The Start of Every Great

Data Center is its Design

ANSI/BICSI 002-2019, Data Center Design and

Implementation Best Practices

The foundation standard for data center design

around the world, ANSI/BICSI 002-2019 continues its
mission to provide requirements, guidelines and best
practices applicable to any data center, from
traditional, modular, and to the edge, hyperscale and
beyond.
With 550 pages of content, the 2019 edition of BICSI
002 covers all aspects of data center design,
including:
 Design Concepts and Planning
 Site Selection and Space Configuration
 Building Shell and Architecture
 Core Systems (e.g., Electrical, Mechanical,
Network and Cable Plant)
 Facility and Building systems
 Security
 Commissioning
Written for international application by experts from all across the globe and representing
all the all disciplines within data center design and implementation, BICSI 002
incorporates standards from ISO, TIA, CENELEC, ASHRAE and the latest in design
concepts, such as the Open Compute Project®, enabling improved data center designs
and operational results regardless of site location.
Given the comprehensive nature of BICSI 002-2019, whether you are a data center
designer, operator or involved in the planning, design, construction, implementation of a
data center, there is something for everyone and more within BICSI 002.

Learn more about BICSI 002 and view the first five
sections for free at www.bicsi.org/002

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 An Overview of the ANSI/BICSI 002-2019 Data Center Availability Class Methodology

People have come to expect ready access to information 24 hours

a day, every day. The Internet as well as more traditional
enterprises—both business and governmental—operate 7 days a
week, 24 hours a day.

With the increased reliance on 24/7 availability over the total time of that interval and can be
of information and data processing support, expressed as the following equation:
the reliance on mission-critical data
processing facilities has also increased.
Mission-critical data centers have not Uptime within Observation Interval
Availability =
traditionally been high-profile projects, yet their Total Time of Observation Interval
design issues are increasingly complex and
critical. With an emerging design terminology
and vocabulary, their rapid evolution calls for While the previous equation can generate the
an exceptional degree of building and IT availability of a system, the result does not
systems coordination and integration. These provide information which can be used to
data centers are not merely warehouses for improve the observed availability value. By
servers; instead, they rival medical operating splitting total time into its two primary elements
rooms or semiconductor plants, with their (uptime and downtime), the equation changes
precise environmental controls and power to the following:
requirements.
To increase the likelihood of success of a
mission-critical facility, required performance Uptime
Availability
levels of availability and reliability should be = Uptime + Downtime
defined, prior to the start or formalization of the
design, procurement, and maintenance
requirements and processes. Failure to define
performance and availability levels prior to the Going one step further, downtime itself can be
project start often yields higher construction, split into two types: scheduled and
implementation, and operational costs as well unscheduled. When the two types of downtime
as inconsistent and unpredictable are inserted into the availability equation, it
performance. results in the following:

What is Availability?
Availability Uptime
Availability is the probability that a component = Uptime
or system is in a condition to perform its + Scheduled Downtime
intended function. While similar to reliability, + Unscheduled Downtime
availability is affected by more events than a
failure requiring repair or replacement of a
component or system.
Thus, availability can be increased by
While there are different formulae to calculate reductions in one or both types of downtime.
availability for calculations involving systems, Examples of common scheduled and
availability, in its simplest form, is the ratio of unscheduled events are shown in Table 1.
uptime observed during a specified interval

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 Data Center Design Tools

Table 1 Common Downtime Events

Scheduled Downtime Unscheduled Downtime
Preventive maintenance Repairs due to failure
System and equipment setup and upgrades Maintenance delay
System testing/optimization Facility-related failures/outages
Scheduled facilities related events
Remedial maintenance

