Quick Answer
Quick Answer
IS 808 is the Bureau of Indian Standards specification for the dimensions and section properties of hot-rolled structural steel sections — beams (ISMB, ISLB, ISWB), column sections (ISHB), channels (ISMC, ISSC), and equal/unequal angles (ISA). It defines depth, flange width, web and flange thicknesses, cross-sectional area, moment of inertia, and radius of gyration for each section designation.
IS 808 (currently IS 808:1989 with amendments) is published by the Bureau of Indian Standards (BIS) and provides the dimensional and section property data for hot-rolled structural steel sections manufactured and used in India. The standard covers the complete geometry of each section designation, enabling structural engineers to perform member design calculations under IS 800 (the Indian steel design code). Material for sections is typically IS 2062 E250, though higher grades (E350, E410) are available on order for special applications. IS 808 is cited in IS 800 and is used in conjunction with IS 2062 for specifying structural steelwork.
Scope and Applicability
IS 808 covers the following section families:
- ISMB — Indian Standard Medium Weight Beam
- ISLB — Indian Standard Light Weight Beam
- ISWB — Indian Standard Wide Flange Beam
- ISHB — Indian Standard Heavy Weight (H-) Column section
- ISMC — Indian Standard Medium Weight Channel
- ISSC — Indian Standard Standard Channel (lighter than ISMC)
- ISA — Indian Standard Angle (equal and unequal legs)
- ISNT / ISST — T-sections (limited range)
The standard does not cover hollow sections (IS 4923 / IS 12778), cold-formed sections (IS 811), or plates and strips (IS 2062).
Grade Coverage
IS 808 defines geometry only. The material standard is IS 2062. Default material grade:
| Application | Default Grade | Common Higher Grade |
|---|---|---|
| General structures | IS 2062 E250A/B | IS 2062 E350A/B |
| Long-span beams, bridges | IS 2062 E300B | IS 2062 E410B |
| Columns in tall buildings | IS 2062 E350A | IS 2062 E410A |
BIS mandatory certification applies to both the section geometry (per IS 808 rolling tolerances) and the base material (IS 2062).
ISMB — Medium Weight Beams: Section Properties
| Designation | Depth d (mm) | Flange Width b (mm) | Web Thick. tw (mm) | Flange Thick. tf (mm) | Area A (cm²) | Ixx (cm⁴) | Iyy (cm⁴) | rxx (cm) | ryy (cm) |
