Components determine the next analysis level: identifying dominant failure modes. Vendor operation and maintenance (O&M) manuals suggest dominant failure modes implicitly with recommended PM tasks. Vendors infer failures that could become dominant in their equipment from users' part orders, complaints, and rework or support service sales. They can't actually learn a facility's operations. Vendor-recommended PM, applied indiscriminately, produces lengthy, enumerative PM WO task lists, many of which have little direct applicability, based upon past experiences. At complex plants, common equipment presents low-risk, based upon design redundancy, low utilization, and absence of dominant failures over economic life. Eliminating low-risk equipment from scheduled maintenance consideration early in strategy development (before detailed failure modes and effects analysis FMEA) streamlines analysis minimizing work.

Classifying part failures by failure modes speeds failure analysis and simplifies risk assessment. For example, a pump may fail to start, fail to deliver flow at pressure, or leak. Several part failures can lead to the same pump failure mode. Consider the failure described as fails to deliver flow at pressure. For a centrifugal pump, this mode could arise from worn seals, impeller erosion, volute erosion, a single-phased motor, or other causes. A loose bearing guide, however, won't cause this type of failure.

Many part failures are inconsequential. Classifying part failures by component failure modes simplifies system effects analysis performed later. FMEA identifies failure modes that can cause system failures.