PSI - Issue 44

Mariano Ciucci et al. / Procedia Structural Integrity 44 (2023) 347–354 Mariano Ciucci, Valerio Vezzari, Alessandra Marino / Structural Integrity Procedia 00 (2022) 000–000

351

5

Fig. 4. accelerometers.

4.3. Leakage detectors Mid-Infrared spectrometer is a system for detection leakage in remote and continuous mode, based on a tunable source of the DFG (Difference-Frequency Generation). This system works in chemically aggressive environments and in the presence of different substances. The laser spectrometer is able to measure methane, nitrogen dioxide, nitrous oxide, water vapor, ammonia, sulfuric acid, methane. The catalytic sensors are devices that use the catalytic combustion of the gases present in the atmosphere. These consist in the coupling of a detector, a compensator and a platinum filament to sense the inflammable gas, material or liquid spill at an early stage and to detect the fire within the working environment. The platinum filament in contact with the gas oxidizes by increasing its electrical resistance and altering the flow of current in proportion to the concentration of the flammable gas. Among leakage detectors can also be considered fire detection sensors. 4.4. FBG / FSI Fiber Optic Sensors The particular environmental condition in which the equipment of major hazard industrial plants are in operation and, following a seismic event, in possible operational shutdown (with a probable increase in the risks of explosions and fires due to product spillage), requires a dynamic-continuous pre and post earthquake control system, robust, multifunctional and remotable. This can be useful in support of an objective assessment of the damage and the actions to be taken to the safety of the damaged tank and in support of the tank farm and pipelines operational continuity. For metrological, functional and operational characteristics, the FBG (Fiber Bragg Grating) and FSI (Fiber Segment Interferometry) fiber optic sensor technology meets all these needs. There is also a non-secondary aspect, which is the safety of operation thanks to the dielectric characteristic and the ATEX certification of fiber optic sensors. The use of light, and not electric current, to transmit the measurements from the field to data collection centers (NOC), always in a perspective maintenance of safety and remote control of maintenance and inspection activities, allows them to operate at a distance of kilometers for the management and control of SHM, EWWS and also PM (Predictive Maintenance) operations.

Fig. 5. FBG / FSI fiber optics sensors metrological chain.