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Pumps & Systems, February 2008

With pumps part of just about every manufacturing operation, proper functioning of entire facilities often relies on a single pump. 

Half of a plant's maintenance budget is very often spent on pumps, and pumps are commonly the single largest source of unplanned downtime. They have a significant impact on environmental compliance, product quality, mission assurance and, ultimately, the bottom line.

Often when a pump fails, the operations manager concludes that maintenance is not adequately maintaining the pump and calls them to task. In turn, the maintenance/reliability manager gets annoyed and asserts that little can be done to improve reliability since operations continues to abuse the equipment. This vicious cycle does not help prevent recurrence.

In contrast, many thought leaders in the industry resist this inaccurate stereotype of the failure-prone pump. Instead, they have dramatically reduced their incident rates and pump maintenance budgets-not to mention impacting the bigger-picture ripple effect-by pinpointing the root causes of the problems and developing truly effective solutions that meet everyone's objectives.

They are carefully fact-finding about:

• People - How are they performing? What are they doing?
• Procedures - What specific procedure is causing the problem?
• Hardware - Is it right for the job? What design choices have been made? What specifications are being followed?
• Nature - How are natural and external environmental conditions affecting reliability?

In my experience helping companies work through pump problems-both from the inside as a reliability engineer and as an outside consultant-the conclusions people instinctively draw are often very different from the causes identified through root cause analysis (RCA). Simply put, the solutions people often implement are an attempt to mitigate consequences of failures rather than to eliminate the causes of the problem. For example, how many of you keep fully built spares in your warehouse and focus on quick change out? Do you "accept the inevitable" and incorporate the expected unreliability of the pump into your production plans?

Having spent numerous years in production, I understand and accept if/when your reliability program is still in the "reactive" state. However, if you are not investing the time to understand and correct the causes of pump failures, you have a significant missed opportunity and you will likely never make it to the ‘proactive' realm.

Common Causes of Failure

The hidden causes of pump failure can be discovered with focused RCA. A few common causes to consider include:

1. The selected pump does not match the need or the process has changed, thus rendering the original design inappropriate.
2. When trying to solve a problem, people inadvertently and unknowingly create separate and new problems.
3. Supervisors often aren't aware of the little things people are doing-usually with good intentions-that have adverse effects on the system. 
4. For equipment that conforms to the specs and operating parameters, it's all too common that the "abnormal" situations are not considered. Steam-outs, acid flushes, loss of tracing and dry-running at the end of a transfer are common events for pumps and should be considered part of the "normal" operating scenario. Rarely are these common operational practices incorporated into the design, specification and installation phases.
5. Slight changes in operation or process chemistry can impact reliability. People often do not realize the impact subtle changes may have and thus don't bother to review the changes with their pump and process experts to understand the potential impact on pump life and performance.
6. Occasionally, a mismatch of goals exists between management and labor. If the reliability culture has not matured, maintenance personnel may view pump unreliability as desirable because of the inherent rewards: overtime pay and recognition of "saving the day" through expeditious pump repairs. Sometimes, known problems are hidden to protect the work. 
7. Maintenance/reliability staff default to looking for hardware solutions-the next big, shiny thing-which are often unnecessary or ineffective.
8. Due to a retiring generation of skilled mechanics and millwrights, there's a shrinking number of people who know how to effectively maintain and repair equipment. The incumbents are being asked to perform a broader array of tasks in less time, which precludes development of skill proficiency. Because this trend is not likely to change, the engineer who specifies pumps the same as 20 years ago will introduce unreliability (failure causes) in the pump before it is even commissioned.