Page 282 - Improving Machinery Reliability

Maintenance and Benchmarking Reliability 253
15% safetv.
34% environment,
equipment

all others

% replacement
programs
improvement
Figure 4-8. Refinery maintenance benefits.

Table 4-3
Equipment density
(Per million units of capacity and complexity)
Items Items
Lowest cost per Highest cost Per
quartile craftsmen quartile craftsmen
Punips 630 4.8 700 1.1
Compressors 35 0.3 40 0.1
Pressure vessels 490 3.1 500 0.8
Heat exchangers 390 2.9 525 0.8
Safety valves 840 6.3 1,150 I .8

Repair-Focused Organization. This organization style embraces the philosophy
that equipment will fail and that the mission of the maintenance force is to respond
quickly to equipment in distress. Failures are expected because they are the norm.
Management and craftsmen stay occupied in repair activity and have no opportunity
to examine failure cause. Staffing is designed to accommodate rapid repair, often
including sizeable maintenance crews on non-day shifts. When failures do not fully
occupy the workforce, the organization focuses on lower priority (frequently unnec-
essary) minor projects to “stay busy.”

Reliability-Focused Organization. Maintenance repairs in this style are viewed
differently. They are not expected to happen. They are viewed as an exceptional
event and a result of a flawed aspect of maintenance policy and management focus.
The specter of a recurring failure and its incumbent cost is unacceptable. The organi-
zation is sized to manage a condition-based monitoring system and assigns high pri-
ority to the elimination of failure. Unnecessary work is not performed regardless of
the current work load.