During construction of a commercial building and pressure testing of the building’s fire sprinkler system, the constructor identified numerous leaks from newly installed high pressure stainless steel flexible hoses which formed part of the fire sprinkler system. Due to the unusual corrosion of the stainless steel pipes observed onsite, CETEC was engaged to investigate the cause of the corrosion on these flexible high pressure stainless steel flexible sprinkler pipes as multiple leaks were observed. As these flexible hoses were only recently installed as new, i.e. within 3-6 months, the corrosion observed on the stainless steel was unusually severe considering that the building was still under construction and the age of the pipes.

Project Details

Services:
• Failure / Corrosion Investigation
• Materials Testing
• Materials Failure

Sectors:
• Construction
• Fire Sprinkler Systems

Location:
Australia

Our Work

• CETEC tested the components of the high pressure hose to investigate and determine the cause failure.
• CETEC provided advice on the cause of the failure, which included remediation recommendations.
• The severity of corrosion was found on both the outer braid and the inner water tubing.

Higher magnification and composition analysis, allowed CETEC to examine the pipe with scanning electron microscopy coupled with Energy Dispersive X-Ray (SEM/EDX) Spectroscopy. The corroded regions revealed multiple pinholes and chlorine induced pitting corrosion attack.

Optical emission spectroscopy determined that the stainless-steel grade used for the sprinkler was stainless steel grade 304 with both Nickel and Chromium present at the lower end of specifications for SS 304 grade. This grade of stainless steel is more prone to chloride-induced pitting corrosion.

Our Impact

• Identified the cause of the corrosion.
• Allowed the client to determine the level of damages and what actions to undertake.
• Allowed the client to determine suitable remediation methods, such as replacement or remediation.