Most storm sewers are simply grouted into a manhole using non-shrink grout and a water-stop gasket, when appropriate. Contech has supplied both the “double fluted” and “single fluted” pipe gaskets for the “water-stop”, which is simply used to help the concrete/grout adhere to something other than the very smooth/slick PVC surface.
The intent is to help stop water from intruding from the exterior to the interior (infiltration). In some cases, preventing any leakage, infiltration & exfiltration, if desired. There are some agencies that require storm sewer manholes to use a booted or compression connection, but those are more the standard in the sanitary sewer segment.
Nearly all sanitary sewers require some type of flexible connection (boot or compression) for plastic pipes to manholes. There are advantages and disadvantages for both types. Contech does recommend the booted connection for A-2000 versus the compression connection. The boots are easier to install and more cost effective.
Contech uses three types of gaskets for A-2000 connections and manholes. Two of the gaskets are the pipe’s actual bell & spigot gaskets that are sent out with each pipe order. The third type (manhole or flat) is strictly used for booted connections. The three gaskets are as follows:
- Double-fluted is also known as the “sanitary” gasket and is the first gasket from the left, in the below pic. This gasket sits in two valleys and has two sealing surfaces in one homogeneous gasket. Because of the double seated nature of the single gasket, this ensures the gasket cannot roll out of the valley if installed correctly. This gasket comes when the quote states the A-2000 PVC pipe. Note that a “fl ute” is considered the sealing surface pointing upward toward the receiving bell.
- O-Ring or single-fluted gasket, also known as the “storm sewer” gasket. This is the middle or second gasket from the left, in the below pic. This gasket is associated with quotes for A-2000 Drainage pipe. This gasket is certified to the same ASTM D3212 water tight testing as the doub le-fluted.
- Manhole Gasket or “flat” gasket is used for booted manhole connections only. Because Contech has used the term “manhole” gasket as the description in some literature and accounting terms, it is mistaken that this gasket is used for the grouted and compression types of connections. IT I S NOT. The intent of this gasket is to create a wider flat surface on the exterior of the profiled pipe for the boot’s stainless-steel strap to seal against. The flat gasket simply fills the valley of the profile/corrugation, widening the hit/sealing zone.
