KhoiLuongThep.com › C and Z purlins
Enter depth H, flange width B, lip C and thickness t. Weight is calculated from the centreline length including bend radii and matches JIS G3350 tables.
kg/m = t × mean length × 7.85 / 1000
Enter dimensions in mm.
Inner bend radius defaults to t (as JIS G3350). Paint area includes both faces of the sheet.
| Quantity | Formulas | Unit |
|---|---|---|
| Mean length C/Z | H + 2B + 2C − 8(r + t) + 2π(r + t/2) | mm |
| Cross-section area | t × mean length | mm² |
| Weight | area × 7.85 / 1000 | kg/m |
r is the inner bend radius. A Z purlin has the same mean length as a C purlin of the same size, so it weighs the same.
| H × B × C × t | kg/m | 6 m length (kg) |
|---|---|---|
| 60×30×10×2.3 | 2.25 | 13.5 |
| 75×45×15×2.3 | 3.25 | 19.5 |
| 100×50×20×2.3 | 4.06 | 24.4 |
| 100×50×20×3.2 | 5.5 | 33 |
| 125×50×20×2.3 | 4.51 | 27.1 |
| 125×50×20×3.2 | 6.13 | 36.8 |
| 150×50×20×3.2 | 6.76 | 40.5 |
| 150×65×20×3.2 | 7.51 | 45.1 |
| 150×75×20×3.2 | 8.01 | 48.1 |
| 200×75×20×3.2 | 9.27 | 55.6 |
| H × B × C | t 1.5 | t 1.8 | t 2.0 | t 2.5 | t 3.0 |
|---|---|---|---|---|---|
| C80×40×15 | 2.12 | 2.52 | 2.78 | 3.41 | 4.01 |
| C100×50×20 | 2.71 | 3.22 | 3.56 | 4.39 | 5.19 |
| C125×50×20 | 3 | 3.58 | 3.95 | 4.88 | 5.78 |
| C150×50×20 | 3.3 | 3.93 | 4.35 | 5.37 | 6.36 |
| C150×65×20 | 3.65 | 4.35 | 4.82 | 5.96 | 7.07 |
| C180×65×20 | 4.01 | 4.78 | 5.29 | 6.55 | 7.78 |
| C200×65×20 | 4.24 | 5.06 | 5.6 | 6.94 | 8.25 |
| C200×75×20 | 4.48 | 5.34 | 5.92 | 7.33 | 8.72 |
| C250×75×20 | 5.06 | 6.05 | 6.7 | 8.31 | 9.9 |
≈ 4.35 kg/m, a 6 m length is about 26.1 kg.
Theo JIS G3350: 9.27 kg/m.
With the same H, B, C and t, Z and C purlins have the same developed length, so they weigh the same. Real Z purlins often have flanges a few mm different for lapping; the difference is negligible.
Some simple tables use (H + 2B + 2C) × t × 7.85, ignoring the bend radius, so they are a few percent heavier. Galvanized purlins also have the zinc coating and sheet thickness tolerance.