IS 808:2021 is the BIS dimensional standard for hot rolled steel sections — I-beams (ISMB), columns (ISSC), channels (ISMC), T-sections (ISST), and angles (ISA/ISEA). It specifies the exact dimensions, mass per metre, and section properties (area, moment of inertia, section modulus) for each standard size. IS 808 is the reference document used by structural engineers across India to select sections and by procurement teams to specify and verify supply.
Technical Overview
IS 808 defines the geometry of standard Indian structural sections, catalogued by the Indian Standards Institution designation system: ISMB (Indian Standard Medium Weight Beam), ISMC (Indian Standard Medium Weight Channel), ISSC (Indian Standard Column Section), ISST (Indian Standard T-section), ISA (Indian Standard Angle), and ISEA (Indian Standard Equal Angle). For each size, the standard tabulates: flange width, web thickness, flange thickness, root radius, sectional area, mass per metre, moment of inertia (Ixx, Iyy), radius of gyration, and section modulus. These properties are used directly in structural design to IS 800. The 2021 revision updated section tables and aligned with current mill production capabilities.
Grades & Mechanical Properties
| Grade | Notes |
|---|---|
| ISMB (I-Beam) | Sizes: ISMB 100 to ISMB 600 — spans, beams, rafters |
| ISMC (Channel) | Sizes: ISMC 75 to ISMC 400 — purlins, bracing, framing |
| ISSC (Column) | Heavy column sections for multi-storey buildings |
| ISA / ISEA (Angle) | Equal and unequal angles — trusses, towers, bracing |
Values are minimum requirements unless otherwise stated. Always verify with the current edition of the standard and the mill test certificate.
Common Applications
- Industrial building frames — columns, rafters, purlins
- Railway bridges and viaducts
- Transmission line towers
- Crane runway girders
- Fabricated structural trusses
- Mezzanine floors and industrial platforms
International Equivalents
IS 12778
Indian standard for parallel flange (H-beam) sections — more efficient alternative to ISMB for heavy structures
EN 10034 / EN 10055
European dimensional standards for I-sections (HE, IPE) and channels
ASTM A6
US standard for W-shape, S-shape, HP sections and structural channels
Frequently Asked Questions
What is IS 808?
What is the difference between ISMB and ISMC?
What material standard does IS 808 use?
Related Standards
IS 2062:2011 — Hot Rolled Medium and High Tensile Structural Steel
IS 2062 is India's primary structural steel standard, specifying hot rolled medium and high tensile steel used in bridges, buildings, industrial structures, and fabricated assemblies. It defines six grades from E250 to E550, covering mild to high tensile performance. Published by the Bureau of Indian Standards (BIS), it is the most referenced steel specification in Indian construction and engineering.
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IS 12778:2004 — Hot Rolled Parallel Flange Steel Sections for Beams, Columns and Bearing Piles
IS 12778:2004 specifies hot rolled parallel flange steel sections — Narrow Parallel Flange Beams (NPB) and Wide Parallel Flange Beams (WPB) — used in modern structural steel construction. Unlike the tapered flange ISMB sections in IS 808, parallel flange sections offer constant flange thickness, better bolting geometry, and higher structural efficiency, resulting in lighter and more economical steel structures.
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IS 1852:1985 — Rolling and Cutting Tolerances for Hot Rolled Steel Products
IS 1852:1985 is the BIS standard governing rolling and cutting tolerances for all hot rolled steel products — plates, sheets, strips, flats, bars, and structural sections. It specifies the permitted deviation from nominal dimensions for thickness, width, length, flatness, camber, and squareness. IS 1852 is the tolerance reference document used alongside IS 2062 and IS 1079 in purchase orders and inspection protocols — any dimension check at goods receipt references IS 1852.
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