In new or existing construction when a pipe must pass through a solid wall, local codes determine to what degree the opening between the outside of the pipe and the wall must be resealed. In some cases an expanding seal is required to guard against the spread of fire. In others, the outside pressure of dirt or water requires a different, more permenant seal. Link-Seal® Modular Seal was created to address the need to hydrostatically seal pipes up to 20 psig. These uses come about in vaults, manholes and when walls must be backfilled with soil or come under water pressure. They are ordered in varying widths and lengths according to a highly specific formula based on the opening but all come shipped as a belt of interconnecting rubbler links. This belt is then wrapped around the pipe and slid into the wall opening. Once in place, the bolts in each link are tightened creating an expanding seal to protect against water and a range of chemicals.