90 ECT AAC triple wall: box compression and stacking table

90 ECT AAC triple wall pairs a 90 lb/in edge crush with a nominal 0.531 in caliper. As an empty 12 × 12 × 12 in box, the simplified McKee formula puts it near 2,668 lbf of top-to-bottom compression before any allowance for storage or humidity.

Compression, derated for storage time

BCT after storage losses, lbf, 90 ECT AAC triple wall
Inside size, in	0 days	10 days	30 days	90 days	180 days
8 × 6 × 4	2,038	1,284	1,223	1,121	1,019
10 × 8 × 6	2,310	1,456	1,386	1,271	1,155
12 × 12 × 12	2,668	1,681	1,601	1,467	1,334
14 × 10 × 8	2,668	1,681	1,601	1,467	1,334
16 × 12 × 10	2,882	1,815	1,729	1,585	1,441
18 × 12 × 12	2,983	1,879	1,790	1,641	1,491
18 × 18 × 18	3,268	2,059	1,961	1,797	1,634
20 × 16 × 14	3,268	2,059	1,961	1,797	1,634
24 × 18 × 18	3,529	2,223	2,118	1,941	1,765
24 × 24 × 24	3,773	2,377	2,264	2,075	1,886

0 days is the McKee estimate itself. Storage losses are Packgent's default assumptions (10 days 37%, 30 days 40%, 90 days 45%, 180 days 50%), not sourced values; edit them in the stacking calculator.

How many high can it stack?

Boxes high, including the bottom one, column stacked for 30 days, before humidity, interlock or overhang losses.

12 × 10 × 8 in, BCT ≈ 2,554 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	154	77	52	39	26

16 × 12 × 10 in, BCT ≈ 2,882 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	173	87	58	44	29

20 × 16 × 12 in, BCT ≈ 3,268 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	197	99	66	50	33

Boxes high = ⌊BCT × (1 − 0.4) ÷ gross weight⌋ + 1. A real stack needs further allowance for humidity, pattern and handling.

Neighbouring grades

Grade	ECT change	BCT change, same flute and size
112 ECT	+22 lb/in	+24%

In McKee, BCT scales directly with ECT, so the percentage change in strength equals the change in ECT.

Freight rule limits

NMFC Item 222 ties each grade to a maximum gross weight and size for LTL shipping. Packgent has not published those limits yet because they could not be checked against the current tariff. See the Item 222 page for status.

Sources

TAPPI T 811: Edgewise compressive strength of corrugated fibreboard (short column test)
McKee, R.C., Gander, J.W. & Wachuta, J.R. (1963). "Compression strength formula for corrugated boxes." Paperboard Packaging 48(8): 149–159
Flute calipers: Foster (1997), Wiley Encyclopedia of Packaging Technology

Last reviewed 2026-10-27. See all sources and how Packgent computes.