Watermain Fittings

Watermain Fittings

 Watermain fittings incorporate the use of mechanical joints, push on, ductile iron and PVC fittings for water and sewer applications. Flanged fittings were developed over 100 years ago using material like hemp to seal joints together.

Mechanical joints were originally developed for the oil and gas industry in the late 1920s but have found a preference in water works. This joint creates a positive seal when the gasket is compressed against the pipe.

The mechanical joint system is designed for deflection as well as expansion and contraction within the piping system. This fitting method allows for up to 5 degrees tolerance on smaller diameter fittings from 4”-12” and 3 degrees on larger fittings 14”-24”.

Mechanical Joint fittings are available as full body C110 or compact body C153.

 

Difference between Full Body and Compact Body mechanical joint fittings

Set by ANSI/AWWA the specifications for fittings correspond to C110 and C153 with the C110 being the original full body specification for cast iron. The development of ductile iron brought better strength and toughness, so it was possible to keep the same structural capabilities with a thinner wall and smaller body. These fittings are lighter, easier to handle, and often have a shorter laying length. Mechanical joint ends are available for both C110 and C153 while flanged ends are only available for C110.

Description:

Today, standard compact fittings C153 are commonly used in place of full Body fittings C110. They are designed to be to be more lightweight and more economical to use while providing better flow characteristics. These fittings include an outer asphalt coating with a cement lining equal to Pipe cl54 as well as a higher-pressure rating (Up to 350 PSI).

Fittings use an integral cast bell or bell socket to accept a standard mechanical SBR gasket. (Other specialty gaskets are available).

A follower gland, gaskets and T-head bolts are used to tie the plain end of the pipe to the fitting when needing to make bends or branches.

Most common restraint glands now used utilize a wedge to tie the pipe to the gland as well as couple the pipe to the fitting.

The standard gasket used for ductile iron pipe and C900 are (CIOD). If iron pipe size is used (IPS), a transition gasket must be used.

 

Types of Mechanical Joint Fittings

• 90 Degree Elbows
• 45 Degree Elbows
• 5 Degree Elbows
• 25 Degree Elbows
• Tees
• Reducing Tees
• Crosses
• Reducing Crosses
• 45 Degree Lateral
• 45 Degree Reducing Lateral
• Reducers

 

90 Degree Elbow	45 Degree Elbow	22.5 Degree Elbow

11.25 Degree Elbow	Tee	Reducing Tee

Cross	Reducing Cross	45 Degree Lateral

Reducer

Push on Ductile Iron Fittings

Another type of fitting used today is the push-on type that has an integral bell including a Tyton or fast-tite gasket. The fittings are rated to 350 PSI. First developed in 1956, the plain end of the pipe pushes into the bell of the fitting. Push-on gaskets are less labor intensive than mechanical joints.

A special field lock gasket is also available where required. This method eliminates the use of thrust blocks while allowing for constant pressure. Gaskets are proprietary to each pipe manufacture and cannot be substituted between brands. Gaskets have stainless steel windings inside of the gasket to give additional strength.

 

Flanged Ductile Iron Fittings

Another type of fitting is the Flange type which has a flat surface to mate up to another pipe or fitting. It utilizes a ring type or full-face gasket that is usually made of rubber material, but other types are available depending on the media.

Flanged fittings are generally only used above ground and are often found in pumping stations, well houses and water treatment plants. They are rated up to 250 PSI and conform under C110 for 3”-64”. Flanged fittings are furnished with asphalt paint or special primer paint can be supplied as well.

Fittings are available in various types, 90, 45, 22-1/2, 11-1/4-degree bends, full and reducing tee’s, solid sleeves, caps, and plugs.

 

Ductile Iron Pipe Restraints

Ductile iron pipe restraints are used on mechanical joint fittings and push on joint fittings to keep the fitting in place and sealed with the joining pipe or another fitting.

Restraining devices are used on ductile iron pipe sizes between 3” – 54”. It includes multiple griping wedges that are incorporated into a follower gland, meeting the AWWA C110 requirement. The restraint has a working pressure of 300 - 350 psi depending on the size of the fitting. The gland body, wedges and actuating components are cast from grade 65-5-12 ductile iron material. The ductile iron gripping wedges are heat treated to a range of 370 to 470 BHN.

 

Restraint for Mechanical Joint

 

Restrain harness for push on ductile iron joint

 

Sewer Fittings

Since the conception of PVC (Pipe Polyvinyl chloride) in the 1960’s, there has been a major need for PVC sewer fittings.

The most prolific sewer pipe for residential and commercial use today is the SDR35 and SDR26.

Designations for PVC sewer pipe are dictated by the standard dimension ratio (SDR) which is the standardization of wall thickness to the outside pipe diameter.

The most common fittings used today are the gasketed bell type, supplied with a rubber gasket inserted in the bell of the pipe. It has a steel ring glued in place inside of the gasket. This stops the gasket from rolling when installing a spigot end of the plain end pipe. Lubricant often applied to the gasket joint after thorough cleaning.

These fittings are designed with specifications for testing by D3034. For installation, gaskets should meet F477 specifications and D1754.

Other types of fittings used on sewer include solvent weld joint with spigot ends. These use a primer to help clean and cement lock the spigot end of pipe to the bell of the pipe.

These fittings are for non-pressure applications for sewerage or drainage applications. Fittings can either be either injection molded or fabricated.

Other fittings are available such as SCH40, ribbed, vylon and pressurized fittings for C900 and CL160/200 Water Pipe.