The following abbreviated sequence of correspondence is real, although we quite obviously had to hide some names. Still, it is quite typical of many discourses our editors carry on with readers or conference participants over a year.
It started with an e-mail from XYZ, a mid-level technical employee with Central Refining Industries (CRI) we had first met decades ago. He asked:
My question is how often our vibration group should be doing their routes on every piece of equipment. We collect data on all fans, gearboxes, pumps and motors monthly. I believe this is too frequent for most machines, but thought I would get your opinion before I stuck my head out too far. I have read a lot of articles and see that no one agrees. We seem to be in the paralysis by analysis mode of doing business.
We answered XYZ by affirming that many reliability managers are unaware of the main reason for gathering vibration data: to get the operators out of the control room. We claimed, somewhat tongue-in cheek, that operators will not leave their control room if:
a) Ambient temperatures climb above +75°F; operators fear the risk of heat stroke
b) Temperature drops below +66°F; theres the real fear of frostbite
c) Wind speed exceeds 4 mph; understandably, they fear being blown off their bicycles.
Who collects the data.
So, best-of-class refineries use a good portable data collector (Fig. 1) to check if and when operators leave their control rooms. For them, vibration monitoring, is often of secondary importance. We explained to XYZ that best-of-class refineries ask experienced vibration analysts to limit their involvement to interpreting out-of-limit data. The operators do the data collecting for the reasons mentioned above. Assigning both the collecting and analyzing of data to a highly trained vibration technician is a rare practice.
| Fig. 1. In addition to warning of component |
deterioration, state-of-art data collectors such
as Ludecas/Prueftechniks VIBXPERT II
serve as monitoring tools to ascertain
scheduled field presence by responsible
At best-of-class companies, experienced reliability professionals will also examine in-house records of failure frequency, repair cost and downtime risk. In oil refineries, considerable judgment is required and equipment criticality is important. Data collection frequency is based on this criticality and can vary from monthly to twice yearly.
Our mid-level technical person replied:
I forwarded this message to our maintenance manager who, by the way, never had anything to do with maintenance in a refinery until four years ago. He is in his late 30s and most of his staff are fresh out of college. However, the maintenance manager often mentions operator involvement in reliability, about which he had heard at a conference.
CRI was not involving its operators in reliability stewardship. To be successful, such an involvement presupposes a well-structured training and technical education program; implementing such a program requires time, competence, monetary resources and continuity of effort. It represents an investment in the future and cannot ever be a flavor of the month thing.
To again quote XYZ:
All or most of our unit supervisors are on too much of a good buddy relationship with their operators to make them get out of the control rooms so as to look, feel and listen to their equipment. They operate by alarms, so to speak. Just recently we lost 4 boiler feedwater pumps out of a total of 7.
We were certain that CRI had never measured the width and concentricity of its slinger rings. They had probably purchased them from the lowest bidder, who probably had skipped the important annealing step. In the future, CRI will have to budget the right price for oil rings that dont distort.
It was again confirmed that best-of-class plants get their exceptional (9.4 years) pump MTBF by systematically upgrading and paying attention to every detail. As always, we appreciated the discourse with CRI because it updated us on the state of affairs in small and mid-size refineries. Some of these refineries become progressively less profitable and the root causes of their problems and issues are often both cumulative and elusive. Putting it more bluntly, the correspondence with CRI filled in the picture, and the picture is not pretty. HP
Bloch, H. P., Pump Wisdom: Problem Solving for Operators and Specialists, John Wiley & Sons, Hoboken, New Jersey, 2011.
|The author |
H. P. Bloch is Hydrocarbon Processings Reliability/Equipment Editor. A practicing consulting engineer with close to 50 years of applicable experience, he advises process plants worldwide on failure analysis, reliability improvement and maintenance cost avoidance topics. He has authored or co-authored 18 textbooks on machinery reliability improvement and over 490 papers or articles dealing with related subjects.