Document M6GbzGr4vqJ3Xke5GMm1qyoa

To: J.R. Holcomb Interoffice Communication From: B.K. Donley Date: July 27, 1987 Subject: Tank Farm Vent Revisions - Follow Up VISTA As recommended in the Tank Farm Vent Evaluation (IOC B.K. Donley to J.R. Holcomb 7/10/87) the tank farm pressure vacuum vents were reset to the recommended values on July 21, 1987, Upon inspection of the vents, it was discovered that all the vents had been damaged due to chemical corro sion. Three vents were damaged beyond repair, and two others were damaged, but usable. Two of the vents beyond repair were from tanks currently out of service, and the third was replaced with an identical model from our stock. The two usable vents were put back in service, but will have to be replaced as soon as possible. The sixth vent, on T-453, did not require a setpoint change, and therefore was not inspected. The damaged vents were constructed of vinyl ester resin (Duracane), which is not resistant to EDC. The EDO first attacks the epoxy used to join pieces of the vent, and then attacks the vent walls and valve seats. One vent was constructed of aluminum, which also shows severe deteriora tion of the vent chambers and valve seats. The attached photographs show evidence of the damage that has occurred. Consultation with our plant engineers and GED in Houston indicates the material of choice is Furan, which is resis tant to EDC corrosion. Incidentally, the vent header and the vent knock-out pot, S-412, are constructed of Furan, and show no visible signs of deterioration. I recommend that the six existing vents be replaced with identical models (Groth 1220), constructed from Furan, including the aluminum vent on T-453. If you have any questions or comments, please contact me. Brian K. Donley Summer Process Engineer cc: RAC-PEM-GEH-WPS-MRK-SCR-HOA-GGB 000009735 CWI" 000009736