Engineers use design and safety factors in sizing and
specifying instrumentation or major process equipment, such as
pumps, valves and compressors. Design factors are applied to
cover the uncertainty in piping and equipment calculations.
Such practices can contribute to over-design and
can negatively affect performance of the process unit,
resulting in higher costs. Several case histories investigate
how over-design factors have caused problems in the operations
of pumps, heat exchangers and control valves.