FIGURE 1: Shown is a data center under construction and the data center’s “white space.”
COMMISSIONING TERMS
The practice of commissioning
a data center project has been
evolving for over 25 years. Given
the different disciplines in the
construction of a data center
(Figure 1), commissioning has
common themes and definitions.
Commissioning is critical in all
aspects of the data center design/
build plan. This article focuses
primarily on the ICT cabling piece
of this complicated puzzle.
The commissioning plan describes
all aspects of the commission process.
The plan defines the guiding
principles detailing schedules,
defined responsibilities, full and
accurate test documentation, and
functional performance guidelines.
Furthermore, commissioning
identifies potential issues before they
become a problem. The realized
benefits of commissioning include
less repairs, fewer moves, adds and
changes (MACs), and unplanned
8 I ICT TODAY
downtime prevention. It is soon
recognized that liability costs and
the resulting damage to a business
reputation far outweigh the costs
associated with a comprehensive
commissioning plan.
DATA CENTER
CLASSIFICATIONS
Data centers are defined into five
classes per the BICSI non-profit
standards body:
• Class-0 (no redundancies,
no backup power)
• Class-1 (no redundancies to
protect IT load from failure)
• Class-2 (component level
redundancy in key systems)
• Class-3 (concurrently
maintainable)
• Class-4 (fault tolerant to most
events, except for severe
building damage/destruction)
The Telecommunication Industry
Association (TIA) non-profit
standards body uses Rated 1-4
criteria to define data centers, while
the Uptime Institute, a for-profit
commercial organization, uses
proprietary Tiers I-IV.
Data center definitions, based
upon “uptime” or “availability”
and derived from TIA and Uptime
Institute formulas, indicate (as does
BICSI) that the higher the number
the better. Per TIA and the Uptime
Institute, a Rated-1 or Tier-I data
center has a minimal 99.671 percent
uptime and 28.8 hours of downtime
per year. Rated-3 or Tier III is a data
center with 99.982 percent uptime
and no more than 1.6 hours of
downtime annually; and one
Rated-4 or Tier IV has 99.995
percent uptime and 26.3 minutes
of annual downtime, approaching
a similar result to that of BICSI’s
Class-4 fault tolerance.
What happens when a backhoe
accidentally digs up an OSP
backbone? Or when a contractor