Barrow Utilities and Electric, Co-op, Inc., 600,000 Gallon Tank and Water Treatment System Upgrades
Barrow, Alaska, residents are served by the Barrow Utilities and Electric Co-op, Inc. (BUECI), for water, wastewater, and power. A one million gallon potable water storage tank was constructed to supplement the original 600,000 gallon potable water storage tank built in 1976. In 2013, BUECI determined that the 600,000 gallon tank needed to be rehabilitated/
The 600K tank had not been inspected since it was installed. The tank had been coated with a spray on urethane coating to help insulate. BUECI wanted to installed the same insulation system as had been installed on the million gallon tank. The utility also wanted the tank to be recoated inside and outside. GVJ&A attempted to have a video inspection done of the inside of the tank. The video showed that the coating below the waterline was mostly intact, but above the water line the coating was very damaged and there was significaant corrosion. In order to account for this in the bidding documentation, there were unit price line items for replacing bolts, welding patches to cover thin spots in the steel and welding along cracks. This saved GVJ&A and the structural engineer from trying to determine the exact condition of the tank interior without draining the tank and allowed the contractor to make whatever repairs that were deemed necessary by the utlity's and engineer's inspections, once the tank was drained and sand blasted. Sand blasting the ceiling did show that most of the bolts on the roof rafters needed to be changed and that there were several patches of corrosion onf the walls that needed patched. The outside of the tank was in good condition. Once the spray urethane was removed and the coating system was sand blsted, no further repairs were needed. However, the sandblasting did show that the tank platform was in much worse shape than originally expected, which led to rehabilitating the platform as well.
In addition to the work done at the 600K tank, some minor changes were made to the inlet and outlet piping. The changes include replacing failing altitude valves with electrically actuated butterfly valves, installing new flow meters, installing a bypass line around the new actuated butterfly valves, and replacing a fire valve. A major change to the piping was to rearrange the outlet of the tank to improve headloss to attain higher fire flows. The ystem originally had two outlet nozzels, one 6 inch and one 12 inch. THe design changed the outlet nozzel to a 14 inch connection that then split into a 12 and a 6 to connect to the fire and distribution piping, respectively. This required a specially field fabricated fitting. Since the 600K tank was drained, the work for these items was fairly straight forward and this project provided the oportunity to complete them. Also, a small amount of work was dcone at the million gallon tank to repair the doghouse at the piping connections. The foundation of the million gallon tank had tilted, putting significant tension onf the piping connections and making the doors to the doghouse inoperable.