Manhole Liners (also referred to a Manhole Inserts) provide a structural repair to manholes that have experienced corrosion or deterioration due to aggressive environments. These liners are designed to fit inside deteriorated manholes. Diameters of the manhole liners are sized 6-inches smaller than the host manhole diameter. Prior to installing the manhole liner, the installer cuts the liner to the proper length and to accommodate all pipe penetrations, as required. Installations typically involve removing the cone section of the host manhole and lowering the manhole liner until it comes to rest on the bench of the host manhole. After insertion, the manhole liner is braced in position, then grouted into place. The portion of the manhole liner that extends above the host manhole riser is, then, backfilled with suitable granular material. The manhole is then brought to grade using grade adjustment rings and ring & cover. Manhole liners are designed to withstand all structural loads (i.e. soil, hydrostatic, H20 traffic) as with direct bury FRP manholes without the aid of the host manhole or annular grout.
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LFM’s fiberglass manhole liners are available in diameters from 36” through 168” (14’). We recommend using a fiberglass manhole liner which is six inches smaller in diameter than the existing structure. Standard depths are available from 2’ through 40’. Greater depths can be custom fabricated per engineer’s specifications.
Strong & Lasting Construction
Our fiberglass manhole liners meet or exceed all ASTM requirements for fiberglass manholes. LFM’s fiberglass manhole liners are designed to withstand the rigid requirements of ASTM Specification D3753 for glass fiber-reinforced plastic (FRP) manholes. In addition to the ASTM standards, our fiberglass manhole liners meet H-20 load requirements. Our products are engineered to provide you with long and trouble-free service.