Risk Analysis
It is impossible to eliminate the risk of  What would be the economic loss to
downtime, but risk reduction is an important the organization from damaged or
planning element. In an increasingly destroyed equipment?
competitive world, it is imperative to address  What would be the impact of disrupted
downtime in business decisions. The design of service to the organization’s
systems supporting critical IT functions reputation? For example, would
depends on the interaction between the subscribers switch to a competitors’
criticality of the function and its operational service?
profile.  What would be the regulatory or
Criticality is defined as the relative importance contractual impact, if any? For
of a function or process as measured by the example, if unplanned downtime
consequences of its failure or inability to resulted in loss of telephone service or
function. The operational profile expresses the electrical service to the community,
time intervals over which the function or would there be penalties from the
process must operate. government?
To provide optimal design solutions for a
mission-critical data center, consider several Data Center Availability Classes
key factors. NFPA 75 identifies seven To a great degree, design decisions are
considerations for protection of the guided by the identified Availability Class.
environment, equipment, function, Therefore, it is essential to understand the
programming, records, and supplies in a data meaning of each Availability Class before
center. These include: determining an Availability Class for a specific
 What are the life safety aspects of the data center
function? For example, if the system
failed unexpectedly, would lives be put Availability Class 0
at risk? Examples of such applications The objective of Class 0 is to support the basic
include automated safety systems, air requirements of the IT functions without
traffic control, and emergency call supplementary equipment. Capital cost
centers. avoidance is the major driver. There is a high
 What is the threat to occupants or risk of downtime because of planned and
exposed property from natural, man- unplanned events.
made, or technology-caused
catastrophic events? Availability Class 1
 What would be the economic loss to The objective of Class 1 is to support the basic
the organization from the loss of requirements of the IT functions. There is a
function or loss of records? high risk of downtime because of planned and
 What is the access to redundant off- unplanned events. However, in Class 1 data
site processing systems (e.g., “high centers, remedial maintenance can be
performance computing”, massively performed during nonscheduled hours.
paralleled systems, cloud service
provider, disaster recovery site,
backup data center)?

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 An Overview of the ANSI/BICSI 002-2019 Data Center Availability Class Methodology

Availability Class 2 Primary Concerns that Define the

The objective of Class 2 is to provide a level of Availability Class
reliability higher than that defined in Class 1 to Each Availability Class is defined in terms of
reduce the risk of downtime because of four areas of concern:
component failure. In Class 2 data centers,
there is a moderate risk of downtime as a 1) Component redundancy increases
result of planned and unplanned events. reliability by providing redundancy for
Maintenance activities can typically be critical high-risk, low-reliability
performed during unscheduled hours. components within systems.
2) System redundancy increases
Availability Class 3 reliability even more by providing
The objective of Class 3 is to provide redundancy at the system level.
additional reliability and maintainability to 3) Quality ensures that high quality is
reduce the risk of downtime because of natural designed and implemented in the data
disasters, human-driven disasters, planned center, thereby reducing the risk of
maintenance, and repair activities. downtime due to failure during initial
Maintenance and repair activities will typically installation and/or premature wear.
need to be performed during full production 4) Survivability refers to reducing the
time with no opportunity for curtailed risk of downtime by protecting against
operations. external events such as physical
forces, security breaches, and natural
Availability Class 4 disasters.
The objective of Class 4 is to eliminate Table 2 summarizes how each of these four
downtime through the application of all tactics factors is defined for each of the five
to provide continuous operation regardless of Availability Classes.
planned or unplanned activities. All
recognizable single points of failure are
eliminated.

Table 2 Summary of Areas of Concern for Availability Class

Component
Class System Redundancy Quality Control Survivability
Redundancy
Standard commercial
Class 0/1 None None None
quality
Moderate hardening
Redundancy is
Premium quality for for physical security
Class 2 provided for critical None
critical components and structural
components
integrity
Redundancy is
required for critical System redundancy
Significant hardening
and noncritical is required where
Premium quality for for physical security
Class 3 components, except component
all components and structural
where the component redundancy does not
integrity
is part of a redundant exist
system.
Redundancy is System redundancy Premium quality for
provided for all critical is provided with all components. All systems are self-
components and to component Recommended to supporting in any
increase redundancy so that use different lots, event and are
Class 4
maintainability; also overall reliability is model, and protected against the
provided for maintained even manufacturer to avoid highest levels of
noncritical during maintenance common fault or natural forces.
components. activities. recall.

