Objective:

The objective of this project is to demonstrate the use of ultrasonic guided wave technology to detect and track the growth of corrosion-induced material damage in steel piping in Department of Defense (DoD) fuel storage and transport facilities. Metal corrosion in fuel piping leads to leaks and potentially large spills, producing environmental hazards that may require costly cleanup. This project will demonstrate the ability to determine nondestructively the rate of material deterioration (as measured by the loss in the thickness of the pipe wall) using the characteristics of signals measured along the pipe many tens of feet away from the unknown locations of metal corrosion.

Technology Description:

Ultrasonic guided wave technology is currently used commercially to locate sites of metal corrosion in piping. Additional measurements at these sites by other techniques are usually necessary to quantify the extent of material damage. This requirement is sometimes difficult to meet because of issues of accessibility, operator safety, and cost. The current project will extend laboratory-based efforts focused on pipes up to 20 feet long to longer pipes with functional protective coatings in live DoD fuel storage facilities. If successful, the results will facilitate more intelligent scheduling of repair and maintenance efforts because the current conditions and the longevity of pipes in these facilities will be better characterized.

Expected Benefits:

Currently, for spill avoidance, a technique known as "smart pigging" is used to assess the conditions of pipe walls. This invasive technique requires a set-up cost of tens of thousands of dollars per pipe, rendering it impractical for pipes only tens of feet long. Another technique is based on pressuring for "strength testing," which is also cumbersome and costly to set up. In contrast, ultrasonic guided wave technology for pipe inspection costs several times less than these current techniques and can potentially provide important information on the rate of material deterioration. However, the real benefit of this approach is in the avoidance of fuel spills that are harmful to the environment and a decrease in potentially costly spill cleanup efforts since the current and future structural integrity of the piping can be better characterized. (Anticipated Project Completion - 2011)

Principal Investigator:
Dr. John Liu
Naval Surface Warfare Center, Carderock Division
Welding, Processing, and NDE Branch (Code 611)
West Bethesda, MD 20817-5700
Telephone: (301) 227-5024
Fax: (301) 227-5776
E-mail: john.liu@navy.mil