BS EN 10219 Cold-Formed Welded Structural Hollow Sections

BS EN 10219:Cold Formed Welded Structural Hollow Sections of Non-alloy and Fine Grain Steels - Part 1: Technical Delivery Conditions and Part 2: Tolerances, Dimensions and Sectional Properties

BS EN 10219 Standard is the EU standard for cold-formed or unheat-treated welded steel tubes, primarily applicable to round, square and rectangular tubes. These products are classified as building materials in the EU and are regulated by a specific directive under the CE marking, namely, CPR-Regulation (EU) No. 305/2011. The implementation of this standard signifies uniformity and standardization in the manufacture, inspection, and use of steel tube products.

Basic Contents of BS EN 10219:

EN 10219 applies primarily to cold-formed (cold-finished) welded hollow sections (such as square tubes, rectangular tubes and round tubes) for building and engineering structures, particularly those used in load-bearing structures. It specifies requirements for the chemical composition, manufacturing process, mechanical properties, dimensional tolerances, appearance quality, welding requirements, and inspection methods.

The BS EN 10219 standard is divided into two main parts:

EN 10219-1: Technical Delivery Conditions

1. Material Requirements: This specifies the grade and properties of the steel used in the manufacture of steel tubes, typically based on the steel specified in EN 10219 itself or EN 10210 (Hot-Finished Hollow Sections).
2. Manufacturing Process: This specifies that the tubes are formed by cold forming (cold bending) and then welded together at the edges. This is different from hot rolling or hot forming.
3. Welding Requirements: This sets out strict standards for welding procedures, welder qualifications, and weld quality (such as non-destructive testing) to ensure weld strength and integrity.

4. Chemical Composition:
EN 10219 also provides detailed specifications for the chemical composition of square, rectangular, and round tubes. The standard requires that the chemical composition of the material comply with the requirements of relevant European standards, such as EN 10028.

The standard specifies the content ranges of key elements such as C, Si, Mn, P, and S to ensure the material's mechanical and weldability. Specific content requirements vary depending on the application and performance requirements of the steel pipe. For example, for steel pipes used in load-bearing structures, lower sulfur and phosphorus contents can improve the steel's toughness and ductility, thereby extending its service life.

5. Mechanical Properties:

EN 10219 sets requirements for the mechanical properties of square, rectangular, and round tubes. The standard stipulates the minimum mechanical properties that the steel must meet, summarized as follows:

Mechanical Property	Typical Minimum Requirement	Significance & What It Indicates
Yield Strength (ReH)	≥ 235 MPa (varies by grade)	The stress at which permanent deformation begins; determines the elastic load-bearing limit.
Tensile Strength (Rm)	≥ 400 MPa (varies by grade)	The maximum stress the material can withstand before fracture; indicates overall strength and safety margin.
Elongation (A)	Minimum value specified per grade	A measure of ductility (plasticity); higher values indicate better formability and toughness.

6. Dimensions and Tolerances: 

Used in conjunction with Part 2, these parameters specify the permissible deviations within dimensions.

During the production process, the outer diameter and wall thickness of steel tubes are critical technical parameters. The outer diameter not only affects the strength and load-bearing capacity of the tube, but also influences the connection and installation methods. Wall thickness directly affects the pipe's pressure resistance and corrosion resistance. Different wall thicknesses are suitable for different applications. For example, thicker wall materials are more suitable for environments subject to high pressure.

EN 10219 specifies the dimensions and shapes of square and rectangular tubes. For square tubes, the standard stipulates that the cross-sectional dimensions must meet the relevant tolerance requirements, while for rectangular tubes, the dimensions specify the ratios of height, width, and diagonal. In addition, shape tolerances, such as curvature and straightness, are specified for square and rectangular tubes.

7. Appearance Quality:
The EN 10219 standard also has corresponding requirements. The surface of steel tubes should be smooth and free of obvious defects such as cracks, dents, and rust. Surface quality directly affects subsequent painting and anti-corrosion treatments. Therefore, during the production process, manufacturers must strictly control and inspect the production process to ensure that the final product's appearance meets the standard.

8. Inspection and Testing: This section specifies the types of tests required (such as tensile tests, impact tests, flattening tests, and flaring tests) and the frequency of these tests.

9. Marking and Certification: This section specifies how products should be marked (such as standard number, steel grade, dimensions, and manufacturer), as well as the required compliance documents (such as the Factory Production Control Certificate (FPC)).

EN 10219-2: Tolerances, Dimensions and Sectional Properties

EN 10219-2 provides detailed dimensions, tolerances, sectional properties (such as cross-sectional area, moment of inertia, section modulus, etc.), and tolerance tables for square, rectangular, and circular tubes. Engineers and designers use the data and tables in this section for structural calculations and design.

Differences between EN 10219 and EN 10210: Cold Forming vs. Hot Forming

This is the most fundamental difference between EN 10219 and another important standard, EN 10210.

Feature / Aspect	EN 10219 (Cold-Formed)	EN 10210 (Hot-Formed)
Forming Process	Cold-bent and welded at room temperature from steel sheet/strip.	Pierced, rolled, or extruded from billets at high temperatures.
Wall Thickness	Typically thinner walls, lighter weight.	Typically thicker walls, heavier weight.
Dimensional Accuracy	High precision, tighter tolerances, smoother surface finish.	Larger dimensional tolerances, rougher surface.
Corner Radius	Smaller outside corner radii, sharper edges.	Larger outside corner radii, more pronounced round corners.
Typical Applications	Light to medium structures, architectural aesthetics, space trusses.	Heavy-duty load-bearing structures, thick-walled support columns.