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 Data Center Design Tools

Availability Class Sub Groups Class F3

The data center is not just a facility or building, The critical power, cooling, and network
but it is a collection of services that supports systems must provide for reliable, continuous
the critical business processes. The data operations even when major components (or,
center services Availability Class model can where necessary, major subsystems) are out
be used to guide design and operational of service for repair or maintenance. To protect
decisions for the following critical services: against unplanned downtime, the power,
 Facility: The facility systems (e.g., cooling, and network systems must be able to
power, cooling, controls) can be sustain operations while a dependent
categorized into one of the sub group component or subsystem is out of service.
Class F0 through Class F4.
Class F4
 Cable Plant: The network cable plant
topology can be categorized into one The critical power, cooling, and network
of the sub group Class C0 through systems in a Class F4 facility must provide for
Class C4. reliable, continuous operations even when
 Network Infrastructure: The network major components (or, where necessary,
architecture and topology can be major subsystems) are out of service for repair
categorized into one of the sub group or maintenance. To protect against unplanned
Class N0 through Class N4. downtime, systems must be able to sustain
 Data Processing and Storage operations while a dependent component or
Systems: The computer processing subsystem is out of service.
and storage systems can be
categorized into one of the sub group Determining the Data Center
Class S0 through Class S4.
 Applications: The applications can be
Availability Class
categorized into one of the sub group While there are innumerable factors that can
Class A0 through Class A4. be evaluated in a mission-critical data center,
there are three factors that can quickly be
Further information, including requirements quantified.
and recommendations for each of these sub-
These factors are:
groups can be found in ANSI/BICSI 002-2014.
 Operational requirements,
 Operational availability, and
Application Examples  Impact of downtime,
Application examples for a Class F2, F3, and
and their interaction, as shown in Figure 1,
F4 include:
provides an easy to apply method of
Class F2 determining an Availability Class.

The critical power, cooling, and network

systems would need redundancy in those
parts of the system that are most likely to fail.
These would include any products that have a Operational
Requirements
high parts count or moving parts, such as
UPS, controls, air conditioning, generators,
ATS or systems that are outside the control of Operational
the data center management such as network Impact of
Availability
Downtime
access carrier services. In addition, it may be Requirements
appropriate to specify premium quality devices
that provide longer life or better reliability.
Required Availability Class

Figure 1 Interaction of Factors in Data

Center Availability Class Determination
The following provides the four steps required
to determine a data center’s availability class.

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 An Overview of the ANSI/BICSI 002-2019 Data Center Availability Class Methodology

Step 1: Identify Operational Requirements Step 2: Quantify and Rank Operational

The first step in determining the Availability Availability Requirements
Class associated with mission-critical data The second step in determining the Availability
center services is to define the data center’s Class is to identify the data center’s
intended operational requirements. Sufficient operational availability requirements,
resources must be available to achieve an specifically the total uptime that the data
acceptable level of quality over a given time center services must support without
period. IT functions that have a high-quality disruption. The term availability includes that
expectation over a longer time period are by ITE is operational and able to perform its
definition more critical than those requiring function; it does not solely refer to operation of
less resources, lower quality, and/or are the supporting infrastructure.
needed over a shorter time period. Operational availability refers only to
While there are many factors in operations, the scheduled uptime—that is, the time during
key factor to be assessed in this step is the which the IT functions are actually expected to
amount of time to be provided for testing and run.
maintenance activities that disrupt normal These operational availability requirements
operation. This is often known as planned are reflected by the determination of an
maintenance shutdown. Once the time for Operational Availability rating. By using the
planned maintenance shutdowns is known, Operational level determined in Step 1 and
this value can be used within Table 3 to indexing that value with the allowed maximum
determine an Operational Level. The value of annual downtime shown in Table 4, an
time used should not include projections for Operational Availability Rating is indicated.
unplanned repairs or events. The Operational Availability Rating will be
The indicated Operational Level is then used used in Step 4 in conjunction with information
in the next step. derived in Step 3

