Steel Channel ISMC Weight Chart & Properties — IS 808
ISMC (Indian Standard Medium Channel) sections are the workhorse of purlins, bracings, staircase stringers, and light framing. Their C-shape allows easy one-sided bolt connections, making them ideal for secondary structural members. This article provides the complete weight chart for all ISMC sections as per IS 808:2021.
Most Commonly Used: ISMC 150 (16.4 kg/m) for purlins, ISMC 200 (22.1 kg/m) for staircase stringers, and ISMC 100 (9.2 kg/m) for light bracings and window frames.
ISMC Weight Chart — All Sizes
| Section | Depth (mm) | Flange Width (mm) | Web (mm) | Flange (mm) | Weight (kg/m) | Wt/6m (kg) | Area (cm²) | Ixx (cm⁴) | Zxx (cm³) |
|---|---|---|---|---|---|---|---|---|---|
| ISMC 75 | 75 | 40 | 4.8 | 7.5 | 7.1 | 42.6 | 9.1 | 108.5 | 28.9 |
| ISMC 100 | 100 | 50 | 5.0 | 7.5 | 9.2 | 55.2 | 11.7 | 259.9 | 52.0 |
| ISMC 125 | 125 | 65 | 5.3 | 8.1 | 12.7 | 76.2 | 16.19 | 541.2 | 86.6 |
| ISMC 150 | 150 | 75 | 5.7 | 9.0 | 16.4 | 98.4 | 20.88 | 1025.1 | 136.7 |
| ISMC 175 | 175 | 75 | 6.0 | 10.2 | 19.1 | 114.6 | 24.38 | 1618.3 | 184.9 |
| ISMC 200 | 200 | 75 | 6.2 | 11.4 | 22.1 | 132.6 | 28.19 | 2420.7 | 242.1 |
| ISMC 225 | 225 | 80 | 6.4 | 12.4 | 25.9 | 155.4 | 33.01 | 3568.6 | 317.2 |
| ISMC 250 | 250 | 80 | 7.2 | 14.1 | 30.4 | 182.4 | 38.67 | 5131.6 | 410.5 |
| ISMC 300 | 300 | 90 | 7.6 | 13.6 | 35.8 | 214.8 | 45.64 | 8603.6 | 573.6 |
| ISMC 350 | 350 | 100 | 8.1 | 13.5 | 42.1 | 252.6 | 53.66 | 13630.3 | 778.9 |
| ISMC 400 | 400 | 100 | 8.6 | 15.3 | 49.4 | 296.4 | 62.93 | 20458.4 | 1022.9 |
ISMC Purlin Selection Guide
Channels are the most common purlin section in India. For typical industrial sheds with metal roofing:
| Purlin Span (m) | Recommended ISMC | Weight (kg/m) | Notes |
|---|---|---|---|
| 3.0 – 3.5 | ISMC 100 | 9.2 | Light roofing (GI sheet) |
| 3.5 – 4.5 | ISMC 125 | 12.7 | Standard industrial shed |
| 4.5 – 6.0 | ISMC 150 | 16.4 | Heavy roofing, moderate wind |
| 6.0 – 7.5 | ISMC 200 | 22.1 | Large span, heavy equipment loads |
Note: These are approximate guidelines. Actual purlin design depends on wind load (IS 875 Part 3), roofing weight, spacing, and connection type.
Common ISMC Applications
- Roof purlins — ISMC 100 to 200, bolted to rafter top flanges at 1.2–1.8m spacing
- Wall girts — ISMC 100 to 150, horizontal supports for wall cladding
- Staircase stringers — ISMC 200 to 300, C-shape hides connections and provides clean finish
- Back-to-back channels — Two ISMCs welded back-to-back form a light column or beam section
- Crane runway brackets — ISMC 150 to 250 as brackets supporting crane rails
- Door/window frames — ISMC 75 to 125 in industrial buildings
ISMC vs ISMB — When to Use Channels
Channels are NOT a substitute for beams. Key differences:
| Property | ISMC (Channel) | ISMB (Beam) |
|---|---|---|
| Cross-section | C-shape (unsymmetric) | I-shape (symmetric) |
| Shear centre | Outside the web — tends to twist | At centroid — no twist |
| Connection | Easy one-sided bolting | Requires both sides |
| Best for | Purlins, girts, secondary members | Primary beams, lintels |
| Lateral stability | Poor — needs lateral bracing | Better than channel |
Weight Calculation Example
Industrial shed with 20 purlins of ISMC 150, 6m span, 1.5m spacing:
20 purlins × 6m × 16.4 kg/m = 1,968 kg (1.97 tonnes)
At ₹68/kg, purlin cost = ₹1,33,824
For the full interactive table with sorting and comparison, use the Steel Section Table. To calculate weight for multiple sections at once, use the Calculate mode in the bottom panel.