There are four condition indicators RMS, Max RMS, PEAK, and Crest Factor. Easy to explain and use, it can give you an overview of an assets health with just one reading.
Ultrasound Four Condition Indicators
Let’s go over them in more detail:
  1. RMS – use it to indicate trends in friction levels (lubrication, stage 1&2 bearing failure)
  2. Max RMS – use it to indicate ultrasound signal stability (steam traps, chain drives, flexible couplings, linear bearings)
  3. PEAK – use it to indicate impacting (shift from stage 2 to stage 3 bearing failure, fatigue, gear mesh, broken gear teeth)
  4. Crest Factor – use it to correlate the relationship between friction and impacting on any asset (perfect for VFDs!!)
Here are some ways in which these condition indicators can be applied. They can be combined as follows:

Friction & Rubbing:

  • Gas & Valve Leak – RMS
  • Lubrication – RMS
  • Steam Trap – RMS & Max RMS (+Peak for flash steam)


  • Bearing, Gears – Peak & RMS (+Crest Factor)


  • Cavitation – Peak


Check out our SDT 200, 270, and 340 featuring the four condition indicators to detect, trend and analyze ultrasound and vibration.

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, by Allan Rienstra - SDT Ultrasound Solutions