Frank Atkinson, the inventor of the Tri-Lock (San Diego, California) ACB system relates, "When tested at Colorado State University using the FHWA protocol, we were pleased to find that certain ACBs could withstand 24 foot per second velocity and 13 pound per square foot
In close proximity to the desk are one or two wood paneled reading rooms whose floors were not constructed to bear the 150 pound per square foot
live loads that library bookstacks presently require.
Due to a weight of only one pound per square foot
(as opposed to 12 pounds per square foot for the ballasted membrane roof), the Seamless Roofing System was selected.
These groundbreaking built-to-order panels are lightweight and weigh less than a pound per square foot
Although the panel is rated Threat Level II by the National Institute of Justice, it weighs less than one pound per square foot
and is only a quarter of an inch thick.