Fan Vibration Baselines Before and After Cleaning

Use the working record

Download the editable worksheet. Record the actual evidence and responsible reviewer against each relevant row. The empty results are inputs for your project, not completed tests. Add the equipment identity, operating period and reference method before assigning an outcome. Retain unsuccessful checks and the evidence from any repeat after correction.

Define the maintenance question

Specify whether the team is investigating a gradual change, checking the result of cleaning or establishing a reference after a planned service. Name the fan, drive, bearings and accessible measurement positions. A useful comparison begins with a bounded question rather than a general expectation that every cleaning operation must lower vibration.

Record what prompted the work: an operator observation, a measured trend or the normal maintenance schedule. Preserve the original evidence before intervention. If no suitable pre-cleaning measurement exists, describe the later observation as a new baseline under its stated conditions, rather than inventing a before-and-after comparison.

Match speed and process condition

Collect the actual rotational speed or an accepted reference for it. Where a variable-speed drive changes demand, an overall vibration value from one speed should not be directly compared with another without the specialist's method. The operating point can change the dynamic behaviour and the frequencies represented in the measurement.

Record relevant process conditions such as damper position, throughput, airflow indication and operating temperature where available. Use the site's meaningful load indicators. A cleaned fan running at a different demand can show a changed measurement even when the physical work achieved its intended purpose.

Preserve the measurement geometry

Identify each position with a photograph, physical label and direction. Keep the sensor mounting method and orientation consistent. A different surface, loose attachment or changed axis can alter the observation enough to obscure the equipment trend. The maintenance record should make the position reproducible by another competent technician.

Inspect the mounting before collecting a new baseline. If it has changed, document the reason and decide whether a new reference series is necessary. Retain the old data with its original mounting information. Historical continuity should be a supported conclusion, not an assumption based on the same dashboard label.

Retain acquisition settings with the result

Record the measured quantity, unit, frequency range, sampling method and duration supplied by the instrument. Keep any filtering, integration and averaging settings. An overall velocity reading and an acceleration measure describe different aspects of the response and should retain their own definitions.

Where waveform or spectral analysis is needed, confirm that the supplied device actually provides it with suitable settings. A periodic overall trend cannot be retrospectively transformed into a diagnostic waveform. The project should align its measurement capability with the maintenance decision before equipment is selected.

Describe the actual cleaning intervention

Record which surfaces and components were cleaned, the method, completion time and observations made during access. Keep photographs where permitted and useful. The work order should distinguish removal of deposits from balancing, alignment, tightening or replacement performed during the same outage.

If several interventions occurred together, the comparison cannot isolate cleaning as the sole cause of a change. Retain the combined maintenance scope and explain that limitation in the engineering review. This still provides useful operating evidence without assigning a more precise causal conclusion than the record supports.

Wait for an appropriate comparison condition

The post-work observation should represent the operating condition agreed with the maintenance and process teams. Startup transients, changing temperatures and unstable demand may require separate treatment. Record when the fan returned to the chosen condition and how that condition was established.

Take the number and spacing of observations required by the specialist's method. A single favourable reading can miss variability or an intermittent condition. Keep unsuccessful or inconsistent readings alongside accepted ones, with the reason for exclusion if a result is unsuitable for the final comparison.

Review changes at the correct level

Start by checking identity, time, units and operating comparability. Then review overall trends and any appropriate diagnostic evidence. A lower overall value can coexist with a new narrow-band feature, while a higher value at another operating point may not represent deterioration. Interpretation belongs with the competent machinery reviewer.

Link the finding to the next action: continue the existing schedule, collect more comparable evidence or undertake a specific inspection. Record the reasoning and the responsible role. Avoid converting the observed difference into an unsupported prediction of failure date or remaining life.

Maintain a useful sequence over repeated work

Keep each cleaning event as a dated intervention in the asset history. Over time, matched observations can help the team understand the relationship between operating conditions, deposits and maintenance. The resulting evidence may support a revised inspection interval, subject to the responsible team's review.

At handover, reproduce one comparison from the exported measurements and work order. The package should include the position record, acquisition configuration, operating evidence and interpretation. A reviewer should be able to distinguish the measured change from the maintenance hypothesis without relying on a coloured dashboard indicator.

Connect the decision to the project

Use Industrial fan monitoring, Vibration motor monitoring pitfalls to place this task within the wider installation. Bring a recent operating record and identify the decision that the proposed measurement should support. A focused discussion should establish the first boundary, the responsible site participants and the evidence needed before expanding the scope.

Agree who maintains the point register and who can change interpretation rules. Preserve the previous version when a device, product, reporting period or responsibility changes. During handover, demonstrate an export that another authorised person can reconcile without relying on the dashboard operator to explain missing fields.

Discuss the scope with addanode using the actual site information, available interfaces and proposed acceptance record.

Sources and method

The PNNL Operations and Maintenance Best Practices guide, Release 3.0 (2010) provides maintenance-method background. Measurement settings, diagnostic interpretation and acceptance criteria require the responsible machinery specialist and actual instrument documentation.

Frequently asked questions