4.1 This practice covers the mathematical calculation of the supersaturation of three principal sulfate scaling compounds found in industrial operations. Application of this standard practice to the prediction of scale formation in a given system, however, requires experience. The calculations tell the user if a water, or mixture of waters, is in a scaling mode. Whether or not scale will in fact form, how quickly it will form, where it will form, in what quantities, and what composition are subject to factors beyond the scope of this practice. However, based on how supersaturated a given water or mixture of waters is, an objective evaluation of the relative likelihood of scale formation can be made.

1.1 This practice covers the calculation of supersaturation of barium sulfate, strontium sulfate, and calcium sulfate dihydrate (gypsum) in brackish water, seawater, and brines in which barium, strontium, and calcium ions either coexist or exist individually in solution in the presence of sulfate ions.

1.2 This practice is not applicable for calculating calcium sulfate dihydrate supersaturation if the temperatures of saline waters under investigation exceed 95°C. At temperatures above 95°C, hemianhydrate and anhydrite would be major insoluble forms.

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

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

1.5 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.