PQ exposes oil samples to a magnetic field where the ferrous debris in the sample distorts the field and the amount of distortion is represented as the PQ Index. This is an arbitrary number specific to the technique. However, as the determination of iron by ICP is dependent on particle size where detection is typically limited to < 10 microns, the PQ offers superior detection when larger particles are present. As no single laboratory test completely represents the amount of ferrous wear present in an oil sample and most wear trends start with smaller sized particles that eventually lead to larger particles, including PQ in your fluid analysis program helps in obtaining a complete assessment of current wear conditions.
Careful monitoring of ICP iron concentrations and trends in PQ Indexes provides a means of triggering an Analytical Ferrography Analysis to qualify the type and severity of the wear. Analytical Ferrography is a powerful tool when used in conjunction with other analysis results and helps a Data Bureau Veritas provide users with a well-defined course of action to remedy the current adverse condition(s).