ANSI AWWA B100-16 pdf download.Granular Filter Material
4.1.2.3 Gravel size. Filter :media support gravel shall be provided in the particle size ranges as required in the purchase documents. For each required size range of gravel, not more than 8 percent by dry weight shall be finer than the low- est designated size limit, and a minimum of 92 percent by dry weight shall be finer than the highest designated size limit.
4.1.2.4 Acid solubility. Acid solubility shall not exceed five percent for sizes smaller than No. 8 (2.36 mm), 17.5 percent for sizes larger than No. 8 (2.36 mm) but smaller than 1.0 in. (25.4 mm), and 25 percent for sizes 1.0 in. (25.4 mm) and larger. If gravels contain materials larger and smaller than the specifed size and if the total sample does not meet the specified solubility limit for the smaller material, the gravel shall be separated into two portions, and the acid solubility of each portion must meet the appropriate designated percent solubility.
4.4.1.1 Cleaning and examining filter cell. Each filter cell shall be cleaned and examined thoroughly before any filter material is placed. Debris, dirt, dust, and any other foreign substances shall be removed from the underdrain plenum (which may need to be vacuumed), filter underdrain system, piping, washwater troughs, walls, and any other filter cell component. Each cell shall be kept clean throughout placement operations. After cleaning, the underdrain system, wash- water troughs, and any air or surface wash piping shall be checked to ensure they are level, undamaged, and complete within the requirements of the purchase docu- ments. Underdrain mechanical connections to the filter cell (if applicable) shall be secure and tightened to manufacturer's tolerances, and underdrain grout (if appli- cable) shall be in place, cured, and free of defects. Deficiencies shall be corrected before any placement of filter material.
4.4.1.2 Testing of new filter cell prior to placing filter material. In new filter construction, the placement of filter material should only follow operational testing of the backwash system, including air and/or surface wash systems if appli- cable, and assurance that the filter box is watertight. See Table 2 for appropriate fuidization backwash rates.ANSI AWWA B100-16 pdf download.