Reliability requirements
Capture concurrent-maintenance and single-component-fault requirements, then identify the state, path, transfer, loading, independence, common-mode, recovery, workload, and contract evidence still needed before topology selection.
Reliability topology requirements
Project topology requires named maintenance and fault states, the exact affected path, transfer interruption, post-event loading, path and control independence, common-mode dependencies, a recovery SLO, and workload and contract consequences. These two choices are useful requirements, but they cannot select N, N+1, distributed-redundant, 2N, a Tier, or a capex premium. Compare and price candidate designs only after that project evidence closes → Ch 12.1.
These are transparent screening estimates, not final designs, financial advice, or project approvals. Replace every default with current project data and have the responsible project authorities validate the result. You can save, share a permalink, or export to CSV; see the full calculator suite.