|---|---|---|---|---|---|---|---|---|---|
| ISMB 100 | 100 | 75 | 4.0 | 7.2 | 14.60 | 257 | 49.5 | 4.20 | 1.84 |
| ISMB 125 | 125 | 75 | 4.4 | 7.6 | 16.60 | 449 | 55.6 | 5.20 | 1.83 |
| ISMB 150 | 150 | 80 | 4.8 | 7.6 | 19.00 | 726 | 72.4 | 6.18 | 1.95 |
| ISMB 175 | 175 | 90 | 5.5 | 8.6 | 24.62 | 1264 | 123.0 | 7.16 | 2.24 |
| ISMB 200 | 200 | 100 | 5.7 | 10.8 | 32.33 | 2235 | 150.0 | 8.31 | 2.16 |
| ISMB 225 | 225 | 110 | 6.5 | 11.8 | 39.72 | 3441 | 218.0 | 9.31 | 2.34 |
| ISMB 250 | 250 | 125 | 6.9 | 12.5 | 47.55 | 5131 | 334.0 | 10.39 | 2.65 |
| ISMB 300 | 300 | 140 | 7.7 | 12.4 | 56.26 | 8603 | 453.0 | 12.37 | 2.84 |
| ISMB 350 | 350 | 140 | 8.1 | 14.2 | 66.71 | 13630 | 538.0 | 14.29 | 2.84 |
| ISMB 400 | 400 | 140 | 8.9 | 16.0 | 78.46 | 20460 | 622.0 | 16.16 | 2.82 |
| ISMB 450 | 450 | 150 | 9.4 | 17.4 | 92.27 | 30390 | 834.0 | 18.15 | 3.01 |
| ISMB 500 | 500 | 180 | 10.2 | 17.2 | 110.74 | 45220 | 1370.0 | 20.20 | 3.52 |
| ISMB 550 | 550 | 190 | 11.2 | 19.3 | 132.11 | 64900 | 1830.0 | 22.17 | 3.72 |
| ISMB 600 | 600 | 210 | 12.0 | 20.8 | 156.21 | 91800 | 2650.0 | 24.24 | 4.12 |
ISLB — Light Weight Beams: Section Properties
| Designation | Depth d (mm) | Flange Width b (mm) | Web Thick. tw (mm) | Flange Thick. tf (mm) | Area A (cm²) | Ixx (cm⁴) | Iyy (cm⁴) | rxx (cm) | ryy (cm) |
|---|---|---|---|---|---|---|---|---|---|
| ISLB 100 | 100 | 50 | 4.0 | 6.8 | 10.36 | 168 | 14.7 | 4.02 | 1.19 |
| ISLB 150 | 150 | 80 | 4.8 | 6.8 | 17.01 | 688 | 55.1 | 6.36 | 1.80 |
| ISLB 200 | 200 | 100 | 5.4 | 9.0 | 27.50 | 2100 | 115.0 | 8.74 | 2.04 |
| ISLB 250 | 250 | 125 | 6.1 | 9.7 | 36.67 | 4568 | 255.0 | 11.17 | 2.64 |
| ISLB 300 | 300 | 150 | 6.7 | 9.4 | 46.50 | 9240 | 534.0 | 14.09 | 3.39 |
| ISLB 350 | 350 | 165 | 7.2 | 11.4 | 58.25 | 17200 | 851.0 | 17.19 | 3.82 |
| ISLB 400 | 400 | 165 | 8.0 | 12.5 | 65.81 | 26340 | 858.0 | 20.00 | 3.61 |
| ISLB 450 | 450 | 170 | 8.6 | 13.4 | 75.26 | 38550 | 1040.0 | 22.63 | 3.72 |
| ISLB 500 | 500 | 180 | 9.2 | 14.1 | 86.27 | 55200 | 1210.0 | 25.29 | 3.75 |
| ISLB 550 | 550 | 190 | 9.9 | 15.0 | 99.46 | 78700 | 1490.0 | 28.15 | 3.87 |
| ISLB 600 | 600 | 210 | 10.5 | 15.5 | 115.62 | 108100 | 1950.0 | 30.58 | 4.11 |
ISHB — Heavy (H-) Column Sections: Section Properties
ISHB sections have nearly equal flange and depth dimensions, making them efficient column sections.
