I-beam — 66.31 kg per metre, 84.4 cm² cross-sectional area. IS 808 Table 3 - Narrow Parallel Flange Beams.
Narrow Parallel Flange Beams (NPB). Reproduced as printed in IS 808 Table 3 - Narrow Parallel Flange Beams.
As printed in IS 808 Table 3 - Narrow Parallel Flange Beams. 400 mm deep, 180 mm wide. Units are shown on every row, because the two standards on this site use different ones for the radius of gyration.
| Depth of section D | 400 | mm |
|---|---|---|
| Width of flange B | 180 | mm |
| Thickness of web t | 8.6 | mm |
| Thickness of flange T | 13.5 | mm |
| Flange slope | 90 | ° |
| Root radius R1 | 21 | mm |
| Toe radius R2 | 0 | mm |
| Mass per metre M | 66.31 | kg/m |
|---|---|---|
| Sectional area A | 84.4 | cm² |
| Second moment of area Izz | 23,100 | cm⁴ |
|---|---|---|
| Radius of gyration rzz | 165 | mm |
| Elastic section modulus Zzz | 1,150 | cm³ |
| Plastic section modulus Zpz | 1,300 | cm³ |
| Second moment of area Iyy | 1,310 | cm⁴ |
|---|---|---|
| Radius of gyration ryy | 39.5 | mm |
| Elastic section modulus Zyy | 146 | cm³ |
| Plastic section modulus Zpy | 229 | cm³ |
| Torsion constant (St Venant) It | 51.3 | cm⁴ |
|---|---|---|
| Warping constant Iw | 4,90,000 | cm⁶ |
Total weight is the mass per metre multiplied by the length and the number of pieces. Ten pieces of NPB 400 × 180 at six metres each is 66.31 × 6 × 10 = 3,979 kg. There is nothing else to it — the standard publishes the mass, so no one needs to compute it from the area.
You can check that mass against the area on this page: 84.4 cm² of steel at 7 850 kg/m³ is 66.25 kg/m. Every row in this dataset was checked that way, which is how the contradictions flagged on some of these pages were found.
Work it out for your own lengths and quantities →
IS 808 : 2021 gives NPB 400 × 180 a mass of 66.31 kg per metre. Its printed cross-sectional area of 84.4 cm² agrees: 84.4 cm² of steel at 7 850 kg/m³ works out at 66.25 kg per metre.
397.86 kg. Mass per metre times length: 66.31 × 6. Ten such pieces come to 3979 kg.
400 mm deep and 180 mm wide, with a 8.6 mm web and 13.5 mm flanges.
Free to browse. Log in to unlock the full Rate Analysis of every Civil and Electrical item in the latest CPWD DSR.
Log in to QuickBOQ →Where these figures come from. IS 808 Table 3 - Narrow Parallel Flange Beams Section properties are facts published in the standards, and they are reproduced here as printed. Where a standard contradicts itself, both of its figures are shown and neither is corrected.
What is ours. The selection and arrangement of these tables, the checks run against them, and the findings those checks produced — which rows disagree with themselves, which figures were superseded by amendment, and which could not be read — are QuickBOQ’s work, and so is this wording. Quote the numbers freely; they belong to everyone. Copying the compilation and the commentary is a different thing, and we would rather you linked to it.