Corrosion-under-Insulation (CUI), if left to its own devices, can and does cause serious and sometimes catastrophic consequences with piping systems and related components and equipment.
CUI is insidious, difficult to detect and can be expensive to mitigate. National Association of Corrosion Engineers (NACE) data now indicate that corrosion costs in the U.S. are approaching $1 trillion annually [NACE Corrosion Costs Study 2011 Update], and will likely surpass that unfortunate milestone in 2012.
Major costs associated with CUI include:
- Removal and replacement of insulation and jacketing on corroded equipment
- Removal and replacement of insulation and jacketing on non-corroded equipment
- Costs associated with detection of CUI
- Costs increase significantly if removed material contains asbestos
For piping systems most leaks occur:
- On pipe less than 4-inches in diameter
- Due to CUI rather than process related factors
How can you reduce the costs associated with CUI? The key is early and smart detection strategies.
Kakivik can reduce many of the costs associated with detecting and mitigating CUI and reduce the likelihood of piping failures. We utilize non-destructive techniques including digital radiography and infrared thermography.
INFRARED THERMOGRAPHY (IR) is a rapid scanning technique that detects the conditions (e.g., wet insulation) that lead to CUI by measuring the temperature profiles of insulated piping. Wet insulation has a higher thermal conductivity than dry. We use IR to scan large areas at once to immediately identify potential trouble spots.
C-ARM RADIOSCOPY locates and confirms the presence of wet insulation and external corrosion of the pipe wall. This examination is done in real-time by highly qualified radioscopic technicians and may be performed using rope access systems.
RTR4 or automated and semi-automated RTR4 radioscopy provides real time investigations for detection and confirmation of wet insulation and external corrosion on piping. This examination may also be done utilizing rope access systems.
CMOS Imaging Panels can image code-quality digital images of welds under proper conditions. These thin, flat panels can be used with either X-ray tubes or gamma sources. However, X-ray applications yield higher quality images. The systems are deployed much like traditional film radiography. They can also be deployed on a robotic scanner. The CMOS imagers are excellent for internal and external corrosion detection, with the thickness equivalent in steel of approximately 400kV, which is up to approximately 14” with product. With natural gas lines, the potential line diameter would be greater.
Amorphous Silicon (a-Si) Imaging Systems are a less expensive alternative to CMOS imaging, and are excellent systems for imaging valves, and internal and external corrosion on pipelines. Under perfect conditions, the system is capable of producing code-quality images. However, the strength of these systems is their ability to produce an image quickly for the detection of internal and external corrosion on small diameter pipelines.
CdWO4 Linear Array - Kakivik has been partnered with a research scientist since 2004 to develop a digital radiography system that can image large diameter, insulated pipelines with product flow. This has resulted in the fielding of a proprietary, cadmium tungstate, linear array deployed by a wireless robotic scanner. The scanner travels along an elevated pipe, typically looking at the six o’clock position (bottom) of the pipe. This system can image internal and external corrosion through pipe filled with water, oil and natural gas. Image averaging (taking several images and averaging them together) improves the image when dealing with dynamic fluid flow.