The energy crisis demanded more sophisticated engineering calculation methods and design, based on quantitative predictions. NBS was ready for the challenge with its background in heat transfer, use of a temperature controlled building shell enclosing a full scale bungalow at the Connecticut Avenue site for measuring efficiency of heating and cooling systems, and the experience of testing and rating heat pumps, including projects in situ. At the Gaithersburg site, NBS had state-of-the-art laboratory facilities, including environmental chambers for controlled temperatures from -45 °C to 65 °C (-50 °F to 150 °F) with humidity control, as well as outdoor testing facilities, including the Bowman house. Engineering (slide rule) calculations normally consisted of estimating the "steady-state" maximum heating and cooling loads using peak weather data, heat and air transfer calculations, and estimates of imponderables like occupant living patterns, rate of window and door openings, and hot water and appliance usage. When energy was cheap and readily available, this system worked well because equipment could be oversized with factors of safety. What was needed for the high-cost energy crisis was accurate predictions based on measured data, hourly weather data covering all seasons of the year in any location and the dynamic profile of hourly energy required by a proposed building design for a full year. A rapid computer capability was available for computations at NBS; the National Oceanic and Atmospheric Administration could supply hourly weather data for a whole year or for many years for many cities in the United States and globally; and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) was rapidly coming up on the learning curve of dynamic computer calculations.

Tamami (Tom) Kusuda at NBS developed a dynamic computer calculation program called the National Bureau of Standards Load Determination Program (NBSLD), described elsewhere in this volume, to address these problems in depth. With availability of a 70,000 cubic foot environmental chamber at NBS, a series of experiments was devised to validate NBSLD using three-dimensional structures whose exteriors could be subjected to dynamic temperature and humidity boundary conditions. The results of experimental validation testing of NBSLD were published in Building Science Series (BSS) 45 in 1973 [6] and in BSS 57 in 1975 [7]. The response factor space load prediction methodology of NBSLD was found to be accurate, and the agreement between calculated and observed heating energy rate was considered excellent. This work had landmark impact because the tools for energy design

and savings procedures were convincingly demonstrated to be reliable.

NBS recommended that its 1974 energy conservation document be used as a basis for development of a national voluntary consensus standard. NCSBCS requested that ASHRAE process the NBS report as a national consensus standard [1]: ASHRAE established an extraordinary effort to analyze and refine the NBS report and, in August 1975, published ASHRAE Standard 90-75 (revised 1977) Energy Conservation in New Building Design, with the technical support of IES (now IESNA).

In January 1977, representatives of NCSBCS and the three model building code organizations put ASHRAE 90-75 into code language under sponsorship of the Energy Research and Development Administration (ERDA) and submitted it to public review and hearings. In December, 1977 the final version was published by the Council of American Building Officials (CABO). Subsequent revisions are known as the Model Energy Code (MEC) [8]. Over the ensuing decade, all 50 states enacted regulations based on the ASHRAE 90 Series Standards, the Model Energy Code, or one of several regional and State codes that also used these ASHRAE Standards as a technical base. ANSI approved a jointly sponsored revision, ANSI/ASHRAE/IES 90A-1980, as an American National Standard [9]. Standard 90A-1980 was a revision of Sections 1-9 of ASHRAE 90-75. An addendum was issued in 1987 to supplement the residential requirements in 90A.

In view of the need for more procedures and data for determining economic efficiency, the NBS/CBT Office of Applied Economics (OAE) addressed the U.S. Department of Energy's (DOE) Building Energy Performance Standards (BEPS) program-and the need to revise ASHRAE Standard 90 to save more nonrenewable energy-with three publications published in 1978-81: The Role of Economic Analysis in the Development of Energy Standards for New Buildings [10], A "Reference Building" Approach to Building Energy Performance Standards for Single-Family Residences [11], and Economics and Energy Conservation in the Design of New Single-Family Housing [12]. These economic applications to standards for building energy design were based on principles published in 1974 by Stephen R. Petersen in BSS 64 [13] and on OAE Chief Harold E. Marshall's support of development by ASTM Committees of consensus standards for economic definitions, terms and practices as tools for evaluating energy conserving investments in buildings and building systems [14]. OAE wrote a separate NBSIR report as the basis for each of these ASTM

Standards. These standards have come into use world wide for making both energy and other types of building investment decisions. The economic methods and software initiated with Petersen's work in 1974 and continued to the present have provided the underpinnings of ASTM standard methods universally used for evaluating the economics of energy conservation in buildings.

