Home / For Designers / Rolled Metal Handbook: Sections, Mass of 1 m, Metres per Tonne / Surface Area of Rolled Metal: m² per Metre and per Tonne for Galvanizing and Painting
Rolled Metal Handbook: Sections, Mass of 1 m, Metres per Tonne
Surface Area of Rolled Metal: m² per Metre and per Tonne for Galvanizing and Painting
The tables give the surface area of I-beams, channels, angles and pipes: how many square metres fall on 1 m of section and on 1 tonne. The area is needed to estimate painting or galvanizing of a steel structure. The GOST designations in this article are former standards: most of them have been withdrawn in Ukraine, so check the sizes against the project requirements.
Contents
Why the surface area matters
Hot-dip galvanizing is usually priced by the mass of the part, while powder coating depends on the surface to be covered. The area is also needed to estimate paint consumption and to compare sections: a thin-walled pipe and a solid bar of the same mass have different surfaces.
The area is given below in two ways: in square metres per 1 m of section length and per tonne. The second is handy when the mass of a structure is known from the metal weight calculator or a specification.
How the area is calculated
The surface area of 1 m of section equals the perimeter of its cross-section outline times 1 m. Ends are not counted. Nominal dimensions are used; fillet radii and the slope of inner flange faces of rolled sections are ignored, so the error does not exceed 1–2 %.
For simple sections the formulas are as follows. Round bar and rebar: π·d. Square bar: 4·a. Hexagon bar across flats s: 3.46·s. Flat bar b×t: 2·(b + t). Equal-leg angle with leg b: 4·b. Unequal-leg angle a×b: 2·(a + b). Channel: 2·h + 4·b − 2·s. I-beam: 4·b + 2·h − 2·s. A sheet is covered on both sides, so 1 m² of sheet has 2 m² of surface.
For a round pipe the outer surface is π·D and the inner one π·(D − 2·s). For a square or rectangular tube of a×b with wall t the outer perimeter is 2·(a + b) minus an allowance for the rounded corners; the inner one is taken at the wall reduced on both sides.
I-beams and channels
The tables give the area of one surface of the section, the outer outline. A No. 20 I-beam, for example, has 0.79 m² per metre, and a tonne of such I-beam has about 37.6 m².
I-beams: surface area · ГОСТ 8239-89 (former)
| Section | Mass of 1 m, kg | Area of 1 m, m² | Per tonne, m² |
|---|---|---|---|
| 10 | 9.46 | 0.411 | 43.4 |
| 12 | 11.5 | 0.486 | 42.3 |
| 14 | 13.7 | 0.562 | 41 |
| 16 | 15.9 | 0.634 | 39.9 |
| 18 | 18.4 | 0.71 | 38.6 |
| 18a | 19.9 | 0.75 | 37.7 |
| 20 | 21 | 0.79 | 37.6 |
| 20a | 22.7 | 0.83 | 36.5 |
| 22 | 24 | 0.869 | 36.2 |
| 22a | 25.8 | 0.909 | 35.2 |
| 24 | 27.3 | 0.929 | 34 |
| 24a | 29.4 | 0.969 | 33 |
| 27 | 31.5 | 1.028 | 32.6 |
| 27a | 33.9 | 1.068 | 31.5 |
| 30 | 36.5 | 1.127 | 30.9 |
| 30a | 39.2 | 1.167 | 29.8 |
| 33 | 42.2 | 1.206 | 28.6 |
| 36 | 48.6 | 1.285 | 26.4 |
| 40 | 57 | 1.403 | 24.6 |
| 45 | 66.5 | 1.522 | 22.9 |
| 50 | 78.6 | 1.66 | 21.1 |
| 55 | 92.6 | 1.798 | 19.4 |
| 60 | 108 | 1.936 | 17.9 |
Section is the I-beam number. Area of 1 m is the perimeter of the cross-section outline in m² per 1 m of length; per tonne is the same perimeter converted to a tonne by the mass of 1 m.
