So is the vibration measurement you have from a machine show that it is bad? How do you determine whether there is a problem or not? The simplest way is trending. If the vibration amplitude reading is steadily increasing, then probably yes, it is showing increased wear. But, if you don't have any other previous vibration data, what do you do? Look it up on the ISO #10816-1 chart!

 

Yes, there is a severity chart, but you have to identify some basic parameters to use the chart. You especially need to determine what "Class" the equipment is-small, medium, or large rotating machine. You really need to do a complete inspection and evaluation of the installation.

 

Identifying the severity of the vibration begins long before you collect that first reading. How does the machine sound? What is normal? Does it have a high pitched noise? Or a very low growling thunder roll? Or is it pulsating heartbeat like noise? Each of these conditions could point to a different cause. Is the installation fixed(bolted down), or flex mount(on vibration pads or spring isolators). Is the load variable, or continuous? The inspection list is very long. Could someone have propped a brace, or attached a cable, against the machine?

 

A high overall vibration level, per the below chart, does not automatically mean the vibration is severe. This is where the trained analyst earns his stripes. Vibration severity involves so many other inputs. It is very seldom cut & dry. The chart is only a guideline to help the analyst determine the cause, and/or severity of the vibration.

 

Some manufacturers provide standard warning and alarm levels with their equipment. Most do not. But even with the manufacturer's levels, you have to be sure the installation is in accordance with the manufacturer's recommendations: such as bolted down, or flex mounted?

 

So when it comes to vibration severity, there is no "one size fits all". But generally, you can depend on the ISO 10816 to at least get you in the right ballpark. It is a good starting point for your in-house vibration analysis preventative maintenance program. Invest in PM, it will save you money!

                                                                    Vibration Chart

 

Copyright © 2015   Snyder Technical Services, LLC.  All Rights Reserved

Maintenance Minute is published each month by Snyder Technical Services, LLC and is based on the work of former Lamson National Service Manager, Bill Snyder.   Should you have any questions, or problems to discuss, please contact me.

Sincerely,