▶  For a more detailed comparison, read our full article: [EN 10219 vs EN 10210: Comprehensive Comparison].

Relationship between EN 10220 and EN 10219:

EN 10220 is a parent standard and foundation: it provides a unified basis for dimension and tolerance definitions across multiple steel tube product standards. In earlier versions of EN 10210 and EN 10219, the dimension and tolerance sections often directly referenced EN 10220.

Commonly Used Steel Grades:

The EN 10219 standard covers a variety of steel grades for structural use. The most common designations for structural hollow sections under this standard use the suffix "H" (for Hollow section), such as S235JRH, S275J0H, S275J2H, S355J0H, S355J2H, and S355K2H. 

Steel Grade	Min. Yield Strength (MPa)	Impact Test Temp.	Key Characteristics & Typical Use
S235JRH	235	0°C	Basic structural applications, general load-bearing.
S275J0H	275	0°C	General purpose structures, higher strength than S235.
S275J2H	275	-20°C	Structural components for low-temperature environments.
S355J0H	355	0°C	High-strength applications, commonly used in bridges and heavy machinery.
S355J2H	355	-20°C	High-strength with good low-temperature toughness for critical parts.
S355K2H	355	-20°C (higher impact energy)	Demanding applications requiring superior low-temperature impact toughness.

The meanings of the grade suffixes are as follows:

S: Structural steel
235/355: Minimum yield strength (MPa)
J0, J2, K2: Impact toughness grade (J0 = 0°C test, J2 = -20°C test, K2 = -20°C test with higher impact strength required)

Suffix "H" : Hollow section

S235JRC: The "C" suffix originates from the EN 10025-2 standard, where it indicates the steel grade is suitable for cold flanging (cold forming). This grade can also be specified for use in cold-formed hollow sections under the EN 10219 standard.

Note: L-series pipeline steels (such as L245NB) have their own independent standard system (such as EN 10216, EN 10217, ISO 3183) and are not included in the EN 10219 standard.

Applications of EN 10219 Standard Steel:

EN 10219 standard hollow sections are widely used in various modern buildings and engineering structures due to their light weight, high strength, flexible and aesthetically pleasing design:

1. Building Structures: These typically serve as supporting and connecting members, bearing the weight and external pressure of the building, such as the roofs and main structures of airport terminals, stadiums, commercial centers, and office buildings. 2. Space trusses and grid structures: Construction of large, column-free spaces.
3. Machinery and equipment manufacturing: Hoisting machinery, agricultural machinery, vehicle chassis, etc.
4. Bridge construction: Used to manufacture bridge girders and support columns, ensuring the stability and safety of bridges, such as pedestrian overpasses and decorative bridge components.

5. Home furnishings and decoration: Furniture, stairs, guardrails, etc.

FAQs

Q1: What does the "H" suffix mean in EN 10219 steel grades (e.g., S355J2H)?
A: The "H" stands for Hollow section. It is the suffix used in EN 10219 to designate structural hollow sections. The suffix "C" (e.g., S235JRC) appears in older versions or other cold-formed product standards; EN 10219 currently uses "H".

Q2: What steel grades are covered by EN 10219?
A: EN 10219 covers non-alloy and fine-grain structural steels. The most common grades are S235JRH, S275J0H, S275J2H, S355J0H, S355J2H, and S355K2H. The numbers (235/275/355) indicate the minimum yield strength in MPa, and J0/J2/K2 indicate the impact test temperature and energy.

Q3: Does EN 10219 require CE marking?
A: Yes. EN 10219 products fall under the Construction Products Regulation (CPR) - Regulation (EU) No. 305/2011. Compliance with this standard allows manufacturers to affix CE marking to their structural hollow sections, certifying they meet EU construction product requirements.

Q4: What are the main applications of EN 10219 hollow sections?
A: EN 10219 hollow sections are widely used in building structures (roofs, stadiums, commercial centers), space trusses, bridge components, machinery (hoisting equipment, vehicle chassis), and architectural applications like furniture, stairs, and guardrails due to their light weight, high strength, and aesthetic appearance.

Q5: What tests are required under EN 10219?
A: EN 10219-1 specifies several tests including tensile tests, impact tests (Charpy V-notch), flattening tests, and flaring tests. The frequency and types of tests depend on the steel grade, dimensions, and the manufacturer's Factory Production Control (FPC) system. Non-destructive testing (NDT) for weld quality may also be required.

Conclusion:

EN 10219 is the comprehensive European product standard for cold-formed welded structural hollow steel sections. It ensures consistent quality, dimensions, and performance across manufacturers, providing structural designers with a reliable design basis and guaranteeing the safety and reliability of the resulting building structure.

In China, the corresponding national standard is GB/T 6728 "Cold-formed Hollow Steel Sections for Structural Use."

Read more:

●  ASTM A500 Structural Tubing

●  S235JRH and S355J2H Structural Steel

●  Steel Hollow Sections: What are HSS, SHS, RHS, and CHS?