LNG workboats' safety demands
Mon, 08 December 2014
It seems LNG is full of chicken and egg problems, not limited to the commonly cited ‘vessel-design versus bunkering-availability’ conundrum. Training will likewise throw up challenges.
“With LNG you have to develop a whole new methodology,” said Andrew Brown of Smit Lamnalco. There is onboard handling as well as bunkering issues and the workboat industry has little experience of either as yet.
“Cryogenic liquid does not behave like a conventional fuel... It’s the physics, the saturation of LNG peaks at -163°C at 250mbar, any variation and it will begin to warm up.” He added: “Though the LNG safety record is spotless, it has been achieved by high standards and experienced people who understand cryogenics.”
Mr Brown believes that technology will – eventually – eliminate some of the more problematic human factor issues and told MJ that engineering will play “a critical role” in this development. However, it will take time “and people still need to be aware of what could happen when something goes wrong”.
So, despite the automatic shutdown and cut-off mechanisms, someone onboard still needs to have a full understanding of LNG’s specific characteristics and handling demands.
“Water, carbon steel and cryogenic liquids don’t mix,” said Mr. Brown. “LNG contact with carbon steel will cause brittle fractures.” Further, he said: “You wouldn’t want to be anywhere near any LNG spillage on the water, poisonous vapour cloud, extreme cold - and its effects next to a vessel may be a concern.” Although spillage or fire is unlikely, emergency response training will need to be practiced on a regular basis: “It is important that the crew are aware and fully understand what to do in any event.”
While the international gas fuel safety (IGF) code will doubtless help the workboat sector to an extent in adapting to LNG as a fuel, there are still challenges when it comes to operations: given crew limitations, he thinks it will probably require training up one of the existing roles in cryogenic dynamics.
Further, he said: “I would like to see a third-party verification of knowledge and emergency response training in the use of LNG in the workboat and support sectors,” and although he is sure “future plans will allow for this verification” he concluded: “Extremely high standards are absolutely vital if the sector is going to keep major incidents at bay.”
One final piece of advice from Mr Brown: “If you decide to select LNG as fuel, design the fuel system first, and include all the safety features. Once this is achieved, design the vessel around the fuel system.” He said safety may be compromised by “trying to squeeze LNG fuel systems into existing designs, as they simply don’t fit”.