Sample Calculation of the Postconsumer Fiber Content of a Corrugated Container
EPA has prepared the following example to demonstrate how to calculate postconsumer fiber content in a corrugated container.
C-flute, a commonly manufactured type of corrugated board, has a take-up factor of approximately 1.44, which means that for each one foot of combined corrugated board there is 1.44 feet of fluted medium. This factor is used to calculate the weight of paperboard in a given area of combined corrugated board, from which the basis weight of the board is derived. Each linerboard contributes 35 percent of the basis weight (42/121.4). The medium contributes 30 percent of the total basis weight (37.4/121.4).
| Board Basis Weight(lbs/MSF) | ||
|---|---|---|
| Linerboard #1 | 42 x 1.00 = | 42.0 |
| Medium | 26 x 1.44 = | 37.4 |
| Linerboard #2 | 42 x 1.00 = | 42.0 |
| Combined Board Weight | 121.4 lbs/MSF | |
If the linerboard used has 20 percent postconsumer fiber and the medium has 80 percent postconsumer fiber, the resulting total postconsumer fiber content of the containerboard is as follows:
| Linerboard: | .35 x .20 = .07 x 2 = .14 (or 14%) |
|---|---|
| Medium: | .30 x .80 = .24 (or 24%) |
| Total Postconsumer Fiber: | .14 + .24 = .38 (or 38%) |