Directorate-General for Energy and Transport
SAFEGUARDING HYDROCARBONS INSIDE
EARTHQUAKE LOCAL DEFENSE SYSTEMS
24 months EC report submitted
to see views of field stations (Sept. 2002)
Contract No: NNE5/1999/381
Contractor: University of Patras, Seismological Lab, Prof. A. Tselentis
University of Patras
Secretariat for Civil Protection
The primary target of SHIELDS
Project is to design, and then provide, an earthquake early-warning shield for
the Revithoussa hydrocarbon site in Greece. The subsidiary target is to design a
secondary shield protecting the point of delivery of gas to a community of
buildings within the city of Athens, thus providing protection from the
secondary earthquake hazard of fire. The methods will be transferable to sites
elsewhere in the world.
EXPECTED RESULTS: The construction of various scenarios
associated with earthquakes external to Revithoussa and Athens will pin-point
hazardous regions creating the highest risk levels to gas storage at Revithoussa
and gas distribution centers in Athens. The successful completion of this
demonstration project will create a shield around Revithoussa and Athens
providing early warning of severe ground vibration and provide protection from
the secondary earthquake hazard of fire and extensive conflagration in urban
quarters in Athens. The proposed system will:
Provide a novel system and accompanying expertise that is marketable to protect other sites in Greece, in other countries of Europe, and worldwide
Safeguard industrial and hydrocarbon storage facilities and individual gas users from fire breaks during major earthquakes.
(for Community support)
The degrading of gas infrastructure is continuing in all countries. It is a growing, underestimated, multidimensional threat for the following reasons: first, older appliances become more risky as they pass 8000 operations, or ten years in operation. Second, new furnaces may contain new source of risks due to light weight, complexity, computer control, and economic pressures to reduce cost and vibration. Third, most appliances are supplied by black iron pipes which are vulnerable to corrosion, shifting earthand most frequently earthquakes. Alternatively, copper piping may be vulnerable to long term sulfur corrosion and even a minor earthquake could destroy them. In both cases, inspection standards are sometimes arbitrary and ineffective. Fourth, existing protection systems ignore threats from malevolent malefactors, either internal or external. Finally, it is outrageous that natural gas is allowed to flow freely into a burning building with no mechanism in place to automatically interrupt it. Clearly, the threat from unprotected gasses is much greater than any one act or event.
Gas protection systems must be improved and fully deployed to mitigate damage and protect people and buildings. Urban gas protection, which is very different from gas transmission line protection, has been justified by a variety of risk analyses. The possible risks presented by gas distribution systems are very wide, ranging from an unprotected lethal pinhole leak at a corrosion site to multiple unprotected leaks in a fire storm over a city after a major earthquake. The first example is relatively common, and of low national consequence. The second example is of low probability, but of very high national consequence.
At the user level there are no generally deployed gas protection systems which will automatically detect and automatically shut off the flow of natural gas or propane in the event of a gas danger, however caused. The absence of gas protection for users is a national vulnerability. Gas flow is not automatically interrupted if a building is on fire. Existing protection systems ignore threats from malevolent malefactors, either internal or external. This lack of gas protection is in sharp contrast to the rich history of electric protection. Electric protection systems are layered, coordinated and interlocked. Gas protection systems are not interlocked, simple, possibly flawed, or nonexistent. The generally available seismic protection device -- a mechanical seismic valve -- violates one of the foundations of electric protection theory, that the protection system operate on the direct risk (e.g. detection of methane), and not on a symptom of a risk (e.g. the vibration of the valve).
Improved gas protection systems are increasingly necessary as the causes of gas leaks and problems are becoming more threatening and as the population becomes more aware of the dangers, and as mitigation becomes a necessity for business, governments and the insurance industry.