ASHRAE Journal - June 2010 - S28

boilers, water heating systems, etc., exceeding a capacity of 500,000 Btu/h (146 kW) must be submetered, and the data retained as well. The meter or the reporting system should be calibrated to account for the heating value content of the fuel used, the pressure of the fuel and the atmospheric pressure at the location of the mater installation. Data collected must be at a minimum, daily data with hourly energy use profiles and must be retained for at least three years. Buildings with low energy use thresholds and residential portions of buildings are exempted from these requirements. Section 10 of Standard 189.1 requires plans to use the data to assess the energy use at least every three years. This key portion of the standard will help identify increases in energy above what is expected. While utility-grade metering is not required, building owners may take advantage of utility “smart” metering where it exists for whole-building metering.
Service Water Heating

lighting controls must meet the requirements of Section 9 of Standard 90.1 with the following modifications. For lighting of building façades, parking lots, garages, canopies (sales and non-sales), and all outdoor sales areas, automatic controls must be installed to reduce the sum of all lighting power by a minimum of 50% within one hour after normal business closing and to turn off outdoor lighting within 30 minutes after sunrise except in certain circumstances.
Performance Options

Minimal changes from those in Standard 90.1 are incorporated in Standard 189.1. There are requirements for increases in the amount of piping insulation and, in many cases, water heating equipment efficiencies to be more stringent than those required in Standard 90.1. Insulation on the sides and bottoms of pools used primarily as spas or for physical therapy is required.
Peak Load Reduction

Standard 189.1 requires that building projects contain automatic systems, such as demand limiting or load shifting, that are capable of reducing electrical peak demand of the building by not less than 10% exclusive of any demand reduction that may be provided by standby power generation. As described in Figure 3, this peak load reduction requirement is lowered to 5% if all the mechanical equipment efficiencies meet the ENERGY STAR requirements and those in Normative Appendix C. Automatic peak load reduction can be accomplished through demand limiting in which load use is curtailed or reduced or through load shifting as load use is moved to off-peak hours.
Lighting

As an alternate compliance path, rather than meeting the requirements of the mandatory and prescriptive sections of Standard 189.1, (sections that begin with 7.3 and 7.4), users may demonstrate compliance if their buildings meet the mandatory requirements of Section 7.3 plus the performance requirements in Section 7.5. In the performance path, compliance is demonstrated in three ways. First, buildings must have an annual building energy cost less than or equal to the annual building energy cost of a baseline building constructed meeting the mandatory and prescriptive requirements of Sections 7.3, 7.4, and seven other sections of the standard. Second, buildings using the performance option must also have an annual CO2e (CO2 equivalent) less than or equal to the level achieved by compliance with Sections 7.3, 7.4, and seven other sections of the standard. To determine CO2e, the energy use by energy source (such as electricity or natural gas) is multiplied by the factors in Table 7.5.3. Third, buildings must have the same or less peak electrical demand than that achieved by compliance with the mandatory and prescriptive requirements of Sections 7.3, 7.4, and seven other sections of the standard. The building also must have a minimum electrical annual load factor of 0.25 or more. Compliance with the performance option requires the use of Appendix D. This appendix is similar to Appendix G in Standard 90.1 and requires a whole building, computer-based, energy simulation tool capable of modeling annual energy use on an hourly basis. Rules for this analysis are presented in Appendix D.
Summary

Standard 189.1 requires compliance with Standard 90.1 lighting levels and further reduces lighting power allowances in Sections 9.5 and 9.6 by 10%. Occupancy sensors, automatic controls for egress and security lighting, automatic controls for lighting in daylight zones and controls for outdoor lighting are also required with appropriate exceptions where necessary. Users may use either the Building Area method of Section 9.5 of Standard 90.1 or the Space-by-Space method defined in Section 9.6 to determine the allowable amount of lighting for Standard 189.1. Even though the lighting power density requirements are reduced in Standard 189.1 the intent is not to result in illumination levels below those recommended by IES. The standard requires occupancy sensor controls to have “manual on” and “automatic off” controls. All outdoor
S28

The intent of the energy efficiency section is to significantly reduce the energy consumption of new buildings through reductions in energy losses through the building envelope, increased efficiencies in mechanical systems, reduced lighting loads, and other energy saving measures. Standard 189.1 requires that buildings comply with Standard 90.1-2007 and then, in general, adds more stringent requirements. Standard 189.1 requires that either on-site renewable energy is used as a prescriptive option, that renewable energy certificates are purchased (only allowed in some cases), or that the building complies with the performance option and uses additional energy-saving measures to make up the deficiency from not using on-site renewable energy.
June 2010

ASHRAE Journal’s Guide to Standard 189.1 ashrae.org

ASHRAE Journal - June 2010

Table of Contents for the Digital Edition of ASHRAE Journal - June 2010