TIA-942
A telecom-industry standard for data-center infrastructure with its own Rated 1-4 reliability classification.
Current numbers
Rated 1–4TIA-942-C resilience scale; full-facility telecom + M&E standard, May 2024 (C) revision
May 2024ANSI/TIA-942-C revision date; renames "Tier" to "Rated-1..4" and adds AI-growth & sustainability accommodations