| Internal dimensions of closed profile less than (mm) | Minimum diameter of holes (mm) at opposite ends of profile to the number of openings: | ||||
|---|---|---|---|---|---|
|
|
|
1 | 2 | 4 |
| 15 | 15 | 20×10 | 8 | – | – |
| 20 | 20 | 30×15 | 10 | – | – |
| 30 | 30 | 40×20 | 12 | 10 | – |
| 40 | 40 | 50×30 | 14 | 12 | – |
| 50 | 50 | 60×40 | 16 | 12 | 10 |
| 60 | 60 | 80×40 | 20 | 12 | 10 |
| 80 | 80 | 100×60 | 25 | 16 | 12 |
| 100 | 100 | 120×80 | 30 | 25 | 14 |
| 120 | 120 | 160×80 | 40 | 30 | 18 |
| 160 | 160 | 200×120 | 60 | 40 | 25 |
| 200 | 200 | 260×140 | 80 | 50 | 30 |
| 250 | 250 | 350×150 | 120 | 80 | 50 |
| 300 | 300 | 400×200 | 150 | 100 | 60 |
| 400 | 400 | 500×300 | 200 | 150 | 100 |
| 500 | 500 | 600×400 | 300 | 200 | 150 |
The above table presents the size and number of holes that need to be made on both ends of a profile, depending on dimensions of a single cross-section. This applies to profiles of length max. 2.8 m. In case of longer profiles, holes must be made bigger or provide more openings so that area of the holes for zinc inflow represents 30% of the area of the profile cross-section.