Page 55 - An Introduction To Predictive Maintenance

Role of Maintenance Organization 45

production hours, reactive or breakdown response is the dominant management phi-
losophy. To be competitive in today’s market, delays caused by maintenance-related
problems should represent less than 1 percent of the total production hours.

Another indicator of management effectiveness is the amount of maintenance over-
time required to maintain the plant. In a breakdown maintenance environment, over-
time costs are a major, negative cost. If your maintenance department’s overtime
represents more than 10 percent of the total labor budget, you definitely qualify as a
breakdown operation. Some overtime is, and always will be, required. Special pro-
jects and the 1 percent of delays caused by machine failures will force some expen-
diture of overtime premiums, but these abnormal costs should be a small percentage
of the total labor costs.

Labor usage is another key to management effectiveness. Evaluate the percentage of
maintenance labor, compared to total available labor hours that are expended on the
actual repairs and maintenance prevention tasks. In reactive maintenance manage-
ment, the percentage will be less than 50 percent. A well-managed maintenance orga-
nization should maintain consistent labor usage above 90 percent. In other words, at
least 90 percent of the available maintenance labor hours should be effectively used
to improve the reliability of critical plant systems, not spent waiting for something to
break.

3.2.1 Three Types of Maintenance
There are three main types of maintenance and three major divisions of preventive
maintenance, as illustrated in Figure 3–1:

• Maintenance improvement
• Corrective maintenance
• Preventive maintenance
• Reactive
• Condition monitoring
• Scheduled

Maintenance Improvement
Picture these divisions as the five fingers on your hand. Maintenance improvement
efforts to reduce or eliminate the need for maintenance are like the thumb, the first
and most valuable digit. We are often so involved in maintaining that we forget to
plan and eliminate the need at its source. Reliability engineering efforts should empha-
size elimination of failures that require maintenance. This is an opportunity to pre-act
instead of react.

For example, many equipment failures occur at inboard bearings that are located in
dark, dirty, inaccessible locations. The oiler does not lubricate inaccessible bearings
as often as those that are easy to reach. This is a natural tendency, but the need for