Table 3 Identifying Operational Requirements: Time Available For Planned Maintenance

Shutdown
Annual Hours Available for
Operational
Planned Maintenance Description
Level
Shutdown

Functions are operational less than 24 hours a day and less

0 > 400 than 7 days a week. Scheduled maintenance down time is
available during working hours and off-hours.

Functions are operational less than 24 hours a day and less

1 100-400 than 7 days a week. Scheduled maintenance down time is
available during working hours and off-hours.

Functions are operational up to 24 hours a day, up to 7 days a

2 50-99 week, and up to 50 weeks per year; scheduled maintenance
down time is available during working hours and off hours.

Functions are operational 24 hours a day, 7 days a week for 50

3 0-49 weeks or more. No scheduled maintenance down time is
available during working hours.

Functions are operational 24 hours a day, 7 days a week for

4 0 52 weeks each year. No scheduled maintenance down time is
available.
NOTE: The term shutdown means that operation has ceased; the equipment is not able to perform its mission during that time.
Shutdown does not refer to the loss of system components if they do not disrupt the ability of the system to continue its mission.

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 Data Center Design Tools

Table 4 Identifying Operational Availability Rating: Maximum Annual Downtime (Availability %)

Allowable Maximum Annual Downtime (minutes)
Availability as %
(Nines of Availability)
x >5000 5000 ≥ x > 500 500 ≥ x > 50 50 ≥ x > 5 5≥x
Operational Level x < 99% 99% ≤ x < 99.9% 99.9% ≤ x < 99.99% 99.99% ≤ x < 99.999% 99.999% ≤ x
(from Table 3) (2-9’s) (3-9’s) (4-9’s) (5-9’s) (6-9’s)
Level 0 0 0 1 2 2
Level 1 0 1 2 2 2
Level 2 1 2 2 2 3
Level 3 2 2 2 3 4
Level 4 3 3 3 4 4

Of note, the cost of downtime must be weighed critical functions helps determine the tactics
against the cost of mitigating risks in achieving that will be deployed to mitigate downtime risk.
high availability. Even an event such as a less As shown in Table 5, there are five impact
than a second of power interruption or a few classifications, each associated with a specific
minutes of cooling interruption can result in impact scope.
hours of recovery time. Thus, the objective is
Step 4: Identify the Data Center
to identify the intersection between the allowed
Availability Class
maximum annual downtime and the intended
operational level. A function or process that The final step in determining the data center
has a high availability requirement with a low Availability Class is to combine the previously
operational profile has less risk associated identified factors to arrive at a usable
with it than a similar function with a higher expression of availability. Since operational
operational profile. level is subsumed within the availability
ranking, the task is to matrix the availability
Step 3: Determine Impact of Downtime ranking against the impact of downtime to
The third step in determining the Availability arrive at an appropriate Availability Class.
Class is to identify the impact or Table 6 shows the intersection of these two
consequences of downtime. This is an values, and the resultant Data Center
essential component of risk management Availability Class.
because not all downtime has the same impact
on mission-critical data center services.
Identifying the impact of downtime on mission-

Table 5 Classifying the Impact of Downtime on the Organization

Classification Description – Impact of Downtime

Local in scope, affecting only a single function or operation, resulting in a minor disruption
Isolated
or delay in achieving non-critical organizational objectives.
Local in scope, affecting only a single site, or resulting in a minor disruption or delay in
Minor
achieving key organizational objectives.
Regional in scope, affecting a portion of the enterprise (although not in its entirety) or
Major
resulting in a moderate disruption or delay in achieving key organizational objectives.
Multiregional in scope, affecting a major portion of the enterprise (although not in its entirety)
Severe
or resulting in a major disruption or delay in achieving key organizational objectives.
Affecting the quality of service delivery across the entire enterprise or resulting in a
Catastrophic
significant disruption or delay in achieving key organizational objectives.

