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SECTION 4 – SANITARY <br />64 <br />8.) Installation of the protective coating shall not commence until the concrete substrate has <br />properly cured in accordance with these specifications. <br />9.) Temperature of the surface to be coated should be maintained between fifty (50) degrees <br />Fahrenheit and 120 degrees Fahrenheit during application. Prior to and during application, care <br />should be taken to avoid exposure of direct sunlight or other intense heat source to the structure <br />being coated. Where varying surface temperatures do exist, care should be taken to apply the <br />coating when the temperature is falling versus rising (i.e. late afternoon into evening vs. <br />morning into afternoon). <br />4-3.12 (b) SURFACE PREPARATION <br />1.) Applicator shall inspect all surfaces specified to receive a protective coating prior to surface <br />preparation. Applicator shall notify City Engineer of any noticeable disparity in the surfaces <br />which may interfere with the proper preparation or application of the repair mortar and <br />protective coating. <br />2.) All contaminants including oils, grease, incompatible existing coatings, waxes, form release, <br />curing compounds, efflorescence, sealers, salts, or other contaminants shall be removed. <br />3.) All concrete or mortar that is not sound, or that has been damaged by chemical exposure, shall <br />be removed to a sound concrete surface or replaced. <br />4.) Surface preparation method(s) should be based upon the conditions of the substrate, service <br />environment, and the requirements of the polyurethane protective coating to be applied. <br />5.) Surfaces to receive protective coating shall be cleaned and abraded to produce a sound surface <br />with adequate profile and porosity to provide a strong bond between the protective coating and <br />the substrate. Generally, this can be achieved with high pressure water cleaning using <br />equipment capable of 5,000 psi at four (4) gpm. Other methods such as high-pressure water <br />jetting (refer to NACE Standard No. 5/SSPC-SP12), abrasive blasting, shot blasting, grinding, <br />scarifying, or acid etching may also be used. Detergent water cleaning and hot water blasting <br />may be necessary to remove oils, grease, or other hydrocarbon residues from the concrete. <br />Whichever method(s) are used, they shall be performed in a manner that provides a uniform, <br />sound, clean, and neutralized surface that is not excessively damaged. <br />6.) Infiltration shall be stopped by using a material which is compatible with the specified repair <br />mortar and is suitable for top coating with the specified protective coating. <br />7.) The area between the manhole and the manhole ring and any other area that might exhibit <br />movement or cracking, due to expansion and contraction, shall be grouted with a flexible grout <br />or gel. <br />8.) All surfaces should be inspected by the City Engineer during and after preparation and bef ore <br />the repair material is applied.