ASTM D792-20 pdf free download.Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement.
1. 1 These test methods describe the determination of the specific gravity (relative density) and density of solid plastics in forms such as sheets, rods, tubes, or molded items.
1.2 Two test methods are described:
1 .2. 1 Test Method A—For testing solid plastics in water, and
1 .2.2 Test Method B—For testing solid plastics in liquids other than water.
1.3 The values stated in Si units are to bc regarded as the standard.
1 .4 Warning—Mercury has been designated by many regulatoiy agencies as a hazardous substance that can cause serious medical issues. Mercun; Use caution when handlmg mercury and mercurycontaining products. See the applicable product Safety Data Sheet (SDS) for additional inforiflatiOn. The potential exists that selling mercury or mercury-containing products. or both, is prohibited by local or national law Users must deiermnine legality of sales in their loca lion.
1 .5 This standard does not purport to addre.ss all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and en environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1 —This standard is not equivalent to ISO 1183—1 Method A. This test method provides more guidelines on sample weight and dimension. ISO I 183-I allows testing at an additional temperature of 27 ± 2°C.
4. Summary of Test Method
4. 1 Determine the mass of a specimen of the solid plastic in air. It is then immersed in a liquid, its apparent mass upon immersion is determined, and its specific gravity (relative density) calculated.
5. Significance and Use
5.1 The specific gravity or density of a solid is a property that is conveniently measured to identify a material, to follow physical changes in a sample, to indicate degree of uniformity among different sampling units or specimens, or to indicate the average density of a large item.
5.2 Changes in density of a single material are due to localized differences in crystallinity, loss of plasticizer, absorption of solvent, or to other causes. It is possible that portions of a sample differ in density because of their differences in crystallinity, thermal history, porosity, and composition (types or proportions of resin, plasticizer, pigment, or filler).
5.3 Density is useful for calculating strength-weight and cost-weight ratios.
6. Sampling
6.1 The sampling units used for the determination of specific gravity (relative density) shall be representative of the quantity of product for which the data are required.
6.1.1 If it is known or suspected that the sample consists of two or more layers or sections having different specific gravities, either complete finished parts or complete cross sections of the parts or shapes shall be used as the specimens, or separate specimens shall he taken and tested from each layer. The specific gravity (relative density) of the total part shall not be obtained by adding the specific gravity of the layers, unless relative percentages of the layers are taken into account.ASTM D792 pdf download.