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ASTM D891-2018 pdf free download

ASTM D891-2018 pdf free download.Standard Test Methods for Specific Gravity, Apparent, of Liquid Industrial Chemicals
1. Scope
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. N OTE 1—Test Method D4052 describes an instrumental procedure. 1.2 In common usage the term specific gravity, apparent, is understood to mean specific gravity. 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 appro- priate safety, health, and environmental practices and deter- mine the applicability of regulatory limitations prior to use. For specific hazard statements, see Sections 8 and 16. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Significance and Use
4.1 Specific gravity, apparent, may be used as a qualitative test in establishing the identity ofa chemical. It may be used to calculate the volume occupied by a product whose weight is known, or to calculate the weight ofa product from its volume. It may be used to determine the composition ofbinary 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. 4.2 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.
9. Procedure
9.1 Cool the sample in the original container to about 2°C below the temperature at which the specific gravity, apparent, is to be determined. Rinse each piece of equipment with a portion of the sample and discard the rinse liquid. Pour the sample into the clean hydrometer cylinder without splashing, so as to avoid formation of air bubbles. Remove any air bubbles adhering to the surface by touching them with a piece of clean filter paper. Select a location that is free from air currents. Place the cylinder vertically in the waterbath and let the temperature ofthe sample reach the temperature ofthe bath 60.05°C as follows: Stir the contents of the cylinder, being careful to avoid formation of air bubbles. When the tempera- ture ofthe sample is about 0.2°C below that ofthe bath, slowly and carefully lower the hydrometer into the sample to a level two smallest scale divisions below that at which it will float and then release the hydrometer. After it has come to rest and floats freely away from the walls of the cylinder, read the gravity as the point at which the surface of the sample apparently cuts the hydrometer scale. When the temperature of the sample matches that of the bath, make this observation by placing the eye slightly below the level ofthe liquid and slowly raise the eye until the surface of the sample first seen as a distorted ellipse seems to become a straight line cutting the hydrometer scale. Determine the temperature ofthe sample just before and also, for referee tests, just after reading the hydrometer. 9.2 Repeat 9.1 and average the results.

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