Tier Classification: TIA-942 defines four different tiers (Tier 1 to Tier 4) that represent the levels of availability and redundancy in a data center. The tiers are:
Tier 1: Basic Site Infrastructure – Non-redundant capacity components, single non-redundant distribution path.
Tier 2: Redundant Capacity Components Site Infrastructure – Redundant capacity components (e.g., UPS, generators) but still a single, non-redundant distribution path.
Tier 3: Concurrently Maintainable Site Infrastructure – Multiple independent distribution paths, but only one active path; all components are redundant, and systems are concurrently maintainable.
Tier 4: Fault-Tolerant Site Infrastructure – Multiple independent and physically isolated distribution paths, all of which are active; components are fully redundant and fault-tolerant.
Space Planning and Layout: The standard outlines various zones within a data center, each serving a specific function:
Entrance Room: Where external network service providers connect to the data center.
Main Distribution Area (MDA): Houses core network equipment, including main routers, switches, and cross-connects.
Horizontal Distribution Area (HDA): Contains the intermediate cross-connects (ICCs) for floor-level distribution of cabling.
Equipment Distribution Area (EDA): Holds the actual computing and storage equipment (e.g., racks and cabinets).
Zone Distribution Area (ZDA): An optional interconnection point between the HDA and the EDA to add flexibility.
Telecommunications Room (TR): A space for housing telecommunications equipment.
Cabling Infrastructure: TIA-942 specifies the types of cabling to be used, including:
Copper Cabling: Usually Category 6A or higher for data transmission up to 10 Gbps.
Fiber Optic Cabling: Multimode (OM3/OM4) and Single mode (OS1/OS2) fibers for longer distances and higher bandwidth needs.
Pathways and Spaces: Guidelines for cable trays, conduits, and other pathways to ensure proper cable management and airflow.
Power and Electrical Systems: The standard includes guidelines for power distribution and redundancy:
Redundant Power Supplies: Use of dual power feeds, UPS systems, and backup generators.
Power Distribution Units (PDUs): Provide conditioned power to the equipment.
Grounding and Bonding: Ensure safety and equipment protection.
Cooling and Environmental Control: TIA-942 provides recommendations for cooling to maintain optimal environmental conditions:
Hot and Cold Aisle Containment: Aligning racks in alternating rows with hot and cold aisles to improve cooling efficiency.
Cooling Redundancy: N+1 or 2N redundancy for cooling systems to prevent overheating in case of equipment failure.
Environmental Monitoring: Temperature, humidity, and air quality monitoring to maintain stable conditions.
Security: The standard also addresses physical security requirements for a data center:
Physical Barriers: Fences, walls, and gates to secure the perimeter.
Access Control: Biometric systems, keycards, and surveillance cameras to control and monitor access.
Fire Protection: Fire detection and suppression systems, including clean agent fire suppression, fire-rated walls, and emergency exits.
Telecommunications and Network Design:
Redundancy: Redundant network paths to ensure network availability.
Scalability: Designing a network that can scale to meet future needs.
Site Selection and Building Construction:
Location: Considerations for geographical risks (e.g., floods, earthquakes), proximity to network providers, and power utilities.
Building Design: Considerations for structural integrity, fire resistance, and layout to support data center operations.
