DIN EN 10220 – Steel Pipe Dimensions

1. What is EN 10220

The DIN EN 10220 standard is commonly referred to as “Seamless and welded steel pipes — dimensions and mass per unit length.”

It was developed from the earlier ENV 10220 standard, with adjustments made to align with ISO 4200:1991 and to reduce differences in international pipe trade.

Table 1 of ENV 10220 is the same as Table 2 of ISO 4200:1991 and therefore remains unchanged for EN 10220.

Table 2 of EN 10220 contains dimensions for thick-walled pipe not covered by ISO 4200:1991.

The following table lists some of the EN 10220 dimensions most frequently encountered in piping and structural applications.

1.1 EN 10220 Common Pipe Dimensions

1.2 Nominal Diameter (DN) and Outside Diameter

In EN 10220, the DN value is a nominal designation used for pipe identification and sizing. It does not represent the actual outside diameter of the pipe.

For example, DN80 corresponds to an outside diameter of 88.9 mm, while DN100 corresponds to 114.3 mm. When selecting pipe dimensions, the outside diameter listed in the standard should always be used as the reference value.

2. Related Standards and System Background

The EN 10220 and EN 1127 norms cover dimensions and tolerances for European pipes, carbon/alloy steels and stainless steels respectively.

While EN 10220 and 1127 are used in Europe, ASME B36.10 and ASME B36.19 cover dimensions and tolerances for American standard pipe.

All parts of the European standard series EN 10305 on steel tubes for precision applications contain tables with preferred dimensions specific to each part of the standard series and to the products and areas of application specified therein.

Therefore, the preferred dimensions of precision tube in Table 3 of ENV 10220 have become unnecessary and are not included in this standard.

3. Scope and Application

The EN 10220 standard is mainly used to define the dimensions and theoretical weight of steel pipes, including outside diameter, wall thickness, and mass per meter.

It applies to both seamless and welded pipes used in general applications such as mechanical systems, pressure pipelines, and structural components.

Unlike standards that specify material grades or mechanical properties, EN 10220 does not deal with performance. Its role is more straightforward — it provides a common dimensional basis so that pipes from different manufacturers can match the same system requirements.

3.1 In real projects

In most projects, EN 10220 is combined with material standards to complete the selection process.

For example, carbon steel or alloy steel grades are selected based on pressure and temperature conditions, while the dimensional standard ensures compatibility between components.

This is why seamless steel pipes, ERW steel pipes, and carbon steel pipes are often discussed together in engineering design and procurement stages.

3.2 Dimension Selection and Availability

One thing worth paying attention to is that not all sizes are equally available.

EN 10220 groups outside diameters into different series, which basically reflect how common those sizes are in the market and whether matching fittings are standardized.

In real procurement:

Some sizes are easy to source and widely supported

Others may exist in the standard but are not commonly stocked

Lead times and costs can vary significantly depending on the selection

So in many cases, choosing a size is not just a design issue — it also affects purchasing and delivery.

3.3 Notes on Special Cases

For certain applications, EN 10220 is used together with other standards.

For example, precision tubes or stainless steel pipes may follow additional specifications such as EN 10305 or EN ISO 1127, which provide more detailed requirements beyond basic dimensions.

4. Outer Diameter Classification (Series 1, 2, 3)

The outside diameters listed in Tables 1 and 2 are grouped into three series, mainly based on how standardized the corresponding fittings and accessories are.

Series 1 includes diameters for which all required piping accessories are fully standardized, making it the most reliable and commonly used option in actual projects.

Series 2 covers diameters where only part of the accessories are standardized, which can sometimes limit availability depending on the project location or supplier.

Series 3 refers to diameters with very limited standardization, and in many cases, matching fittings may be difficult to source.

(1) Engineering Notes

In practice, Series 1 is generally recommended when the pipe is intended to be part of a complete piping system, mainly because fittings and components are widely available.

For Series 2 and 3, availability can be less predictable, especially in international procurement scenarios.

It is also worth noting that heavy-wall fittings listed in Table 2 may not always be readily available, regardless of the series classification.

