ASTM D4904-99(2020)

1.1 This practice covers a standard procedure for the cooling of analytical solutions such as those prepared in Practices D4901, D4905, or D6405. The tannin analysis results for an analytical solution are to some extent dependent on the conditions of the cooling of that solution.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

4.1 The solubility of extracts is influenced by temperature. The analytical solutions prepared from tanning extracts are dissolved or diluted in hot water. It is necessary to exercise caution in cooling these solutions, and to do so in such a way as to avoid chilling, under-cooling, or uneven cooling of the solutions.