This standard specifies the method for determining the apparent density of powdery vinyl chloride homopolymer and copolymer resins. Apparent density, defined as mass per unit volume, is a crucial indicator for evaluating the physical properties of such plastic resin powders. The test is primarily conducted using standardized instruments, where the density is calculated by measuring the mass and occupied volume of a resin powder sample. The core testing instrument required for the entire process is an apparent density tester (or measuring funnel). This instrument typically consists of a funnel with specific specifications and a measuring cup of known volume. During the experiment, the resin powder freely falls through the funnel into the measuring cup below, is leveled, and the mass of the powder in the cup is then weighed to calculate the result.