Plastic pall ring Diameter: 16, 25, 38, 50, 76mm PP, PE, PVDF, PVC, RPVC, RPP ... surface area (m2/m3)Void volume(m3/m3)Dry packing factor ( m-1 )Heaping number (n/m3)Heaping weight (kg/m3)Φ1616×16×11880.91275112000141Φ2525 ... .90127650056Φ7676×76×2.6730.9294193060 Plastic polypropylene pall ring (16, 25, 50, 76mm)