Langelier Saturation Index

Definition

The Langelier Saturation Index evaluates whether a water has the thermodynamic tendency to precipitate or dissolve calcium carbonate under bulk conditions. It indicates the potential to support a protective calcium carbonate layer.

LSI describes whether calcium carbonate can participate in raising cathodic resistance, but it does not predict corrosion directly. Local conditions at the metal surface such as oxygen availability, flow, deposits, aggressive anions, and microbiology ultimately determine how fast corrosion occurs. It is used alongside the Ryznar Stability Index to assess whether the fugitive calcium carbonate film is even possible.

Related concepts

pH Drift · Ryznar Stability Index · Saturation pH

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Part of The Blueprint of Water · 📏 measurement