In 1983-84 the ASHRAE 90 project was reorganized into two project committees, 90.1 covering commercial and high-rise residential buildings and 90.2 covering low-rise residential buildings. A major revision of the commercial building requirements, ASHRAE/IESNA 90.1-1989, was approved by the ASHRAE Board of Directors (BOD) on June 24, 1989 for publication, later updated by seven addenda. ANSI approved ANSI/ ASHRAE/IESNA 90.1-1989 with addenda as an American National Standard on July 9, 1996 [15]. In this revision, the complexity and size of the Standard 90 Series was considerably increased by incorporating

building design criteria based on dynamic (e.g., diurnal) heat flow analysis and hourly weather conditions rather than assuming steady-state conditions.

ASHRAE/IES Standard 90.1-1989 for commercial and high-rise residential buildings and the CABO Model Energy Code 1992 for low-rise residential buildings were referenced as minimum requirements in Congressional legislation entitled the Energy Policy Act of 1992 [16]. An energy conservation standard for federal buildings was also developed by DOE under this Public Law and published in DOE regulations, in recognition of different tax laws and economic objectives.

During the 1990s, Standing Standard Project Committee (SSPC) 90.1 maintained the standard by issuing numerous addenda and three public reviews of a major rewrite. The ASHRAE Board of Directors (BOD) voted on June 24, 1999 to approve publication of the revised Standard 90.1-1999 as an ASHRAE/IESNA Standard [17] (Fig. 2), pending ANSI approval of the

revision as an American National Standard. This revision incorporates nine addenda to 90.1-1989, a reorganized document, scope expanded to cover new systems and equipment in existing buildings, code compatible language, and publication in separate IP (inch-pound) and SI versions. More than two-dozen newly proposed addenda were also recommended by the SSPC for public review approval. Over the years, the Standard 90 Series has been the best seller among ASHRAE Standards.

A case study in NISTIR 5840, Benefits and Costs of Research: Two Case Studies in Building Technology [18], provided estimates of the economic impacts from past BFRL research leading to the introduction of ASHRAE Standard 90-75-specifically, that portion of the standard dealing with single-family residential energy conservation. The goal of this study was to demonstrate how standardized evaluation methods can be used to evaluate the benefits and costs of research. The energy costs of houses designed according to 90-75 was compared to those of pre-1973 oil embargo standards. More than $900 million (in 1975 dollars) of the energy savings from 90-75 modifications in single-family houses were directly attributable to BFRL activities that promoted the development of ASHRAE 90-75.

The late Paul R. Achenbach, a mechanical engineer and chief of the Building Environmental Division of the Center for Building Technology, was born in Alberta, Canada. During his 43 year career at NBS, which started in 1937, he pioneered many new developments in the testing, evaluation, and modeling of the performance of building heating and air-conditioning equipment. Many dealt with improving the energy efficiency of this equipment and buildings decades before a concern for energy conservation became widespread. He initiated the programs on energy conservation in buildings and communities at NBS in 1970, for which he received the Department of Commerce Gold Medal in 1975. He had previously received the DOC Silver Medal in 1956 and the NBS Edward B. Rosa Award in 1970 for outstanding achievement in the development of engineering standards.

Throughout his career, Achenbach placed great emphasis on getting his work and that of his staff transferred into practice through the publications, conferences, and standards of ASHRAE. He served on the ASHRAE Board of Directors, and as its Vice President, receiving its Distinguished Service Award; he was named a Fellow and received its highest award for technical achievements, the F. Paul Anderson Award. He served as the Department of Commerce representative on the U.S. National Committee of the International

Institute of Refrigeration (IIR) and was an honorary president of Commission VII of IIR.

Prepared by Jim L. Heldenbrand.

Bibliography

[1] Jim L. Heldenbrand (ed.), Design and Evaluation Criteria for Energy Conservation In New Buildings, NBSIR 74-452, National Bureau of Standards, Washington, DC (1974). Revised in 1976. Includes a February 27, 1974 letter, bound into the document, from F. Karl Willenbrock, Director of the Institute for Applied Technology, NBS, to Bernard E. Cabelus, 1973-74 NCSBCS President.

[2] Jim L. Heldenbrand, Development and Application of Design Performance Standards for Energy Conservation in Buildings, Industrialization Forum, 8 (3), 9-20 (1977) (Ref. p. 9). [3] P. R. Achenbach and J. L. Heldenbrand, Development of Performance-Based Energy Conservation Standards for Buildings, in Proceedings, First Canadian Building Congress: Energy and Buildings, Toronto, 25 to 27 October 1976, NRCC 15870, Canadian Committee On Building Research of the National Research Council of Canada, Ottawa, Canada (1976) pp. 213-224 (p. 214).

