It ruptured due to pitting corrosion of the stainless steel wires. Besides the rupture, there were 9 discreet areas on the hose that exhibited brown
discoloration and pitting corrosion. Based on the evaluation of other similar ruptured hoses, the hoses somehow get contaminated with acid mist or droplets. The two most probable causes for this is 1) exposure to soldering flux fumes during sweating of nearby joints, or 2) exposure to other chemicals in the
plumber's toolbox. The plumbers buy these hoses in bulk, and carry them around in their truck until they install them in someone's home. The hoses are not protectively wrapped, and can come into contact with chemicals that are corrosive to stainless. Another possible cause for this is contamination by household cleaners. However, in this case it is unlikely because the hose outside of the spots of corrosion was free of deposits (from cleaners), and the hose was located under the bathroom sink. Cleaners as a cause for pitting corrosion is more likely when the flex line is the toilet water supply line, because it would more easily contact mops and toilet bowl cleaners.(21460)
To Do:1. Determine who installed the line, and when it was installed.
2. Determine where other similar lines were installed in the home, and whether they were installed at the same time by the same person, i.e., in the original construction of the home.
3. Purchase several exemplar lines, if possible. They will be helpful in having your expert analyze the loss. In addition, the manufacturer's instructions, warnings, and installation guidelines will assist you in analyzing the case and in convincing the manufacturer the product was poorly designed or manufactured, or was accompanied by inadequate warnings.