EN 10162 Cold Rolled Steel Sections Tolerances

1. Definition and Purpose

EN 10162 is a European standard that specifies dimensional and mass tolerances for cold-rolled steel sections produced from flat products by continuous bending (roll forming). The standard applies to open profiles and split tubes whose cross-sections are formed without welding along the longitudinal seam, using cold-rolled strip as feedstock. EN 10162 does not define mechanical properties or steel chemistry; those requirements are taken from referenced material standards such as EN 10025, EN 10142, and EN 10147.

For roll forming manufacturers and their customers, EN 10162 provides a common language for specifying profile geometry, agreeing on acceptable deviation from nominal dimensions, and resolving disputes over dimensional conformity. The standard was first published in 1995 and remains the primary European reference for tolerance specification on roll-formed light-gauge structural and non-structural profiles used in building frames, cladding support systems, racking, and industrial equipment.

2. Scope and Profile Families

EN 10162 covers sections manufactured by roll forming from cold-rolled flat products with thickness typically in the range of 0.35 mm to 4.0 mm, although the standard itself does not set a thickness limit — thickness is governed by the referenced steel grade standard. The profile families explicitly addressed include angle sections (L), channel sections (U), C-sections, Z-sections, Omega profiles, and split tubes (open seam tubes formed from a single strip and not longitudinally welded).

2.1 Profile Family Summary

2.2 Manufacturing Process Covered

The standard applies exclusively to sections formed by progressive bending of strip through a series of contoured rollers. Each pass incrementally changes the bend angle until the final profile shape is achieved. Sections produced by other cold-forming methods — drawing, pressing, folding, or brake forming — fall outside the scope of EN 10162 and are covered by separate standards or bilateral agreements between supplier and purchaser.

3. Referenced Steel Grades

EN 10162 references material standards for the base steel from which sections are formed. The mechanical properties, chemical composition, and coating requirements of the finished section depend on the grade specified in the order, not on EN 10162 itself.

3.1 Primary Material Standards

When ordering roll-formed sections, the purchaser specifies both the profile designation per EN 10162 and the steel grade per the applicable material standard. For example, a C-section purlin might be ordered as a 200×75×20×2.0 mm profile in grade S350GD+Z275 per EN 10346, with tolerances per EN 10162.

4. Standard and Special Sections

EN 10162 distinguishes between standard sections and special sections. Standard sections follow predefined dimensional tables within the standard, with fixed tolerance values for leg length, flange width, web depth, lip length, and thickness. Special sections are profiles that deviate from the standard tables — custom geometries designed for a specific application — and require individually agreed tolerances between manufacturer and purchaser.

4.1 Standard vs Special Section Comparison

4.2 Tolerance Class Selection

EN 10162 defines tolerance classes that control the precision of leg lengths, angles, straightness, twist, and mass per unit length. Class 1 represents the tightest tolerances and is specified for precision applications such as racking systems and automated assembly lines. Class 2 is the normal commercial tolerance and applies to the majority of building and industrial profiles. The selected class must be stated in the order document alongside the profile designation.

5. Designation System

The designation of a cold-rolled steel section per EN 10162 follows a structured format that identifies the profile type, key dimensions, steel grade, coating (if applicable), and tolerance class. While the exact syntax varies slightly between manufacturers, the underlying logic is consistent across European supply chains.

5.1 Designation Components

5.2 Worked Designation Examples

6. Tolerance Classes and Key Dimensions

Dimensional tolerances in EN 10162 apply to leg length, flange width, lip length, included angle, straightness, twist, and mass per metre. The values depend on the nominal dimension and the selected tolerance class. The tables below summarize representative tolerance ranges commonly cited in manufacturer data sheets aligned with EN 10162; exact values should be verified against the current standard text for the specific profile and dimension range.

6.1 Leg and Flange Length Tolerances (Class 2, Representative)

6.2 Straightness, Twist, and Mass Tolerances

Thickness tolerance is not defined in EN 10162 but is taken from the feedstock standard (typically ±0.05 to ±0.10 mm for 1.0–2.0 mm strip per EN 10130 or EN 10346). Roll forming can slightly thin the material at bend radii, and this effect is accounted for in the theoretical mass calculation rather than as a separate EN 10162 tolerance.

7. Exclusions

EN 10162 explicitly excludes several categories of cold-formed steel products. Understanding these exclusions prevents misapplication of the standard and directs engineers to the correct specification document.

Roll-formed split tubes covered by EN 10162 must not be confused with welded tubes. A split tube retains an open seam or a mechanically interlocked seam without fusion welding; once the seam is welded (even by laser), the product falls under EN 10219 or EN 10305 depending on application.

8. Roll Forming Quality Assurance

Compliance with EN 10162 depends on controlled roll forming process parameters, accurate tooling, and systematic dimensional inspection. The standard defines what to measure; the roll forming line determines whether the product meets those measurements consistently.

8.1 Process Parameters Affecting Tolerance

8.2 Inspection Protocol

A typical EN 10162 inspection routine for roll-formed sections includes first-article measurement of all leg dimensions, lip length, and included angles using digital calipers and angle gauges. Straightness is checked with a 1 m straightedge or string line on a flat surface. Twist is measured with an inclinometer at 1 m intervals along the length. Mass per metre is verified by weighing a cut sample of known length. Production runs require periodic sampling at intervals defined in the manufacturer's quality plan, typically every 30–60 minutes or every coil change.

9. Application Scenarios and Technical Requirements

EN 10162-toleranced profiles appear across building construction, storage systems, and industrial fabrication. The following table maps common applications to typical profile types, steel grades, and tolerance class requirements.

When specifying profiles for structural applications, EN 10162 tolerances must be used together with the relevant structural design code (Eurocode 3 EN 1993-1-3 for cold-formed members, or national equivalents). Dimensional tolerance directly affects section properties used in structural calculations: a ±2.0 mm deviation on flange width changes the effective cross-section area and moment of inertia, which the design engineer must consider when selecting the tolerance class.