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 An Overview of the ANSI/BICSI 002-2019 Data Center Availability Class Methodology

Table 6 Determining Data Center Services Availability Class

Operational Availability Rating (from Table 4)
Impact of Downtime
(from Table 5)
0 1 2 3 4

Isolated Class 0 Class 0 Class 1 Class 3 Class 3

Minor Class 0 Class 1 Class 2 Class 3 Class 3

Major Class 1 Class 2 Class 2 Class 3 Class 3

Severe Class 1 Class 2 Class 3 Class 3 Class 4

Catastrophic Class 1 Class 2 Class 3 Class 4 Class 4

It is unlikely that a single data center would have all the

applications, data processing, and storage platform systems
aligned within a single reliability classification no matter what the
targeted base data center reliability classification is.

Prior to virtualization, location transparent One of the values of the BICSI data center
applications and cloud services, the optimal services reliability framework model is it can
data center services configuration consisted of be used to:
an alignment of the reliability classes across all  Identify the minimum reliability targets.
the data center service layers. This provided  Provide a structured methodical
the minimum required level of reliability and approach to guide decisions on how to
redundancy without over building any one of adjust lower layer services to
the data center service layers. compensate for higher layer services
System designs with clustered systems having reliability inadequacies.
nodes spread across two or more Class 3 data  Guide discussions regarding the
centers can meet or exceed the uptime of a possible technical and cost benefits of
system in a single Class 4 data center. In such increasing the reliability of the network
a design, the first failover is to the local node architecture and higher layers above
(synchronous), the second failover is to a the targeted reliability class across
nearby data center (~16 km [10 miles], and still multiple data centers so that cost
synchronous), and the third is to a remote data savings can be realized by building
center (but asynchronous). each of the data centers facilities to a
Such a design does increase the facility’s lower Class than the targeted
overhead and therefore, the cost. However, it reliability classification.
offers a way for designers to avoid many of the On the following pages, three examples are
costs associated with Class 4 data centers, provided to illustrate how the framework
whether owned, leased or collocated. provides for multi-data center architecture.

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 Data Center Design Tools

High Availability In-House Multi- There are times when there are man-made or
Data Center Architecture Example natural event common mode risks to both data
centers that have been deemed an acceptable
In this example, a customer has identified risk to the organization. An example would be
Class 3 as the targeted data center services multi-regional events, such as multi-State
reliability level. The customer has multiple power outages, that an organization deems
facilities that can support critical data center acceptable. There would be no loss of data
functions. By provisioning the applications with within the data center (running on backup
high-availability configuration across two data power sources); however, the users would not
center facilities, the customer will be able to have access to the applications or data as their
achieve the targeted reliability and availability networks and systems would be off-line
objectives. throughout the multi-state region. The
It is important that any man-made or natural organization might determine that the users
event common mode risks that may exist would not have an expectation of accessing
within the geographical region that is common the data in this scenario, and there would be
between the two data centers be identified and no loss of revenue or business reputation as a
evaluated. The communications between the result. Therefore, the costs associated with
two data centers can be synchronous or building out multiple data centers across a
asynchronous, depending on the recovery wider geographical area (possibly outside
point objective (RPO) and recovery time synchronous communication capabilities) may
objective (RTO) of the disaster not be justified.
recovery/business continuity requirements
and the physical distance limitations between
the two data centers.

