6. Conclusion
The severe pitting attack at the top inner portion of the pipe was due to highly oxygenated water. While, the bottom surface of the pipe suffered from under deposit corrosion problem. The deposition on the bottom surface of the pipe is an evidence of stagnancy or a very low flow rate of water in this area of the system. No material upgrade is required as the carbon steel is suitable material for this application however, stagnant conditions or very low flow rates must be avoided. In addition, corrosion severity can be reduced by maintaining a proper circulation and flow rate in the system. As the corrosion took place in part of the fire system, appropriate inspection must be carried out for all fire water piping system. Also, special measures shall be made to check any plugging problem of sprinkler/nozzles in the system.