The Arrangement of the Seal dips into the stored product surface hence it is known as Liquid Mounted Primary Foam log Seal. The seal of this type depends upon the resilience of the polyurethane foam log to bridge the annulus of the Rim gap from tank roof to the Shell. The seal consists of polyurethane solid foam blocks of octagonal or ‘D’ Shaped encased in a Casing / Envelope made of a suitable polymer. The Casing/Envelope and foam blocks are held in place with Hold down arrangements made out of Galvanized/stainless plates. Galvanized/stainless steel compression plates are provided over the assembly as weather protectors/ shields. The entire arrangement is clamped with galvanized/stainless steel flats and bolted to the Rim angle or flats with fasteners.

By virtue of the design of the Seal, there is no Gap and hence least vapourization.