5. Calculation Method of Mass per Unit Length

The mass per unit length values listed in Tables 1 and 2 are calculated based on the pipe’s outside diameter (D) and wall thickness (T), using the formula below:

M = (D - T) × T × 0.02466151 kg/m

In this formula, M represents the pipe weight per meter, while D and T correspond to the outside diameter and wall thickness respectively, both expressed in millimeters.

For values below 100, results are typically rounded to three significant figures, while larger values are rounded to the nearest whole number.

This calculation is widely used in engineering design and procurement for estimating total weight and transportation cost.

In practical projects, these values are usually checked against standard pipe size and weight tables for seamless and welded steel pipes before final ordering.

5.1 Density Adjustment Factors

When applying this calculation to stainless steel pipes, the result should be adjusted depending on the material type.

A factor of 1.015 is typically used for austenitic stainless steel, while 0.985 is used for ferritic and martensitic grades.

For more precise calculations, EN 10088-1 provides detailed density values for different stainless steel groups.

6. Dimensions and Mass per Unit Length

Table 1 includes pipe dimensions across the three diameter series, with wall thickness up to 65 mm, along with the corresponding calculated weight per meter.

Table 2 extends this range to thick-wall pipes, covering wall thickness from 70 mm up to 100 mm, again with calculated mass per unit length.

How to Read EN 10220 Dimension Tables

- Outside Diameter (OD) – the actual external diameter of the pipe.

- Wall Thickness (T) – the thickness of the pipe wall.

- Mass per Unit Length – the theoretical weight of the pipe expressed in kilograms per meter.

These values are used together during pipe selection, transportation planning, structural calculations, and procurement activities.

For standard OD and wall thickness dimensions, refer to the complete Seamless Steel Pipe Size Chart.

7. EN 10220 vs ISO 4200

Because EN 10220 and ISO 4200 contain many of the same pipe dimensions, they are often treated as equivalent references during engineering design and procurement. In fact, the main dimensional table in EN 10220 is directly aligned with ISO 4200, which helps maintain consistency in international projects.

The difference becomes more noticeable when heavy-wall pipe dimensions are involved. EN 10220 includes additional dimensional data beyond the scope of ISO 4200, particularly for wall thicknesses covered in Table 2. For this reason, EN 10220 is often referenced when thicker pipe sections are required.

In practical terms, ISO 4200 serves as the international foundation for pipe dimensions, while EN 10220 adapts those dimensions within the European standard system and extends the range where necessary.

8. FAQs

Q1. What is the difference between EN 10220 and ISO 4200?

EN 10220 is the European dimensional standard for steel pipes and is largely aligned with ISO 4200. However, EN 10220 also includes additional dimensions for heavy-wall pipes that are not fully covered in ISO 4200.

Q2. Is DN80 pipe equal to 88.9 mm outside diameter?

Yes. According to EN 10220, DN80 corresponds to an outside diameter of 88.9 mm. The nominal size (DN) is a designation only and should not be confused with the actual outside diameter.

Q3. Does EN 10220 apply to seamless and welded steel pipes?

Yes. EN 10220 specifies dimensions and mass per unit length for both seamless and welded steel pipes. Material grades and mechanical properties are defined in separate product standards.

Q4. What is the difference between DN and outside diameter in EN 10220?

DN is a nominal designation used for pipe identification, while outside diameter is the actual measured dimension of the pipe. For example, DN80 corresponds to an outside diameter of 88.9 mm under EN 10220.

Q5. Is EN 10220 a material specification?

No. EN 10220 only defines dimensions and theoretical mass. Material grade requirements are covered by other standards such as EN 10216, EN 10217, or EN 10297 depending on the product type.

9. Summary

EN 10220 provides a standardized dimensional system for steel pipes, covering outside diameter, wall thickness, and theoretical mass for both seamless and welded products.

Although the standard does not specify material grades or mechanical properties, it serves as the dimensional foundation for many European piping applications. In practice, EN 10220 is often used together with material standards such as EN 10216, EN 10217, EN 10297, and ISO 4200 to complete pipe specification and selection.

Read more: EN10220 vs EN10210 Pipes or EN 10220 Pipe Weight Chart