CIVIL ENGINEERING 365 ALL ABOUT CIVIL ENGINEERING


Whether your state or city is updating its building energy codes or you’re planning ahead for the forthcoming release of LEED v4, it will soon be vital to familiarize yourself with the 2010 version of ASHRAE 90.1.

The standard establishes the baseline building performance in LEED v4 (which officially premieres in November) and is also a compliance path for the 2012 IECC.

Among the energy efficiency upgrades in the new version are a host of new and updated lighting requirements. Here are three major changes to consider in your long-term strategic planning.

1) Daylighting
The latest version is the first to address daylighting by requiring controls to compensate for available natural light.

This helped the 90.1 committee meet the goal of reducing the allowable energy use under the previous version of the standard by 30%, says Jeff Boldt, principal and director of engineering at KJWW Engineering. Boldt is also a voting member of the 90.1 committee and chair of several related working groups.

“Let’s say you’ve got a conference room and it has an outside wall that contains a lot of glass,” Boldt explains. “What the code is requiring is that when the sun is shining in and the room is bright, the lights should automatically dim or turn off in there to save energy instead of staying fully illuminated.”

2) Controls and Sensors
The 2010 version of 90.1 includes many new requirements for lighting controls in addition to the daylight-specific requirements, says Eric Richman, chair of 90.1’s lighting subcommittee. These include:

Shutoff and dimming: Office spaces up to 250 square feet, restrooms, training rooms, lecture halls, and storage areas from 50-1,000 square feet are among the many areas that must now include vacancy sensors, which automatically turn the lights off when the room is empty but require the next visitor to manually turn the lights on.

Spaces where lighting is required for 24-hour use or where automatic off would be unsafe are exempted from this rule.

Many spaces must also include bi-level control, Boldt explains. This is easily accomplished with multiple wall switches or an occupancy sensor that turns lights back on at no more than 50% brightness after the room is reoccupied.

“Past experience has shown a divergent preference between a vacancy sensor and an auto-on occupancy sensor at 50% brightness,” explains Shanna Olson, senior lighting designer for KJWW Engineering. “Typically, the former is preferred for all spaces with a secondary light source – an office with a window, for example. The latter seems to be preferred in fully enclosed spaces. Note that the vacancy sensor will likely save more energy than the 50% auto-on occupancy sensor in the long run.”

Parking garages: Bridging the divide between interior and exterior lighting, parking garages present a special challenge. The new version requires garages reduce power by 30% if no activity is detected within a 3,600-square-foot area.

“Parking garages are a new requirement in 90.1. What the standard is saying is that you need to shut off the lights in most spaces whenever there is no occupancy or movement,” says Michael Clemens, senior value stream manager for Sensor Switch and nLight controls at Acuity Brands. “However, you might not want to turn off the lights in some areas for safety reasons, just dim them. With LEDs and fluorescents, you can dim the lights by 30% or more and then have them come up to 100% illumination only when there is movement in the space.”

Exterior: Instead of only the dawn to dusk controls specified in previous versions, the 2010 version also accounts for business occupancy, Richman says. Exterior lighting must be turned off when enough daylight is available, which is easily accounted for with an astronomical timer or daylight sensor. Facade and landscape lighting must also be off from midnight or closing until 6 a.m. or opening, Boldt adds.

All other outdoor lighting power must be reduced by at least 30% from either midnight or closing until 6 a.m. or opening, or when no activity has been detected within 15 minutes.

3) Commissioning
This requirement has been somewhat controversial, Boldt notes. An addendum to the new version calls for independent third-party testing of lighting control devices and systems to ensure all are properly calibrated.

“The thought was that if we require all of these lighting controls and they don’t work or people find ways to defeat them, organizations will spend a lot of money and not save any energy,” Boldt explains. “It has been controversial both from the standpoint of people wondering whether it’s cost-justified and from consultants asking why it has to be done by a third party.”

However, behind the controversy is a path to saving nearly a third of the energy consumed by a building that meets the 2004 version per the committee’s goal. Smart implementation and advance planning will ensure a smooth transition when you upgrade your facility to meet the new requirements.

“Embrace it instead of trying to resist it,” Clemens says. “Hopefully people will be able to see that the money they’re saving is well worth the investment.”

 

Janelle Penny janelle.penny@buildings.com is associate editor of BUILDINGS.

 



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