Most recently, the green building movement has resulted in the development and use of several third-party green building rating systems that have their own requirements for lighting systems installed in commercial buildings. This presents a new challenge for electrical contractors because lighting system requirements may vary for different energy codes, standards and green building rating systems encountered on the same project.
Electrical contractors need to be aware of this and know how to decipher and untangle these requirements. This is especially true when the EC is working with incomplete design documents or is operating in a design/build or design/assist mode.
Consider a commercial building in a city that has adopted the International Code Council’s (ICC) International Energy Conservation Code (IECC). Section 805.2.2.1 of the IECC requires that manual lighting controls installed in most building spaces allow occupants to reduce the connected lighting load by at least 50 percent through dual-level switching, dimming or other approved method. This requirement is similar to Section 131(b) of the California Energy Efficiency Standards (Title 24, Part 6).
Assume the project owner also is seeking green building certification, using the United States Green Building Council’s (USGBC) Leadership in Energy and Environmental Design (LEED) Green Building Rating System for New Construction and Major Renovations (LEED-NC), and wants to earn credits in the Energy and Atmosphere (EA) category. To earn credits toward certification in this category, all prerequisites must be met, which includes EA prerequisite two, Minimum Energy Performance.
EA prerequisite two requires that the installation comply with both the mandatory and prescriptive lighting requirements of the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE) and the Illuminating Engineering Society of North America’s (IESNA) ASHRAE/IESNA Standard 90.1-2004 titled Energy Standard for Buildings Except Low-Rise Residential Buildings. They are addressed in Sections 9.4 and 9.5, respectively. ASHRAE/IESNA Standard 90.1 does not require light-reduction controls, so multilevel switching or dimming is not necessary for either ASHRAE/IESNA Standard 90.1 or LEED-NC EA prerequisite two.
In the end, the IECC would require the installation of light-reduction controls in order to comply with the city’s energy code. Without taking time to untangle the lighting system requirements and understand exactly what is required by applicable codes and standards, the electrical contracting firm could easily miss a requirement in bidding or installation that would result in additional direct costs or costly rework
Unlike light-reduction controls in the previous example, both IECC Section 805.3 and Section 9.4.2 of ASHRAE/IESNA Standard 90.1 require tandem-wired luminaires. Tandem ballasts usually are used when adjacent luminaires have an odd number of lamps to reduce energy use. Two-lamp ballasts typically are more efficient than single-lamp ballasts. Therefore, it is more energy efficient for two luminaires to share a common two-lamp ballast rather than installing a single-lamp ballast in each luminaire.
A common application of tandem-wired luminaires is adjacent three-lamp fluorescent troffers where one luminaire has two two-lamp ballasts with one ballast serving the two outboard lamps in the luminaire and the other ballast serving the inboard lamp in the two adjacent luminaires. The other luminaire then needs only a single two-lamp ballast to serve its two outboard lamps.
Lighting manufacturers usually offer tandem-wired luminaires as an option. However, the contractor must be aware of this requirement when asking for quotations during bidding and when ordering with the supplier after contract award. The need for tandem-wired luminaires could be missed if the contract documents are not clear on this requirement and rely instead on reference to the applicable energy code, standard or third-party green building rating system.
Today, when bidding, buying out and installing lighting systems for commercial buildings, the electrical contracting firm needs to become familiar with the energy codes, standards and third-party green building rating systems on its commercial building projects in order to avoid possible bid errors and rework. EC
This article is the result of a research project investigating the emerging IBS market for the electrical contractor sponsored by ELECTRI International. The author would like to thank EI for its support.
GLAVINICH is an associate professor in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. He can be reached at 785.864.3435 or firstname.lastname@example.org.