What does ISMB 300 mean?

It stands for Indian Standard Medium Weight Beam with a nominal overall depth of 300 mm.

Where can I find the moment of inertia for standard steel sections?

In the respective tables of IS 808 (e.g., Table 1 for Beams, Table 3 for Channels).

Does IS 808 cover manufacturing tolerances for these steel sections?

No, manufacturing, rolling, and cutting tolerances are covered in a separate code, IS 1852.

What is the standard slope of the inner flange for typical ISMB beams?

The standard inner flange slope is 94 degrees, which corresponds to roughly 1 in 6 or 16.67%.

IS 808

: 1989

Dimensions for Hot Rolled Steel Beam, Column, Channel and Angle Sections

CurrentEssentialSpecificationBIMStructural Engineering · Steel and Reinforcement

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IS 808 provides standard dimensions, cross-sectional areas, mass, and section properties (such as moment of inertia, radius of gyration, and section modulus) for hot-rolled steel beams, columns, channels, and angle sections. Structural engineers and steel detailers rely on this code to select standardized Indian steel profiles (like ISMB, ISMC, ISA) and use their geometric properties for safe structural design and BIM modeling.

Specifies the dimensions, weights, and section properties of hot rolled steel structural sections.

Quick Reference Values

density for mass calculation7850 kg/m³

standard flange slope ISMB94 degrees (approx 16.67% or 1 in 6)

standard flange slope ISMC94 degrees (approx 16.67% or 1 in 6)

designation conventionProfile symbol (e.g., MB) followed by depth in mm

angle designation conventionProfile symbol (ISA) followed by leg lengths and thickness in mm

Practical Notes

The sectional properties given in this code are nominal. Actual dimensions and weights supplied by manufacturers may vary within the rolling and cutting tolerances specified in IS 1852.

Not all sections listed in IS 808 are commonly rolled by steel mills today. Engineers should verify market availability of specific profiles (like ISWB or ISJB) before specifying them in design.

Software section databases for the Indian market are built directly from the tables in this code; verifying older legacy software databases against the 1989 values is recommended.