Detection of hydrocarbon fuel spills using a distributed fibre optic sensor

A fibre optic sensor capable of the distributed detection of multiple hydrocarbon fuel and solvent spills is described. The sensor incorporates liquid-swelling polymers that convert the swelling into a microbend force on an optical fibre when activated. Sensor interrogation is conducted using a standard optical time domain reflectometry (OTDR) technique. This provides the potential of locating target hydrocarbon fuel and solvent spills at many separate positions along the sensor length. Typical sensor response time after exposure to the fuel is 30s using the current design. Sensors that are capable of locating 1m long spill events with a location accuracy of 2.5 m over a range of 2 km are reported. A brief description of the underlying technology and the material evaluation tests are presented followed by initial sensor evaluation results. Laboratory and experimental field trials demonstrating repeatability and the simultaneous location of multiple fuel spills are summarised. Automatic detection of events using a custom-built OTDR instrument is briefly discussed and finally the potential applications for this type of sensor technology are outlined. (C) 2003 Elsevier B.V.