What is the acceptable tolerance on the overall depth (d) of a parallel flange beam?

The tolerance on depth is ±3.0 mm for all sections (Table 1).

What is the tolerance on the mass per metre for a steel column section?

The tolerance on mass per metre for a single piece or a batch is ±2.5% (Clause 3.6).

How much can the flange be out of square with the web?

The out-of-squareness (deviation 's' in Fig. 1) shall not exceed 1.0 mm (Clause 3.7).

How much out-of-straight can a 12-meter-long beam be?

The maximum permissible sweep or camber is Length/1000, which is 12,000 mm / 1000 = 12 mm over the entire length (Table 2).

IS 12779

: 1989

Rolling and cutting tolerances for hot rolled parallel flange beam and column sections

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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

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

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.