Pumps & Systems, April 2013
Editor’s note: The following article is based on a Pumps & Systems webinar presented by Mr. Kernan in October 2012. Readers can register for the presentation slides and audio under the “Webinars” section of www.pump-zone.com.
Industrial facilities have the same fundamental goals, no matter the product they manufacture or the market they serve. From top executives to the plant floor, a common goal is to cut costs while improving reliability and process control. A recent poll confirmed that energy efficiency and maintenance were the top two concerns of industrial pump users in 2012. From an investment perspective, focusing on these concerns makes sense. More than 50 percent of the life-cycle costs of a typical chemical pump are made up of energy, maintenance and repair costs (see Figure 1). But what is actually being done to address these concerns?
When pressure is applied to maintain the steady pace of plant operations, the approach to maintenance could fulfill Albert Einstein’s definition of insanity, “...doing the same thing over and over again and expecting different results.” Getting caught in “firefighting” mode is common—fixing critical assets that have failed and putting them back into production as quickly as possible, and then moving to the next piece of problematic equipment. However, with the abundance of data on rotating equipment that are readily available, operators can implement different pump maintenance strategies to mitigate risks and optimize budgets.
This article addresses how to achieve a balanced maintenance approach, illustrating the pitfalls of a “one-size-fits-all” mentality. It describes the spectrum of maintenance philosophies and gives applicable advice on how to improve the bottom-line benefits of total pump system investments.
Above: A South American copper mine implemented a condition-based maintenance system to monitor 16 pumps and motors at four remote locations. The system gives mine operators real-time data on all pumps and motors, allowing them to monitor vibration levels, temperatures and more.
Not All Industrial Equipment is Equal
Certain pieces of the process will have a greater impact on plant productivity. Although the boundaries are often blurred, the industrial equipment population can be broken down into four tiers: critical, essential, important and the remaining balance of the plant.
Smallest in volume, critical equipment failure can pose significant production losses and safety threats. Less important, balance-of-plant equipment generally represents more of the total assets, but failure will not result in substantial plant downtime. The balance-of-plant assets can quickly consume maintenance resources and budgets if not managed properly.
Before determining which maintenance philosophy to apply, end users should consider the equipment’s relative impact to the overall process and critically rank all assets. Four maintenance philosophies for consideration are:
- Reactive—Running a piece of equipment to failure and fixing it when it breaks
- Preventive—Time-based maintenance activities
- Predictive—Using condition-based data to help predict the likelihood of a failure
- Proactive (Precision)—Understanding why the failure occurred and implementing a change to prevent future failures
Figure 1. This breakdown of life-cycle costs highlights the importance of finding the right equipment for the right job. The combined cost of energy, along with maintenance and repair, makes up more than half the overall life-cycle cost for equipment. Cutting these costs down can lead to big savings. Source: Top 10 Global Chemical Manufacturer, FY 2006
Reactive Maintenance: Not Always Wrong
Practicing predictive or proactive maintenance wherever possible seems ideal. However, this may not be cost effective for all equipment. For instance, balance-of-plant equipment that has a smaller impact on profitability may not be worth as much of an investment to closely monitor as critical or essential equipment. Reactive maintenance—otherwise known as “fix it when it breaks” mode—may suffice in these cases.
The bottom line is that end users should consider the costs to fix or replace a particular asset when determining what they are willing to spend on respective maintenance efforts.
The Problem with
Under normal circumstances, one could assume that the probability of equipment failure increases with time. In the 1960s, this maintenance paradigm prevailed. After the initial burn-in phase in which a high likelihood of infant mortality exists, the probability of failure evens out, followed by an eventual increase in probability of failure near the end of life. For preventive maintenance, the thought process is simple: if repaired before end of life, catastrophic failure can be prevented.