Preventing Pinhole Corrosion (Chilled Water Piping)
Several hospital chillers were developing pinhole leaks in cooling coils, traced to dormant “dead legs” in the piping layout. Dead legs are unused pipe sections where water stagnates, fostering bacterial and corrosive attack. Our survey identified six long dead-leg branches. Following best practice, we removed or shortened unnecessary tees and installed jumper loops to eliminate stagnant zones. We also programmed the BMS to flush any seldom-used branches with biocide twice weekly.
- Actions: Reconfigured piping to eliminate all dead legs (capped spurs, added drain loops). Ensured weekly flow through all chiller circuits with oxidizing biocide.
- Results: No new pinholes have appeared. Lab tests show lower microbial counts and no acid corrosion indicators. By addressing the stagnation issue (which otherwise “provides ideal conditions for biofilm”), the chillers now run leak-free. The customer expects to avoid replacement costs in the tens of thousands of AED that recurring pinhole failures had threatened.
