Safety

LNG production facilities, storage facilities and ships are designed to include numerous safeguard systems including gas/heat/fire detection and suppression systems, spill containment systems, emergency shutdowns, pressure release systems and advanced communications systems.

The LNG industry is continuously working to enhance the safety and security of LNG production and transport by minimising potential risks.

The potential risks associated with LNG are well understood and are successfully mitigated by the following four elements that provide multiple layers of protection for LNG production and transport:

1. primary containment
   
2. secondary containment
   
3. safeguard systems
   
4. separation distances (safety and security zones).

These elements, when integrated with industry standards, regulatory compliance and best management practices, form the foundation of the strong safety and security performance in the LNG industry.

Safety facts

• LNG is a clear, odourless, non-toxic, non-corrosive liquid.
• As a liquid, LNG cannot explode.
  
• LNG is not stored or transported under pressure.
  
• LNG vapour is only flammable if it is within the range of 5–15% natural gas in air. If it is less than 5% natural gas in air, there is not enough natural gas concentration in the air to burn. If it is more than 15% natural gas concentration in air, there is too much gas in the air and not enough oxygen for it to burn.
  
• The lower flammable limit of LNG is about two to three times that of other common hydrocarbon fuels, which means that it takes more vapours to accumulate to pose a fire hazard.
  
• Methane is lighter than air and will disperse more rapidly than most other hydrocarbon fuels.
  
• There has never been a major release of LNG from a ship.

LNG production

LNG production facilities adhere to strict international standards that provide criteria for siting, layout, equipment fabrication and installation, construction and operation of LNG facilities.

Personnel at a LNG production facility are highly trained and specialised. They are versed in detailed contingency plans to cover even the most unlikely incidents. Regular exercises are conducted to test their response capabilities.

Best management practices are integral for safe and secure LNG production and include such things as continuous training of plant personnel in process operations and safety, detailed procedures, planned and unannounced safety and security inspections and audits.

Site security at a LNG facility is maintained by limiting access via protected enclosures, constant monitoring and security personnel.

LNG storage

LNG is stored in specialised, sealed, non-pressurised tanks at -161°C. LNG tanks have a primary and secondary containment system.

Tanks have a nickel steel primary tank designed for low temperatures. The secondary containment ensures that any potential leaks or spills are contained and isolated. Secondary containment usually consists of a second outer concrete tank or dike surrounding the tank. Storage facilities use advanced monitoring systems to immediately detect any potential liquid or natural gas leaks or fires.

All tank piping enters and exits the tank from the top above the liquid levels to avoid the consequences of LNG leakages at nozzle connections, and tanks are equipped with abundant safety systems such as level alarms and emergency shutdowns.

LNG shipping

The LNG shipping industry has had an impressive safety record since international commercial LNG shipping began in 1959, with over 47,000 LNG shipments without a serious accident at sea or in port.

LNG is transported in ships specifically designed to handle the low temperature of LNG. LNG is stored in non-pressurised cargo containment systems made up of a primary and secondary containment all within the double hull of the ship. With a gap of at least 2 metres between the outer hull and the cargo, these vessels are designed to protect the cargo and prevent leaks in the event of an accident.

Inherent in the design are numerous levels of safety systems including gas/heat/fire detection and suppression systems.

Security is ensured through conformance with the International Ship and Port Facility Security Code.

The Anchorage and Harbour Transit Safety Zones document describes the proposed safety zone for LNG carriers transiting Gladstone Harbour channels.

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