Channels: surface area · ГОСТ 8240-89 (former)
| Section | Mass of 1 m, kg | Area of 1 m, m² | Per tonne, m² |
|---|---|---|---|
| 5 | 4.84 | 0.219 | 45.3 |
| 6,5 | 5.9 | 0.265 | 44.9 |
| 8 | 7.05 | 0.311 | 44.1 |
| 10 | 8.59 | 0.375 | 43.7 |
| 12 | 10.4 | 0.438 | 42.2 |
| 14 | 12.3 | 0.502 | 40.8 |
| 16 | 14.2 | 0.566 | 39.9 |
| 16a | 15.3 | 0.582 | 38 |
| 18 | 16.3 | 0.63 | 38.6 |
| 18a | 17.4 | 0.646 | 37.1 |
| 20 | 18.4 | 0.694 | 37.7 |
| 22 | 21 | 0.757 | 36.1 |
| 24 | 24 | 0.829 | 34.5 |
| 27 | 27.7 | 0.908 | 32.8 |
| 30 | 31.8 | 0.987 | 31 |
| 33 | 36.5 | 1.066 | 29.2 |
| 36 | 41.9 | 1.145 | 27.3 |
| 40 | 48.3 | 1.244 | 25.8 |
| 6,5 | 5.9 | 0.265 | 44.9 |
Section is the channel number.
Angles
The area of an angle depends only on the leg widths and hardly on the thickness. That is why thinner angles have more square metres per tonne.
Equal-leg angles: surface area · ГОСТ 8509-93 (former)
| Section | Mass of 1 m, kg | Area of 1 m, m² | Per tonne, m² |
|---|---|---|---|
| L20×3 | 0.89 | 0.08 | 89.9 |
| L20×4 | 1.15 | 0.08 | 69.6 |
| L25×3 | 1.12 | 0.1 | 89.3 |
| L25×4 | 1.46 | 0.1 | 68.5 |
| L28×3 | 1.27 | 0.112 | 88.2 |
| L30×3 | 1.36 | 0.12 | 88.2 |
| L30×4 | 1.78 | 0.12 | 67.4 |
| L32×3 | 1.46 | 0.128 | 87.7 |
| L32×4 | 1.91 | 0.128 | 67 |
| L35×3 | 1.6 | 0.14 | 87.5 |
| L35×4 | 2.1 | 0.14 | 66.7 |
| L35×5 | 2.58 | 0.14 | 54.3 |
| L40×3 | 1.85 | 0.16 | 86.5 |
| L40×4 | 2.42 | 0.16 | 66.1 |
| L40×5 | 2.98 | 0.16 | 53.7 |
| L45×3 | 2.08 | 0.18 | 86.5 |
| L45×4 | 2.73 | 0.18 | 65.9 |
| L50×4 | 3.05 | 0.2 | 65.6 |
| L50×5 | 3.77 | 0.2 | 53.1 |
| L50×6 | 4.47 | 0.2 | 44.7 |
| L56×4 | 3.44 | 0.224 | 65.1 |
| L56×5 | 4.25 | 0.224 | 52.7 |
| L63×4 | 3.9 | 0.252 | 64.6 |
| L63×5 | 4.81 | 0.252 | 52.4 |
| L63×6 | 5.72 | 0.252 | 44.1 |
| L70×4.5 | 4.87 | 0.28 | 57.5 |
| L70×5 | 5.38 | 0.28 | 52 |
| L70×6 | 6.39 | 0.28 | 43.8 |
| L70×7 | 7.39 | 0.28 | 37.9 |
