ISMB 100 weight and dimensions
8.95 kg/m · 6.01 lb/ft
ISMB 100 is a 100 mm deep beam with a 50 mm flange, 4.7 mm web and 7 mm flange thickness. It weighs 8.95 kg per metre (6.01 lb/ft). It belongs to the ISMB medium weight beam series, Indian Standard (IS 808).
Many weight charts list ISMB 100 as 11.5 kg/m. That figure comes from the 1964 ISI handbook. The current standard, IS 808:2021, gives 8.95 kg/m (IS 808:1989: 8.9 kg/m).
ISMB 100 weight calculator
Weight of standard lengths
| Pieces | 6 m each (kg) | 12 m each (kg) |
|---|---|---|
| 1 | 53.7 | 107.4 |
| 5 | 268.5 | 537.0 |
| 10 | 537.0 | 1,074.0 |
| 20 | 1,074.0 | 2,148.0 |
| 50 | 2,685.0 | 5,370.0 |
Pieces per tonne
| 6 m lengths per metric tonne | 18.6 |
| 12 m lengths per metric tonne | 9.3 |
| Length per tonne | 111.7 m |
Useful for converting a tonnage order into a number of bars.
Surface area for painting
| Per metre of length | 0.375 m²/m |
| Per foot of length | 1.23 ft²/ft |
| Per tonne of steel | 41.9 m²/t |
| A 12 m length | 4.50 m² |
Outside perimeter × length, all faces, calculated from the dimensions. Use it to estimate paint, primer, fireproofing or galvanizing quantities.
Cross-section
Drawn to scale. Dimensions in mm.
Dimensions
| Depth h | 100 mm | 3.937 in |
| Flange width b | 50 mm | 1.969 in |
| Web thickness tw | 4.7 mm | 0.185 in |
| Flange thickness tf | 7 mm | 0.276 in |
| Root radius r | 9 mm | 0.354 in |
| Toe radius r2 | 4.5 mm | 0.177 in |
| Flange slope (deg) | 98° | |
| Mass | 8.95 kg/m | 6.01 lb/ft |
Section properties
| Property | Value | Unit |
|---|---|---|
| Area | 11.40 | cm² |
| Moment of inertia Ix | 182 | cm⁴ |
| Moment of inertia Iy | 12.50 | cm⁴ |
| Elastic modulus Zx | 36.40 | cm³ |
| Elastic modulus Zy | 5.01 | cm³ |
| Plastic modulus Zpx | 42.60 | cm³ |
| Plastic modulus Zpy | 8.58 | cm³ |
| Radius of gyration rx | 3.99 | cm |
| Radius of gyration ry | 1.04 | cm |
| Torsion constant J | 2.15 | cm⁴ |
Equivalent sections in other standards
The closest sections by depth and weight. They are not direct substitutes: check bending, buckling and connection details before swapping one for another.
ISMB 100 and its closest equivalents, drawn over each other at the same scale.
| Section | Standard | Depth (mm) | kg/m | Weight vs ISMB 100 |
|---|---|---|---|---|
| ISMB 100 | IS | 100 | 8.95 | — |
| IPE 100 | EN | 100 | 8.10 | -9.5% |
| M4x6 | AISC | 96.5 | 8.90 | -0.6% |
| S4x7.7 | AISC | 102 | 11.50 | +28.5% |
ISMB series weights
Next heavier: ISMB 125 (13.35 kg/m).
Stiffness and strength per kilogram
The elastic section modulus Zx governs bending strength. Dividing it by the weight shows how efficiently each size uses its steel: higher is better when weight is the cost driver.
| Section | kg/m | Ix (cm⁴) | Zx (cm³) | Zx per kg/m |
|---|---|---|---|---|
| ISMB 100 | 8.95 | 182 | 36.4 | 4.07 |
| ISMB 125 | 13.35 | 445 | 71.3 | 5.34 |
| ISMB 150 | 14.96 | 718 | 95.7 | 6.40 |
| ISMB 175 | 19.50 | 1,260 | 144.0 | 7.38 |
Full table: ISMB weight chart (PDF).
How the weight is calculated
Mass per metre = cross-sectional area × density of steel = 11.40 cm² × 0.785 kg/(cm²·m) = 8.95 kg/m.
Rolled sections are made to a nominal mass, and the actual mass can differ by a few percent within the tolerances of IS 1852. For purchasing, invoicing by weight or checking deliveries, use the producer's stated mass.
Typical uses
Beams of this shape are used as floor and roof beams, lintels, crane girders and frame members, where bending about the strong axis governs.
Frequently asked questions
What is the weight of ISMB 100 per metre?
ISMB 100 weighs 8.95 kg/m, which is 6.01 lb/ft.
How much does a 6 m or 12 m length of ISMB 100 weigh?
A 6 m length weighs about 53.7 kg and a 12 m length about 107.4 kg.
Why do some weight charts show 11.5 kg/m for ISMB 100?
11.5 kg/m is the value in the 1964 ISI handbook SP 6(1). IS 808 was revised in 1989 and the section dimensions changed; IS 808:2021 gives 8.95 kg/m. Many charts still copy the old figure, so confirm which standard your supplier rolls to.
What is the equivalent of ISMB 100 in other standards?
By depth and weight the closest match is IPE 100 (8.1 kg/m, 100 mm deep). Check section properties before substituting one for the other.
Source: IS 808:2021; earlier values from IS 808:1989 and SP 6(1):1964. Values are nominal; verify with the producer before ordering.