The flexible foam-filled primary rim seal is installed so that the bottom of the seal remains in contact with the stored product. The TTS-FS7 Foam Seal consists of a series of polyurethane foam blocks enclosed in an envelope and compressed between the tank shell and the floating roof rim, with the blocks secured by steel plates. This product-mounted type design eliminates the vapor space, while the curtain seal prevents vapors from passing between the roof and the metal frame or hanger bar.