The BS&W test is used to detect what types of contamination in lube oil?

• A. Only water contamination
• B. Water and particle contamination
• C. Only sediment contamination
• D. Gas contamination

Answer: (B)

BS&W stands for Bottom Sediment and Water. This test is used to reveal two common contaminants in lube oil: water and solid particles that settle to the bottom. Water enters oil from condensation or leaks and can cause corrosion, emulsions, and reduced lubrication efficiency. Solid contaminants, like dirt or wear debris, act as abrasives and accelerate wear or clog filters. The procedure lets the sample sit or uses centrifugation so immiscible water separates from oil and any solids settle to the bottom; the bottom layer(s) are measured as a percentage of the total sample to indicate contamination. Gas contamination isn’t identified by this test because gases don’t form a measurable bottom layer in a BS&W analysis.