| Designation | Depth d (mm) | Flange Width b (mm) | Web Thick. tw (mm) | Flange Thick. tf (mm) | Area A (cm²) | Ixx (cm⁴) | Iyy (cm⁴) | rxx (cm) | ryy (cm) |
|---|---|---|---|---|---|---|---|---|---|
| ISHB 150 | 150 | 150 | 5.4 | 9.0 | 34.48 | 1395 | 493.0 | 6.36 | 3.78 |
| ISHB 200 | 200 | 200 | 6.1 | 9.0 | 47.54 | 3613 | 967.0 | 8.72 | 4.51 |
| ISHB 225 | 225 | 225 | 6.5 | 9.9 | 56.11 | 5593 | 1539.0 | 9.98 | 5.24 |
| ISHB 250 | 250 | 250 | 6.9 | 9.7 | 64.96 | 8106 | 2276.0 | 11.17 | 5.92 |
| ISHB 300 @0.577 kg | 300 | 250 | 7.6 | 10.6 | 74.84 | 13173 | 2194.0 | 13.27 | 5.41 |
| ISHB 300 @0.630 kg | 300 | 250 | 8.4 | 12.4 | 80.25 | 14952 | 2523.0 | 13.66 | 5.61 |
| ISHB 350 @0.634 kg | 350 | 250 | 7.4 | 11.6 | 80.60 | 21878 | 2366.0 | 16.47 | 5.42 |
| ISHB 350 @0.724 kg | 350 | 250 | 8.3 | 13.7 | 92.21 | 25385 | 2787.0 | 16.59 | 5.50 |
| ISHB 400 @0.721 kg | 400 | 250 | 8.0 | 12.7 | 91.80 | 35153 | 2561.0 | 19.57 | 5.28 |
| ISHB 400 @0.806 kg | 400 | 250 | 9.0 | 14.7 | 102.65 | 40284 | 2942.0 | 19.81 | 5.35 |
| ISHB 450 @0.794 kg | 450 | 250 | 8.6 | 13.7 | 101.12 | 51644 | 2769.0 | 22.60 | 5.23 |
| ISHB 450 @0.907 kg | 450 | 250 | 10.0 | 16.0 | 115.51 | 60440 | 3200.0 | 22.87 | 5.26 |
ISMC — Medium Weight Channels: Section Properties
| Designation | Depth d (mm) | Flange Width b (mm) | Web Thick. tw (mm) | Flange Thick. tf (mm) | Area A (cm²) | Ixx (cm⁴) | Iyy (cm⁴) | rxx (cm) | ryy (cm) |
|---|---|---|---|---|---|---|---|---|---|
| ISMC 75 | 75 | 40 | 4.4 | 7.3 | 8.68 | 73.8 | 10.8 | 2.91 | 1.11 |
| ISMC 100 | 100 | 50 | 4.7 | 7.5 | 11.70 | 186 | 26.2 | 3.99 | 1.50 |
| ISMC 125 | 125 | 65 | 5.0 | 8.1 | 16.19 | 416 | 60.0 | 5.07 | 1.93 |
| ISMC 150 | 150 | 75 | 5.4 | 9.0 | 20.88 | 779 | 103.0 | 6.11 | 2.22 |
| ISMC 175 | 175 | 75 | 5.7 | 10.2 | 24.38 | 1260 | 114.0 | 7.19 | 2.17 |
| ISMC 200 | 200 | 75 | 6.1 | 11.4 | 28.21 | 1819 | 122.0 | 8.03 | 2.08 |
| ISMC 225 | 225 | 80 | 6.4 | 12.4 | 33.00 | 2773 | 157.0 | 9.16 | 2.18 |
| ISMC 250 | 250 | 82 | 6.9 | 14.1 | 38.67 | 4081 | 188.0 | 10.27 | 2.20 |
| ISMC 300 | 300 | 90 | 7.8 | 13.6 | 46.30 | 6362 | 263.0 | 11.72 | 2.38 |
| ISMC 350 | 350 | 100 | 8.1 | 13.5 | 53.66 | 10010 | 356.0 | 13.66 | 2.58 |
| ISMC 400 | 400 | 100 | 8.6 | 15.3 | 60.38 | 15083 | 385.0 | 15.80 | 2.53 |
ISA — Equal Leg Angles: Section Properties
| Designation | Leg Size (mm) | Thickness (mm) | Area A (cm²) | Ixx = Iyy (cm⁴) | rxx = ryy (cm) | ruu (cm) | rvv (cm) |
|---|---|---|---|---|---|---|---|
