Application of fiber optic high temperature sensors for structural monitoring of structures submitted to fire

Recent events such as the fires on St. Gotthard (2001), the Twin Towers in New York (2001) and the Windsor Building in Madrid (2005) show the importance and the necessity of a monitoring strategy for fire vulnerable structures. Through this strategy, the assessment of fire damaged structures would be possible and if necessary, their demolition operation could be guided. To monitor structures subjected to fire it is essential to have high temperature sensors. Nowadays, the measurements of temperatures during fires are done by high temperature thermocouples, that have the typical drawbacks of the electric sensors. This paper presents a new high temperature fiber optic sensor (FOS) able to measure temperatures up to 1200ºC developed at the Universitat Politècnica de València in Spain. The paper explains the operating principle of the FOS to measure temperatures as well as experimental (fire test) and numerical studies conducted to verify the sensor performance.