The UK division of international oil and gas engineering company J P Kenny has launched a system to detect possible leaks in airport fuel- hydrant networks. Developed in association with Texas-based software companies PMA and Modisette, the LeakLoc system is undergoing acceptance trials at London Stansted Airport.
The LeakLoc works on the principle that an aperture in a pipeline will, for most liquids, create pressure waves which travel up and down the pipeline at a constant rate of 197,000ft/min (1,000m/s) - approximately the speed of sound.
These waves are detected by a series of sensors, or data-acquisition stations, which are strategically placed across the pipeline network and are able to discriminate, fresh "pressure sounds" from the regular "background noise" of the pipeline during operation.
By comparing the arrival time of the waves at two sensors, one either side of the leak, the exact location of the leak can be identified to within a 1m length of pipe. The timing accuracy of all the sensors in the network is established and synchronised by referral to global-positioning-system satellites.
Calvern Newby, BAA special projects engineer at Stansted, says that, previously, leaks in an airport-hydrant system, which typically may be buried in concrete up to 3m deep, would only be detected "when escaping fuel began to affect the environment, or when so much fuel was being lost, that it became apparent through mass bulk analysis. Even then, location of the leak could take several days and may involve the costly excavation of up to 300m of pipeline."
Depending on the size of the network and the number of sensors installed, a leak can be detected and pinpointed by the LeakLoc within 7-20s of occurrence, says Dr Shahrokh Mohammadi, J P Kenny's engineering specialist.
Although Stansted has not suffered a leak, Newby regards the installation of the LeakLoc, as an "insurance policy against possible future problems". He says that the system is relatively easy to retro fit and provides 24h-a-day automatic monitoring.
If the trials prove successful, it is expected that the LeakLoc will be applied to the entire fuel system at Stansted. It has already been specified for installation by the US Air Force at Kelly AFB in San Antonio, Texas.
Source: Flight International