Intelligent Building Dictionary

 

Fig. 5: Data Center Tiers

 

Tier I

Tier II

Tier III

Tier IV

Typical Availability

99.67%

99.75%

99.98%

99.99%

Annual IT Downtime

28.8 hours

22.0 hours

1.6 hours

0.8 hours

Concurrent Maintenance

No

No

Yes

Yes

Fault Tolerance

No

No

No

Yes

UPS Configuration

Capacity N

N+1
Redundant

Distributed Redundant

2N or 2N+1