The transfer of fluids from a storage facility to a tanker vessel always includes a flexible part. This flexible part is needed to follow the ship’s movements in the horizontal plane, like drift and sway, and in the vertical plane as a result of the water level. Marine loading arms with swivelling joints provide a fully rigid but flexible connection, offering almost as much reliability as a fixed pipeline connection.
In order to replicate the benefits of a rigid pipeline connection between ship and shore, the mechanical design of the Marine Loading Arm (MLA) (MLA) and the performance of the swivel joints are crucial. For liquefied gasses, improving reliability and safety becomes more and more important.
In addition to existing standards like the OCIMF1999, the Technical Committee CEN/TC 282 ‘Installation and equipment for LNG’ has prepared the Euro norm EN1474-1:2009 for designing and testing marine transfer systems. According to the CEN/CENE: EC Internal Regulations, all EU countries are bound to implement this European Standard. Swivel qualification against the EN1474-1:2009 What does the latest standard mean in terms of the design of swivel joints in transfer arms? Until recently, swivel joints in general were qualified against the OCIMF guidelines, including liquefied gasses like LPG and LNG. The EN1474-1:2009 standard has governed LNG applications since January 2009.
There is a lot of similarity between the OCIMF 3rd edition 1999 and the EN1474-1:2009 when comparing the load test criteria for swivel joints. The OCIMF distinguishes ‘General Liquid’ and ‘Liquefied Gas,’ whereas the EN1474 is written specifically for LNG application.
We will view the load test requirement, since the strength and leak tightness are the first features to be tested.