A Fire Hose Fitting Failure: Addressing Electrolytic Corrosion in Maritime Safety
In a recent incident that occurred during routine pressure and leak testing, a fire hose fitting failed, prompting the International Marine Contractors Association (IMCA) to issue a Safety Flash to draw attention to the incident and emphasize the lessons learned. The incident involved the failure of a fire hose fitting at the neck of the stub inserted into the hose, highlighting the dangers of electrolytic corrosion. This comprehensive reiteration aims to provide a detailed account of the incident, its causes, and the actions taken to prevent similar incidents in the future. The Incident As part of their annual testing of fire hydrant hoses, a maritime crew was assigned to conduct leak testing on the main deck fire hoses. During this routine test, a Number 3 hose (20m x 52mm (2”)) was connected to a fire hydrant valve and nozzle, and visual inspections of the hose and valve were conducted before testing. Unfortunately, during the test, it was observed that one end of the fire hose had become disconnected, leading to the immediate cessation of the test and the initiation of a subsequent investigation. Investigation Findings The initial investigation revealed that the fire hose involved in the incident appeared to be different from most of the other hoses onboard. While the majority of the hoses were equipped with an aluminum 'floating' flange, this hose featured a Storz 'C' coupling with fixed flanges on the hose neck. Further examination revealed that the coupling was, in fact, the same as the others on board, but due to corrosion, the floating part had become tightly seized on the hose barb shaft. The presence of a steel retaining ring buried in powdery aluminum oxides inside the coupling confirmed this finding. Moreover, investigation from the other end of the hose showed no immediate signs of concern. However, small pitting marks were detected on the inside of the hose neck, and the removal of the rubber sleeve exposed further indications of corrosion. Attempts to free the floating flange caused the fitting to fail. The severity of corrosion on this coupling was comparable to the fitting that had failed. Lessons Learned and Actions Taken Following the incident, the IMCA issued a set of recommendations to prevent similar incidents in the future and promote maritime safety. The key actions advised by IMCA include:
Maritime operators are urged to inspect existing fire hose couplings for signs of corrosion, seized floating flanges, and any inability to rotate freely. Regular maintenance and visual inspections can help identify potential issues before they escalate.
When replacement of fire hose couplings is necessary, it is recommended to specify appropriate fittings. In this case, brass fittings are suggested as a preferable alternative to aluminum due to their increased resistance to corrosion.
It is vital to ensure that planned maintenance systems encompass detailed guidelines for the inspection of fire hose fittings. These guidelines should specifically address the examination for corrosion, seizing, and other signs of deterioration to enable early detection and necessary corrective actions.
All personnel involved in the day-to-day use and maintenance of fire hoses must be briefed on the potential risks associated with electrolytic corrosion. Increased awareness and training will help them recognize the signs of corrosion and report any concerns promptly. Conclusion The incident involving the failure of a fire hose fitting due to electrolytic corrosion serves as a reminder of the importance of regular maintenance, thorough inspections, and adequate training in maritime safety. By implementing the recommended actions provided by IMCA, maritime operators can enhance their safety protocols, mitigate the risks of similar incidents, and ensure the integrity of fire hose systems on board. A proactive approach to identifying and addressing potential corrosion issues will undoubtedly contribute to a safer working environment for maritime personnel. |