Column Condition-based Maintenance Maintenance Predictive Maintenance

Systems Thinking Leads to Savings

Klaus M. Blache | January 18, 2019

In 2002, the U.S. Department of Energy Office of Scientific and Technical Information, Washington, published material stating:

“Industries worldwide depend upon pumping systems for their daily operation. These systems account for nearly 20% of the world’s industrial electrical-energy demand and range from 25% to 50% of the energy usage in certain industrial-plant operations. Purchase decisions for a pump and its related system components are typically based upon a low bid, rather than the cost to operate the system over its lifetime. Additionally, plant facilities personnel are typically focused on maintaining existing pumping-system reliability rather than optimizing the systems for best energy efficiency. To ensure the lowest energy and maintenance costs, extended equipment life, and other benefits, the system components must be carefully matched to each other, and remain so throughout their working lives.”

“Energy Savings Tips for Small Businesses: Small and Medium Manufacturers” (energystar.gov) states:

• “For equipment that runs at different speeds, consider installing adjustable-speed drives (ASD) or variable-speed drives (VSD) to better match speed-to-load requirements for motor operations, and therefore ensure that motor energy use is optimized to a given application. Energy savings may vary from 7% to as high as 60%.”

• “A typical plant that has not been well maintained could have a leak rate of 20% to 50% of total compressed-air-production capacity. Leak repair and maintenance can reduce this number to less than 10%. Overall, fixing leaks in a compressed-air system typically reduces annual energy consumption by 20%.”

• “A simple program of checking steam traps to ensure that they are operating properly can save significant amounts of energy for very little money. In the absence of such a program, it is common to find 15% to 20% of steam traps in a distribution system malfunctioning.”

The purpose of predictive/condition-based motor maintenance is to continually monitor motor conditions such as surface temperature, current levels, vibration, and other performance information. This allows one to use hard data to make rebuild/replace decisions. “The savings associated with an ongoing motor-maintenance program could range from 2% to 30% of total motor-system energy use.

The chart shows relative cost for various maintenance approaches in a power-generation study that compares dollars/horsepower in the form of precision, which is normalized at 1. Source: Electric Power Research Institute, Palo Alto, CA, epri.com

The accompanying chart, adapted from a power-generation study conducted by EPRI (Electric Power Research Institute, Palo Alto, CA, epri.com), compares dollars/horsepower by types of maintenance. The study indicates that it is four times more expensive to do reactive versus precision maintenance. So, it’s probably not a coincidence that my 2016 study showed that the minimum annual benefit of precision-maintenance training is at least four times more valuable (documented implementation savings) than general-maintenance training. These savings do not include the cost of downtime, which can typically be reduced by as much as 50%, based on the current level of reactive practices.

Unlock your systems thinking and implement reliability, maintenance, and energy as a synergistic process for maximum performance and savings. EP

Based in Knoxville, Klaus M. Blache is director of the Reliability & Maintainability Center at the Univ. of Tennessee, and a research professor in the College of Engineering. Contact him at kblache@utk.edu.

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Klaus M. Blache

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