Applications A0 A1 A2 A3 A4

Data Processing and

Storage Platform S0 S1 S2 S3 S4
Systems

Network
Architecture
N0 N1 N2 N3 N4 Sync Sync

Telecommunications
Cabling C0 C1 C2 C3 C4
Infrastructure

Facilities F0 F1 F2 F3 F4

Class 3

Figure 2 Multi-Data Center Class 3 Example

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 An Overview of the ANSI/BICSI 002-2019 Data Center Availability Class Methodology

Private Cloud Multi-Data Center regions. By provisioning the private cloud

Architecture Examples applications across three Class 2 data center
facilities, the customer may be able to achieve
Private cloud services are implemented in similar reliability and availability objectives.
customer-owned data centers. Private cloud The applications can move around each of the
applications are developed to improve data center facilities with the loss of any one
scalability, speed of deployment, and reliability facility having little or no impact on the
with the abstraction on the reliance on the enterprise.
lower layer data center services. Private cloud
applications may enable the customer to The two data centers connected via
implement highly reliable applications without synchronous communications would be
requiring highly reliable lower layer data center located within a common region. The data
services. center that is connected via asynchronous
communications would be located outside the
Private Cloud Multi-Data Center region, ensuring no natural or man-made
Architecture – Class 3 Solution/Three event represents a common mode of failure.
Class 2 Facilities This example is not provided as a solution that
The first example is a customer that has will always equate to two Class 3 data centers;
identified at least two Class 3 data centers as rather, it is provided to show how the data
the targeted data center services reliability center services reliability framework can be
level. The private cloud applications would be used to evaluate various options.
implemented across diverse geographical

Applications A0 A1 A2 A3 A4

Data Processing and

Storage Platform S0 S1 S2 S3 S4
Systems

Async Async
Network
N0 N1 N2 N3 N4
Architecture

Telecommunications
Cabling C0 C1 C2 C3 C4
Infrastructure
Sync

Facilities F0 F1 F2 F3 F4

Class 3

Figure 3 Multi-Data Center Class 3 Example With Three Class 2 Facilities

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 Data Center Design Tools

Private Cloud Multi-Data Center Two of the data centers are connected via
Architecture – Class 4 Solution/Four Class synchronous communications located within a
2 Facilities common region. The pair of data centers
The second example is a customer that has located within each common region are
identified two Class 4 data centers as the connected via asynchronous communications.
targeted data center services reliability level. The pair of data centers would be located
By provisioning the private cloud applications outside each other’s region, ensuring no
across four Class 2 data center facilities, both natural or man-made event represents a
within a common region and outside common common mode of failure.
regions, the customer may be able to achieve This example is not provided as a solution that
similar reliability and availability objectives. will always equate to two Class 4 data centers,
The applications can move around each of the but it is provided to show how the data center
data center facilities with the loss of any one services reliability framework can be used to
facility or facilities within a region having little evaluate various options.
or no impact on the enterprise.

Applications A0 A1 A2 A3 A4

Data Processing and

Storage Platform S0 S1 S2 S3 S4 Sync
Systems

Network
N0 N1 N2 N3 N4 Async Async
Architecture

Telecommunications
Cabling C0 C1 C2 C3 C4
Infrastructure

Sync
Facilities F0 F1 F2 F3 F4

Class 4

Figure 4 Multi-Data Center Class 4 Example with Four Class 2 Facilities

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 An Overview of the ANSI/BICSI 002-2019 Data Center Availability Class Methodology

Reliability Planning Worksheet

Use the following planning guide to determine the data center availability class.

Project name:
Project number:
Project description:

Project location:

STEP 1: Determine Operational Requirements

1) How many hours of operation must be supported during a production week? _____
2) How many scheduled production weeks are there? (if production occurs every week enter 52.14)
_____
3) Multiply line 1 by line 2, and enter here. This is annual production hours: ______
4) Subtract line 3 from 8,760, and enter the result here: _______
5) Are there additional available days or weekends each year for scheduled downtime that have not
been accounted for in lines 2 or 3? Enter the total annual available hours: ______
6) Add lines 4 and 5 and enter the result (allowable annual maintenance hours) here: ______
7) If line 6 is greater than 400, the Operational Level is 0; otherwise, proceed to the next line.
8) If line 6 is greater 100, the Operational Level is 1; otherwise, proceed to the next line.
9) If line 6 is between 50 and 99, the Operational Level is 2; otherwise, proceed to the next line.
10) If line 6 is between 1 and 49, the Operational Level is 3; otherwise, the Operational Level is 4.

