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IS 12779:1989 is the Indian Standard (BIS) for rolling and cutting tolerances for hot rolled parallel flange beam and column sections. This standard specifies the manufacturing tolerances for hot-rolled parallel flange steel beam and column sections. It defines the acceptable deviations from nominal dimensions for depth, width, thickness, weight, straightness, and cutting length. This code is essential for quality control in steel mills and for engineers and fabricators specifying and using these structural sections.
Rolling and cutting tolerances for hot rolled parallel flange beam and column sections
Overview
Status
Current
Usage level
Frequently Used
Domain
Structural Engineering — Structural Engineering and Structural Sections
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Always check mill test certificates against these tolerances, especially for web and flange thickness, as these directly impact calculated section properties like moment of inertia and section modulus.
! Straightness tolerances (camber and sweep) are critical for long compression members and members requiring precise alignment. The standard tolerance is L/1000.
! For members requiring precise fit-up, specify 'exact length' cutting tolerances by agreement with the supplier, as the standard tolerance is a relatively loose ±50 mm.
EN 10034:1993CEN (European Committee for Standardization), Europe
HighCurrent
Structural steel I and H sections - Tolerances on shape and dimensions
Directly specifies dimensional and shape tolerances for hot-rolled structural steel I and H sections.
ASTM A6/A6M-22ASTM International, USA
HighCurrent
Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
Contains a comprehensive section (Section 13) on permissible variations for structural shapes, including beams and columns.
JIS G 3192:2014JSA (Japanese Standards Association), Japan
HighCurrent
Dimensions, mass and permissible variations of hot rolled steel sections
Covers dimensions, mass, and tolerances for hot-rolled H-sections and other structural shapes.
AS/NZS 3679.1:2016Standards Australia/Standards New Zealand, Australia/New Zealand
MediumCurrent
Structural steel - Part 1: Hot-rolled bars and sections
Specifies requirements for hot-rolled sections, including a dedicated section on dimensional and shape tolerances.
Key Differences
≠IS 12779 specifies a single straightness (camber) tolerance of 0.2% of length, whereas EN 10034 provides different values for different section types (e.g., 0.15% for I & H sections) and ASTM A6 uses a formula based on length in feet (e.g., 1/8 inch x [length in ft / 5]).
≠The mass tolerance in IS 12779 is ±2.5% for an individual piece. This is tighter than EN 10034 (±4.0% for individual piece) and the range specified in ASTM A6 (-4% to +6% for a group).
≠Standard cutting length tolerance for sections over 12m is +75mm/-0mm in IS 12779. In EN 10034, the standard tolerance is a more generous +100mm/-0mm, but it also formally defines 'exact length' categories with much tighter tolerances (e.g., ±2 mm) which are not standard in IS 12779.
≠The categorization of dimensional ranges for applying tolerances differs. For example, IS 12779 specifies web thickness tolerance for sections 'Over 200 up to 400 mm' depth, while EN 10034 uses ranges like 'h > 180 up to 400 mm', leading to slight differences in applicability at the boundaries.
Key Similarities
≈All standards (IS 12779, EN 10034, ASTM A6) cover the same fundamental set of tolerances: section depth, flange width, web/flange thickness, out-of-square, straightness (camber/sweep), and length.
≈The default cutting length tolerance is specified asymmetrically in all comparable standards, allowing for over-length but having a zero-negative tolerance (e.g., +X / -0 mm). This ensures the customer always receives at least the ordered length.
≈Tolerance values in all standards are not constant but are dependent on the nominal dimensions of the section. Larger and heavier sections are generally permitted larger absolute dimensional variations.
≈All standards define and control web eccentricity or 'web off-centre', ensuring the web is reasonably centered between the flanges, which is critical for symmetric load-bearing.
Parameter Comparison
Parameter
IS Value
International
Source
Mass Tolerance (Individual Piece)
± 2.5%
± 4.0%
EN 10034:1993
Mass Tolerance (Batch > 10 tonnes)
± 2.0%
± 2.5%
EN 10034:1993
Straightness (Camber in strong axis)
≤ 0.2% of length
≤ 0.15% of length
EN 10034:1993
Cutting Length (Standard, for 15m piece)
+75 mm / -0 mm
+100 mm / -0 mm
EN 10034:1993
Section Depth (h) for a 300mm deep section
± 3.0 mm
± 3.0 mm (for h > 180 up to 400)
EN 10034:1993
Flange Width (b) for a 250mm wide flange
± 4.0 mm
± 4.0 mm (for b > 180 up to 270)
EN 10034:1993
Web off-centre (e) for 200mm wide flange
≤ 5.0 mm
≤ 3.0 mm (for HE sections, 120 < b ≤ 220)
EN 10034:1993
⚠ Verify details from original standards before use
Key Values7
Quick Reference Values
Tolerance on overall depth (d)±3.0 mm
Tolerance on flange width (b) for b ≤ 200 mm+4.0 mm / -2.0 mm
Tolerance on web thickness (tw) for tw ≤ 20 mm±0.5 mm
Tolerance on mass per metre±2.5%
Standard cutting length tolerance±50 mm
Tolerance on straightness (camber/sweep)Length / 1000
Maximum flange out-of-squareness1.0 mm
Tables & Referenced Sections
Key Tables
Table 1 - Rolling Tolerances for Parallel Flange Beams and Columns
Table 2 - Tolerances on Straightness, Camber and Sweep