ASHRAE 90.1 adds multi-res lighting proviso

LED advances factor into 2016 update of the energy performance standard
Monday, November 7, 2016
By Barbara Carss

Developers of multi-residential buildings can expect more pointed direction on their lighting choices as North American jurisdictions update their building regulations. The newly released 2016 edition of the ASHRAE 90.1 standard for energy efficiency includes first-time requirements for lighting within dwelling units. Previously, the standard’s ascribed lighting power density applied only to common areas such as lobbies, corridors and laundry rooms.

“In 2016, there is an added requirement that no less than 75 per cent of lamps in permanent lighting installations in dwelling units have to be of a high efficacy — at least 55 lumen per watt,” reports Eric Richman, senior research engineer at the U.S. Pacific Northwest National Laboratory who serves as chair of the ASHRAE 90.1 lighting subcommittee. “That could be a good compact fluorescent or an LED.”

ASHRAE 90.1 is regarded as the de facto guidance document for energy performance in all types of buildings except low-rise residential given that regulators across the continent reference it in their codes and bylaws. Proposed changes to Canada’s National Energy Code for Buildings (NECB), now open for public comment, include lighting criteria harmonized with ASHRAE 90.1-2016, while the United States Department of Energy conventionally adopts the standard as the minimum compliance requirement that states and municipalities must enforce in their building regulations.

All 90.1 lighting requirements are premised on the light levels that the Illuminating Engineering Society (IES) deems adequate to carry out tasks in various types of space. From there, the standard devisors employ energy modelling to determine how the required light level could be achieved with available technologies. This is then expressed as an allowable wattage per square foot, known as the lighting power density (LPD).

ASHRAE 90.1-2016 introduces more stringent lighting power densities for dozens of designated types of space, attributed to the inclusion of LED technology in the 2016 modelling.

“The same thing happened going from 2010 to 2013,” Richman notes. “Most of the space type LPDs went down because there were more efficacious products available for the modelling.”

Yet, he stresses that the standard does not mandate LEDs nor prohibit less efficient lighting options. Designers could theoretically specify any legally available product provided the cumulative LPD for the space can be attained.

“The number is technology-neutral,” he says. “It’s going to be impossible to light the space with all incandescents, but you can mix and match. If you do a good job of designing, you might be able to use incandescents for a part of the space.”

Quirkily, and in contrast to most other building types, the multi-res LPD has actually become more generous in the 2016 standard because of changing design practices and IES light level recommendations. “If IES increases a recommendation, which has happened in the past, then our LPD number is likely to go up,” Richman explains.

Ultimately, the efficacy requirement for fixed installations in dwelling units is considered more significant. Even if unit occupants choose less efficient floor and table lamps, the new multi-res lighting proviso addresses energy efficiency in a vast amount of hardwired wall and ceiling lighting that was previously exempted from consideration.

For developers, the resulting capital cost increase should be modest relative to the overall construction budget. LED or compact fluorescent ballasts are comparably priced to other types of lighting even if the bulbs are more costly than halogen or incandescent. Meanwhile, improved energy efficiency within suites can be marketed to both prospective homebuyers and renters.

The new requirement isn’t necessarily imminent, however, since ASHRAE’s triennial cycle for revising the 90.1 standard tends to be well in front of provincial, state and municipal regulators’ slower pace for updating their building regulations. The majority of such documents will continue to reference the 2013, 2010 or even 2007 versions of 90.1 as the threshold standard for energy performance for awhile yet.

Barbara Carss is editor-in-chief of Canadian Property Management.

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