Page 358 - Reciprocating Compressors Operation Maintenance

Preventive Maintenance for Reciprocating Compressors 343

At the same time, repairs performed on an emergency basis are three
times more costly in labor and parts than repairs conducted on a pre-
planned schedule. More difficult to calculate, but high nevertheless, are
costs which include the shutting down of the production process or time
and labor lost in such an event.
Bad as these consequences of poorly planned maintenance are, much
worse is the negative impact from frequent breakdowns on overall per-
formance, including the subtle effect on worker morale, product quality,
and unit costs,

Preventive maintenance, when used correctly, has shown to produce
maintenance savings in excess of 25%, but beyond this, its benefit quick-
ly approaches a point of diminishing return. It has been estimated that
one out of every three dollars spent on preventive maintenance is wasted.
A major overhaul facility reports that "60% of the hydraulic pumps sent
in for rebuild had nothing wrong with them." This is a prime example of
the disadvantage of performing maintenance to a schedule as opposed to
the individual machine's condition and needs.
However, when a preventive maintenance program is developed and
managed correctly, it is the most effective type of maintenance plan
available. The proof of success can be demonstrated in several ways:

• Improved plant availability
• Higher equipment reliability
• Better system performance or reduced operating and maintenance
costs
• Improved safety

A plant staff's immediate maintenance concern is to respond to equip-
ment and system functional failures as quickly and safely as possible.
Over the longer term, its primary concern should be to systematically
plan future maintenance activities in a manner that will demonstrate
improvement along the lines indicated. To achieve this economically,
corrective maintenance for unplanned failures must be balanced with the
planned preventive maintenance program. Figure 6-1 shows that opti-
mization of maintenance expenditures requires a sound balance between
corrective and preventive maintenance of the compressor equipment.