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AMERICAN Mechanical Joint Pipe For Water, Sewage or Other Liquids
Description
Description | Standard Dimensions | Allowable Joint Deflection | To Top of Page
The AMERICAN Mechanical Joint was developed by the American Cast Iron Pipe Company and first marketed in 1929. Since that time, millions of feet of AMERICAN pipe equipped with this joint have been installed to give dependable service across the nation and in many foreign countries. The joint is designed with a stuffing box into which a rubber gasket is compressed by a ductile iron gland drawn up with low-alloy steel bolts. It affords liberal deflection and allows expansion and contraction of the line without leakage. It is rated for a water working pressure of up to 350 psi.
Originally designed to meet the rigid requirements of the gas industry for a pressure-tight joint, the AMERICAN Mechanical Joint was instrumental in starting a nationwide trend toward rubber-packed joints for water service as well as gas service. Its design was widely accepted and it soon became the standardized mechanical joint of the cast iron pipe industry.
The popularity of the AMERICAN Mechanical Joint among utility officials, contractors, and engineers steadily increased until the majority of cast iron piping furnished for gas, water, sewage, and other services was equipped with this joint. However, push-on joint pipes, which are less labor intensive and reliant with push-on or mechanical joint fittings, currently make up the vast majority of ductile iron pipelines being installed for underground service. Mechanical joint pipe is now used to a much lesser extent.
The AMERICAN Mechanical Joint meets the requirements of ANSI/AWWA C110/A21.10 and ANSI/AWWA C111/A21.11.
AMERICAN Ductile Iron Mechanical Joint Pipe is centrifugally cast in nominal 18' or 20' laying lengths, depending on size, under rigid production and quality control procedures in accordance with ANSI/AWWA Standards. AMERICAN Ductile Iron Mechanical Joint Pipe is produced in 4"-12" sizes and in Special Thickness Class 53 only.
The AMERICAN Mechanical Joint provides easy installation under the most adverse conditions. Plain rubber gaskets of SBR are normally used for water and domestic sewage service. Fabric tipped plain rubber gaskets are available, as well as other special gaskets such as oil-resistant rubber. Plain rubber gaskets or tipped gaskets are used for air or liquid temperatures up to 120°F. For applications involving temperatures in excess of 120°F, or for other special service applications, and for installations in contaminated soils where permeation through gaskets might be a concern, consult AMERICAN for recommendations. See Table No. 2-6 below.
Standard joint accessories furnished with mechanical joint pipe and fittings include ductile iron glands, low-alloy steel tee head bolts with hex nuts and plain rubber gaskets. The cost of these accessories is normally included in the price of the pipe or fittings.
Mechanical Joint Gaskets
ADIP Table No. 2-6
| Common Name and Description* |
Maximum Service Temp.
Water & Sewer** |
Maximum Service Temp.
Air** |
Common Uses |
SBR
(Styrene Butadiene) |
150°F |
125°F |
Fresh Water, Salt Water, Sanitary Sewage |
EPDM
(Ethylene Propylene Diene Monomer) |
212°F |
150°F |
Water, Sewage, Ketones, Dilute Acids and Alkalies, Vegetable Oil, Alcohols, Air |
Nitrile Buna-N (NBR)
(Acrylonitrile Butadiene) |
150°F |
125°F |
Non-Aromatic Hydrocarbons, Petroleum Oil, Hydraulic Fluids, Fuel Oil, Fats, Oil, Grease+ |
| Neoprene (CR) (Polychloroprene) |
200°F |
150°F |
Fresh Water, Sewage |
Fluroelastomer (FKM)
(Viton®)***
(Fluorel®) |
212°F |
300°F |
Aromatic Hydrocarbons, Gasoline, Refined Petroleum Products, most Chemicals and Solvents, High Temp. Air (least permeable of all available Fastite gasket rubbers) |
Notes:
*AMERICAN reserves the right to furnish any Trade or Brand rubber for the chemical formulation specified.
**Temperature is in reference to conveyed fluid.
Gaskets shown for use in "Sanitary Sewage" service are also suitable for use with sewage gas.
Refer to Linings and Coatings for temperature and service capabilities of pipe linings.
Refer other special requirements to AMERICAN for recommendation regarding suitable gasket material.
***Viton® is a registered trademark of DuPont Dow Elastomers.
Note that temperature ratings of MJ gaskets per Table No. 2-6 (above) are in some cases lower than the ratings for similar material Fastite gaskets. See Table No. 2-1. The designer may wish to consider the use of Fastite pipe and fittings in high-temperature applications.
