Aluminum equivalent
Aluminum equivalent means the thickness of aluminum (type 1100 alloy) 1 affording the same attenuation, under specified conditions, as the material in question.
1 The nominal chemical composition of type 1100 aluminum alloy is 99.00 percent minimum aluminum, 0.12 percent copper, as given in “Aluminum Standards and Data” (1969). Copies may be obtained from The Aluminum Association, New York, NY.