| L70×8 | 8.37 | 0.28 | 33.5 |
| L75×5 | 5.8 | 0.3 | 51.7 |
| L75×6 | 6.89 | 0.3 | 43.5 |
| L75×7 | 7.96 | 0.3 | 37.7 |
| L75×8 | 9.02 | 0.3 | 33.3 |
| L75×9 | 10.07 | 0.3 | 29.8 |
| L80×5.5 | 6.78 | 0.32 | 47.2 |
| L80×6 | 7.36 | 0.32 | 43.5 |
| L80×7 | 8.51 | 0.32 | 37.6 |
| L80×8 | 9.65 | 0.32 | 33.2 |
| L90×6 | 8.33 | 0.36 | 43.2 |
| L90×7 | 9.64 | 0.36 | 37.3 |
| L90×8 | 10.93 | 0.36 | 32.9 |
| L90×9 | 12.2 | 0.36 | 29.5 |
| L100×6.5 | 10.06 | 0.4 | 39.8 |
| L100×7 | 10.79 | 0.4 | 37.1 |
| L100×8 | 12.25 | 0.4 | 32.7 |
| L100×10 | 15.1 | 0.4 | 26.5 |
| L100×12 | 17.9 | 0.4 | 22.3 |
| L100×14 | 20.63 | 0.4 | 19.4 |
| L100×16 | 23.3 | 0.4 | 17.2 |
| L110×7 | 11.89 | 0.44 | 37 |
| L110×8 | 13.5 | 0.44 | 32.6 |
| L125×8 | 15.46 | 0.5 | 32.3 |
| L125×9 | 17.3 | 0.5 | 28.9 |
| L125×10 | 19.1 | 0.5 | 26.2 |
| L125×12 | 22.68 | 0.5 | 22 |
| L125×14 | 26.2 | 0.5 | 19.1 |
| L125×16 | 29.65 | 0.5 | 16.9 |
| L140×9 | 19.41 | 0.56 | 28.9 |
| L140×10 | 21.45 | 0.56 | 26.1 |
| L140×12 | 25.5 | 0.56 | 22 |
| L160×10 | 24.67 | 0.64 | 25.9 |
| L160×11 | 27.02 | 0.64 | 23.7 |
| L160×12 | 29.35 | 0.64 | 21.8 |
| L160×14 | 34.2 | 0.64 | 18.7 |
| L160×16 | 38.52 | 0.64 | 16.6 |
| L160×18 | 43.01 | 0.64 | 14.9 |
| L160×20 | 47.41 | 0.64 | 13.5 |
| L180×11 | 30.47 | 0.72 | 23.6 |
| L180×12 | 33.12 | 0.72 | 21.7 |
| L200×12 | 36.97 | 0.8 | 21.6 |
| L200×13 | 39.92 | 0.8 | 20 |
| L200×14 | 42.8 | 0.8 | 18.7 |
| L200×16 | 48.65 | 0.8 | 16.4 |
| L200×20 | 60.08 | 0.8 | 13.3 |
| L200×25 | 74.02 | 0.8 | 10.8 |
| L200×30 | 87.56 | 0.8 | 9.1 |
| L220×14 | 47.4 | 0.88 | 18.6 |
| L220×16 | 53.83 | 0.88 | 16.3 |
| L250×16 | 61.55 | 1 | 16.2 |
| L250×18 | 68.86 | 1 | 14.5 |
| L250×20 | 76.11 | 1 | 13.1 |
| L250×22 | 83.31 | 1 | 12 |
| L250×25 | 93.97 | 1 | 10.6 |
| L250×28 | 104.5 | 1 | 9.6 |
| L250×30 | 111.4 | 1 | 9 |
| L250×35 | 128.5 | 1 | 7.8 |
L is the angle designation: leg width and thickness, mm.
