ISMB Weight Chart — All 14 Sizes as per IS 808:1989

The ISMB weight chart gives the mass per metre, depth, flange width, and web and flange thickness for all 14 Indian Standard Medium Weight Beam sizes specified in IS 808:1989. ISMB sections are the most widely used structural beams in Indian fabrication — for mezzanine floors, portal frames, crane girders, and industrial platforms. Use this chart for material take-off, freight estimation, and procurement.

What Is an ISMB Section?

ISMB stands for Indian Standard Medium Weight Beam. It is an I-section (also called an H-section or wide-flange beam) with a web connecting two flanges. IS 808:1989, titled Dimensions for Hot Rolled Steel Beam, Column, Channel and Angle Sections, specifies the exact dimensions and mass per metre for all 14 ISMB designations. The number in the designation equals the depth of the section in millimetres — ISMB 250 has a depth of 250 mm.

ISMB sections are manufactured in IS 2062 E250 and E300 grades by SAIL, Tata Steel, and JSW Steel. They are stocked in 6-metre, 9-metre, and 12-metre standard lengths at steel stockyards across India. ISMB 200, ISMB 250, and ISMB 300 are high-volume stock items; larger sizes such as ISMB 500 and ISMB 600 are typically sourced on indent from primary mills.

ISMB Weight Formula

Formula: Weight (kg) = Weight per metre (kg/m) × Length (m)

Weight per metre (kg/m)

Tabulated value from IS 808:1989 for the specific ISMB designation — use the chart below

Length (m)

Actual cut length of the piece in metres

Result

Total weight of the piece in kg; divide by 1,000 for tonnes

The kg/m values in IS 808:1989 are computed from the exact cross-sectional area (accounting for root and flange toe radii) multiplied by steel density 7,850 kg/m³. Do not use the simple rectangular formula — it overestimates because it ignores the radii.

ISMB Weight Chart — IS 808:1989

All values per IS 808:1989 (Reaffirmed 2001). Mass tolerance: ±2.5% per piece per IS 808. Click any designation for full sectional properties including I_xx, Z_xx, r_xx.

6-Metre Length Weight Reference

Standard stock length in India is 6 metres. The table below gives the weight of one 6-metre piece for each ISMB size — useful for freight and crane lift planning. For full sectional properties of the heavier sizes used in such lifts, see the ISMB 400, ISMB 500, and ISMB 600 reference pages.

Weights calculated as kg/m × length. Apply IS 808:1989 mass tolerance of ±2.5% for procurement allowance.

How to Choose the Right ISMB Size

ISMB sections are selected by structural engineers based on bending moment and shear requirements, not by weight alone. For a given span and load, the required section modulus Z_xx determines the minimum ISMB designation. A few practical rules from Indian fabrication practice:

ISMB 200 is the standard size for mezzanine secondary beams at 3-metre spans with 300 kg/m² live load. ISMB 250 handles the same load at 4-metre spans and is the most common primary beam in light industrial mezzanines. ISMB 300 and ISMB 350 are typical for crane runway girders up to 5-tonne SWL. ISMB 450 and above are used for heavy crane girders, long-span industrial roofs, and transfer beams.

Worked Example

A fabricator in Pune is procuring steel for an industrial mezzanine: 12 primary beams of ISMB 300, each 7.5 m long. Total length = 12 × 7.5 = 90 m. Weight = 90 × 46.1 = 4,149 kg (4.149 tonnes). At ₹60,000 per tonne (June 2026 indicative rate), estimated material cost is approximately ₹2,48,940. Add 2.5% for IS 808 mass tolerance on the procurement quantity: order for 4,253 kg minimum. If modifying the design for different spans, check the complete properties on the ISMB 250 or ISMB 350 reference pages.