Abstract: A system of insulation for double wall tanks includes a plurality of insulation layers held on the outside of an inner wall of the double wall tank by a plurality of orthogonally arranged bands. The bands include bands oriented longitudinally of the tank and bands oriented laterally of the tank. The insulation layers include abutting units, with each unit having a facing sheet thereon. The outermost insulation layer has abutting units with overlapping facing sheets, and the insulation layers assume a quilted pattern.

Abstract: An emergency roof drain for floating roof storage tanks includes a siphon carried by the roof with an intake end above the roof and an outlet end below the roof. The siphon is normally closed by a valve and a valve operator is connected to open the valve in response to a predetermined emergency water level on top of the floating roof to thereby siphon the water from the roof and thus prevent sinking of the roof.

Abstract: A seal arrangement for a floating roof in a storage tank, wherein the roof is spaced at its outer periphery from the inner surface of the tank, thus defining a rim space, includes support members secured at one edge to the roof and extending angularly outwardly into close proximity with the tank wall, and yieldable material carried by the support members in a position to engage the tank wall and effect a seal between the roof and tank wall, said yieldable material having a predetermined shape, whereby engagement thereof with the tank wall covers a predetermined, varying area upon variations in the rim space to thus maintain acceptable contact pressure with the tank at different rim spaces between the roof and tank wall, while at the same time maintaining an effective seal.