Unequal-leg angles: surface area · ГОСТ 8510-86 (former)
| Section | Mass of 1 m, kg | Area of 1 m, m² | Per tonne, m² |
|---|---|---|---|
| L25×16×3 | 0.91 | 0.082 | 90.1 |
| L30×20×3 | 1.12 | 0.1 | 89.3 |
| L30×20×4 | 1.46 | 0.1 | 68.5 |
| L32×20×3 | 1.17 | 0.104 | 88.9 |
| L32×20×4 | 1.52 | 0.104 | 68.4 |
| L40×25×3 | 1.48 | 0.13 | 87.8 |
| L40×25×4 | 1.94 | 0.13 | 67 |
| L40×25×5 | 2.37 | 0.13 | 54.9 |
| L40×30×4 | 2.1 | 0.14 | 66.7 |
| L40×30×5 | 2.57 | 0.14 | 54.5 |
| L45×28×3 | 1.68 | 0.146 | 86.9 |
| L45×28×4 | 2.2 | 0.146 | 66.4 |
| L50×32×3 | 1.9 | 0.164 | 86.3 |
| L50×32×4 | 2.49 | 0.164 | 65.9 |
| L56×36×4 | 2.81 | 0.184 | 65.5 |
| L56×36×5 | 3.46 | 0.184 | 53.2 |
| L63×40×4 | 3.17 | 0.206 | 65 |
| L63×40×5 | 3.91 | 0.206 | 52.7 |
| L63×40×6 | 4.63 | 0.206 | 44.5 |
| L63×40×8 | 6.03 | 0.206 | 34.2 |
| L65×50×5 | 4.36 | 0.23 | 52.8 |
| L65×50×6 | 5.18 | 0.23 | 44.4 |
| L65×50×7 | 5.98 | 0.23 | 38.5 |
| L65×50×8 | 6.77 | 0.23 | 34 |
| L70×45×5 | 4.39 | 0.23 | 52.4 |
| L75×50×5 | 4.79 | 0.25 | 52.2 |
| L75×50×6 | 5.69 | 0.25 | 43.9 |
| L75×50×7 | 6.57 | 0.25 | 38.1 |
| L75×50×8 | 7.43 | 0.25 | 33.6 |
| L80×50×5 | 4.99 | 0.26 | 52.1 |
| L80×50×6 | 5.92 | 0.26 | 43.9 |
| L80×60×6 | 6.39 | 0.28 | 43.8 |
| L80×60×7 | 7.39 | 0.28 | 37.9 |
| L80×60×8 | 8.37 | 0.28 | 33.5 |
| L90×56×5.5 | 6.17 | 0.292 | 47.3 |
| L90×56×6 | 6.7 | 0.292 | 43.6 |
| L90×56×8 | 8.77 | 0.292 | 33.3 |
| L100×63×6 | 7.53 | 0.326 | 43.3 |
| L100×63×7 | 8.7 | 0.326 | 37.5 |
| L100×63×8 | 9.87 | 0.326 | 33 |
| L100×63×10 | 12.14 | 0.326 | 26.9 |
| L100×65×7 | 8.81 | 0.33 | 37.5 |
| L100×65×8 | 9.99 | 0.33 | 33 |
| L100×65×10 | 12.3 | 0.33 | 26.8 |
| L110×70×6.5 | 8.98 | 0.36 | 40.1 |
| L110×70×8 | 10.93 | 0.36 | 32.9 |
| L125×80×7 | 11.04 | 0.41 | 37.1 |
| L125×80×8 | 12.53 | 0.41 | 32.7 |
| L125×80×10 | 15.47 | 0.41 | 26.5 |
| L125×80×12 | 18.34 | 0.41 | 22.4 |
| L140×90×8 | 14.13 | 0.46 | 32.6 |
| L140×90×10 | 17.46 | 0.46 | 26.3 |
| L160×100×9 | 17.96 | 0.52 | 29 |
| L160×100×10 | 19.85 | 0.52 | 26.2 |
| L160×100×12 | 23.58 | 0.52 | 22.1 |
| L160×100×14 | 27.26 | 0.52 | 19.1 |
| L180×110×10 | 22.2 | 0.58 | 26.1 |
| L180×110×12 | 26.4 | 0.58 | 22 |
| L200×125×11 | 27.37 | 0.65 | 23.7 |
| L200×125×12 | 29.74 | 0.65 | 21.9 |
| L200×125×14 | 34.43 | 0.65 | 18.9 |
| L200×125×16 | 39.07 | 0.65 | 16.6 |
L is the angle designation: wide leg, narrow leg and thickness, mm.
Pipes: outer and inner surface
A pipe has two surfaces. For hot-dip galvanizing an open pipe is dipped into the bath completely, so the zinc also covers the inside: use the “outer + inner” columns. Powder coating is usually applied to the outer surface.
