where V is the volume of the shielding sheet; Vp the volume of the shielding materials; Vf the volume of the shielding floor; Vair the air volume of the shielding sheet; Dm the density of the shielding materials; Dp the density of the polymer; Wp the weight of the polymer; Wm the weight of the shielding materials; and Wi is the weight fraction of the shielding materials.