The Invar®, low 36% nickel seel primary membrane contains the LNG cargo, while the secondary membrane, identical to the primary, ensures a 100 % redundancy in case of leakage. Each of the Invar® strakes is continuously spread along the tank walls and is evenly supported by the primary and the secondary insulation layers.
NO96 MAX SPECIFICITIES
NO96 Max uses a pillar structure and a non-structural insulation to withstand the high pressures induced by certain sloshing conditions.
Thanks to a numerical validation of the design, the box reinforcement can be easily upgraded in order to sustain higher loads and provide increased flexibility to the market (offshore, ship-to-ship, heavier liquid gases).
IMPROVED THERMAL PERFORMANCES
Significant bearing structure lightening can be obtained by combining the use of more efficient materials such as densified wood and the change from bulkhead to pillar geometry. This improvement associated with the use of an efficient insulation material like glass wool contributes to reach a low boil-off rate.
This modular system calls for standard prefabricated components that can accommodate all designs and capacities of LNG tankers. The number of pillars may vary to accomodate the highest specific load the box may have to sustain.
Dual Invar® membrane technology, continuously improved since 1969, is approved by all the major classification societies. It benefits from more than 45 years of experience at sea.
The two independent insulation spaces are continuously flushed with nitrogen gas. The integrity of both membranes is permanently monitored by detection of hydrocarbon in the nitrogen.
MINIMAL THERMAL STRESSES
The Invar® material offers an extremely low thermal contraction coefficient, thus reducing the thermal stresses in the material.
The membrane strakes are fixed to the boxes by a tongue device enabling the sliding of the membrane on the top of the boxes (no shear stress) and the absorption of the transverse loads through the deflection of the raised edges.
SMOOTH TRANSFER OF LONGITUDINAL LOADS
Along the transverse bulkhead corners, the two membranes are connected to the hull through an Invar® tube. This ensures that all the dynamic and thermal loads are directly and uniformly transferred to the steel structure.
Due to liquid motion in the tank, well identified boxes are expected to face pressure impacts. In order to reach the necessary resistance level and sustain these loads, the box internal structure is strengthened thanks to an increase of pillar size and number.
Densified wood and glasswool are easily procured, low cost raw materials, available worldwide.
The system has been reviewed and validated trough an approval in principal by two major classification societies: DNV-GL and Bureau Veritas.