Ductile Iron Pipe Sizes and Dimensions Explained: A Quick Reference Guide

Ductile iron pipes are considered the most popular pipes in various industries and projects since they come in different sizes and dimensions. Understanding these variations will help you choose the most commonly used ones. You should be aware of standard diameters and wall thickness specifications. Ductile iron pipe pressure ratings and pipe wall thickness are correlated and classified into various classes.

While other materials, such as PVC pipes and steel pipes, are available, ductile iron pipes have proven to be more advantageous. When selecting the best size and dimension of these pipes, essential factors include flow rate requirements, pressure rating, application type, installation environment, and cost considerations.

Understanding Ductile Iron Pipe Sizes

Understanding ductile iron pipe sizes is highly essential. By choosing the right ductile iron pipe size and dimension, you can ensure the compatibility of ductile iron pipe fittings in the piping system. The appropriate performance of ductile iron pipes depends highly on the right sizes. DN, which stands for nominal pipe size, represents the approximate internal diameters, also known as ID.

The actual ID of pipes would be slightly different than what is set.
DN sizes vary in the range of DN80 to Dn200.
To choose the right ductile iron pipe sizes and dimensions, flow capacity, and pressure rating must be considered.

Commonly Used Ductile Iron Pipe Sizes

Though there are various ductile iron pipe sizes and dimensions, some of them are more commonly used. Factors such as pressure rating, flow rate, and installation requirements determine the specific size to be used. However, some of these commonly used sizes and their applications are listed below.

DN80 to DN200: They are considered smaller sizes. These ductile iron pipe sizes are mostly used in fire protection lines and water service connections.
DN250 to DN500: These are medium-sized pipes. The applications of medium pipes are in water distribution systems, sewage systems, and industrial uses for water lines.
DN600 to DN1200: these ductile iron pipe sizes are considered large ones. They are typically used for sewage force mains, transmission mains, and large-scale applications in industry.
DN1400 to DN2000: They are the largest ductile iron pipes that are commonly used for large sewage trunk mains, bulk water transmission, and large industrial process lines.

Understanding Ductile Iron Pipe Dimensions

According to Electrosteel, there are various ductile iron pipe sizes and dimensions. Understanding these dimensions will help you use the most standardized pipe based on technical specifications. These dimensions generally refer to the nominal diameter. Here are what some standard dimension systems include:

AS/NZS 2280 (Australia and New Zealand): This is a system that is metric-based. However, the dimensions vary from the European standard.
AWWA C151 (US): The nominal diameter varies in the range of 3 to 64 inches in size.
ISO 2531/ EN 545/598 (Europe): This system is metric-based with varying dimensions.

Common Diameter Ranges

For each application, there is a specific ductile iron pipe size and dimension to use. The various diameters would fit a wide range of applications, especially for water and wastewater systems. The common diameters for standard dimension systems are as follows:

ISO 2531/ EN 545/598 (Europe): The nominal diameters in this standard vary from DN80 to DN2000.
AWWA C151 (US): In this standard, nominal diameters go from 3 to 64 inches, which are equal to DN75 to DN1600.
AS/NZS 2280 (Australia and New Zealand): The nominal diameters in this standard commonly range from DN100 to DN750, which makes it suitable for water and wastewater applications.

Wall Thickness Specifications

The wall thickness for ductile iron pipes comes in several classes based on the pressure rating. This factor holds great importance since it ensures the durability and performance of the pipe. As a matter of course, thicker walls show more resistance against heavy loads and pressure.

ISO 2531 / EN 545/598 (Europe): This standard categorizes ductile iron pipes into Class C25, Class C30, Class C40, Class C64, and Class C100.
AS/NZS 2280 (Australia and New Zealand): For this standard, PN16, PN25, PN35, and PN45 are used to represent thickness classes.
AWWA C151 (US): Class 50, Class 51, Class 52, and Class 53 are considered thickness classes.

