1. ANSI/ASHRAE 90.4 Energy Standard for Data Centers
The Importance of Adoption by Standards and Code Governing Bodies

2. Agenda What is the New Std. 90.4? Why Std. 90.4 Was Needed
90.4 as “Sister” to 90.1
Reasons for New Design Metrics
90.4 and the AHJ
Why is Code Adoption Important?
Good Codes Ensure Good Practices

3. What is ANSI/ASHRAE Std. 90.4?
A New Energy Efficiency Standard
Developed Specifically for Data Centers
Performance-based Design Standard
Recognizes “Mission Critical” Nature of Data Centers
Recognizes that Not Every Room with ITE is a “Data Center”
Differentiates “Data Centers” and “Computer Rooms”
Based on Information Technology Equipment (ITE) Design Loads
Data Centers Covered by Std. 90.4
>10 kW and >20 W/sf (215 W/m2)
Computer Rooms Covered by Std. 90.1
< 10kW or <20W/sf (215 W/m2)

4. Why Is 90.4 Needed Data Centers Differ from Other Commercial Buildings
90.1 Tailored to Commercial Buildings, Not Data Centers
Minimal Human Occupancy in Data Centers
High Power and Heat Densities
Magnitudes Greater than Office Buildings
Very High Reliability Requirements
Data Centers are Mission Critical Facilities
Failure, Even for Seconds, is Not An Option
Cost of Failures can be Astronomical
Failures Can Even Have Life-Safety Implications
Recovery From Very Short Failures Can Take Many Hours
Use Specialized Power and Cooling Systems
Must Test & Maintain Systems Without Interruption
Unique Cooling Systems and Designs
Redundant Designs are the Norm
Very Different Level of Commissioning

5. Why is 90.4 Needed Data Centers Exempted from 90.1 Prior to 2010
Formerly Recognized as Special Spaces
Exemption Removed in 90.1 – 2010 Revision
Prescriptively Mandates Economizers
Very Limited Exemptions
Data Center Technology is Constantly Innovating
Prescriptive Approaches Cannot Keep Up With Industry Advances
Many High Efficiency Solutions Available Without Economizers

6. Why is 90.4 Needed
Society Now Dependent on Constant Availability of Data Centers
Telecom Facilities now being Replaced by Data Centers
Telecom Criticality (911) Previously Given Exemptions by AHJ
Also Municipal OEM’s (Offices of Emergency Management)
Critical Facilities Recognized in Std. 90.4
Data Centers now Key to Utility Infrastructure, IoT, etc.
“The Cloud” is Many Data Centers.
Two Most Important Data Center Criteria
Reliability
Availability
Prescriptive Systems
Can have Major Negative Impact on Both of These
Economizers are a Serious Reliability Concern

7. Why is 90.4 Needed Data Centers are Constantly Evolving
Dramatic Technology Changes Each Year
Heat Loads and Densities Continue to Increase
Typical Load Changes Dramatically Every 5 Years with IT Equipment Innovations
Changes are Too Rapid for any Single Approach to Keep Up With
Enormous Efficiency Improvements in Recent Years
Design Professionals Also More Creative
Wider Understanding of Energy Efficient Techniques
Significant Innovation in Mechanical and Electrical Designs
Energy Efficient Design is a Top Priority for the Industry

8. What is ANSI/ASHRAE Std. 90.4?
A Performance-Based Standard – Namely 90.4
Allows Engineers to Use Most Effective Solutions for Each Project
Makes it Easy to Demonstrate Compliance to the AHJ
Allows, but does not Prescribe, Economizers
Intended as “Sister Standard” to 90.1
Follows 90.1 Format
Complimentary in Application
References Most 90.1 Definitions
References 90.1 Requirements for:
Building Envelope
Service Water Heating
Lighting
Compliance with Those Sections is Same as 90.1
90.4 Electrical Section More Comprehensive Than 90.1

9. How Is Std. 90.4 Constructed? Two Simple New Design Metrics
Mechanical Load Component (“MLC”)
Electrical Loss Component (“ELC”)
MLC & ELC Can Be Used Individually
If Project is Mechanical Only, Calculate: < Table Figures
If Project is Electrical Only, Calculate: < Table Figures
If Combined, MLC + ELC Must Be < Compliance Numbers
Allows Tradeoffs Between MLC and ELC
< Table Figures
MLC
ELC
MLC
ELC
MLC
ELC

10. MLC How Is Std. 90.4 Constructed? MLC Tables are by Climate Zone
19 Newest ASHRAE Climate Zones Recognized
Can Be Calculated in Power (kW) or Annualized Energy (kWh)
MLC Developed from Four Quantities
Cooling Design kW or Cooling + Pump kWh
Heat Rejection Peak Fan kW or kWh
Air Handler Unit (AHU) Fan Design kW or Fan kWh
Total Data Center ITE Design kW or kWh
Cooling
Heat Rejection Fans
AHU Fans
Total ITE Load
MLC

11. Incoming Service Segment
How Is Std Constructed?
ELC Tables Not Affected by Climate Zone
Based on Circuit Losses to Information Technology Equipment (ITE)
Calculated from Worst Case Path Losses
Losses Can Be Calculated from Efficiencies
May Require Calculating Several Paths to Determine “Worst Case”
ELC Developed in Three Segments
Incoming Service Segment Loss
UPS Segment Loss
Distribution Segment Loss
Utility Xfmr
Service Point
Incoming Service Segment
UPS Segment
Distribution Segment
UPS
ELC
Highest Loss Path

12. How Is Std. 90.4 Used? Compliance is Simple for Both Engineer and AHJ
Consulting Engineer Calculates:
Design MLC or Annualized MLC
Design ELC
AHJ Verifies:
MLC Value < Listed Value for Data Center Climate Zone
ELC Values < Listed Values Based on Redundancy & ITE Design Load
Tables for < 100 kW or > 100 kW ITE Load
Full & Partial Load Columns for < “2N” and >“2N” Redundancy
OR “Trade-off Method:
Combined MLC + ELC < Table MLC Value + Table ELC Value
Higher Effic. MLC can Offset Lower Effic. ELC, or Vice-Versa
Particularly Useful Where Existing Equipment is Re-used

13. Importance of Std. 90.4 Adoption by Standards and Code Governing Bodies
Build Alignment Across Data Center Industry
Data Center Designers, Users and AHJ’s
Provide Recognized Standard for Sustainable Design Practices
Advance the Cause of Data Center Energy Efficiency
Validate that Uptime/Availability and Energy Efficiency are Compatible, and Not Mutually Exclusive
Establish 90.4 as the Presiding Standard for Data Center Energy Efficiency

14. Why New Metrics Instead of PUE?
PUE (Power Utilization Effectiveness)
An Operational Efficiency Metric, Not a Design Metric
Developed by The Green Grid
Recognized Internationally as Power Efficiency Metric
Measures Electrical Energy, not Mechanical Efficiency
Ratio of Total Data Center Energy / IT Equipment Energy
Requires Actual Measurement of Total and ITE Energy
Never Intended to Compare Data Centers, or as a Design Metric
If Used as a Design Metric, Would:
Require Massive Electrical Calculations and Detailed CFD Modeling
Still Not Yield Accurate PUE
Mislead Owners into Expecting Calculated Number
PUE is Excellent Metric for Tracking Data Center Efficiency
Totally Unsuitable as a Design Metric

15. Conclusion: Standard 90.4 is Published
Solves Industry Concerns With 90.1
It Will be Easier for the AHJ
The Industry Wants to Use It
Code Adoption is Essential