The Contaminated Fuel Detector measures solid contaminants in which units?

• A. Milligrams per liter
• B. Parts per million
• C. Percent
• D. Grams per liter

Answer: (A)

Measuring solids in a liquid is about how much mass is present in a given volume. For fuel, the readout is milligrams per liter because it directly shows how many milligrams of particulate are in each liter of fuel, which fits typical contamination levels and calibration practices. For example, 5 mg of solids in 1 liter of fuel equals 5 mg/L. While parts per million is a related way to express concentration, the instrument and standards for this context use mg/L for precision at small contamination levels. Percent would represent a mass fraction, which isn’t convenient for trace solids, and grams per liter is too coarse for the small amounts usually measured. So the detector reports in milligrams per liter.