What Is Restrained Joint Ductile Iron Pipe? Top tips You Need to Know

One of the most secure types of pipes is the restrained joint ductile iron pipe. Push-on joints, mechanical joints, and welded joints are examples of different types of joints. Installing these fittings requires following a step-by-step guide to achieve the best results. Preparing, aligning, installing the gasket, assembling, and inspecting are the steps that must be followed precisely.

Restrained joint ductile iron fittings provide users with plenty of advantages, such as high durability, flexibility, internal pressure resistance, external load resistance, cost efficiency, and low maintenance. Due to these benefits, professionals use them in various applications, such as water mains, sewage systems, fire protection lines, and industrial piping systems. Both restrained and unrestrained joints can be used in projects; however, restrained joints offer more positive features to ensure the security and durability of the connections.

What Are Restrained Joint Ductile Iron Pipes?

Restrained joint ductile iron pipes are a specific form of piping system. This type of piping system includes a built-in restraining mechanism for securing the joints. The security of the joints provides a reliable and durable water and wastewater system. Also, this mechanism helps the pipe endure heavy external loads and pressure.

How Do Restrained Joint Ductile Iron Pipes Work?

Restrained joint ductile iron pipes perform with a simple mechanism. There is a spigot end for every pipe. Also, each pipe has a bell end. The spigot end of a pipe is put into the bell end of the following pipe. This connection is sealed by a rubber gasket. This is the restraining mechanism that secures the joints against heavy forces.

Push-on Joints

This type of restrained joint ductile iron pipe works with the same mechanism that was mentioned. According to Electrosteel, the spigot end goes into the bell end, and the locking mechanism is created. Security and longevity of the joints are provided by sealing the connection of the spigot end and bell end. Normally, a rubber gasket is used to seal joints. There are many ductile iron pipe applications these joints offer due to the advantages they have.

Mechanical Joints

Mechanical joints are another type of restrained joint ductile iron pipes. Mechanical joint fittings ensure good resistance against heavy external loads, high pressure, and high temperature. The mechanism of cooperation of the spigot end and the bell end is the same as other types. The significant specification of this type of joint is using bolts. Such pipe joint types provide you with a durable restrained joint system.

Welded Joints

Welded joints perfectly show resistance against longitudinal forces due to the type of restrained joint installation that is applied. The main difference between this type of joint and other types is the assembly of the joints. For welded joints, a restraint collar or ring is used to get welded onto the spigot end. This welded connection provides reliable ductile iron pipe fittings.

How to Install Restrained Joint Ductile Iron Pipes?

Restrained joint ductile iron pipe installation concludes a few simple yet vital steps. These steps must be done carefully and precisely. If so, achieving a secure and durable piping system is assured. The proper step-by-step guide is as follows.

Prepare: As the first step, tools must be gathered and inspected for any potential defects.
Align: The alignment of the pipes must be considered by maintaining a proper position.
Install Gasket: The rubber gasket must be placed on the spigot end after being properly lubricated.
Assemble: Assemble the joints by following the mentioned mechanism of connecting the spigot and bell ends.
Inspect Joints: After the installation process is done, inspect the joint for the smallest signs of leaks.

What Are the Benefits of Restrained Joint Ductile Iron Pipes?

There are several benefits and advantages to restrained joint ductile iron pipes. However, a few of these benefits are more crucial to consider. It is because of these benefits that restrained joint ductile iron pipe is considered one of the most suitable choices.

High durability: As these types of joints can perfectly endure wear and tear, they offer a long-lasting service life.
Flexibility: They have no problem moving, especially due to thermal changes, such as contraction or expansion.
Internal pressure resistance: Internal loads that are within the piping system are resisted perfectly due to the built-in restraint system.
External loads resistance: Soil or the above vehicle loads are highly endured as these joints are highly resistant to external loads.
Cost efficiency: They offer a cost-saving system as they need less maintenance costs. The long service life is also a superior help to saving expenses.
Low maintenance: The required maintenance is as low as it gets with restrained joint ductile iron pipes.

When Do Professionals Use Restrained Joint Ductile Iron Pipes?

Restrained joint ductile iron pipes are typically the perfect choice for professionals. The reason that this type of joint is popular was just mentioned above. However, the applications of these restrained joints are in several forms. The most essential ones are listed below.

Water Main

The fittings used for the water distribution system must be totally resistant to pressure. Being leak-proof is also essential for such fittings. This is why professionals mainly use restrained joint ductile iron pipes for water mains.

Sewage System

The restrained joints provide a leak-proof connection, which is a major factor to consider for the sewage system. Corrosion resistance is also a primary feature the piping system for sewage must contain.

Fire Protection line

Restrained joint ductile iron pipes are perfect for application in fire suppression systems. The reason is that they show proper strength and have internal pressure resistance.

Industrial Piping System

Restrained joint ductile iron pipes are highly popular in industrial applications. They are able to withstand heavy external loads, thermal changes, and vibrations. The strength they show makes them the most appropriate option for industrial settings.

Restrained and Unrestrained Joints: Which One Is Better?

Restrained and unrestrained joints are both proper options for several different applications. They provide the system with secure, durable, and reliable connections. Referring to AMERICAN, the key factor in deciding on one of them relies on the specifications of the project.

Restrained Joints

This type of joint is specifically better in such conditions you see below:

When longitudinal forces are crucial to consider, such as pressure thrust, temperature changes, or external loads, restrained joints are the best option.
If being cost-saving, especially in the short term, is not essential, restrained joints become a good option due to the restraining mechanism.
They can be used to reduce the requirement of thrust blocks or restraints and make the installation process easier.

Unrestrained Joints

Unrestrained joints can be a good choice, too, if there are some factors already taken care of, such as the following:

If the longitudinal forces are not significant and the external loads are already restrained, this type of joint works well.
When the restraining mechanism is not required, unrestrained joints offer a more cost-saving system.
If external restraints are already provided to withstand longitudinal forces, unrestrained joints can do the job fairly.

The chart below compares the technical specifications of restrained joints with unrestrained joints to help you find out the significant differences between them.

Technical Feature/Property	Restrained Joint	Unrestrained Joint
Joint Design	Bell and spigot with integrated restraining mechanism	Bell and spigot without integrated restraining mechanism
Resistance to Longitudinal Forces	High resistance due to built-in restraint	Requires external thrust blocks or restraints
Sealing Mechanism	Rubber gasket for leak-proof seal	Rubber gasket for leak-proof seal
External Restraint Requirement	Generally not required	Required to manage longitudinal forces
Assembly Complexity	More complexity due to restraining mechanism	Relatively simple joint design

Why Choose Us?

With all said, it can be concluded that restrained joint ductile iron pipes are generally the most appropriate option for several different applications. They offer a secure, durable, and reliable connection for various usages. However, there is a wide range of factors and features that might be essential to consider based on your project. To learn more about the information you would require to make the wisest decision, contact our professionals. We will provide you with all the needed information to help you.