[4] Delmont C. Thurber, NCSBCS Lifetime Historian, History of the National Conference of States on Building Codes and Standards, Inc. 1967—. . . ., NCSBCS, Herndon, VA (updated annually). The foreword includes a useful, edited version of early NCSBCS history written by Gene A. Rowland, first NCSBCS President, 1967-68, with comments by Bernard E. Cabelus, NCSBCS President in 1973-74. The main document includes a chronology and narratives of events of the first 20 years, and yearly updates of later NCSBCS conferences.

[5] Paul R. Achenbach, Building Research at the National Bureau of Standards, Building Science Series 0, National Bureau of Standards, Washington, DC, October 1970.

[6] Bradley A. Peavy, Frank J. Powell, and Douglas M. Burch, Dynamic Thermal Performance of an Experimental Masonry Building, Building Science Series 45, National Bureau of Standards, Washington, DC, July 1973.

[7] B. A. Peavy, D. M. Burch, F. J. Powell, and C. M. Hunt, Comparison of Measured and Computer-Predicted Thermal Performance of a Four-Bedroom Wood-Frame Townhouse, Building Science Series 57, National Bureau of Standards, Washington, DC, April 1975.

[8] Robert Brown and Carolyn Fitch, Introduction to Energy Codes, originally published in Technical Bulletin, National Conference of Building Codes and Standards, May 1994, and republished in Southern Building, September/October 1994, pp. 29-31 (Ref. p. 30).

[9] Energy Conservation In New Building Design, ANSI/ASHRAE/ IES 90A-1980, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., New York, May 16, 1980.

[10] Stephen R. Petersen, The Role of Economic Analysis in the Development of Energy Standards for New Buildings, NBSIR 78-1471, National Bureau of Standards, Washington, DC, May 1978.

[11] Stephen R. Petersen and Jim L. Heldenbrand, A "Reference Building" Approach to Building Energy Performance Standards for Single-Family Residences, NBSIR 80-2161, National Bureau of Standards, Washington, DC, October 1980.

[12] Stephen R. Petersen, Economics and Energy Conservation in the Design of New Single-Family Housing, NBSIR 81-2380, National Bureau of Standards, Washington, DC, August 1981. [13] Stephen R. Petersen, Retrofitting Existing Housing For Energy Conservation: An Economic Analysis, Building Science Series 64, National Bureau of Standards, Washington, DC, December 1974. Also, Stephen R. Petersen, BLCC-The NIST Building Life-Cycle Cost Program, first software release, 1985, is based on BSS 64.

[14] Standard Practice for Measuring Life-Cycle Costs of Buildings and Building Systems, ASTM E917, American Society for Testing and Materials, West Conshohocken, PA.

Standard Practice for Measuring Benefit-to-Cost and Savings-
to-Investment Ratios for Buildings and Building Systems, ASTM
E964, American Society for Testing and Materials, West
Conshohocken, PA.

Standard Practice for Measuring Internal Rate of Return and
Adjusted Internal Rate of Return for Investments In Buildings
and Building Systems, ASTM E1057, American Society for
Testing and Materials, West Conshohocken, PA.

Standard Practice for Measuring Net Benefits for Invest-
ments in Buildings and Building Systems, ASTM E1074,
American Society for Testing and Materials, West
Conshohocken, PA.

Standard Practice for Measuring Payback for Investments in
Buildings and Building Systems, ASTM E1121, American
Society for Testing and Materials, West Conshohocken, PA.
Standard Guide for Selecting Economic Methods for Evaluating
Investments in Buildings and Building Systems, ASTM
E1185, American Society for Testing and Materials, West
Conshohocken, PA.

[15] Energy Efficient Design of New Buildings Except Low-Rise Residential Buildings, ANSI/ASHRAE/IESNA 90.1-1989, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA, June 29, 1989; with supplemental addenda approved as an American National Standard on July 9, 1996.

[16] Energy Policy Act of 1992, Public Law 102-486, Title I-Energy Efficiency, Subtitle A-Buildings, Sec. 101. Building energy efficiency standards, October 24, 1992.

[17] Energy Standard for Buildings Except Low-Rise Residential Buildings, ASHRAE/IESNA 90.1-1999, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA, June 24, 1999.

[18] Robert E. Chapman and Sieglinde K. Fuller, Benefits and Costs of Research: Two Case Studies in Building Technology, NISTIR 5840, Office of Applied Economics, Building and Fire Research Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, July 1996 (Ref. pp. 47 and 69).