42 ECT BC double wall: box compression and stacking table

42 ECT BC double wall pairs a 42 lb/in edge crush with a nominal 0.281 in caliper. As an empty 12 × 12 × 12 in box, the simplified McKee formula puts it near 906 lbf of top-to-bottom compression before any allowance for storage or humidity.

Compression, derated for storage time

BCT after storage losses, lbf, 42 ECT BC double wall
Inside size, in	0 days	10 days	30 days	90 days	180 days
8 × 6 × 4	692	436	415	381	346
10 × 8 × 6	785	494	471	432	392
12 × 12 × 12	906	571	544	498	453
14 × 10 × 8	906	571	544	498	453
16 × 12 × 10	979	616	587	538	489
18 × 12 × 12	1,013	638	608	557	506
18 × 18 × 18	1,110	699	666	610	555
20 × 16 × 14	1,110	699	666	610	555
24 × 18 × 18	1,198	755	719	659	599
24 × 24 × 24	1,281	807	769	705	641

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 ≈ 867 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	53	27	18	14	9

16 × 12 × 10 in, BCT ≈ 979 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	59	30	20	15	10

20 × 16 × 12 in, BCT ≈ 1,110 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	67	34	23	17	12

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
48 ECT	+6 lb/in	+14%

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.