In preparation for teaching his Packaging Materials class, Clemson Universi
ty faculty member LeRoy Dear was reviewing equations used to calculate perm
eability for laminated materials using Hanlon's Package Engineering textboo
k. He immediately noticed that the equation in the second edition (Hanlon,
1984) was different from that in the third edition (Hanlon, 1998). After ch
ecking other references, he asked other faculty in the nearby offices for t
heir opinions to determine the correct equation.