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The future of 90.1.

Some have said that ANSI/ASHRAE/IESNA Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, describes "the worst building that may be built" from an energy-efficiency standpoint while still complying with energy code requirements. Despite this assessment, Standard 90.1 has been the benchmark for local and national codes because it defines minimum requirements. Here are some examples of how the standard has been implemented.

* The 2006 International Energy Conservation Code[R] (IECC), developed by the International Code Council (ICC), directly references Standard 90.1 by stating, in Chapter 5:

501.1 Scope. The requirements contained in this chapter are applicable to commercial buildings, or portions of commercial buildings. These commercial buildings shall meet either the requirements of ASHRAE/IESNA Standard 90.1, Energy Standard for Buildings Except for Low-Rise Residential Buildings, or the requirements contained in this chapter.

* Chapter 6 specifically references Standard 90.1-2004.

* The balance of Chapter 5 of the IECC covers envelope, mechanical systems, service water heating, electrical power and lighting, and allows a total building performance path. A number of the requirements in these sections are identical to those in Standard 90.1 and an additional number are similar. Some requirements in Standard 90.1 are not included in the IECC. A practitioner may follow either path and comply with the IECC.

* NFPA 900: Building Energy Code, explicitly cites Standard 90.1 in Chapter 4, Technical Provision for All Buildings Except Low-Rise Residential Buildings.

* Within the United States many jurisdictions:

* Reference 90.1 directly; or

* Adopt 90.1 indirectly through the IECC; or

* Adopt 90.1 through NFPA 5000--Building Construction and Safety Code[R].

Use by Other Entities

In addition to code adoption, the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED[R]) products reference Standard 90.1. For example:

* LEED for New Construction (NC) Version 2.2 requires compliance with Standard 90.1-2004 as a prerequisite for any level of certification, and requires reducing energy cost by 14% to obtain two "Optimize Energy Efficiency" credits.

* The first public comment version of LEED 2009 included a prerequisite of exceeding the energy efficiency of Standard 90.1-2007 by 10%.

In both documents, "Optimize Energy Efficiency" credits may be earned by exceeding the requirements of the prerequisite version of Standard 90.1 by specific percentages. The basis of demonstrating this performance is the Performance Rating Method detailed in Appendix G of Standard 90.1.

The Green Buildings Initiative has developed the Green Globes[TM] building rating system, which requires compliance with--and in some cases, exceeding--the requirements of Standard 90.1.


The Standard 90.1 committee is a standing standards project committee (SSPC), which means that it is not disbanded once the standard is published.

The committee, comprised of volunteers with assistance from ASHRAE staff, performs the bulk of the work developing and refining proposals, and responding to public review comments and developing consensus. The membership includes individuals and groups representing building owners, builders, code officials, architects, engineers, lighting designers, utilities, industry, as well as the public interest. Members serve on one of five subcommittees that deal with format and compliance, building envelope, mechanical systems, lighting systems, and building simulation. The SSPC meets four times per year, with each meeting lasting three to four days.

Those interested in joining can read about membership expectations of the chair on the 90.1 Web site: http://sspc901. There are links for those who wish to be considered for membership.


How is Standard 90.1 Updated?

As an ANSI standard, 90.1 follows a rigorous process prior to approval, including one or more public reviews for each change. ASHRAE standards are updated by the cognizant committee through an established process of issuing addenda for public review, receiving comments, responding to commenters, and reaching consensus. Standard 90.1 is under "continuous maintenance." This means that anyone may submit changes to be considered through the continuous maintenance proposal process (details available at www.ashrae. org/technology/page/812). This allows the committee to continuously--rather than periodically--develop addenda for public review and publication in response to continuous maintenance proposals from the public or from committee members.

Each proposal goes through a public review process, which requires the SSPC formally respond to comments. Often, these comments result in a full second public review of an addendum or an independent substantive change (ISC). In these cases, the changing sections must be sent out for another review.

Following approval by the SSPC, approval by other ASHRAE committees, including the Standards Committee and Board of Directors, is mandatory prior to publication. Because IESNA is a cosponsor of 90.1, approval by its Board of Directors is also required.

Work Plan Goals

In the Work Plan adopted unanimously by the SSPC in June 2007, the goal is: "A 2010 standard that results in 30% total energy-cost savings improvement compared to 90.1-2004."

The overall goal is national average based on aggregate construction and climate-weighted energy cost savings and may not be achieved for every building type in every climate. Energy cost is the agreed upon normalized metric, and is used as a surrogate for environmental emissions.

