Types of Maintenance Programs
5.4 Predictive Maintenance
Predictive maintenance can be dened
as follows: Measurements that detect the
onset of system degradation (lower functional
state), thereby allowing causal stressors to be
eliminated or controlled prior to any signicant
deterioration in the component physical state.
Results indicate current and future functional
capability.
Basically, predictive maintenance differs
from preventive maintenance by basing
maintenance need on the actual condition of the
machine rather than on some preset schedule.
You will recall that preventive maintenance
is time-based. Activities such as changing
lubricant are based on time, like calendar time
or equipment run time. For example, most
people change the oil in their vehicles every
3,000 to 5,000 miles traveled. This is effectively
basing the oil change needs on equipment
Advantages
• Increased component operational life/availability.
• Allows for preemptive corrective actions.
• Decrease in equipment or process downtime.
• Decrease in costs for parts and labor.
• Better product quality.
• Improved worker and environmental safety.
• Improved worker morale.
• Energy savings.
• Estimated 8% to 12% cost savings over preventive
maintenance program.
Disadvantages
• Increased investment in diagnostic equipment.
• Increased investment in staff training.
• Savings potential not readily seen by management.
run time. No concern is given to the actual condition and performance capability of the oil. It is
changed because it is time. This methodology would be analogous to a preventive maintenance task.
If, on the other hand, the operator of the car discounted the vehicle run time and had the oil analyzed
at some periodicity to determine its actual condition and lubrication properties, he/she may be able to
extend the oil change until the vehicle had traveled 10,000 miles. This is the fundamental difference
between predictive maintenance and preventive maintenance, whereby predictive maintenance is
used to dene needed maintenance task based on quantied material/equipment condition.
The advantages of predictive maintenance are many. A well-orchestrated predictive
maintenance program will all but eliminate catastrophic equipment failures. We will be able to
schedule maintenance activities to minimize or delete overtime cost. We will be able to minimize
inventory and order parts, as required, well ahead of time to support the downstream maintenance
needs. We can optimize the operation of the equipment, saving energy cost and increasing plant
reliability. Past studies have estimated that a properly functioning predictive maintenance program
can provide a savings of 8% to 12% over a program utilizing preventive maintenance alone.
Depending on a facility’s reliance on reactive maintenance and material condition, it could easily
recognize savings opportunities exceeding 30% to 40%. In fact, independent surveys indicate the
following industrial average savings resultant from initiation of a functional predictive maintenance
program:
• Return on investment: 10 times
• Reduction in maintenance costs: 25% to 30%
• Elimination of breakdowns: 70% to 75%
• Reduction in downtime: 35% to 45%
• Increase in production: 20% to 25%.
O&M Best Practices Guide, Release 3.0 5.4