Near-Ir Fiber Optic Sensors for Contaminant Release Monitoring

Underground pipelines and distribution systems are routinely monitored for leakage. The methods used can find large, longterm leaks but are unable to quickly locate leaks in complex systems. Pipeline leaks are particularly harmful in permeable substrates due to rapid spreading of the spill. In the past ten years, advancements have been made in spectroscopic methods and fiber optic techniques which have the potential for making direct in-situ monitoring of underground systems a practical and cost effective reality. The proposed fiber optic chemical sensors (FOCS) does not utilize a sensitized coating for interaction with the leaking liquid and the required signal processing subsystems and sensors are relatively inexpensive vs. other fiber optic systems. High sensitivity and specific chemical species selectivity of this system would permit the development of a retrofit sensors for leak detection. Under the proposed program, FOCAS (Fiber Optics for Comminications and Sensors, Ltd.) will demonstrate the technical feasibility of using Fourier Transform Infrared (FTIR) Spectroscopic methods and a near-IR evanescent wave FOCS to perform in-situ leak monitoring of hydrocarbon fuels in a simulated underground installation environment. Integration of the sensor with currently available instrumentation makes the transistion of this technology into the commercial environment technicall and financially feasible.