R2007-140 AUTHORIZING AGREEMENT TANK INDUSTRY CONSULTANTS, INC.

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Mr. Richard N. Berard Page 2 ' ' City of Decatur,Illinois July 18, 2007 outlining our observations and recommendations for rehabilitation and maintenance. Underwater Evaluation of the Interior: Our diving Underwater Evaluation includes a careful study of the tanks' interior wet surfaces by specially trained divers. Although this method ! does not require the tank to be drained, the tank must be taken off line and isolated from the sys- I tem the entire time the diver is in the tank. Tank Industry Consultants will utilize one of our own I� field technicians who is also a certified diver, specifically trained in underwater evaluation tech- ' niques. Because the diver is also a member of TIC's staff,the tank is evaluated by a qualified ' technician who knows what to look for,not a diver who takes random photographs. When performing an underwater evaluation the diver utilizes a full dry suit and full-face diving , mask to avoid contact between the diver's body and the potable water. Prior to entering the tank, I the diver and all related equipment are thoroughly disinfected in accordance with AWWA C652-02. Exterior Field Evaluation: During the field evaluation of the visible exterior surfaces, TIC technicians will access the tank surfaces as required by the condition of the tank to identify sani- tary, safety, or structural deficiencies. The tank surfaces will be closely reviewed for spalling concrete, exposed reinforcing wire, evidence of leakage, and other items requiring rehabilitation. In addition, TIC will locate large surface cracks in the concrete tank container. TIC will use a hammer to "sound" the concrete(at accessible locations) in attempt to locate voids or hollow ar- eas in the concrete. At a minimum, the following items will be addressed: • Measurements of the tank members will be taken • Measurements of the tank accessories will be taken • Observed sanitary deficiencies will be noted • Observed safety deficiencies will be noted • Observed structural deficiencies due to deterioration will be noted • Observed irregularities or unusual circumstances will be noted • Photographs will be taken to document the condition of the tank • Floor deposits in the clear well will be observed and quantified Coating Evaluation: If coatings are present on the tanks, coatings samples will be taken during the field evaluation to be tested to determine their lead, chromium, and cadmium content. The coating thickness and adhesion tests performed during the coating evaluation will offer in- sight into the "topcoat-ability" of the existing coating. If the existing coating type, thickness, condition, and adhesion allow for topcoating, the cost of recoating the tank could be significantly reduced. Structural Evaluation: Included in TIC's evaluation and report is identifying any observed structural deficiencies or damage that may have occurred since the tank was erected. These ob- served deficiencies could be deviations of the existing tank condition from how the tanks were originally designed and constructed and/or deterioration which may have occurred (e.g. metal