Square tubes: surface area · ГОСТ 8639-82 (former)
| Size | Mass of 1 m, kg | Outer, per 1 m, m² | Outer + inner, per 1 m, m² | Outer, per tonne, m² | Outer + inner, per tonne, m² |
|---|---|---|---|---|---|
| 20×20×2 | 1.13 | 0.073 | 0.134 | 64.7 | 118.3 |
| 25×25×2 | 1.44 | 0.093 | 0.174 | 64.7 | 120.6 |
| 30×30×2 | 1.76 | 0.113 | 0.214 | 64.3 | 121.4 |
| 40×40×2 | 2.31 | 0.153 | 0.294 | 66.3 | 127.1 |
| 40×40×3 | 3.3 | 0.15 | 0.281 | 45.4 | 85 |
| 40×40×4 | 4.2 | 0.146 | 0.267 | 34.8 | 63.7 |
| 50×50×2 | 2.93 | 0.193 | 0.374 | 65.9 | 127.5 |
| 50×50×3 | 4.25 | 0.19 | 0.361 | 44.6 | 84.8 |
| 50×50×4 | 5.45 | 0.186 | 0.347 | 34.2 | 63.7 |
| 60×60×2 | 3.56 | 0.233 | 0.454 | 65.5 | 127.4 |
| 60×60×3 | 5.19 | 0.23 | 0.441 | 44.3 | 84.9 |
| 60×60×4 | 6.71 | 0.226 | 0.427 | 33.7 | 63.7 |
| 80×80×3 | 7.07 | 0.31 | 0.601 | 43.8 | 84.9 |
| 80×80×4 | 9.22 | 0.306 | 0.587 | 33.2 | 63.7 |
| 80×80×5 | 11.27 | 0.303 | 0.574 | 26.9 | 51 |
| 100×100×3 | 8.96 | 0.39 | 0.761 | 43.5 | 84.9 |
| 100×100×4 | 11.73 | 0.386 | 0.747 | 32.9 | 63.7 |
| 100×100×5 | 14.41 | 0.383 | 0.734 | 26.6 | 51 |
| 120×120×3 | 10.84 | 0.47 | 0.921 | 43.3 | 84.9 |
| 120×120×4 | 14.25 | 0.466 | 0.907 | 32.7 | 63.7 |
| 120×120×5 | 17.55 | 0.463 | 0.894 | 26.4 | 51 |
| 140×140×4 | 16.76 | 0.546 | 1.067 | 32.6 | 63.7 |
| 140×140×5 | 20.69 | 0.543 | 1.054 | 26.2 | 51 |
| 140×140×6 | 24.52 | 0.539 | 1.041 | 22 | 42.5 |
| 160×160×4 | 19.27 | 0.626 | 1.227 | 32.5 | 63.7 |
| 160×160×5 | 23.83 | 0.623 | 1.214 | 26.1 | 51 |
| 160×160×6 | 28.29 | 0.619 | 1.201 | 21.9 | 42.5 |
| 200×200×4 | 24.1 | 0.786 | 1.547 | 32.6 | 64.2 |
| 200×200×5 | 29.8 | 0.783 | 1.534 | 26.3 | 51.5 |
| 200×200×6 | 35.3 | 0.779 | 1.521 | 22.1 | 43.1 |
Size is the side and wall thickness, mm. The outer outline accounts for rounded corners by the rule R = 2t for t up to 6 mm.
