Page 35 - Machinery Component Maintenance

20 Machinery Component Maintenance and Repair

The system aids in scheduling inspection activities. Each piece of
equipment covered by the system is scheduled for periodic inspection.
Inspections that can be performed while the equipment is operating are
placed on a monthly schedule for routine execution by the inspection
team. Inspections which must await equipment shutdown are placed on a
standing work list for coordination with operating and maintenance de-
partments.
Inspection systems also may provide inspection history for particular
pieces of equipment, standard inspection procedures for the equipment,
forms for recording equipment conditions and thickness measurements,
and automatic computation of corrosion rate (based on multiple inspec-
tions). The well-designed inspection system also can accommodate thick-
ness measurement data produced by inspection tools such as ultrasonic,
infrared, or radiographic devices.
Using results from system computations, inspection groups may report
equipment condition to maintenance groups if repair, service, or replace-
ment is required. Maintenance, in turn, would generate a work order
consistent with the inspector’s requirements. Information also may be
routinely provided to engineering personnel to plan equipment replace-
ment or to improve equipment and parts selection as equipment is re-
placed.
Planning and scheduling major maintenance projects using computer-
supported Critical Path Method (CPM) techniques was onc of the earliest
applications of computers in support of the maintenance function. The
central idea behind development and use of such systems was to identify
opportunities for parallel execution of tasks associated with a turnaround
project so that available manpower and resources may be utilized as effi-
ciently as possible to minimize equipment downtime.
In spite of the CPM system’s “head start” in use by maintenance
groups, this potentially profitable tool soon was abandoned by a surpris-
ingly large number of plants and companies. Most companies said the
available CPM systems were too complex or too cumbersome for effec-
tive use in maintenance turnaround projects or small construction jobs.
There is, however, a resurgence of computer-based CPM systems to-
day. Systems currently designed and used for planning and scheduling
major maintenance projects are simplified versions of the earlier sys-
tems. They are, in fact, designed specifically for use by process industry
maintenance personnel. They incorporate terminology readily under-
stood by maintenance people and combine simplicity of operation with
flexibility.
Typically, the well-designed CPM system produces reports which
show how limited resources may be used to complete a project in the
shortest possible time. Alternatively, the system may show the man-
power necessary for completion of a project in a given length of time.