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Pipe-to-manhole seal
Concrete Manhole Adapters
Give the grout something to grip. A flexible PVC adapter goes on plastic or cast iron pipe where it enters a concrete manhole, so the grouted connection is improved and can move with the pipe.
Five standard sizes, 4″–12″
Large diameter made to order
Plastic and cast iron
The problem
Grout doesn’t stick to plastic pipe
Where a pipe enters a manhole, the opening is packed with grout. Grout won’t bond to smooth plastic pipe, so the joint depends on grout packed around a surface it can’t grip. Where that connection lets groundwater in, it adds to infiltration, part of the I&I every sewer system works to keep out. A Concrete Manhole Adapter sits between the pipe and the grout to improve that connection.
A grip for the grout
Gives the grout an interface to lock onto where it won’t adhere to the pipe itself.
Moves with the pipe
Flexible construction permits lateral pipe movement without destroying seal integrity.
Resists corrosion
Elastomeric PVC that resists corrosion and the acids and alkalis common in sewer service.
Plastic or cast iron
For plastic and cast iron pipe entering concrete manholes and similar structures.
Two ways to order
Five standard sizes. Large diameter made to order.
Standard adapters fit common 4″ to 12″ sewer pipe. For pipe 8.5″ O.D. and up that a standard size doesn’t cover, Large Diameter CMAs are made to your pipe’s outside diameter.
Standard sizes
Concrete Manhole Adapters
4CMA · 6CMA · 8CMA · 10CMA · 12CMA
- Five pipe O.D. ranges between 4.20″ and 12.80″
- Order by part number. Find your size
Made to order
Large Diameter CMAs
8.5″ O.D. and up
- Order by specifying the O.D. of the pipe that will receive it
- Same flexible, corrosion-proof PVC
Pouring a new structure? For pipe cast into new concrete, see the Dual Puddle Flange, a cast-in waterstop that goes on the pipe before the pour.
Cutaway of a pipe entering a concrete manhole wall. Not to scale.
Where it works
Pipe entering a concrete wall
The adapter goes on the pipe where it passes through the wall, and the opening is grouted around it. It’s most useful with smooth plastic pipe, where grout won’t adhere to the pipe surface.
- Concrete manholes and similar structures
- Sanitary sewer and wastewater structures
- Storm structure pipe penetrations
- Plastic or cast iron pipe, grouted in
Size selection
Find your size by pipe outside diameter
Measure the O.D. of the pipe entering the structure and choose the adapter whose range covers it. For pipe 8.5″ O.D. and up that falls outside a standard range, order a Large Diameter CMA by O.D.
inches
Enter decimal inches (6.275) or a fraction (6 1/4).
| Part | Adapter I.D. | Min. pipe O.D. | Max. pipe O.D. | Typical pipe | Availability |
|---|---|---|---|---|---|
| 4CMA | 4.10″ | 4.20″ | 4.50″ | 4″ SDR 35* · 4″ IPS* · 4″ no‑hub | Standard |
| 6CMA | 6.10″ | 6.20″ | 6.70″ | 6″ SDR 35 · 6″ IPS · 6″ no‑hub | Standard |
| 8CMA | 7.90″ | 8.20″ | 8.70″ | 8″ SDR 35 · 8″ IPS · 8″ no‑hub | Standard |
| 10CMA | 9.90″ | 10.20″ | 10.70″ | 10″ SDR 35 · 10″ no‑hub | Standard |
| 12CMA | 11.70″ | 12.50″ | 12.80″ | 12″ SDR 35* · 12″ IPS · 12″ no‑hub* | Standard |
| Large Diameter CMA | – | 8.50″ | and up | Sized to your pipe O.D. | Made to order |
Adapter I.D. and pipe O.D. ranges from Fernco product data. Typical pipe uses standard published ODs: SDR 35 is PVC sewer pipe (ASTM D3034); IPS covers Schedule 40 PVC, steel and IPS HDPE; no-hub is cast iron soil pipe. * Standard OD is within 0.02″ of the range limit, so measure the actual pipe. 10″ Schedule 40 (10.75″ O.D.) is above the 10CMA range.
Specifications
Specification data
| Material | Flexible elastomeric PVC (4CMA–12CMA: 60 Shore A durometer) |
| Material standard | 4CMA–12CMA comply with ASTM D5926 |
| Chemical resistance | Resists the acids and alkalis common in sewer service |
| Temperature | 4CMA–12CMA: −30°F to 140°F |
| Pipe | Plastic and cast iron |
| Structures | Concrete manholes and similar structures, sanitary and storm |
| Sizes | 4CMA, 6CMA, 8CMA, 10CMA and 12CMA standard. Large Diameter CMA made to order, 8.5″ O.D. and up |
Important application information
Concrete Manhole Adapters are subject to conditions beyond the manufacturer’s control, such as high groundwater tables, grout quality, workmanship and field conditions, that can affect sealing performance. Discretion must be used in product selection and installation. Fernco does not warrant this product as a positive water seal.
Technical documents
Part drawings, application diagram and catalog for Concrete Manhole Adapters.
Frequently asked questions
What does a Concrete Manhole Adapter do?
It fits on the pipe where the pipe passes through a concrete manhole wall and gives the grout an interface to hold onto. That matters most with smooth plastic pipe, where grout won’t adhere to the pipe itself.
Which size do I need?
Measure the pipe’s outside diameter and use the size finder. Five standard adapters cover O.D. ranges between 4.20″ and 12.80″. For pipe 8.5″ O.D. and up outside those ranges, order a Large Diameter CMA by specifying the pipe O.D.
What happened to Large Diameter Waterstops?
They’re now called Large Diameter CMAs: the made-to-order version of the Concrete Manhole Adapter for bigger pipe, listed on this page. Order them by pipe O.D., 8.5″ and up.
Is it a watertight seal?
It improves the grouted connection, but sealing performance depends on conditions beyond the manufacturer’s control, such as groundwater, grout quality and workmanship. Fernco does not warrant it as a positive water seal.
Can I use it on cast iron?
Yes. It’s designed for plastic and cast iron pipe entering concrete manholes and similar structures.
What about pipe cast into a new pour?
For pipe cast into new concrete, the Dual Puddle Flange is clamped to the pipe and cast into the wall or slab.
Got questions?
Whether it’s sizing, a large diameter order or the right seal for the structure, our team can help. Reach out, or find your Fernco rep.