12-28-2015 Council Packet - Laserfiche WebLink

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Prior to start-up of the Project, samples of the Contractor's selected abrasive shall be submitted to the Engineer for testing and approval. Random field testing of the abrasive shall be done as directed by the Engineer to ensure the abrasive used complies with these requirements. C. All compressed air supply shall be properly equipped with suitable oil and moisture separators to prevent contamination of abrasive and/or blasted surfaces. These separators shall be of the continuous bleeding or automatic dumping type. In order to prevent contamination of abrasives and/or blasted surfaces, it is recommended that the separators be installed at both the compressor air outlet and the blasting pot compressed air inlet. D. Stop abrasive blast cleaning in sufficient time to remove all dust, spent abrasive, and other foreign matter from and around all blasted surfaces (including rigging and equipment) and to allow the atmosphere to clear before any coating is done. Removal of these materials shall be by clean brush or suitable industrial vacuum with particular attention given to welds, pockets, poorly accessible areas, or any overhead areas. E. Apply the first coat to all prepared surfaces, except that there shall remain uncoated a 3 inch to 4 inch border of blasted steel at the end of each work day. When blast cleaning resumes the following work day, this border shall be reblasted up to and including 1 inch to 3 inches of the previous primer coating. F. Take extra care during all blasting operations to prevent damage or abrasive impingement upon previously applied coated areas. G. A prime coat shall be applied within 8 hours after sandblasting. When the humidity exceeds 80 percent, the prime coat shall be applied within 4 hours after sandblasting. If conditions are questionable, the Engineer or Resident Project Representative shall make the decision and the Contractor shall accept his interpretation as final and binding. See Article 3.05 for additional temperature and humidity limitations. H. A daily inspection of the separators and compressed air supply will be required to insure cleanliness of all compressed air supplied for abrasive blasting. This test will be performed by a blotter test. A clean white blotter is held no more than 18 inches from the air supply, down stream of moisture and oil separators. The air supply is directed at the blotter for approximately 2 minutes. The blotter is then examined visually for signs of oil and moisture. A clean blotter at test completion means a successful passing of the air supply test. Failure to pass the compressed air test will be justification for rejection of abrasive blasting performed that day. The Engineers discretion will be final in this determination. 3.04 PAINT APPLICATION A. Wet Interior: 1. Prime Coat: After surface preparations specified above are completed, all wet interior surfaces (interior surfaces of the water compartment) shall receive a coat of Tnemec Series 91H20 Hydro -Zinc primer. Prime coat shall be applied to provide 2.5 mils minimum dry film thickness, an average of 3 -mils dry film thickness, and a maximum of 3.5 -mils dry thickness. 2. Intermediate Coat: All interior surfaces shall then be painted with Tnemec Series N140/N140F Pota-Pox Plus, in 11WH White color, to an additional 4 mils minimum dry film thickness an average of 5 -mils dry film thickness. Maximum total thickness allowed shall be 6 -mils dry film thickness. An additional stripe coat shall be applied to all weld seams below the HWL. 3. Finish Coat: All interior surfaces shall then be painted with Tnemec Series N140/N140F Pota- Pox Plus, in 15BL Tank White color, to an additional 4 mils minimum dry film thickness. Total dry film thickness, including prime, intermediate coat and finish coat, shall not be less than WATER TOWER REPAINTING © 2012 Stantec 1 193803415 09 91 55 - 6