CITY COUNCIL AGENDA ITEM
ACTION REQUESTED:
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Approve the Emergency Procurement 23-175 West-Southwest Elevated Tank Painting Project - Additional Work to ERA-Valdivia Contractors, Inc. for an amount not to exceed $581,000
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DEPARTMENT: Water Utilities
SUBMITTED BY: Darrell Blenniss, Director
BOARD/COMMISSION REVIEW:
N/A
BACKGROUND:
ERA-Valdivia Contractors, Inc. (EVC) is currently in the process of completing the West-Southwest Elevated Tank painting project, as specified in Contract 22-024. This work is in its final stages of completion with the exterior painting remaining.
While performing work on the tank column exterior, EVC encountered conditions with existing coatings that differed from those specified. The existing topcoat was degraded and flaked off at a rate greater than anticipated when cleaned with a power washer according to the specifications. The process left a residue on the column that may inhibit the adhesion of the new coating materials.
EVC consulted with the paint manufacturer, Sherwin-Williams, and concluded that existing conditions were marginal to meet work specifications. At question were the adhesion qualities of existing coatings and if they can accept additional coats of paint as specified.
On May 30, 2023, EVC requested guidance from the City on how to proceed.
DISCUSSION:
Water Utilities staff contacted Dixon Engineering Inc. (Dixon), an independent third party, to inspect the existing coating conditions of the column exterior and provide opinions with recommendations on how to continue with this work. Dixon performed adhesion testing, based upon a scale of A0 (poor) to A5 (very good), on the column exterior and attained the following adhesion results:
a. Topcoat results were very poor (A0)
b. Intermediate coat results were slightly better but still poor (A1)
c. Epoxy prime coat results, where tested, were very good, (A5)
Dixon recommended that the exterior column be cleaned with a high-pressure power wash to remov...
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