ATT Tank MRS-12 Secondary Shoe-Mounted Seal (EFR Rim Seal)
A rim-mounted secondary seal installed over a primary seal provides a barrier for volatile organic compound (VOC) emissions that escape from the small vapor space between the primary seal and the wall and through any openings or tears in the seal envelope of a metallic shoe seal.
Another type of secondary seal is a shoe-mounted secondary seal. A shoe-mounted seal extends from the top of the shoe to the tank wall. These seals do not provide protection against VOC leakage through the envelope. Holes, gaps, tears, or other defects in the envelope can permit direct exchange between the saturated vapor under the envelope and the atmosphere. Wind can enter this space through envelope defects, flow around the circumference of the tank, and exit saturated or nearly saturated with VOC vapors.
Our ATT Tank MRS-12 Secondary Shoe-Mounted Seal is suitable for tanks without appreciable tank shell distortion. Unsuitable for distorted tanks shells.
The most commonly used ATT Tank Mechanical Shoe Seals either used as a single or combined configuration are:
• MRS-1/750 Primary Mechanical Shoe Seal
• MRS-1/1000 Primary Mechanical Shoe Seal
The MRS-1 models can be combined with
• MRS-12 Secondary Shoe-Mounted Seal
All ATT Tank EFR Rim Seals can be combined with;
• MRS-20S Secondary Compression Plate Seal
• MRS-25 Weather Shield
Finally, when the local requirements are pushing local terminals or refineries to add a tertiare or tertiary or triple rim seal, on request these extra rim seals can be provided by ATT Tank.