Carrier equipment and the demarcation point for access providers is located in the Entrance Room.

The Telecom Room hosts Office & Operations Center LAN switches. It is connected to Offices, Operations Center, and Support Rooms (not shown).

The Main Distribution Area (MDA) contains the data center’s Routers, Backbone LAN/SAN Switches, PBX, and Multiplexers.

The Horizontal Distribution Area (HDA) is where LAN, SAN, and KVM Switches (a KVM switch is a hardware device that allows a user to control multiple computers from a single keyboard, video monitor and mouse) are located.

The Equipment Distribution Area (EDA) hosts Racks and Cabinets.

Temperature: 18-27°C (64-81°F) dry bulb
Maximum relative humidity: 60%
Maximum dew point: 15°C (59°F)
Maximum rate of temperature change: 5°C (9°F) per hour

Level 1: data center unoccupied
Level 2: initial entry into the data center
Level 3: occupied space
At Level 1, the lighting should allow effective use of video surveillance equipment.

At Level 2, at the initial entry into the data center, motion sensors should be used to activate lights in the immediate area of entry and be programmed to illuminate aisles and passageways.  Sufficient lighting should be provided to allow safe passage through the space and to permit identification via security cameras.

At Level 3, when the data center is occupied for purposes of maintenance or interaction with equipment, lighting shall be 500 lux in the horizontal plane and 200 lux in the vertical plane, measured 1 m (3 ft) above the finished floor in the middle of all aisles between cabinets. In data centers larger than 230 m2 (2500 ft2) zone lighting is recommended that provides Level 3 in the immediate area of work and Level 2 in all other zones.

1. Passive cooling with hot and cold aisles
2. Cooling fans with hot and cold aisles
3. Chimneys with hot and cold aisles

Rating/Tier* Level

ANSI/TIA-942 describes four Rating/Tier* levels in which data centers can be classified. Below is the high level description of each Rating/Tier* level.  Detailed specifications are given in the ANSI/TIA-942 standard.

Rated-1/Tier-1*: Basic Site Infrastructure

A data center which has single capacity components and a single, non-redundant distribution path serving the computer equipment. It has limited protection against physical events.

Rated-2/Tier-2*: Redundant Capacity Component Site Infrastructure

A data center which has redundant capacity components and a single, non-redundant distribution path serving the computer equipment.  It has improved protection against physical events.

Rated-3/Tier-3*: Concurrently Maintainable Site Infrastructure

A data center which has redundant capacity components and multiple independent distribution paths serving the computer equipment. Typically, only one distribution path serves the computer equipment at any time. The site is concurrently maintainable which means that each and every capacity component including elements which are part of the distribution path, can be removed/replaced/serviced on a planned basis without disrupting the ICT capabilities to the End-User. It has protection against most physical events.

Rated-4/Tier-4*: Fault Tolerant Site Infrastructure

A data center which has redundant capacity components and multiple independent distribution paths serving the computer equipment which all are active. The data center allows concurrent maintainability and one (1) fault anywhere in the installation without causing downtime. It has protection against almost all physical events.

Validity

TIA-942 standard certification is valid for 3 years.  By the end of year-1 and year-2, the data center should undergo a surveillance audit.  By the end of year-3, the data center has to undergo a recertification audit in order to keep its certification valid.

* The term ‘Tier’ was used in the ANSI/TIA-942 Standard until the ANSI/TIA-942:March-2014 edition. In the March 2014 edition the term ‘Tier’ has been replaced by either ‘Rated’ or ‘Rating’.