By Facility Executive Staff
From the April 2017 Issue
In October 2016, numerous energy savings measures resulting from industry input were presented in a newly published energy efficiency standard from ASHRAE and IES. ANSI/ASHRAE/IES Standard 90.1-2016, Energy Standard for Buildings Except Low-Rise Residential Buildings, contains 121 addenda published since the 2013 standard. The 2013 standard currently serves as the commercial building reference standard for state building energy codes. This 2016 version is the 10th edition published since the original standard was first published in 1975 during the energy crisis of the United States.
“It is the overall goal of each version to create a consensus standard that saves energy and is technically feasible and cost effective,” said Drake Erbe, chair of the Standard 90.1 committee, upon publication last fall. “In addition, as a result of a strategic initiative begun in the 2013 cycle, the 2016 version has a new format that we believe will be easier for users, a new way of incorporation of reference material from other standards starting with climate data, and a performance path for compliance that rewards designs for achieving energy cost levels above the standard minimum.”
The 2016 version of Standard 90.1 addresses lighting, building envelope, and mechanical systems. This article takes a look at several aspects related to lighting. Facility Executive recently asked Eric Richman and Michael Rosenberg, both from Pacific Northwest National Laboratories, to elaborate on a few of the changes.
Lighting Power Allowances
What factors impacted the committee’s decision to set the reduced lighting power allowances set forth in the 2016 version?
Richman: The reduction in lighting power allowance (LPA) limits, across both interior and exterior applications, are primarily a result of the inclusion of LED lighting technology. As LED technology continues to improve and more cost-effective products become available on the market, these are included in the calculations used to determine the LPA limits in the standard. The 2016 LPAs include the efficiency of LED technology in most space types, which makes lighting power needs and the corresponding lighting power allowance lower.
However, less efficient lighting technology is still part of the mix of lighting for interior spaces where it is still appropriate and where LED products are still limited. For example, some retail merchandising and museum display applications still rely on high intensity halogen sources to provide effective spotlighting but as LED products improve in this area, they will replace halogen technology in future versions of the standard.
In the 2016 version of ASHRAE 90.1, exterior and parking garage lighting is required to reduce power by 50% when unoccupied/after hours. This was 30% in the previous version. What enables facility operators to achieve this, without sacrificing visibility and safety?
Richman: The revised 50% reduction in lighting power allowance in parking garage lighting for 2016, as well as the previous 30% reduction requirement, only applies when there are no occupants in the space and therefore will not affect any required light levels for visibility or safety for occupants. The increase to a 50% reduction level was simply the realization that additional savings were available and achievable with available controls technologies.
Modified control requirements are included in version 2016 to simplify advanced lighting control applications. Can you provide an overview of the modifications?
Richman: There were several clarifications to controls application and one significant exemption added that makes advanced lighting control easier. The previous version [of the Standard] had required manual controls for open office areas that inhibited the use of advanced lighting controls in these areas. Open office spaces represent a significant portion of lighting square footage in commercial buildings, and new, advanced automatic lighting controls have been shown to be very effective at saving energy in these areas.
The new exemption for the 2016 version removes manual control requirements for open offices, which then makes it easy to apply these advanced controls.
Paths To Standard 90.1 Compliance
Please explain the new compliance option—Performance Rating Method. What does it mean for building owners who are aiming for baseline compliance? What does it mean for those who are aiming higher (e.g., LEED or other green building certification)?
Rosenberg: Prior to 2016, Standard 90.1 included two paths for compliance. The prescriptive path regulates individual building component efficiencies, including things like the R-value of insulation in walls or roofs, maximum lighting power allowance, and the efficiency of air conditioners and boilers.
The performance path (known as the Energy Cost Budget (ECB) Method) provided greater flexibility for owners and designers, since it allows the use of some components less efficient than the prescriptive requirements if that can be made up for by improvements in other components, as demonstrated by building simulation models.
For example the prescriptive path in Standard 90.1 limits the amount of window area allowed to a maximum of 40% of the gross exterior wall area. The ECB path would allow a designer to exceed 40% window area if, for example, the design included more roof insulation and a high efficiency boiler, and that made up for the energy impact of more windows.
In addition to the ECB method, Standard 90.1 includes a second performance path known as the Performance Rating Method, commonly referred to as Appendix G for its location in the Standard. Like ECB, Appendix G uses building simulation to assess energy performance of a proposed building design. However, unlike ECB, Appendix G was not allowed for compliance but instead was meant to rate the performance of buildings designed well in excess of the Standard and used for “beyond code” programs such as USGBC’s LEED, the International Green Construction Code, and the federal tax credit program.
Because it was not used for compliance, Appendix G was able to provide credit for energy efficient design features that have not traditionally been regulated by code, such as optimized orientation and window area, selection of appropriate HVAC systems, “right sizing” of HVAC systems, and use of lower cost energy sources.
Having one performance path for code compliance and another for beyond code programs was confusing and often meant that an engineer would need to create multiple building models each following different rules. With the publication of 90.1-2016, Appendix G is now approved as a third compliance path. This means that the same model will now have multiple uses, which should encourage the development of software and other tools to automate the modeling process.
In summary, the 2016 edition of Standard 90.1 includes a third compliance path that provides more flexibility for designers, better recognition of energy efficient designs, and lower modeling costs for building owners.
ASHRAE President, Timothy Wentz, P.E., has stated that the “challenge to improve energy efficiency derived by using the Standard is due to technology becoming more efficient”. Focused on lighting, what factors would you say have helped keep the push forward in efficiency with Standard 90.1-2016?
Richman: The 2016 version incorporates changes in both lighting power allowance limits and controls where there is additional, practical energy savings. This included the addition of LED technology as well as improved savings from controls and some new requirements for dwelling unit lighting and some parking areas. Going forward, there is very likely going to be further reductions in lighting power density limits based on the inclusion of more LED technology in applications where it was not included for 2016. Additional changes in controls are also likely in limited applications as advanced lighting control continues to evolve.
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