Immediate Plans for the Standard

Supplement to 90.1-2007

Since the publication of 90.1-2007, SSPC 90.1 and all levels of ASHRAE have approved a number of addenda. Every 18 months, ASHRAE collects those addenda that have been approved and issues a supplement to the standard. A list of those addenda already approved is provided in Table 1. Note that there is no "official" subject for these items; the subjects in the table are general titles used here to organize the addenda. Also included for some addenda are estimated savings according to the foreword of the addendum.

The addenda that are likely to help save significant energy cost include:

* VAV zone controls;

* Boiler efficiency;

* Single-zone VAV;

* Vestibules; and

* Heat pump pool heaters.

Possible Addenda to Supplement to 90.1-2007

As this article is being written, in addition to the addenda already discussed, there are six more items that may be included in the supplement. Inclusion of these addenda is dependent on final approval and the publication date of the supplement.

Proposed Addenda in Public Review Process

Because the standard is under continuous maintenance, as of July 2008, a significant number (19) of additional proposed addenda are in one of the public review stages. Seven of these proposed addenda are summarized in Table 3. Recall these are proposed addenda subject to ASHRAE and ANSI processes.

Possible Future Changes

SSPC 90.1 also has recommended a change to expand the title, purpose, and scope (TPS) of the standard to include industrial, commercial, and manufacturing processes. Even if the TPS recommendation is approved, most industrial, commercial, and manufacturing processes will not be covered unless an additional addendum is approved. For example, the standard contains no efficiency requirements for refrigerated cases. To add such a requirement, the TPS must first be changed via the addendum process, then a separate addendum adding a table for refrigerated case efficiency requirements would need to be approved. The SSPC is working closely with cognizant ASHRAE technical committees, process and building owners, and the building community to ensure such changes would be made where appropriate.

In addition to this possible modification, Standard 90.1 subcommittees are considering possible changes as addenda in daylighting, mechanical system efficiency, envelope criteria, and more cost-effective lighting technology.

Each addendum is subject to the same rigorous public review process.


Due to the work of volunteer members of SSPC 90.1 and other ASHRAE and IESNA committees, and the rigorous continuous maintenance process, Standard 90.1 is changing to reflect society's increased interest in energy and energy cost savings. As the standard changes, building owners and operators will reap the benefits of higher efficiency as engineers, designers, code officials, manufacturers, and others comply with--and exceed the requirements of--the standard that defines the minimum efficiency for most commercial buildings.

Mick Schwedler, P.E., is chair of ASHRAE SSPC 90.1. He is manager, applications engineering with Trane in La Crosse, Wis.
Table 1: Addenda slated for inclusion in the Supplement to 90.1-2007.
(See Page 48 for a discussion of the 2007 Supplement.)

Addendum           Subject                      Comments

   A            Cooling Tower          The standard did not cover
                Clarification        closed circuit cooling towers,
                                      but this was not obvious to

   B              Vivariums          Changes made to address issues
                                     of vivaria with respect to fan
                                           power requirements.

   C              Vivariums          Additional changes in response
                                            to public input.

   G           Metal Buildings          Insulation requirements

   H          VAV Zone Controls      To allow ASHRAE Standards 55,
                                      62.1, and 90.1 to be used in
                                     conjunction more easily, this
                                      addendum revises the airflow
                                     limits for which new energy may
                                        be used for reheating or
                                        recooling in DDC systems.

   I          Exterior Lighting         Categories for external
                                        lighting allowances were
                                      expanded and lighting power
                                           densities defined.

   J             Mechanical                References updated.

   K              Furnaces           Clarifies warm air furnace and
                                        duct furnace references.

   L           Closed-Circuit        Efficiency requirements added
               Cooling Towers          for closed circuit cooling
                                     towers--this was a continuation
                                             of Addendum A.

   N           Single-Zone VAV        Establishes requirements for
                                     single zone VAV systems and fan
                                         modulation on DX units
                                           above 110,000 Btu/h
                                            on Jan. 1, 2012.

   P          Lab Exhaust Fans       Added pressure drop allowances
                                      for laboratory exhaust fans.

   Q             Vestibules            Added the requirement for
                                      vestibules to Climate Zone 4
                                      (near the Mason-Dixon Line).

   Y           Heat Pump Pool         Establishes ARI 1160 as the
                   Heaters            test procedure for heat pump
                                     pool heaters and requires that
                                       the minimum coefficient of
                                     performance (COP) of 4 be met
                                     at the low outdoor temperature
                                     of 50[degrees]F (instead of the
                                        high outdoor temperature
                                       of 80[degrees]F currently

   AC         Lighting Control              Incentives added.

