Add to cart 12″ VGB Main Drain Covers $125.00 Waterway grates and frames are compliant with the Virginia Graeme-Baker Pool and Spa Safety Act (ASME/ANSI A112.19.8-2007) and are UL Certified. They are designed for single or multiple drain use. Dimensions12″ x 12″ Square. Floor Flow Rate: 289 gpm at 2.33 ft./sec. Wall Flow Rate: 198 gpm at 1.59 ft./sec. Flow Rate at 1.5 ft./sec.: 186. Total Open Area: 39.9 sq. inches.