ATP Uptime Institute Tier Classification 2 — Questions and Answers
Question 1: What is the minimum availability percentage guaranteed by a Tier IV data center?
- 99.671%
- 99.741%
- 99.982%
- 99.995% (Correct answer)
Correct answer: 99.995%
Tier IV data centers guarantee 99.995% availability, equating to no more than 26.3 minutes of downtime per year.
Question 2: Which Tier classification requires 2N+1 redundancy for all cooling, power, and network systems?
- Tier II
- Tier III
- Tier IV
- No tier requires exactly 2N+1 (Correct answer)
Correct answer: No tier requires exactly 2N+1
No tier specifically mandates exactly 2N+1; Tier IV requires fault tolerance via multiple independent distribution paths, but the specific redundancy topology can vary.
Question 3: A data center has two independent utility feeds but only one UPS system. Which tier does this most closely describe?
- Tier I
- Tier II
- Tier III (Correct answer)
- Tier IV
Correct answer: Tier III
Tier III requires multiple independent distribution paths with at least N+1 redundancy on active components, but the second path need not be active simultaneously.
Question 4: What distinguishes a Tier III data center from a Tier II data center in terms of maintenance?
- Tier III has no planned maintenance windows
- Tier III allows concurrent maintainability without IT load impact (Correct answer)
- Tier III requires hot-swap of all components
- Tier III mandates 72-hour fuel storage
Correct answer: Tier III allows concurrent maintainability without IT load impact
Tier III's defining characteristic is concurrent maintainability — any single planned maintenance activity can be performed without impacting the IT load.
Question 5: How many distribution paths does a Tier IV facility require to be simultaneously active?
- One active, one standby
- Two active (Correct answer)
- Three active
- Four active
Correct answer: Two active
Tier IV requires two simultaneously active distribution paths, ensuring a fault in one path does not affect IT equipment.
Question 6: What is the maximum allowable annual downtime for a Tier III data center?
- 8.8 hours
- 22 hours
- 1.6 hours (Correct answer)
- 26.3 minutes
Correct answer: 1.6 hours
Tier III allows up to approximately 1.6 hours (96 minutes) of downtime per year, corresponding to 99.982% availability.
Question 7: Which Uptime Institute certification validates the operational practices of a data center, separate from its physical infrastructure tier?
- Tier Certification of Design Documents (TCDD)
- Tier Certification of Constructed Facility (TCCF)
- Tier Certification of Operational Sustainability (TCOS) (Correct answer)
- Tier Certification of Performance (TCP)
Correct answer: Tier Certification of Operational Sustainability (TCOS)
The Tier Certification of Operational Sustainability (TCOS) evaluates whether a facility's management and operational behaviors support the tier level claimed.
ATP Uptime Institute Tier Classification 2
What is the minimum availability percentage guaranteed by a Tier IV data center?