STEP 2: Determine Operational Availability Rank.

1) Based on the operational level from Step 1 above:
– Level 0; Proceed to line 2.
– Level 1: Proceed to line 3.
– Level 2: Proceed to line 4.
– Level 3: Proceed to line 5.
– Level 4: Proceed to line 6.

2) Operational Level 0: If the maximum annual downtime is:

– 500 minutes or greater, then the availability requirement is Operational Availability Rank 0.
– Between 50 and 500 minutes, then the availability requirement is Operational Availability Rank
1.
– Less than 50 minutes, then the availability requirement is Operational Availability Rank 2.
Proceed to Step 3.

3) Operational Level 1: If the maximum annual downtime is:

– 5000 minutes or greater, then the availability requirement is Operational Availability Rank 0.
– Between 500 and 5000 minutes, then the availability requirement is Operational Availability
Rank 1.
– Less than 500 minutes, then the availability requirement is Operational Availability Rank 2.
Proceed to Step 3.

<Worksheet continues on the next page>

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 Data Center Design Tools

4) Operational Level 2: If the maximum annual downtime is:

– 5000 minutes or greater, then the availability requirement is Operational Availability Rank 1.
– Between 5 and 5000 minutes, then the availability requirement is Operational Availability Rank
2.
– Less than 5 minutes, then the availability requirement is Operational Availability Rank 3.
Proceed to Step 3.

5) Operational Level 3: If the maximum annual downtime is:

– 50 minutes or greater, then the availability requirement is Operational Availability Rank 2.
– Between 5 and 50 minutes, then the availability requirement is Operational Availability Rank 3.
– Less than 5 minutes, then the availability requirement is Operational Availability Rank 4.
Proceed to Step 3.

6) Operational Level 4: If the maximum annual downtime is:

– 50 minutes or greater, then the availability requirement is Operational Availability Rank 3.
– Less than 50 minutes, then the availability requirement is Operational Availability Rank 4.
Proceed to Step 3.

STEP 3: Define Mission-Critical Risk Level

Downtime will reduce or negatively impact operations (select one):
 Catastrophic (e.g., across the entire enterprise) ______
 Severe (e.g., across a wide portion of the enterprise) ______
 Major (e.g., across a single region or department) ______
 Minor (e.g., at a single location) ______
 Isolated (e.g., a single non-critical function) ______

STEP 4: Determine the Availability Class (using the following table)

1) Select the column from the Operational Availability Rank in Step 2.
2) Select the row from the Risk Level in Step 3.
3) Your Availability Class is where the two intersect: _____

Data Center Services Availability Class

Operational Availability Rating
Impact of Downtime
0 1 2 3 4

Isolated Class 0 Class 0 Class 1 Class 3 Class 3

Minor Class 0 Class 1 Class 2 Class 3 Class 3

Major Class 1 Class 2 Class 2 Class 3 Class 3

Severe Class 1 Class 2 Class 3 Class 3 Class 4

Catastrophic Class 1 Class 2 Class 3 Class 4 Class 4

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 Further Your Data Center
Career and Knowledge
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Essentials of Data Center Projects, 1st Edition

Surrounding the design process is the actual project that

brings a data center from idea to actuality. The Essentials
of Data Center Projects, developed from years of data
center professional experience, provides a holistic view of
the overall data center project, from conceptualization and
the design process, and through construction,
commissioning, and closeout.

The Essentials of Data Center Projects, in conjunction with

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Learn more about all that BICSI has to offer for data
centers and the DCDC at www.bicsi.org/dcdc

15