One of the questions we get asked frequently is what is the best way to establish baselines on our equipment? For me, what I like to recommend is the historical method.
To do this you first set up a route in DMS and then you go out and begin to collect data. It’s important to note that the frequency that the readings are taken depends on how critical the asset is. Conducting an Asset Criticality Assessment should always precede any PdM activities you are implementing. That being said, I would recommend initial data should be taken at a minimum of once per month, and then adjusted once the baseline and alarms have been set. From here it is a bit of a domino effect in that once the history has been established, the baseline can be set and once the baseline is set, the alarm levels can be set. Typical alarm levels are 8dB above the baseline and represent a lack of lubrication, and 16dB above the baseline represents the next stage of bearing failure, something that lubrication will not fix.
Once the baseline is established, the user will just go out and record decibel readings and will not have to capture additional sound files. The only time a sound file would need to be recorded once the baseline is established is when it reaches an alarm level.
If you are using the Ultraprobe 10,000 and Ultraprobe 15,000 you can actually alarm on the spot if the user is at a point along the route that is at an alarm level.
When determining how much time needs to be allotted for working your routes, just keep in mind that if you are recording both sound files and dB’s at the same time, you typically want a 20 second sound file, so allot 30 seconds per point.
Setting up your routes, determining baselines and alarms is a critical piece to implementing an effective ultrasound program. If you have additional questions or tips to share, please feel free to email me at firstname.lastname@example.org.
Adrian Messer (subbing this month as Software Sage)