Fiber-Optic Sensing-Based Quantification of Leakage in Spiral Wound Gaskets

Bolted flange connections play a crucial role in industrial process plants. They serve as interconnections between piping systems and process flow equipment. Ensuring their leak-tight operation is essential for personnel safety, for environmental protection, and for decreasing CO2 emissions. In this context, this article proposes a novel approach to assess the sealing performance of flange gaskets during both assembly and service life. The focus is on direct measurement of the gasket surface pressure using fiber Bragg grating (FBG)-based sensors. To do so, we instrumented two spiral wound gaskets with an optical fiber containing 8 wavelength-multiplexed Bragg gratings. We subjected the gaskets to multiple loading and unloading cycles up to 90 kN. The proposed method allows for the measurement of tightness classes according to EN 13555, offering a valuable tool for predictive maintenance strategies. Our study establishes the link between the measured strain and actual leakage in view of assessing the sealing quality during both assembly and service. We demonstrate the measurement during gasket assembly down to tightness class ${L}_{{0.001}}$ . In addition, we identify a threshold to detect the tightness class ${L}_{{0.01}}$ , which remains valid following three loading and unloading cycles and therefore has the potential to support predictive maintenance strategies.