Ductile Iron Pipe Pressure Ratings and Wall Thickness

The right ductile iron pipe size and dimension must be selected to have a safe and reliable system with ideal performance, which is feasible by considering the right ductile iron pipe pressure rating. Also, the pressure rating is highly related to the wall thickness. The thicker the wall gets, the more pressure it can withstand. The most common pressure ratings with a look at wall thickness include:

AWWA C151 (US): referring to The Engineering ToolBox, the pressure class ranges from 50 to 53. Class 50 withstands the maximum pressure of 50 psi.
ISO 2531 / EN 545/598 (Europe): C25 to C100 are the pressure classes they provide. C25 corresponds to the pressure of 25 bar at the maximum level, which is approximately 363 psi.
AS/NZS 2280 (Australia and New Zealand): Pressure classes are from PN16 to PN4; PN16 is suitable for the maximum working pressure of 1600 kPa, which is approximately equal to 232 psi.

How Are Ductile Iron Pipes Superior to Other Materials?

Ductile iron pipes in different sizes and dimensions would make a much more suitable option compared to other materials. They offer several different benefits and advantages other materials don’t. Here is a comparison with potential alternatives.

Ductile Iron vs. PVC

A very crucial factor is the service life of the material. Ductile iron pipes generally have longer service lives, especially compared with PVC ones.
PVC pipes can tolerate much less internal pressure and external loads, while ductile iron pipes are capable of withstanding higher pressures.
Ductile iron pipes show higher resistance to damage from impact. This feature makes them a much better choice for harsh environments and complex installations.

Ductile Iron vs. Steel

When it comes to expenses, ductile iron pipes are the best option compared to steel pipes. They are cheaper and also require less maintenance.
Ductile iron pipes show more flexibility compared to steel pipes. As a result, they are able to withstand ground movement, vibrations, and temperature changes that cause expansion and contraction.
Steel pipes show less corrosion resistance. Ductile iron pipes have an internal cement-mortar lining, making them highly corrosion-resistant.

The table below perfectly compares ductile iron pipe specifications with steel pipes and PVC pipes:

Property/Feature	Ductile Iron Pipe	PVC Pipe	Steel Pipe
Internal Pressure Resistance	High	Moderate to high, depending on pipe thickness	High
External Load Resistance	High	Moderate to high, depending on pipe thickness	Moderate to high, depending on pipe thickness
Corrosion Resistance	High	High	Low without protective coatings or treatments
Flexibility	High	Low to moderate	Low to moderate
Lifespan	Long (100+ years)	Moderate (50-100 years, depending on conditions)	Long with proper maintenance and corrosion protection

How to Choose the Right Ductile Iron Pipe Size for Your Project

There are a few factors to consider when choosing the perfect ductile iron pipe size and dimension. Some primary factors are to be considered to determine the required pipe length and weight. These factors help you make an informed decision based on your project needs. The key factors to make sure of are listed below.

Flow Rate Requirements

The flow rate needs to be established in order to facilitate effective fluid transportation via pipelines. By choosing a larger size, greater flow is allowed through the pipeline.

Pressure Rating

The maximum pressure that will be forced upon the pipe in the system must be determined. Thicker walls are required for higher pressure ratings.

Application Type

Different ductile iron pipe sizes and dimensions are required for different applications. Each application will need a specific type of pipeline for the best results.

Installation Environment

Many factors must be considered for the installation environment. The condition of where the pipe is going to be installed must be evaluated. Depth of burial, soil type, and external loads can be of high importance.

Cost Considerations

The overall cost of materials, installation, and maintenance of the pipes must be evaluated and considered. Normally, the costs increase with the increase in the size or pressure ratings.

Conclusion

Ductile iron pipes are manufactured in several sizes and dimensions to meet your needs the best. For each application in your projects, you may find the best-fitting size with the proper pressure rating. Ductile iron pipes are highly beneficial, especially compared to alternative materials, such as PVC pipes and steel pipes. If you are looking forward to getting more information about these pipes, contact our professionals for more precise help.