influenced or accelerated by the presence of microbial organisms, typically bacteria that thrive in stagnant water and low-oxygen environments. In dry pipe systems, residual water left behind after hydrostatic testing, false trips, or condensation creates the perfect breeding ground for MIC. These microbes form biofilms inside the pipes, which can:

• Accelerate corrosion rates
• Lead to pinhole leaks
• Cause internal tuberculation (blockages)
• Weaken the structural integrity of pipes
• Reduce flow and impair system performance during a fire event

Once MIC is detected—either through system inspection, internal pipe assessments, or water testing—flushing the dry system should be the immediate response. Flushing helps remove accumulated sediment. If left untreated, this could potentially clog sprinkler heads and impair flow during activation. This slows or stops the corrosion process and protects against further degradation. A clean, flushed system has fewer flow restrictions and is more responsive when activated.

Once flushing is complete, piping should then be reexamined to determine if it is free from foreign material. This demonstrates a proactive approach to maintenance and risk reduction, which is especially important for insurance and code compliance.

If MIC has been detected in your dry system, don’t delay. Flush the system, consult with professionals, and build a mitigation plan that protects your property and ensures life safety.