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Guidance on Risk Analysis and Safety Implications of a Large LNG Spill Over Water - LNG Review 2005
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Sandia National Laboratories
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Originally printed in:
LNG Review
- 2005
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For an LNG terminal, regulations developed under the authority of the Ports and Waterways Safety Act assign to the Coast Guard the responsibility for safety issues within the ‘marine transfer area’ of LNG terminals. This area is defined as that part of a waterfront facility that is between the vessel, or where the vessel moors, and the first shut-off valve on the pipeline immediately before the receiving tanks. Safety issues within the marine transfer area include:
- electrical power systems;
- lighting;
- communications;
- transfer hoses and piping systems;
- gas detection systems and alarms;
- firefighting equipment; and
- operations such as approval of the terminal’s operations and emergency manuals and personnel training.
New maritime security regulations have recently been developed for terminal facilities. These regulations require the LNG terminal operator to conduct a facility security assessment and develop a threat-scalable security plan that addresses the risks identified in the assessment. Much like the requirements prescribed for vessels, the facility security plan establishes the following:
- access control measures;
- security measures for cargo handling and delivery of supplies;
- surveillance and monitoring;
- security communications;
- security incident procedures; and
- training and drill requirements.
Risk Reduction Examples
Table 5 presents selected scenarios that provide examples of potential events and several prevention and mitigation approaches that could be used to reduce risks to public safety and property.
Table 5: Examples of Risk Prevention and Mitigation Strategies for Potential Threats
Many of the prevention and mitigation strategies identified are already under consideration or being implemented by the US Coast Guard. Other strategies identified might be considered in conjunction with existing strategies at many sites. While risks can seldom be reduced to zero, prevention of the higher consequence events can significantly reduce hazards to public safety and property and facilitate mitigation of the remaining lower consequence and lower risk events.
Prevention and mitigation strategy implementation should focus on effectiveness, costs and operational impacts. The level of risk reduction required should be determined in conjunction with local public officials and public safety organisations, such as police and fire departments, emergency response services, port authorities, the coast guard and other appropriate stakeholders.
Risk reduction strategies that are effective at one site might not be effective at another site. Therefore, the examples provided in Table 5 should be considered in the context of how a risk management approach might be customised to yield benefits to public safety and property while having limited operational impacts.
Ramming
Ramming could occur between an LNG tanker and a fixed object or between a boat and an LNG tanker. Unless the LNG tanker speed is above 5 to 7 knots or the object is very sharp, ramming of the LNG tanker into an object is unlikely to penetrate both hulls and the LNG cargo tank. Likewise, if the LNG tanker is rammed by a small boat, such as a pleasure craft, the kinetic energy is insufficient to penetrate the inner hull of a double-hulled LNG ship.
Therefore, while ramming does not appear to be a major concern or present significant hazards, changes in some safety and security operations could reduce the risk of a ramming event. For example, requiring tugboat escorts for LNG ships in high-consequence areas would reduce the potential for an insider to intentionally ram an LNG vessel into a critical infrastructure element. Another option would be to ensure that crew members have been properly evaluated and the ship interdicted and searched sufficiently prior to entry into the US to thwart a hijacking attempt or insider sabotage. These efforts reduce the ability of an adversary to pick the time, place and target for a ramming event and reduce the risk from a potential ramming scenario.
Triggered Explosion
Triggered explosion events assume pre-placed explosives, either on the ship or in a fixed location. At some sites, sweeping of the waterway, harbour bottom and terminal areas for explosives or mines might be required. This is especially true for highhazard areas, shallow waterways or terminals where explosives might be hidden. To prevent sabotage of an LNG cargo tank through a triggered explosive on board a ship, the same type of early interdiction, searches and control of the ship discussed in the ramming prevention scenario could be applicable.
Categories:
LNG
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Gas Processing
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Plant Operations Management
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