Firewall performance and engineering is underwritten primarily by Factory Mutual who provides insurance for large corporations and buildings. When you perform an installation, you must abide by the insurance requirements of your customer. This is why you will find this information spec'd out in the stamped, sealed prints.
Again, not everything you need to know is in the NEC. If you live and die by the NEC alone you will never have enough knowledge to be competent on commercial and industrial jobs. Multiple NFPA manuals, I-Codes, UL books, ASTM requirements, ANSI requirements and job specs are needed to perform a proper installation.
This is directly from Factory Mutual.
Factory Mutual said:
1. Pipes, conduit and cables (regardless of size) penetrating MFL firewalls should be positioned to pass through the wall as close as practical to, but no more than 3'-0" above the finished floor level. A steel sleeve with a 1-inch clearance should be left around the pipe or conduit, to be filled with an approved fire-resistive pipe or cable sealer with a 3-hour fire rating. It is preferred that mesh reinforcement be provided in the horizontal joints above and below pipes in concrete block walls and that all cores of the concrete block immediately adjacent to pipe penetrations be filled with concrete. Pipe and conduit should not penetrate the wall in clusters. If more than one pipe penetrates the wall in the same area, the pipes should be spaced at least three times the larger pipe diameter on center. Exposed cable with combustible insulation should be wrapped with a fire-resistive tape for at least 3'-0" on each side of the wall.
The 3 foot rule has been in place for years. I first came across it when performing work at a Sears warehouse in 1991 and most recently on another project for Diapers.com who is taking over a recently built warehouse. This is common knowledge in the insurance and construction industry as these walls are designed to remain standing and the building on either side can collapse. Even the type of anchors are regulated.