Rectangular tubes: surface area · ГОСТ 8645-68 (former)
| Size | Mass of 1 m, kg | Outer, per 1 m, m² | Outer + inner, per 1 m, m² | Outer, per tonne, m² | Outer + inner, per tonne, m² |
|---|---|---|---|---|---|
| 30×20×2 | 1.39 | 0.093 | 0.174 | 67 | 125 |
| 40×20×2 | 1.7 | 0.113 | 0.214 | 66.5 | 125.7 |
| 40×25×2 | 1.86 | 0.123 | 0.234 | 66.2 | 125.6 |
| 40×25×3 | 2.66 | 0.12 | 0.221 | 45 | 82.9 |
| 40×25×4 | 3.36 | 0.116 | 0.207 | 34.6 | 61.7 |
| 40×30×2 | 2.02 | 0.133 | 0.254 | 65.9 | 125.6 |
| 50×25×3 | 3.13 | 0.14 | 0.261 | 44.6 | 83.2 |
| 50×25×4 | 3.99 | 0.136 | 0.247 | 34.2 | 62 |
| 50×30×2 | 2.32 | 0.153 | 0.294 | 66 | 126.6 |
| 50×30×3 | 3.36 | 0.15 | 0.281 | 44.6 | 83.5 |
| 50×30×4 | 4.3 | 0.146 | 0.267 | 34 | 62.2 |
| 60×30×2 | 2.65 | 0.173 | 0.334 | 65.3 | 125.9 |
| 60×30×3 | 3.78 | 0.17 | 0.321 | 44.9 | 84.8 |
| 60×30×4 | 4.93 | 0.166 | 0.307 | 33.7 | 62.4 |
| 60×40×2 | 2.96 | 0.193 | 0.374 | 65.2 | 126.2 |
| 60×40×3 | 4.3 | 0.19 | 0.361 | 44.1 | 83.8 |
| 60×40×4 | 5.56 | 0.186 | 0.347 | 33.5 | 62.5 |
| 80×40×2 | 3.59 | 0.233 | 0.454 | 64.9 | 126.4 |
| 80×40×3 | 5.25 | 0.23 | 0.441 | 43.8 | 83.9 |
| 80×40×4 | 6.82 | 0.226 | 0.427 | 33.2 | 62.7 |
| 80×60×2 | 4.22 | 0.273 | 0.534 | 64.7 | 126.5 |
| 80×60×3 | 6.13 | 0.27 | 0.521 | 44 | 84.9 |
| 80×60×4 | 8.07 | 0.266 | 0.507 | 33 | 62.9 |
| 100×50×3 | 6.6 | 0.29 | 0.561 | 43.9 | 84.9 |
| 100×50×4 | 8.7 | 0.286 | 0.547 | 32.9 | 62.9 |
| 120×60×3 | 8.01 | 0.35 | 0.681 | 43.7 | 85 |
| 120×60×4 | 10.48 | 0.346 | 0.667 | 33 | 63.7 |
| 120×80×3 | 8.96 | 0.39 | 0.761 | 43.5 | 84.9 |
| 120×80×4 | 11.74 | 0.386 | 0.747 | 32.9 | 63.7 |
| 120×80×5 | 14.58 | 0.383 | 0.734 | 26.3 | 50.4 |
| 150×100×4 | 14.88 | 0.486 | 0.947 | 32.7 | 63.7 |
| 150×100×5 | 18.34 | 0.483 | 0.934 | 26.3 | 50.9 |
| 150×100×6 | 21.93 | 0.479 | 0.921 | 21.9 | 42 |
| 160×80×4 | 14.25 | 0.466 | 0.907 | 32.7 | 63.7 |
| 160×80×5 | 17.55 | 0.463 | 0.894 | 26.4 | 51 |
| 160×80×6 | 20.75 | 0.459 | 0.881 | 22.1 | 42.5 |
| 160×120×6 | 24.52 | 0.539 | 1.041 | 22 | 42.5 |
| 180×140×8 | 36.46 | 0.606 | 1.161 | 16.6 | 31.8 |
Size is height, width and wall thickness, mm.
