Aluminum Foil Barrier of 0.001” and Above

Aluminum foil, even in very thin gauges, provides a total water vapor and gas barrier if in perfect condition (no pinholes or imperfections). At thickness of 0.001 inch and above, aluminum foil is considered to be pinhole free. The expectation is that the barrier provided by aluminum foil will not improve as the thickness of the foil is increased above 0.001 inch.

To test this theory, samples of 0.001 inch foil and 0.002 inch foil were tested for oxygen transmission rate (O2TR) and water vapor transmission rate (WVTR). A T-Test comparing the populations was conducted to determine if they could be considered statistically the same. A T-Test yielding a P value of greater than 0.05 indicates that there is a 95 percent (or greater) confidence that the populations are equivalent. The results are shown below.

O2TR
(cc/100 in2/day)
WVTR
(g/100 in2/day)
Thickness
(inch)
Average St. Dev. Average St. Dev.
0.001 0.00034 0.00033 0.0029 0.0032
0.002 0.00010 0.00017 0.0021 0.0025
P Value 0.092 0.563

Based upon these results, the barrier provided by aluminum foil of thickness ranging from 0.001 to 0.002″ is statistically equivalent.