12-28-2015 Council Packet - Laserfiche WebLink

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7 3.1.7 Remove all erection bracket scab marks below the HWL by air arc gouging, cutting torch, or grinding. Repair the tank surface by welding and grinding. This will comply with AWWA D100-11. This work will require approximately 50 man-hours. 3.1.8 Grind off all weld spatter and other surface defects below the HWL. This will comply with AWWA D100-11. This work will require approximately 15 man-hours. 3.1.9 Remove the abandoned C. P. system support brackets from the interior. See photo 21. 3 1.10 Replace the gasket on the 24 -inch diameter round bowl manway. See photo 23. 3 1.11 Cathodic Protection (see 3.3). 3.2 Interior Wet Coating 3.2.1 The tower was built and the interior wet area was last coated in 1992 and is now 22 years old. The interior wet coating above the high water line (HWL) is in fair to poor condition, with failures occurring at unwelded seams and rust streaking emanating from areas inaccessible to coating. The coating below the HWL is in fair condition with failures occurring at random locations primarily on the cone section. The coating failures are occurring primarily due to age and general deterioration. The poor substrate condition under the coating along with the age of the coating means that the coating is not repairable. The tank will require a complete new interior coating within three to five years. See photos 2 through 24. 3.2.2 After structural repairs are completed, all the reservoir surfaces should be abrasive blasted to an SSPC-SP-10 Near White Metal Blast and coated with a light-colored zinc/polyamide epoxy system (similar to the Tnemec Series 91-H20 Hydro-Zinc/Series N140 Pota-Pox Plus Epoxy coatings). 3.2.3 Widespread staining is occurring on the submerged areas of the interior (those areas below the normal high water level). After a new coating system is applied, the City of Lino Lakes should consider periodic cleaning of the tank surfaces with approved cleaning agents and methods in conjunction with scheduled inspections and evaluations. KLM can provide recommendations on cleaning methods and assistance with the cleaning upon request. See photos 12 through 21.