External Visual Inspection

An external visual inspection is performed to determine the condition of the outside of the piping, insulation system,painting and coating systems, and associated hardware; and to check for signs of misalignment, vibration, and leakage.

When corrosion product buildup is noted at pipe support contact areas, lifting off such supports may be required for inspection. When doing this, care should be exercised if the piping is in-service.

External inspections shall include surveys for the condition of piping hangers and supports. Instances of cracked or broken hangers, “bottoming out” of spring supports, support shoes displaced from support members, or other improper
restraint conditions shall be reported and corrected. Vertical support dummy legs also shall be checked to confirm that they have not filled with water that is causing external corrosion of the pressure piping or internal corrosion of the support leg.

Horizontal support dummy legs also shall be checked to determine that slight displacements from horizontal are not causing moisture traps against the external surface of active piping components.

Bellows expansion joints should be inspected visually for unusual deformations, misalignment, or displacements that may exceed design.

The inspector should examine the piping system for the presence of any field modifications or temporary repairs not previously recorded on the piping drawings and/or records.

The inspector also should be alert to the presence of any components in the service that may be unsuitable for long-term operation, such as improper flanges, temporary repairs (clamps), modifications (flexible hoses), or valves of improper specification. Threaded components that may be more easily removed and installed deserve particular attention because of their higher potential for installation of
improper components.