Building energy codes have been around for a long time and compliance is mandatory. They are the requirements that Authorities Having Jurisdiction (AHJs), aka “building inspectors,” enforce. The codes provide design criteria that architects and engineers must satisfy to get construction documents approved and “permitted” for construction. One of the most important standards is ASHRAE 90.1 “Energy Standards for Buildings except Low-Rise Residential Buildings.” Until recently, data centers were primarily exempt from 90.1, but that is changing.

The two main building energy codes that are adopted by state and local jurisdictions for enforcement are the International Energy Conservation Code (IECC) and ANSI/ASHRAE 90.1. The IECC covers all commercial and residential buildings. ASHRAE 90.1 covers buildings other than single-family dwellings and multi-family buildings three stories or less above grade. The IECC has adopted ASHRAE 90.1 by reference which means compliance with 90.1 qualifies as compliance with IECC for commercial buildings.

The American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) published the original standard 90.1 in 1975. It was revised and updated in 1980, 1989, and 1999 in accordance with the American National Standards Institute (ANSI) and ASHRAE periodic maintenance procedures. In 1999, ASHRAE placed the standard in continuous maintenance, meaning that it can be updated several times each year through the publication of approved addenda; starting in 2001, the standard has been updated and republished in full in the autumn every three years. So we have since had 90.1-2004, 90.1-2007, and 90.1-2010.

The 90.1-2010 edition has the stated goal of reducing energy usage by 30% compared to what was allowed by 90.1-2004. The 90.1-2010 forward cites, among other things, “The most significant changes included are: 1. The scope has been expanded so that 90.1 can cover receptacles and process loads (e.g., data centers).” So if the 2010 version eliminated the exclusion of data centers from compliance, why is this news today two years later? The answer is in how ASHRAE 90.1 gets adopted, or codified, by state and local jurisdictions.

As with most aspects of government legislation, the adoption of energy standards into enforceable codes is a deliberate and bureaucratic process that varies from state to state and, in some cases, by local jurisdiction. Energy codes can be adopted directly through legislation or by regulatory agencies authorized through legislation. The process can include appointed committees or panels that make recommendations which go through a public review process, etc. The result in most instances is that the adopted code tends to lag behind the most recently published version of the standard by several years.

My research has found that as of late 2012 only three states have adopted ASHRAE 90.1-2010: Maryland, Oregon, and Texas. Thirty-two states are using 90.1-2007 and others use IECC 2009 or a previous version of 90.1, or in some cases none at all. My source includes the Building Codes Assistance Project’s Online Code Environment & Advocacy Network (OCEAN) at

Perhaps the most significant aspect of the changes made to 90.1 in the 2010 version that have the potential for impact on the data center industry is that 90.1 now mandates the use of free-cooling economizers in almost all geographical regions of the United States. Compliance is required in most cases for all new buildings, additions to existing buildings, alterations to existing buildings, replacement of portions of existing buildings, and when existing unconditioned or semi-heated spaces are converted to conditioned spaces. Exceptions still exist for “Essential Facilities” but these are limited to:

  • Hospitals and certain health care facilities
  • Fire, rescue, and police stations
  • Earthquake, hurricane, and other emergency shelters
  • Emergency preparedness, communication, and operations centers
  • Power-generating stations and other public utilities required for backup to other essential facilities
  • Structures containing highly toxic materials in defined large quantities
  • Aviation control towers and air traffic control centers
  • Buildings and structures having critical national defense functions

In other words, most data centers and commercial mission-critical facilities are not exempted and will be required to comply if and when 90.1-2010 gets adopted in their respective jurisdictions. There are still some existing exemptions regarding the mandatory use of economizers based on geographic location and for relatively small computer rooms. Computer rooms are defined as “a room whose primary function is to house equipment for the processing and storage of electronic data and that has a design electronic data equipment power density exceeding 20 watts/sq ft of conditioned floor space.” These exceptions are based on geographic location where there is limited economizer availability due to climate and by the required cooling capacity.

The biggest challenge to data center owners and the industry as a whole will not be in the design and construction of new data centers. Pretty much all of these already include economizers (either airside economizers or waterside economizers) for enhanced energy efficiency and accepted best practice. The challenge will be when applying for building permits to expand, upgrade, or complete the fit-out of existing facilities. The cost and complexity of these projects may increase significantly when faced with the requirement to retrofit existing buildings and HVAC systems with economizers and the associated controls and sequences-of-operations that 90.1-2010 requires. This may be especially true of adding or modifying computer rooms within existing buildings that will now require either retrofitting central cooling plants with waterside economizers or adding exterior penetrations, louvers, dampers, and ducting for airside economizers to the CRACs, CRAHs, or AHUs serving the computer room.

ASHRAE has been collaborating with representatives of the data center industry over the last few years on ways to how best include data centers in current building energy codes. The ASHRAE 90.1 committee has solicited input from “ASHRAE’s TC9.9 (Technical Committee 9.9 Mission Critical Facilities, Technology Spaces, and Electronic Equipment) and other interested parties. The 90.1-2010 version has generated a fair amount of concern in the data center industry, including from members of TC9.9.”

The fear is that the standard could result in inadvertent harm by causing unnecessary or disproportionate costs for data center construction, adding operational risk, and hindering innovative engineering and design solutions to what is a unique and rapidly changing built environment. In response to these concerns, and to better address the needs of the data center industry while still establishing energy efficiency standards, ASHRAE has recently formed a new standard committee specific to drafting energy standards for data centers called SPC-90.4 “Energy Standard for Data Centers and Telecommunications Buildings.”

No one wants to save energy more than data center owners and operators. The huge amounts of energy used by these facilities, and the associated escalating costs, have brought energy efficiency to the forefront of the industry. Still, reliability and the capability to adapt to ever-changing technology are paramount to these facilities sustaining their critical missions. The industry has embraced modular, plug-and-play, phased fit-out, and expansion strategies. It needs supporting construction codes that promote innovation while fostering improved energy efficiency. All I can say is, stay tuned.