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Manhole Installation

Watertight Connections

Cemcast Pipe and Precast manufactures all pipe, arch pipe, and manhole products with a single-offset gasket joint. These gaskets ensure a watertight connection to 13 psi when installed properly. The 13-psi rating is equivalent to a column of water 30’ deep. To achieve such a high psi rating, the single-offset joint is precisely manufactured with minimal annular space for the gasket. When installing manholes, follow the same basic steps detailed in our concrete pipe section to ensure trouble-free watertight connections.

Sanitary manhole
72” HDPE lined manhole using an A-Lok gasket. The project is for Brookings Municipal Utilities.
Nice installed manhole showing external joint wrap.
Ensure joint surface is clean

1) Check that the joint surface is clean

Ensure the joint is free of dirt and other foreign debris. If the manhole spigot is not clean, the gasket will not seal properly.

Gasket install

2) Place the gasket on the spigot in the proper direction.

The gasket must be seated against the offset all the way around the spigot. A gasket that is improperly seated may roll, preventing the gasket from sealing and potentially breaking the bell. Before homing the joint, inspect the gasket to ensure that it is correctly installed all the way around the offset.
square it up

3) Square it up

When joining gasketed sections, be sure to square up the manhole sections that are going to be joined. This is an important step. Because the tolerances are tight (as small as 1/8” per side), the manhole sections cannot be joined by first fitting the pieces together on one side and then attempting to home the joint with an excavator by applying pressure on the opposite side. This process will damage or break the bell.
Manhole installation - Ensure no gaps and the gaskets are sealed

4) Ensure no gaps and the gaskets are sealed

When the pieces are properly aligned and then mated, push them all the way home. A properly homed joint will not have a gap, ensuring the gasket seals properly.

GASKETS ARE SELF-LUBRICATING

Finally, it’s also important to note that the Hamilton Kent Tylox SuperSeal gasket we supply is self-lubricating and does not require lube or equalization. Following the steps above will ensure a trouble-free installation and a watertight system.