SVO:How To

How to test for water in SVO
Smear a finger of SVO accross a fry pan (cast iron preferred) as a temp check.

Keep the sample of WVO to be tested handy; enough for 1/4"-3/8" thickness covering the bottom works best. Heat the pan on high until the smear begins to really smoke, then pour in the sample.

NOTE: Do not pour in a sample with any visible water. If water droplets are visible, no testing is needed: there is water present in your sample. Visible droplets of water will spatter hot oil out of the pan and may cause burns or fire.

Look closely at the bottom of the pan where the oil meets the surface. The formation of small bubbles indicates some suspended water. The number of bubbles indicates how much water is present in suspended form.

A few bubbles may be acceptable. Many small bubbles is usually unacceptable. If crackling or popping is heard, there is way too much water present.

The Crackle Test
Noria Learning Center

There are a number of ways to measure the presence of water in oil. However, most of them are complicated, expensive or difficult to use in the field because they employ wet chemistry. One easy way of detecting the presence of free and emulsified water in oil is with the hot-plate crackle test. This simple, tried-and-true method alerts the user to the presence of any free water.

For years, oil analysis laboratories have screened samples with the crackle test, performing more expensive analysis only when the crackle test is positive. Under carefully controlled lab conditions, the crackle test is sensitive to around 500 ppm (0.05 percent) of water-in-oil depending on the type of oil.

In this application, the crackle test has been used as a reliable indicator of free and emulsified water, as a “go/no-go” test. However, with practice and keen eyes and ears, the procedure can be advanced considerably and made more quantitative. Rather than simply listening for the crackle (scintillation), adding a visual observation and rating of the number and size of the vapor bubbles produced allows a rough indication of the amount of moisture present to be obtained.

The revised method is referred to as the visual crackle. Success in using the procedure depends on practice with varying moisture concentrations in different common fluids, and maintaining a constant hot-plate temperature around 320°F (160°C). A laboratory syringe and a paint shaker can help create a more homogenous suspension, resulting in more consistent results. While the visual crackle does not replace the need for other more precise techniques, it does provide vital information when and where you need it. Simple, inexpensive onsite tests such as this can make a real difference in the effectiveness of oil analysis and contamination control.

Method

The crackle test is a simple test to identify the presence of free and emulsified water suspended in the oil, provided a few simple rules are followed.


 * 1) Raise the hot plate temperature to 320°F (160°C). Always use the same temperature.
 * 2) Violently agitate oil sample to achieve homogenous suspension of water in oil.

Using a clean dropper, place a drop of oil on the hot plate.

Observations


 * 1) If no crackling or vapor bubbles are produced after a few seconds, no free or emulsified water is present.
 * 2) If very small bubbles (0.5 mm) are produced but disappear quickly, approximately 0.05 to 0.10 percent water is present.
 * 3) If bubbles approximately 2 mm are produced, gather to the center of the oil spot, enlarge to about 4 mm, then disappear, approximately 0.1 to 0.2 percent water is present.
 * 4) For moisture levels above 0.2 percent, bubbles may start out about 2 to 3 mm then grow to 4 mm, with the process repeating once or twice. For even higher moisture levels, violent bubbling and audible crackling may result.
 * 5) Be wary of the presence of dissolved gases, fuel, refrigerants and volatile solvents, which can cause false positives.

Limitations

Although generally applicable, the crackle test does have some limitations:


 * 1) The method is nonquantitative.
 * 2) Hot plate temperatures above 320°F (160°C) induce rapid scintillation that may be undetectable.
 * 3) The method does not measure the presence of chemically dissolved water.