BC double wall: thickness, flutes per foot and strength
BC double wall pairs a B flute and a C flute with three liners, about 0.28 in thick in Packgent's nominal sum. It is the common heavy-duty shipping board.
Key numbers
| Construction | Double wall: two mediums, three liners |
|---|---|
| Plies | B flute + C flute |
| Nominal caliper | 0.2813 in · 7.2 mm |
| OD minus ID, length and width | 0.563 in |
| OD minus ID, depth | 0.844 in |
| McKee strength vs C flute, same ECT | 134% |
Caliper is the sum of B flute (0.125 in) and C flute (0.1563 in), computed by Packgent. Real board is slightly thinner after combining and converting.
Strength ratio = √(caliper ÷ C-flute caliper), from the McKee formula with ECT and perimeter held equal.
Trade-offs
- Nearly twice the caliper of C, so much stronger in McKee at the same ECT
- Heavier and bulkier: more board weight and larger outside dimensions
- The B ply on one face gives a better print or wear surface
Typical uses
- Heavy cases and long-term pallet storage
- Industrial parts and export packs
Estimated box compression at 10 sizes
| Inside size, in | 42 ECT | 51 ECT | 71 ECT | 82 ECT |
|---|---|---|---|---|
| 8 × 6 × 4 | 692 | 840 | 1,170 | 1,351 |
| 10 × 8 × 6 | 785 | 953 | 1,326 | 1,532 |
| 12 × 12 × 12 | 906 | 1,100 | 1,531 | 1,769 |
| 14 × 10 × 8 | 906 | 1,100 | 1,531 | 1,769 |
| 16 × 12 × 10 | 979 | 1,188 | 1,654 | 1,910 |
| 18 × 12 × 12 | 1,013 | 1,230 | 1,712 | 1,977 |
| 18 × 18 × 18 | 1,110 | 1,347 | 1,876 | 2,166 |
| 20 × 16 × 14 | 1,110 | 1,347 | 1,876 | 2,166 |
| 24 × 18 × 18 | 1,198 | 1,455 | 2,026 | 2,340 |
| 24 × 24 × 24 | 1,281 | 1,556 | 2,166 | 2,501 |
BCT ≈ 5.87 × ECT × √(caliper × perimeter), perimeter = 2(L + W) of the inside size. An estimate; confirm with ASTM D642. Grades shown are ECT values Packgent computes for this wall type, not a list of what mills sell.
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.