Playing Hide and Seek with CUI

Corrosion under insulation can be difficult to locate, but we know that in order for CUI to be present, there must be the presence of water in a system. Many times you don’t know that CUI is an issue until something goes wrong—such as loss of containment, processes becoming unstable, or your personnel getting injured.

After years of aiding customers in defending against CUI with Pyrogel, we offer the following tips for places to check for CUI in your facility.

• Piping near or above open bodies of water, such as jetty lines.
• Areas exposed to mist over-spray from cooling water towers, steam vents, and deluge systems.
• Steam-traced systems, especially those insulated with water-absorbent, and/or rigid insulation materials.
• Equipment in cyclic (i.e., operating both above and below the atmospheric dewpoint) or intermittent service.
• Areas where proper application of surface coating is either not feasible, not guaranteed, or where coatings have degraded.
• Areas subject to heavy foot traffic.
• Tank roofs, especially those with sub-girt systems and fibrous insulation.
• Pipe running through sub-surface road crossings.
• Areas where moisture can pond, such as vertical pipe supports, valve bonnets, and insulation- and/or vacuum support rings.
• Piping expansion loops, where the elbow jacketing tends to open up and fish-mouth.
• At the bottom elbow of any vertical pipe run.
• On horizontal equipment, the areas directly beneath any top-side penetration (nozzles, ladder clips, davits, etc.).
• Sub-surface vaults where buried pipe systems are joined and valved.
• Any pipe running within a trench or impoundment area.
• Low points where the horizontal pipe is insulated with ill-fitting, rigid insulation.
• Piping systems that have a tendency to move or vibrate, causing damage to insulation jacketing.
• Top heads of insulated tanks.