【国外标准】 Standard Test Methods for Calcium and Magnesium In Water

4.1 Calcium and magnesium salts in water are the primary components of water hardness which can cause pipe or tube scaling.1.1 These test methods cover the determination of calcium and magnesium in water by complexometric titration and atomic absorption spectrometric procedures. Two test methods are included, as follows:  SectionsTest Method A—Complexometric Titration 7 – 15Test Method B—Atomic Absorption Spectrometric 16 – 251.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversion to inch-pound units that are provided for information only and are not considered 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. Specific hazard statements are given in 12.2.6 and 20.6.1.4 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.