Areas Prone to Corrosion Under Insulation
General areas: Areas downwind of cooling towers exposed to cooling tower mist, Areas of protrusions (i.e. transitions) through the jacketing at manways, nozzles, & other components, Areas of protrusions through insulation for systems operating at or below ambient, or in cold service, Areas where insulation jacketing is damaged or missing, Areas where caulking is missing or hardened on insulation jacketing, Areas where the jacketing system is bulged or stained, Areas where banding on jacketing is missing, Areas where thickness monitoring plugs are missing, Areas where vibration has caused damage to the insulation jacketing, Areas exposed to steam vents, Areas exposed to process spills, the ingress of moisture, or acid vapors, Areas exposed to deluge systems, Areas insulated solely for personnel protection, Areas under the insulation with deteriorated coatings or wraps, Areas with leaking steam tracing, Pipe and flanges on pressure safety valves, Systems that operate intermittently above 250 °F (120 °C), Systems operating below the atmospheric dew point, Systems that cycle through the atmospheric dew point, Ice-to-air interfaces on insulated systems that continually freeze and thaw.
Piping: Dead-legs, vents, and drains, Pipe hangers and supports, Valves and fittings, Bolted on pipe shoes, Steam-tracing/electric-tracing tubing penetrations, Termination of insulation at flanges and other piping components, Carbon/low alloy steel flanges, bolting, and other components in high alloy piping, Jacketing seams on the top of horizontal piping, Termination of insulation on vertical piping, Areas where smaller branch connections intersect larger diameter lines, Low points in piping with breaches in the insulation, Close proximity to water (e.g. wharf) and/or ground (e.g. increased absorption), Wet due to flooding or submerging into water, Damage due to foot traffic.