   AD         Liquid to Liquid         Added a new reference for
               Heat Exchangers            liquid-to-liquid heat
Addendum      Estimated Savings
            (* Denotes According
                   to the





   H         *"... about $0.20/
            [ft.sup.2]/yr with a
             simple pay-back of
             less than 2 years."

   I        * Varies by exterior
              lighting zone and
            square footage. For a
             15,000 [ft.sup.2]
            area, savings are from
            16% to 50% of exterior
               lighting power.




   N        Significant, but not



   Y        *"... significantly
                increase the
                stringency of
            Standard 90.1 as heat
              pump pool heaters
            will now be required
            to deliver a COP of 4
                 at a higher
             temperature lift."



Table 2: Addenda awaiting final approval. (See Page 48 for a discussion
of the 2007 Supplement.)

Addendum           Subject                      Comments

    D            Daylighting        In response to research performed
                                      by an owner of a significant
                                     number of buildings, provides
                                        appropriate provisions to
                                        better allow daylighting.

    M        Chiller Efficiency        Adds a Column B to chiller
                and Equation            efficiency requirements.
                                      Column B increases part load
                                     efficiency requirements, but in
                                     some cases, decreases full load
                                        efficiency requirements.
                                      Also applies the use of the
                                    adjustment factor for centrifugal
                                    chillers selected at nonstandard
                                     conditions to more situations.

    S          Heat Pump Part       Updates the COP at 17[degrees]F
                 Load Change        efficiency levels for commercial
                                    heat pumps and introduces a new
                                       part load energy efficiency
                                     descriptor for all commercial
                                         unitary products above
                                    65,000 Btu/h of cooling capacity.

    T               PTAC            Clarifies use of "standard" and
                                     non-standard packaged terminal
                                        air conditioners (PTACs).

    U        Centrifugal Cooling     Requires centrifugal fan units
              Tower Fan Energy         over 1,100 U.S. gpm at the
                 Limitation          rating conditions to meet the
                                     energy efficiency requirements
                                          for axial fan units.
                                        Exceptions are available.

    W            Appendix G                  Clarifications.

Addendum      Estimated Savings
             (* Denotes According
              to the Foreword)


    M        * "...457.6 GWh of
             energy per year ..."





Table 3: Selected proposed addenda presently in the public review

Addendum           Subject                       Comments

   E           Energy Recovery         Expands the requirement for
                                       outdoor air energy recovery.

   F          Ballasted, Vented,        In response to continuous
               And "Cool" Roofs         maintenance proposals, adds
                                          a number of roof types
                                           available to be used.

   O             Transformers         Adds federal requirements for

   R          Make Appendix G A        Appendix G defines modeling
             Normative Reference        requirements for buildings
                                      "intended for use in rating the
                                         energy efficiency of the
                                       building designs that exceed
                                         the requirements of this
                                       Appendix G is used by USGBC
                                           for LEED energy cost
                                            savings estimates.

   AB            Expansion Of            Daylighting requirements.
                  Addendum D

   AF            Pipe Sizing          Defines minimum pipe sizes by
                                                flow rate.

   AK         Hydronic Variable       Reduces threshold for efficient
                 Flow Systems           part load pumping to pumps
                                              exceeding 5 hp.
                                       Established requirement for
                                         critical valve reset" for
                                               DDC systems.

   AL             Skylights           Requirements in large enclosed

Addendum      Estimated Savings
            (* Denotes According
               to the Foreword)



   O         * "...4.74 quads of
                primary energy
                over 28 years
             (2007 to 2035). In
             terms of cumulative
            electric site energy
              savings, that is
            roughly equivalent to
            596 billion kWh over 28
            years, or 21.3 billion
                kWh per year."


   AB       Preliminary estimates
             of the effect of Ad-

            dendum D and AB are an
              8.8% reduction of
            lighting energy across
             all building types.

   AF            Significant

   AK            Significant

   AL       If Title, Purpose, and
            Scope recommendations
             are accepted and the
            standard is applied to
             lighting in unheated
              warehouses, it is
            estimated that for each
            year of construction,
            160 GWh will be saved.
COPYRIGHT 2008 American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
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Author:Schwedler, Mick
Publication:ASHRAE Journal
Date:Oct 1, 2008
Previous Article:2007-2008 ASHRAE research report.
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