Page 48 - Root Cause Failure Analysis

Root Cause Failure Analysis Methodology 39
Poor Design Practices

Some equipment problems result from inadequate plant-engineering practices. Down-
sizing, a growing trend in U.S. industry, often diminishes or eliminates in-house
design and plant-engineering capabilities. However, this can result in poor design
practices, which have a major impact on equipment reliability. Even in those facilities
where in-house design capability is not eliminated, the quality of procedures and
practices can suffer such that it affects the design process and contributes to problems.

During the design-review phase of an investigation, the investigating team should
have evaluated the design process to determine if it is adequate for the particular
application. If not, the obvious corrective action is to modify the procedures and prac-
tices that are used for the design function.

Procurement Practices
The methods for procuring new and replacement equipment often contribute to equip-
ment-related problems. The major factors contributing to procurement deficiencies
are inadequate specifications, substituting vendors or machines, omitting life-cycle
cost evaluations, and not obtaining vendor evaluations.

Inadequate Specifications

A major contributor in this category is the absence of adequate procurement specifica-
tions. Generally, specifications do not include enough detail to ensure that the correct
part or machine is purchased. Too often, the specifications are limited to a model or
part number. However, this type of specification does not define the specific applica-
tion or range of operations that the machine must provide.

Substitutions
The defined role for the purchasing process is to limit the cost of new and replacement
parts and machinery. As a result, procurement personnel often substitute parts or
machines that they perceive to be equal. Unfortunately, the substitutes are not always
exactly the same. The vendors themselves also contribute to this type of problem.
They will offer their equivalent to the requested specification without reviewing the
intended application. In some cases, this merely is an oversight. In others, it is an
intentional effort to obtain the order, regardless of the impact on plant performance.

Low Bid versus Life-Cycle Cost
Procuring replacement or new equipment based strictly on low bid rather than life-
cycle cost is another major contributor to equipment-reliability problems. In an effort
to reduce costs, many plants have abandoned the process of vendor selection based on
the total lifetime cost of equipment. This error continues to lower equipment reliabil-
ity and may be the root cause of many problems.