In 1999 , NIST found , the Port Authority issued guidelines to upgrade the fireproofing to a thickness of 1 1 / 2 inches .
The NIST discovered that in 1999 the Port Authority issued guidelines to upgrade the fireproofing to a thickness of 1 1 / 2 inches .
in a pert network, the sequence of tasks that takes the longest time to complete  the path requiring the greatest amount of time