Round pipes: surface area · ГОСТ 10704-91 (former)
| Size | Mass of 1 m, kg | Outer, per 1 m, m² | Outer + inner, per 1 m, m² | Outer, per tonne, m² | Outer + inner, per tonne, m² |
|---|---|---|---|---|---|
| 57×3 | 4 | 0.179 | 0.339 | 44.8 | 84.8 |
| 57×3.5 | 4.62 | 0.179 | 0.336 | 38.8 | 72.8 |
| 57×4 | 5.18 | 0.179 | 0.333 | 34.6 | 64.3 |
| 76×3 | 5.4 | 0.239 | 0.459 | 44.2 | 84.9 |
| 76×3.5 | 6.26 | 0.239 | 0.456 | 38.1 | 72.8 |
| 76×4 | 7.1 | 0.239 | 0.452 | 33.6 | 63.7 |
| 89×3 | 6.36 | 0.28 | 0.54 | 44 | 85 |
| 89×3.5 | 7.38 | 0.28 | 0.537 | 37.9 | 72.8 |
| 89×4 | 8.38 | 0.28 | 0.534 | 33.4 | 63.7 |
| 102×3 | 7.32 | 0.32 | 0.622 | 43.8 | 85 |
| 102×3.5 | 8.5 | 0.32 | 0.619 | 37.7 | 72.8 |
| 102×4 | 9.67 | 0.32 | 0.616 | 33.1 | 63.7 |
| 102×5 | 11.96 | 0.32 | 0.609 | 26.8 | 51 |
| 108×3 | 7.77 | 0.339 | 0.66 | 43.7 | 84.9 |
| 108×3.5 | 9.02 | 0.339 | 0.657 | 37.6 | 72.8 |
| 108×4 | 10.26 | 0.339 | 0.653 | 33.1 | 63.7 |
| 133×3 | 9.62 | 0.418 | 0.817 | 43.4 | 84.9 |
| 133×3.5 | 11.18 | 0.418 | 0.814 | 37.4 | 72.8 |
| 133×4 | 12.73 | 0.418 | 0.811 | 32.8 | 63.7 |
| 133×4.5 | 14.26 | 0.418 | 0.807 | 29.3 | 56.6 |
| 159×3 | 11.54 | 0.5 | 0.98 | 43.3 | 84.9 |
| 159×3.5 | 13.42 | 0.5 | 0.977 | 37.2 | 72.8 |
| 159×4 | 15.29 | 0.5 | 0.974 | 32.7 | 63.7 |
| 159×4.5 | 17.15 | 0.5 | 0.971 | 29.1 | 56.6 |
| 219×5 | 26.39 | 0.688 | 1.345 | 26.1 | 51 |
| 219×6 | 31.52 | 0.688 | 1.338 | 21.8 | 42.5 |
Size is outside diameter and wall thickness, mm.
Worked example
A No. 20 I-beam 6 m long. Outline perimeter: 4·100 + 2·200 − 2·5.2 = 789.6 mm, that is 0.79 m² per metre. Surface of a six-metre beam: 0.79 × 6 ≈ 4.7 m². The beam weighs 21 × 6 = 126 kg, so a tonne of such I-beam has about 37.6 m².
A 108×4 mm pipe 6 m long: outer surface π·0.108 × 6 ≈ 2.04 m². If the inside (diameter 100 mm) is counted too, the total area rises to about 3.9 m².
Calculator and ordering
The metal weight calculator now shows the surface area of a part as well. The cost of hot-dip galvanizing can be estimated in the galvanizing calculator. If you need galvanizing or painting of a structure to your drawings, send them with the request and we will price it.
Updated:
Surface area of rolled metal: frequently asked questions
How many square metres are in 1 tonne of I-beam?
It depends on the number: about 43 m² per tonne for a No. 10 I-beam, about 38 m² for No. 20, about 25 m² for No. 40. The larger the section, the fewer m² per tonne.
Is the inner surface of a pipe counted?
The tables have both versions: outer surface only, and outer together with inner. For hot-dip galvanizing of an open pipe the second one is used.
Why do thin sections have more m² per tonne?
Because with a smaller mass of 1 m the perimeter of the section falls more slowly than the mass. A thin strip or angle has a lot of surface for little weight.
How accurate are these values?
They are calculated from nominal dimensions; fillets and the slope of inner faces of rolled sections are ignored. The error is up to 1–2 %, which is enough for estimating painting or galvanizing.
Related products: Custom steel fabrication · Hot-dip galvanising · Powder coating of steel structures
More on this topic: I-beam Sections: Mass of 1 m, Dimensions and Section Properties · Rebar Sections: Mass of 1 m, Section Area and Metres per Tonne · Round, Square and Hexagon Bar Sections: Mass of 1 m and Sizes · Sheet and Flat Bar Sections: Mass of 1 m² and 1 m · Channel Sections: Mass of 1 m, Dimensions and Section Properties · Equal-leg Angle Sections: Mass of 1 m and Section Properties
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