Specialty Manhole Solutions

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Classic Internal Chimney Seals stops inflow between the manhole frame and cone. LSS Internal Chimney Seal are internal rubber sleeves developed to stop inflow under the manhole frame.

Classic Internal Chimney Seal

Internal Chimney Seal stops inflow between the manhole frame and cone.

The Classic Internal Chimney Seal is available in standard 8-3/8″, wide 10″, and extra-wide 13″. The sleeves are made of rubber that conforms to the physical requirements of ASTM C-923, as modified, with a minimum of 3/16′ thickness for durability and resistance to puncturing or tearing. The pleated configuration provides for a minimum 2″ vertical or 1/2″ horizontal movement before stretching the material. Flexibility of the material allows one size to fit a frame or chimney diameter differential up to 20%.


•Provides watertightness with the flexibility to allow the manhole frame to move with the surrounding pavement as it reacts to frost heave, thermal expansion/contraction and traffic loadings.

•Reduces excess clearwater in sanitary sewer system by stopping manhole frame/chimney inflow, thereby providing more system capacity, and reducing treatment and pumping costs.

•Installed inside existing manholes, no expensive and time-consuming excavating and pavement replacement needed.

•Installed in new manholes after paving is complete without interfering with or delaying paving operations.

•Reusable – can be moved or removed and reused elsewhere if needed.

•Constructed of high-quality, long-lasting materials.

LSS Internal Chimney Seal

Internal rubber sleeve developed to stop inflow under the manhole frame.

Available in four widths with unexpanded vertical heights of 8″ (LSS 0-6), 10″ (LSS 6-12), 14″ (LSS 12-18), and 18″ (LSS 18-24). The flexible rubber sleeves are extruded or molded from a high-grade rubber which conforms to the applicable material requirements of ASTM C-923. The seals have a minimum thickness of 0.130″ for durability and resistance to tearing and puncturing, and a range of coverage which allows a span of up to 24 vertical inches without the use of an extension. The flexibility of this material allows one size to fit a frame/chimney diameter range of up to 20%.


• Lower cost

• Easier installation

• More range of coverage

• Eliminate the need for extensions

• Provides flexible, water tight seal

• Mechanical seal, does not rely on chemical bond

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