Uptime Institute Tier II - Constructed Facility

The facility must maintain completely redundant and independent power distribution chains from utility feeds through to equipment racks, with each critical load path capable of carrying 100% of facility demand simultaneously.

This requires dual utility feeds from separate substations or distribution points, separate uninterruptible power supply (UPS) systems, separate static transfer switches (STS), and segregated power distribution units (PDUs) serving identical infrastructure capacity.

N+1 redundancy means that loss of any single power component—including a utility feed, UPS module, STS unit, or distribution branch—cannot degrade facility capacity or availability.

All redundant systems must be designed such that scheduled maintenance on any critical component can occur while the facility maintains full operational capacity through the redundant system.

This requires that UPS modules, cooling units, electrical switches, and infrastructure management systems be independently operable, with maintenance access points that do not require shutdown of production systems.

Facilities must document and validate maintenance windows that can be performed at full capacity without requiring customer notifications or service degradation.

The cooling infrastructure must be designed with N+1 redundancy such that any single cooling component failure does not cause temperature excursions beyond acceptable operating parameters (typically 59-90°F or 15-32°C for equipment inlets).

This requires multiple independent cooling loops, separate computer room air conditioning (CRAC) or computer room air handler (CRAH) units, redundant chillers or cooling towers, and separate piping or airflow paths.

Cooling capacity must be sized so that loss of the largest cooling component still allows the facility to maintain thermal control during peak load conditions.

Critical infrastructure systems—including power, cooling, and management—must be physically and logically separated into distinct zones or compartments to prevent cascading failures and limit the blast radius of any single component fault.

Electrical panels, UPS rooms, cooling distribution areas, and management control systems must be geographically separated with independent environmental controls, ensuring that a localized failure (such as a UPS module fire or cooling leak) cannot propagate to other critical infrastructure.

Documentation must clearly delineate these compartments and the failures they are designed to contain.

Tier II facilities must establish documented maintenance windows and procedures that allow for planned equipment maintenance, testing, and replacement without degrading facility availability or requiring emergency operational modes.

This includes procedures for UPS system battery testing, generator preventive maintenance, CRAC/CRAH servicing, and electrical system inspections, all of which must be executable while maintaining full N+1 redundancy.

Facilities must track and document all maintenance activities to demonstrate compliance with scheduled replacement cycles and fault-tolerance validation.

Building management systems (BMS), power monitoring systems, environmental controls, and security systems must operate with redundant management pathways and independent control mechanisms to ensure continued facility oversight during component failures.

This requires separate management networks, independent sensor arrays for environmental monitoring, redundant control loops for critical functions, and failover capabilities in all monitoring and management systems.

The facility must maintain visibility and control over all critical infrastructure even if the primary management path experiences failure.

Facilities must maintain documented strategies and physical space allocation for the planned replacement of aging critical infrastructure components without disrupting operations.

This includes replacement procedures for UPS batteries (which degrade over 3-5 years), CRAC/CRAH units, electrical distribution components, and monitoring systems.

Documentation must specify how equipment will be physically removed, replaced, and tested while maintaining the N+1 redundancy model and facility availability commitments.

Tier II certification guarantees a maximum of 21.6 minutes of downtime per year (52.6 minutes per quarter) due to infrastructure deficiencies, with specific exclusions for utility outages beyond the facility boundary, client-caused events, and force majeure circumstances.

This metric is calculated based on the facility's designed N+1 redundancy and assumes proper maintenance and operation.

The facility must maintain records demonstrating achievement of this metric or provide documentation of excluded events that would have caused downtime.