All MJ gaskets made from the materials in the above table are suitable for use with water containing normal concentrations of chloramine. Where greater concentrations of chloramines are present, please contact AMERICAN.
+This gasket rubber is chemically resistant for the non-potable water uses shown, but NBR is not as resistant to permeation in potable water applications as FKM.
AMERICAN Ductile Iron Mechanical Joint Pipe
ANSI/AWWA C151/A21.51
Standard Dimensions
Description | Standard Dimensions | Allowable Joint Deflection | To Top of Page
ADIP Table No. 3-6
Size
in. |
Nominal
Laying
Length
ft. |
Dimensions in Inches |
Bolts |
| A |
B |
J |
K1** |
K2 |
L+ |
M |
No. per
Joint |
Size
in. |
| 4 |
20 |
4.8 |
2.5 |
7.5 |
9.06 |
9.12 |
0.91 |
0.75 |
4 |
3/4 x 3 1/2 |
| 6 |
20 |
6.9 |
2.5 |
9.5 |
11.06 |
11.12 |
0.94 |
0.88 |
6 |
3/4 x 3 1/2 |
| 8 |
20 |
9.05 |
2.5 |
11.75 |
13.31 |
13.37 |
0.98 |
1 |
6 |
3/4 x 4 |
| 10 |
20 |
11.1 |
2.5 |
14 |
15.62 |
15.62 |
0.98 |
1 |
8 |
3/4 x 4 |
| 12 |
20 |
13.2 |
2.5 |
16.25 |
17.88 |
17.88 |
0.98 |
1 |
8 |
3/4 x 4 |
Notes:
Mechanical Joint Pipe is available in Special Thickness Class 53 only.
**These dimensions for pipe only. Refer to Table No. 5-1 for fitting joint dimensions.
+The bell flanges may be furnished thicker than specified under "L" above as provided in AWWA C111.
Bolt holes are 1/8" larger than bolt diameters.
See Historical Data when retainer glands are being considered in lieu of regular glands.
When bell flanges tapped for studs are required, alloy steel stud bolts with the required stud length equal to the length of the tee head bolt it replaces should normally be specified.
Boltless Fastite, Fast-Grip, Flex-Ring, and Lok-Ring push-on joint pipe and fittings are normally less labor-intensive and labor-reliant than mechanical joints pictured and are often preferred for many applications.
See appropriate sections of this Web site for more information with regard to these joint configurations.
For weights, see Weights for Special Thickness Classes.
AMERICAN Ductile Iron Mechanical Joint Pipe
Allowable Joint Deflection
Description | Standard Dimensions | Allowable Joint Deflection | To Top of Page
ADIP Table No. 2-9
Size
in. |
Nominal
Laying
Length
ft. |
Maximum Recommended Deflection |
X
Offset
per Nominal
Length
in. |
Y
Deflection
Angle |
Radius
of Curve*
ft. |
| 4 |
18 |
31 |
8°-18' |
140 |
| 6 |
20 |
30 |
7°-07' |
160 |
| 8 |
20 |
22 |
5°-21' |
220 |
| 10 |
20 |
22 |
5°-21' |
220 |
| 12 |
20 |
22 |
5°-21' |
220 |
| 14 |
** |
** |
3°-35' |
** |
| 16 |
** |
** |
3°-35' |
** |
| 18 |
** |
** |
3°-00' |
** |
| 20 |
** |
** |
3°-00' |
** |
| 24 |
** |
** |
2°-23' |
** |
| 30 |
** |
** |
2°-23' |
** |
| 36 |
** |
** |
2°-05' |
** |
| 42 |
** |
** |
2°-00' |
** |
| 48 |
** |
** |
2°-00' |
** |
Notes:
*Approximate radius of curve produced by a succession of nominal lengths of pipe fully deflected. A shorter radius can be obtained using shorter pipes.
The joint should be assembled with the pipe in reasonably straight alignment. Joint deflection to the maximum shown above may be made after assembly but before tightening bolts. Offset distances are based on 18' or 20' lengths as shown.
**14"-48" Mechanical Joints are provided on fittings and valves only.
Maximum Allowable Separation
ADIP Table No. 2-10
Size
in. |
S
Separation
in. |
| 24 |
1 |
| 30 |
1 1/4 |
| 36 |
1 3/8 |
| 42 |
1 1/2 |
| 48 |
1 3/4 |
Notes:
Maximum Allowable Separation, "S", is provided for information only and should not be used to determine precise joint deflection.
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