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| Perforation diameter (mm) | Wind pressure change interval (mm) | ||
|---|---|---|---|
| X1 | X2 | |X1-X2| | |
| 30 | 2931 | 3075 | 144 |
| 60 | 2859 | 3153 | 294 |
| 90 | 2829 | 3183 | 354 |
| 120 | 2781 | 3225 | 444 |
| 150 | 2715 | 3267 | 552 |
| 180 | 2691 | 3315 | 624 |