| ISA 45×45×5 | 45 | 5 | 4.28 | 6.59 | 1.24 | 1.57 | 0.80 |
| ISA 50×50×5 | 50 | 5 | 4.80 | 9.17 | 1.38 | 1.74 | 0.89 |
| ISA 50×50×6 | 50 | 6 | 5.69 | 10.71 | 1.37 | 1.73 | 0.88 |
| ISA 60×60×6 | 60 | 6 | 6.91 | 18.80 | 1.65 | 2.08 | 1.07 |
| ISA 65×65×6 | 65 | 6 | 7.50 | 24.00 | 1.79 | 2.26 | 1.16 |
| ISA 75×75×6 | 75 | 6 | 8.72 | 37.60 | 2.08 | 2.62 | 1.35 |
| ISA 75×75×8 | 75 | 8 | 11.42 | 48.50 | 2.06 | 2.60 | 1.33 |
| ISA 90×90×8 | 90 | 8 | 13.88 | 85.30 | 2.48 | 3.12 | 1.61 |
| ISA 100×100×8 | 100 | 8 | 15.48 | 118.0 | 2.76 | 3.48 | 1.79 |
| ISA 100×100×10 | 100 | 10 | 19.20 | 144.0 | 2.74 | 3.46 | 1.78 |
| ISA 110×110×10 | 110 | 10 | 21.20 | 193.0 | 3.01 | 3.80 | 1.95 |
| ISA 130×130×10 | 130 | 10 | 25.20 | 321.0 | 3.57 | 4.50 | 2.31 |
| ISA 150×150×12 | 150 | 12 | 35.10 | 630.0 | 4.24 | 5.34 | 2.75 |
| ISA 200×200×15 | 200 | 15 | 58.50 | 1970.0 | 5.80 | 7.31 | 3.76 |
ruu = radius of gyration about major principal axis; rvv = about minor principal axis.
ISWB — Wide Flange Beams: Section Properties
| Designation | Depth d (mm) | Flange Width b (mm) | Web Thick. tw (mm) | Flange Thick. tf (mm) | Area A (cm²) | Ixx (cm⁴) | Iyy (cm⁴) | rxx (cm) | ryy (cm) |
|---|---|---|---|---|---|---|---|---|---|
| ISWB 150 | 150 | 100 | 5.4 | 9.0 | 26.67 | 1010 | 154.0 | 6.16 | 2.40 |
| ISWB 200 | 200 | 140 | 6.1 | 9.0 | 36.71 | 2635 | 422.0 | 8.47 | 3.39 |
| ISWB 250 | 250 | 200 | 6.7 | 9.7 | 53.60 | 7055 | 1296.0 | 11.47 | 4.92 |
| ISWB 300 | 300 | 200 | 7.4 | 10.0 | 61.33 | 12581 | 1340.0 | 14.31 | 4.67 |
| ISWB 350 | 350 | 200 | 8.0 | 11.4 | 72.63 | 21441 | 1418.0 | 17.19 | 4.42 |
| ISWB 400 | 400 | 200 | 8.6 | 13.0 | 85.11 | 34770 | 1507.0 | 20.20 | 4.21 |
| ISWB 450 | 450 | 200 | 9.2 | 15.4 | 99.63 | 54510 | 1600.0 | 23.38 | 4.01 |
| ISWB 500 | 500 | 250 | 9.9 | 14.7 | 118.46 | 79690 | 2988.0 | 25.94 | 5.02 |
| ISWB 550 | 550 | 250 | 10.5 | 17.6 | 142.28 | 120860 | 3620.0 | 29.17 | 5.05 |
| ISWB 600 | 600 | 250 | 11.2 | 21.3 | 170.38 | 175700 | 4490.0 | 32.12 | 5.13 |
Additional Tests and Requirements
Rolling Tolerances
IS 808 specifies tolerances on:
- Depth: ±2 mm for sections up to 200 mm depth; ±3 mm for larger sections
- Flange width: ±3 mm
- Web thickness: +1.5 mm / −0.5 mm
- Flange thickness: +1.5 mm / −0.5 mm
- Straightness (camber): 1/1000 of length
- Twist: 1°/m length
Mass Tolerance
Sections must be within ±2.5% of the theoretical mass per metre (for beams and columns); ±3.5% for angles and channels.
