How is alkalinity in boiler water typically measured?

Alkalinity in boiler water is typically measured using a titration test, which involves adding a reagent to a water sample until a specific endpoint is reached, indicating that all alkaline substances in the sample have reacted. This method provides a quantitative measurement of the concentration of alkalinity present in the water, typically expressed in terms of calcium carbonate equivalent. Titration is preferred because it accurately distinguishes between different types of alkalinity present, such as hydroxide, carbonate, and bicarbonate ions.

Other methods, like a pH test, provide indirect indications of alkalinity but do not quantify it accurately. Conductivity tests measure the overall ionic concentration in the water, which can include both alkaline and non-alkaline ions, thus lacking specificity. Visual match tests lack precision and scientific rigor, making them unsuitable for accurate measurements of alkalinity. Hence, titration is the most reliable method for determining alkalinity in boiler water.