An American petroleum company with
two refineries on the West Coast of the United States embraced the
concepts of condition monitoring early in its evolution. They saw
measurable returns from the new approach. However, when they evaluated
their maintenance activities and costs, they found they still had
heavy expenditures, especially on their many pumps. They began to
evaluate the incidence of failures and found that bearings or seals
were failing in many of their pumps on an average of once every six
months. The company then began to assess the causes of their high
incidence of seal and bearing failure in pumps and found three general
areas that required improvement: alignment, balance, and assembly.
The company addressed this problem
by developing a new precision program with the full cooperation of
upper management, operations, and maintenance, all of whom worked
together to solve their machinery problems. By adopting precision
standards for alignment, balance, and assembly, these refineries extended
the mean time between failure from six months to more than six years.
The company in the preceding case history
understood that the costs incurred by the excessive pump failures were
more than those of just simple parts and labor. They also included the
additional real costs of managers/supervisors and purchasing personnel’s
time, of stocking and maintaining inventory, and of the planners who
scheduled the maintenance. What was not recognized, however, was the
further effect that machinery failure has on production and/or productivity.
The actual impact on production can vary greatly depending on industry,
process, and equipment criticality. For example, in a refinery where
there are redundant (backup) machines, a failure may have no effect
on production. In the paper industry, however, there may only be one
machine producing a particular type or grade of product. A failure may
result in a complete halt in production. The cost savings resulting
from precision maintenance practices in this case would be tremendous.
The savings from reduced equipment downtime often far exceed the maintenance