Probability of LNG Tanker Collision Low, of Tank Rupture Even Lower


Risk report Update: Probability of LNG tanker collision low, of tank rupture even lower


A recent report according to a Nautical Risk Assessment Study published in the Environment and Resources Authority has stated that the probability that that Floating Storage Unit and the LNG Carriers inside Marsaxlokk port involved in a collision is very low and the probability that such a collision will lead to a gas tank rupture is even lower.  This particular report was drawn up by Maritime Research Institute Netherlands (MARIN).

The study focuses on different circumstances, including the likelihood that the LNG carriers – which are expected to make 12 entries into the port each year to supply the Floating Storage Unit – are involved in a collision with another vessel or run aground inside the harbour.

It was found that the total expected number of collisions when the LNG carrier is sailing is ‘once every 71,866 years.  When next to a pilot boat and a restricted area (around the vessel) is imposed the total expected number of collisions will be once in 718,657 years.

The widespread study, which took many factors and deliberations into account, also found that the probability that the LNG carrier becomes grounded (specifically in the area near the Freeport breakwater) is once every 92,081 years.  “The probability of loss of cargo due to grounding is assumed to be negligible.”

The probability that the LNG carrier is hit by another vessel while it is berthed alongside the FSU is also low.  The probability will be lowered further if other ships are not allowed to visit the refuelling dolphin and the power station during this time (around 24 hours).  The probability that the FSU is hit by a passing vessel when not refuelling (when there is no LNG carrier alongside) is much higher – once in 264 years.  The probability is larger for the fact that the FSU will be berthed near the power station all year round.

The MARIN study also looked at the possibility of a collision leading to a rupture in the LNG tanks of either the carrier or the FSU.  “Several collision scenarios may result in a hole in the outer shell of the LNG carrier but only 2 of the calculated collision cases lead to a hole in the inner shell.”

“In spite of a larger collision probability compared to other considered scenarios, the probability of a hole in the cargo tank of the moored FSU or the moored LNG carrier can be considered as negligible, taking into account the traffic database and the assumptions of the speed of the other traffic.  This is mainly due to the fact that the speed of other traffic in port is relatively low.”

(The report states that some 2,600 ships entered Marsaxlokk in 2013 – including 1,920 container ships and 417 double hull tankers. It says that smaller fishing vessels would not do any significant damage if involved in a collision.)

The study concluded that the probability of tank penetration after a collision with a sailing LNG carrier is low.

  • “It can, however, be reduced by imposing a speed limit in the area, or a restriction of vessels sailing in port while the LNG carrier is arriving or departing.”
  • “The probability that the cargo tank of the LNG carrier is damaged due to grounding is negligible.”
  • “The probability that the cargo tank of the FSU is penetrated is extremely low.”
  • “The probability that the cargo tank of the LNG carrier is penetrated when being moored at or manoeuvring near the terminal is low compared to other projects.”

Opposition Leader calls for extra time

Opposition Leader Simon Busuttil today wrote to the chairman of the Environment and Resources Authority, Prof. Victor Asciak, requesting an extension to the public consultation period of 30 days.

The public consultation, which opened today, is 30 days long.  The reports made public today are 15,000 pages long, and the Opposition said it needs more time to analyse them

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Source: Independent