Data Center and Equipment Room Design Flashcards

What is Power Usage Effectiveness (PUE) and what does a PUE of 1.0 indicate?

Answer: PUE is total facility power divided by IT equipment power; 1.0 means 100% of power goes to IT with zero overhead losses

PUE = Total Facility Power / IT Equipment Power; a perfect PUE of 1.0 is theoretical, meaning no power is consumed by cooling, lighting, or other overhead—all power goes directly to computing.

In a Tier IV data center per the Uptime Institute standard, what level of redundancy is required?

Answer: Fault-tolerant (2N or 2N+1) with concurrent maintainability and no single point of failure

Tier IV requires fully fault-tolerant infrastructure (2N minimum) with concurrent maintainability, meaning the facility continues operating at full load even during a worst-case unplanned event.

What is the purpose of an overhead cable management system (cable runway) in a data center hot aisle/cold aisle layout?

Answer: To route cables above the racks for organized distribution while keeping the cold aisle free of obstructions that impede cooling airflow

Overhead cable runways route telecommunications and power cables above the rack tops, preventing cables from blocking cold aisle floor tiles and maintaining efficient airflow distribution.

Per TIA-942, what is the recommended minimum width of a hot aisle or cold aisle in a data center?

Answer: 1.2 m (4 ft) for equipment access and airflow management

TIA-942 recommends a minimum aisle width of 1.2 meters (approximately 4 feet) for both hot and cold aisles to allow equipment installation, maintenance access, and adequate airflow.

What is a 'top of rack' (ToR) switching model in data center design?

Answer: A network architecture where switches are placed at the top of each equipment rack, with short patch cord connections to servers and uplinks to the main distribution

Top of Rack switching places network switches within each rack, connecting servers via short patch cords and running only uplink cables out of the rack, reducing cable complexity across the data floor.

Why is raised floor height important in a data center using underfloor air distribution (UFAD)?

Answer: Greater raised floor height provides more plenum volume for lower-velocity, more uniform cold air distribution to perforated tiles

A taller raised floor plenum (typically 600–900 mm) provides larger air volume for lower air velocity and more uniform pressure distribution, improving cooling efficiency for perforated floor tile delivery.