Brief introduction

It is a great challenge for buyers and engineers to browse the European standards of welded steel pipes. EN 10255 and EN 10217 are two standards that often cause confusion. At first glance, they may appear similar, and their standard pipe sizes can even overlap, leading to costly procurement mistakes if chosen incorrectly. The core difference is that EN 10255 is designed for threading and general fluid transportation, while EN 10217 is specially designed for pressure purposes, which is very important for the understanding of search engines.

en 10255 vs en 10217 steel pipe comparison

 

Choosing the wrong type of welded steel pipe can lead to installation failure, compliance problems and even security risks. This guide will reveal the mystery of these two important standards. We will provide a detailed comparison of their history, material grades, size systems and main applications. Finally, you will master the knowledge of specifying the correct welded steel pipe for your project to ensure the performance and safety.

Understanding the Standards – History and Definition

It is very important to understand what each standard stands for before delving into the technical details.

EN 10255: The Standard for Threading and General Use

The formal name is “Non-alloy Steel Pipe Suitable for Welding and Threading”, and EN 10255 is the modern European successor to two historic specifications: the British BS 1387 and the German DIN 2440. Many buyers are still looking for these old codes, so it is very important to know this lineage. This standard covers welded steel pipe mainly used for water and gas transportation and fire sprinkler systems. Its fundamental design premise is to provide a pipe that is easy to cut, weld, and, most importantly, thread without failure.

EN 10217-1: The Standard for Pressure Applications

EN 10217 is a broader standard titled “Welded steel pipe for pressure purposes.” Part 1 (EN 10217-1) specifically covers “Non-alloy steel tubes with specified room temperature properties.” This standard is the successor to other European standards for pressure pipes (such as DIN 1626). It is specifically manufactured and tested to withstand internal pressure, making it the go-to choice for applications such as pressure vessels, boiler tubes, HVAC circulation systems, and general industrial pressure piping. The key point here is to ensure the mechanical properties and accurate dimensions so as to operate safely under pressure.

Core Comparison 1 – Material Grades and Properties

The most significant difference between these standards is the chemical and mechanical properties of the steel used.

S 195 t – The Grade for EN 10255

The material grade for EN 10255 is usually s 195 tons.

  • S stands for “structural” or “universal”
  • 195 represents the minimum yield strength (MPa, 195 MPa).
  • The most critical feature of s 195 t is its formula. This is a relatively soft steel with good ductility. This is not a defect, but an intentional feature. The purpose of this enhanced ductility is to prevent the end of the pipe from cracking when threads is cut into the pipe. This makes it the ideal choice for applications that require threaded connections.

P 235 TR 1 – The Grade for EN 10217

The general score of EN 10217-1 is p 235 TR 1.

  • P stands for “stress” clearly
  • 235 denotes a relatively high minimum yield strength (235 MPa).
  • This grade of products has higher strength and better pressure bearing capacity. However, it offers no guarantee of suitability for threading. Attempting to pass through the p 235 TR 1 pipeline could cause rupture. Its value is in its reliable performance under continuous stress.

The main differences are summarized in the table below.

Feature EN 10255 (S195T) EN 10217-1 (P235TR1)
Grade Meaning​ Structural, General Use Pressure Application
Min. Yield Strength​ 195 MPa 235 MPa
Key Property​ High ductility for threading High strength for pressure
Suitable for Threading​ Yes, specifically designed for it Not guaranteed, often unsuitable

Core Comparison 2 – Dimensional Systems

The approach to defining standard pipe sizes and wall thicknesses is another major differentiator.

EN 10255: the “Series” System

EN 10255 does not sell pipes based on a specific wall thickness in millimeters. Instead, it uses a series system: light, medium and heavy. Each nominal diameter (such as, 1/2 inch, 1 inch, 2 inch) have these three predefined weight categories. The system simplifies selection for general pipeline and low pressure applications. For instance, the Heavy Series is often specified for fire sprinkler systems due to its added mechanical strength and durability.

EN 10217: the “Exact Dimension” System

In contrast, EN 10217 specifies pipes by their exact outer diameter (OD) and wall thickness (WT), for example, outer diameter is 88.9 mm x wall thickness is 3.2 mm.. This precise system is essential for engineers performing detailed pressure vessel and pipeline calculations. It allows accurate specification according to the required rated pressure and mechanical loads, which goes beyond the general method of the “series” system. This precision is very important to ensure the safety and integrity of pressure systems using this welded steel pipe.

Buyer’s Guide – When to Choose Which?

This is the most critical part of making the right purchase decision. Use the following guidelines to choose the correct welded steel pipe.

When do you buy EN 10255?

EN 10255 welded steel pipe shall be specified in the following cases.

  • Thread joint: Whenever you need to connect pipes using threaded fittings (screwed joints), EN 10255 is the mandatory choice. Its S 195 t class is designed for this purpose.
  • Automatic sprinkler systems: It is a very common application. Many national and local fire laws and regulations refer to the standards in EN 10255, especially the heavy-duty series.
  • Water and Gas Conveyance: For non-pressure critical water supply pipelines and low-pressure gas pipelines, they are usually called “water and gas pipelines”.
  • General pipes and buildings: used for scaffolding, structural support and other general applications where compression resistance is not the main consideration.

When should I buy EN 10217?

In these cases, EN 10217 welded steel pipe shall be specified.

  • Welded Pressure systems: When the piping system will be assembled mainly by welding and designed to transport fluids under considerable pressure (for example, Steam piping, hydraulic piping).
  • Exact wall thickness Requirements: When your engineering calculations requires a specific non-standard wall thickness, and the “series” system of EN 10255 can not provide it.
  • Observe the pressure equipment directive (PED): For equipment belonging to PED in Europe, you will need a pipe manufactured according to a pressure standard of EN 10217.
  • High temperature Applications fields:EN 10217-1 is aimed at room temperature characteristics, while other parts of the standard (for example. EN 10217-2) Casing for high temperatures.

Summary

In the world of industrial piping, understanding the distinction between EN 10255 and EN 10217 is fundamental. This choice is not about which welded steel pipe is “better”, but which welded steel tube is correct for the application. Choosing EN 10255 for a high-pressure system has the risks of catastrophic failure, while choosing EN 10217 for a threaded pipeline system could lead to pipeline fracture and leakage during installation.

Remember this simple rule of thumb: “Need threading? Choose EN 10255. Need pressure resistance with welded joints? Choose EN 10217.” This will guide you to select the correct standard pipe sizes and specifications for the project.

At All land Steel, we have a large number of EN 10255 and EN 10217 welded steel pipe in stock. Our technical experts are always ready to help you browse these standards and ensure that you get the right product that meet your specific requirements. Please contact us immediately for quotation or technical advice.