ASTM D891-09

Specific gravity, apparent, may be used as a qualitative test in establishing the identity of a chemical. It may be used to calculate the volume occupied by a product whose weight is known, or to calculate the weight of a product from its volume. It may be used to determine the composition of binary mixtures of pure chemicals. In the case of most refined industrial chemicals specific gravity, apparent, is of minimal value in defining quality, although it may detect gross contamination.

Of the two test methods described, the pycnometer method (Test Method B, 1.1.2) is the most accurate and precise. For this reason it is the preferred method in case of disputes. The hydrometer method (Test Method A, 1.1.1) is the least accurate and precise, but it is also the simplest and fastest to perform and is often entirely satisfactory for many purposes. If the sample is too viscous to permit the hydrometer to float freely, the pycnometer test method should be used.

1.1 These test methods cover the determination of the specific gravity, apparent, of liquid industrial chemicals. Two test methods are covered as follows:

1.1.1 Test Method A, specific gravity, apparent, by means of a hydrometer.

1.1.2 Test Method B, specific gravity, apparent, by means of a pycnometer.

Note 1—Test Method D 4052 describes an instrumental procedure.

1.2 In common usage the term specific gravity, apparent, is understood to mean specific gravity. Since this test method is to be in conformity with Terminology E 12, all terms reading specific gravity were changed to specific gravity, apparent, without altering the meaning of specific gravity and, the term apparent could be dropped in everyday operations after establishing the use term equivalency.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in these test methods with the exception of Fahrenheit (°F) in 5.1 as an example of a possible industrial specification unit.

1.4 This standard does not purport to address 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 and health practices and determine the applicability of regulatory limitations prior to use.

1.5 Review the current Materials Safety Data Sheets (MSDS) for detailed information concerning toxicity, first aid procedures, handling, and safety precautions.