CCP 01-23-2006 - Laserfiche WebLink

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I I I I I I I I I I I I I I I I I I I The safety, sanitary, structural and sound design and operational deficiencies noted above are not intended to be a complete list of the deficiencies on this tank. The complete report and accompanying photographs should be reviewed to obtain a complete account of the condition and the deficiencies of this tank. This inspection did not include the review of the original design documents nor was the tank condition compared to the current wind, snow and seismic loads mandated in current building codes and A WW A Standards. That structural analysis is beyond the scope of this evaluation. FIELD INVESTIGATION Mr. Michael Reina, P.E. of KTA-Tator, Inc. completed the inspection on November 17,2005. The following tests were performed during the inspection: A. Visual - Visual assessment of the percentage and distribution of corrosion across the surfaces was made. In addition, other visual observations; such as, peeling, chalking, cracking, blistering, etc. were noted. B. Coating Thickness - Dry-film thickness was determined using a Positector 6000. The Positector 6000 is a portable, battery operated, digital coating thickness gage that non-destructively measures non-magnetic coating thickness over ferrous substrates using a magnetic principle. Calibration was completed prior to and after use. This test was performed in accordance with ASTM D 1186-93. C. Number of Coats - The number of coats present and thickness of each were determined using a Tooke Gage Mark IV with a 2X cutting tip. This hand-held portable microscopic (SOX) destructively measures the thickness of each coat in multi-coat systems (up to 50 mils). Observation of a coating cross-section created with a cutting tip of a known angle shows coating thickness in addition to intercoat contamination, voids, underlying rust, mill scale, and pinholes. D. Adhesion - Adhesion testing was conducted in accordance with ASTM 03359, "Measuring Adhesion by Tape Test." Method A of this standard was utilized. Method A involves scribing an "X" through the coating down to the substrate, followed by the application of pressure sensitive tape (Permacel 99). The tape is then sharply removed from the X-cut and the amount of coating detached is rated in accordance with the ASTM rating scale. Typical ratings of 4-5A are considered by KTA to represent good adhesion, 2-3A represent fair adhesion, while O-IA represent poor adhesion. E. Ultrasonic Thickness Testing - A Check-Line Model TI-25M Wall Thickness was used to measure the thickness ofthe steel in various representative locations. The gage injects a pulse of high frequency sound (ultrasound) into the steel. Because the speed of sound in a given material is constant, the time that it takes for the sound to travel and be reflected from the far surface can be used to determine its thickness. The instrument provides readings in inches. Verification of gage readings was performed using known steel calibration blocks. Elevated Water Storage Tank City of Arden Hills South Tank 15