Corrugated flute sizes: A, B, C, E, F and multi-wall
A flute is the wave of paper inside corrugated board. Its size is named by a letter and identified by how many flutes fit in a foot. Bigger flutes make thicker board that stacks better; smaller flutes print better and resist crushing.
Flute table
| Board | Walls | Caliper, in | Caliper, mm | Flutes per ft | BCT at 32 ECT, 12×12 box |
|---|---|---|---|---|---|
| A flute | single | 0.188 | 4.8 | 33 ± 3 | 564 lbf |
| B flute | single | 0.125 | 3.2 | 47 ± 3 | 460 lbf |
| C flute | single | 0.156 | 4 | 39 ± 3 | 514 lbf |
| E flute | single | 0.063 | 1.6 | 90 ± 4 | 325 lbf |
| F flute | single | 0.031 | 0.8 | 125 ± 4 | 230 lbf |
| BC double wall | double | 0.281 | 7.2 | — | 690 lbf |
| EB double wall | double | 0.188 | 4.8 | — | 564 lbf |
| AC double wall | double | 0.344 | 8.8 | — | 763 lbf |
| AAC triple wall | triple | 0.531 | 13.6 | — | 949 lbf |
Multi-wall calipers are the sum of their plies' nominal calipers, computed by Packgent. BCT is a simplified McKee estimate at the same ECT to show the effect of thickness alone; real boards of different flutes rarely share an ECT.
Sources
- Foster, G. (1997). "Boxes, Corrugated." In Brody & Marsh (eds.), The Wiley Encyclopedia of Packaging Technology, 2nd ed. Wiley. ISBN 0-471-06397-5 (table reproduced in Wikipedia, "Corrugated fiberboard")
- Packaging Corporation of America: Profiles with a purpose
Last reviewed . See all sources and how Packgent computes.