SCG Addresses Tier IV Requirements for a
Data Center
A Tier IV
data center meets the most stringent requirements for fault tolerance and
uninterruptable operation.SCG meets the
requirements of the Tier IV standard, and exceeds them in many cases. According to
the Uptime Institute, a respected provider of educational and consulting
services for Facilities and Information Technology organizations interested in
maximizing data center uptime, the Tier IV standard can be broken down into
three areas of compliance:Fundamental
requirements, performance confirmation tests, and operational impact.
Fundamental
Requirements1:
A fault tolerant data center has multiple, independent,
physically isolated systems that each have redundant capacity components
and multiple, independent, diverse, active distribution paths
simultaneously serving the computer equipment.
All IT equipment is dual powered and installed properly to
be compatible with the topology of the site's architecture.
Performance
Confirmation Test(s) 1:
A single failure of any capacity system, capacity component,
or distribution element will not impact the computer equipment.
The system itself automatically responds to a failure to
prevent further impact to the site.
Each and every capacity component and element in the
distribution paths must be able to be removed from service on a planned
basis without impacting any of the computer equipment.
Complementary systems and distribution paths must be
physically isolated from one another (compartmentalized) to prevent any
single event from simultaneously impacting both systems or paths.
Continuous cooling is required.
There is sufficient capacity to meet the needs of the site
when redundant components or distribution paths have been removed from
service.
Operational
Impact (s) 1:
The site is not susceptible to distribution from a single
unplanned event.
The site is not susceptible to disruption from any
unplanned work activities.
In order to establish concurrent maintainability of the
critical power distribution systems between the UPS and the computer
equipment, Tier IV sites require all computer hardware to have dual power
inputs as defined by the Institute's Fault
Tolerant Compliance Specification, Version 2.0.Transfer devices, such as
point-of-use switches, must be incorporated for computer equipment that
does not meet specification.
The site infrastructure maintenance can be performed by
using the redundant capacity components and distribution paths to safely
work on the remaining equipment.
The Tiered
design requirements are listed below, as well as how the data center at SCG
meets or exceeds the standard:
Reliability
Tier I
Tier II
Tier III
Tier IV
SCG
Number of delivery paths for power and cooling distribution
1
1
1 active, 1 passive
2 active
2 + 1 active on electric, 3rd with addition of generator;
N+1 chillers, N+1 pump controls, N+1 air handlers
Redundant components
N
N+1
N+1
2(N+1) or S+S
2(N+1)
Support space to raised floor ratio
20%
30%
89-90%
100%
100% for equipment, 2,000 sq ft of soft space available
Initial watts/sq ft
20-30
40-50
40-60
50-80
125 watts per sq ft; 1,000KW/8,000=125. (300KW power set aside for
A/C)
Ultimate watts/sq ft
20-30
40-50
100-150
150+
250 watts per sq ft; 2,000KW/8,000=250. (600 power KW set aside for
AC)
Raised floor height
12"
18"
30-36"
30-36"
Only 15" needed for cooling due to our alternative design for high-efficiency cooling (note: wiring
and cables are over-head with 22 ft ceilings)
Floor loading pounds/sq ft
85
100
150
150
150 standard, up to 300
Utility voltage
208, 480
208, 480
12-15KV
12-15KV
15KV; dual sub-stations
Months to implement
3
3 to 6
15 to 20
15 to 20
Ready for equipment placement
Annual downtime due to site
28.5 hrs
22 hrs
1.6 hrs
.4 hrs
0.00 hrs
Site availability
99.671%
99.749%
99.982%
99.995%
99.999%
Source of
table, the Uptime Institute
1The Uptime Institute, White Paper:Tier Classifications Define Site Infrastructure
Performance.Downloaded November 18,
2008 atwww.uptimeinstitute.org
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