Water contamination in industrial oils can cause severe issues with machinery components. The presence of water can alter the viscosity of a lubricant as well as cause chemical changes resulting in additive depletion and the formation of acids, sludge, and varnish. Water testing is always a part of any lubricant condition monitoring program. Water contamination in industrial oils with strong water separation properties has been historically difficult to measure with any technique.
Water can coexist as three phases in an oil sample: dissolved, emulsion mix, and free globules which makes it challenging to obtain a representative sample. The additive formulations in these types of oils are designed to separate water efficiently above saturation limits of 50-250 ppm water. Above saturation, the water will form discrete water droplets and eventually separate from the oil if left to sit (Figure 1). Dissolved water is typically not too much of a concern for industrial applications but free water or emulsified water must be stringently controlled