Continuous Underground Monitoring of Gas Leaks

ABSTRACT A gas-leak-detection system was designed based on the concept of oxygen-level measurement. Optical fibers were produced with gas-permeable polymeric cladding material doped with oxygen-responsive porphyrin sensor molecules and subsequently interrogated via the evanescent field along the fiber length. Tests were performed with simulated methane-gas leaks in air and under dry and saturated sand. Results of sensor sensitivity, response time, and reversibility are presented.