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 shear stress.
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.