Cross-Standard Equivalents
| IS 808 Section | EN 10034 Equivalent | AISC (USA) Approximate | JIS G 3192 Approximate |
|---|---|---|---|
| ISMB 200 | IPE 200 | W8×10 | H-200×100×5.5×8 |
| ISMB 300 | IPE 300 | W12×22 | H-300×150×6.5×9 |
| ISMB 400 | IPE 400 | W16×26 | H-400×150×8×13 |
| ISMB 500 | IPE 500 | W20×35 | H-500×200×10×16 |
| ISHB 250 | HE 240B | W10×49 | H-250×250×9×14 |
| ISMC 200 | UPN 200 | C8×11.5 | [C]-200×80×7.5×11 |
Equivalences are dimensional approximations only. Section moduli and weights differ; always check section tables before substituting.
MTC Verification Checklist
For IS 808 sections (combined with IS 2062 material), confirm:
- Section designation stated clearly (e.g., ISMB 300 IS 808)
- Material grade stated (e.g., IS 2062 E250B)
- BIS licence number of the rolling mill present on MTC
- Heat number traceable to section bundle/end-markings
- Chemical analysis and mechanical properties (per IS 2062) within grade limits
- Section mass per metre within tolerance (±2.5% for beams/columns)
- Rolling tolerances on depth, flange width, web thickness stated as satisfactory
- Tensile test per IS 1608; sample cut from same heat as supplied sections
Frequently Asked Questions
What is the difference between ISMB, ISLB, and ISWB beams?
All three are I-section beams but with different proportions. ISLB (Light Weight Beam) has the narrowest flanges relative to depth and the lightest mass per metre — economical for lightly loaded spans. ISMB (Medium Weight Beam) has intermediate proportions and is the most common general-purpose beam in India. ISWB (Wide Flange Beam) has significantly wider flanges, giving better lateral stability and higher weak-axis (Iyy) moment of inertia — preferred where lateral buckling governs or where beams frame into connections from both sides.
Why are ISHB sections preferred for columns over ISMB?
ISHB sections have nearly equal depth and flange width, producing similar radii of gyration about both axes (rxx ≈ ryy ratio closer to 1). Columns loaded in compression buckle about the weak axis; a section with nearly equal rxx and ryy is efficient because both axes have similar buckling resistance. ISMB sections have rxx >> ryy, meaning the weak axis governs heavily, wasting material capacity about the strong axis. ISHB sections also have heavier flanges relative to web, providing better compression stability and easier bolted connections.
Can IS 808 sections be supplied in IS 2062 E350 grade?
Yes. IS 808 defines geometry only; the material grade is specified separately as IS 2062. Higher grades (E300, E350, E410) are available from major steel mills in India for beams and columns, subject to rolling programme availability. For standard stock items (ISMB 200–400, ISMC 100–250), E250A/B is typically ex-stock; E350 sections are usually ordered to schedule. The MTC must clearly state both IS 808 (section designation) and IS 2062 (grade and sub-grade).
How is the section modulus calculated from IS 808 data?
The elastic section modulus Zxx = Ixx / (d/2), where Ixx is the second moment of area about the major axis and d is the total depth. For example, ISMB 300: Zxx = 8603 / (300/2) = 8603 / 150 = 57.4 cm³. The plastic section modulus Zpxx = Zxx × shape factor; for I-sections the shape factor is approximately 1.12–1.17. IS 800 (the design code) requires both elastic and plastic moduli for limit-state design; IS 808 tabulates both in its full section property tables.
Are ISWB sections equivalent to European wide-flange (HE or IPE) sections?
ISWB sections have wider flanges than IPE sections of the same depth, making them closer to the European HE series. However, the flange and web thicknesses differ, and the fillet radius geometry is not identical. They are not directly interchangeable on a designation basis; each section must be individually checked against project drawings. When substituting, verify that the section modulus, moment of inertia, and mass per metre all meet the design requirement.
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