The difference between predictive and preventive maintenance programs

A predictive and preventive maintenance program is essential to efficient, reliable and safe operations. However, it takes tons of discipline.

Predictive and preventive maintenance programs (PPM) involves the regular and systematic application of engineering knowledge and maintenance of equipment and facilities. PPM ensures proper functionality and reduced rates of deterioration of facilities and equipment.

To work effectively, predictive and preventive maintenance programs involve dedicated engineering, regular examinations, inspections, lubrication, testing and adjustments of equipment without prior knowledge of equipment failure. Combined, these tactics work to prevent equipment failure, and should not be reserved only for equipment that has presented problems in the past.

preventive maintenance program experiment
PM doesn’t achieve reliability, it preserves reliability!

PPM also involves creating a framework for all planned maintenance activity, including planning work orders to correct potential problems identified by inspections. The desired effect of a properly implemented PPM program is a proactive, rather than reactive, workplace environment.

Total maintenance cost of equipment owned is the sum total of the material cost, as well as the labor cost to repair the item, the preventative maintenance costs to avoid repairs, and the cost of lost production while the item is being repaired. Predictive and preventive maintenance is designed to extend the life of equipment, and reduce unnecessary failures and repairs by implementing a selective program effort for corrective, or “fix it when it fails” maintenance.

Requirements of predictive and preventive maintenance programs

Predictive maintenance monitors the condition and performance of equipment to detect units’ degradation. To do this, predictive maintenance utilizes testing and measuring techniques to determine the status of equipment before breakdowns occur. These predictive maintenance programs complement preventative maintenance, however to be successful a few things must happen. After predictive maintenance is performed, it is used to determine preventive maintenance, which is a performed at regular intervals on a piece of equipment to lessen its likelihood of failure. For example, predictive maintenance can determine that a unit must be checked every two weeks to avoid failure. Preventive maintenance would then be performed at those intervals.

Diligent scheduling creates success in preventive maintenance, while predictive maintenance contributes to diligent scheduling. Predictive and preventive maintenance must stick to a planning and schedule program, providing structure into which PPM routines follow. If they are not followed, the environment will remain reactive. The greatest barrier to effective scheduling is the occurrence of emergency breakdown repairs, which can distract a maintenance crew from their other duties. However, if a crew follows a predictive and preventative maintenance program diligently, these emergency breakdown repairs all but be eliminated or reduced to a minimum.

Predictive and preventive maintenance programs must be viewed as an ongoing and controlled experiment to maintain consistency and punctuality. Just as one continually nurtures and refines an experiment, controlling for variables and sticking to schedules, maintenance engineers must do the same for PPM or the program will fall apart. An effective maintenance engineer will design a personalized PPM program and schedule suited to their company’s industry, assets, and equipment. Studies have found the preventive maintenance ROI is  $0.33/ square foot.

 


References | Life Cycle Engineering Preventive and Predictive Maintenance