Designing Green

LOS ANGELES Responding to mounting concerns over energy usage, the California Energy Commission adopted an emergency set of tighter energy standards for new construction beginning June 1, 2001. The emergency regulations have significantly reduced the amount of installed watts per square foot of lighting that electrical engineers and lighting designers can specify for a building. But even as Title

LOS ANGELES — Responding to mounting concerns over energy usage, the California Energy Commission adopted an emergency set of tighter energy standards for new construction beginning June 1, 2001.

The emergency regulations have significantly reduced the amount of installed watts per square foot of lighting that electrical engineers and lighting designers can specify for a building. But even as Title 24 gets stricter, the building design industry has surprisingly little objection.

Many in the construction industry see California's Title 24 Building Energy Efficiency Standards, which focus on building envelope materials, HVAC systems and electrical systems in buildings, as a model for other states. And several states, such as Washington and Illinois, have or will adopt building energy efficiency standards — such as the International Conservation Energy Code (based on the old Model Energy Code) — this year, although perhaps none will be as rigorous as California's.

With Title 24, electrical engineers and lighting designers must comply with the standards on the majority of projects built in the state. However, some projects, like hospitals, are exempt.

To comply with Title 24, engineers must produce documentation showing the lighting, as designed, meets a target, or total allowed wattage. The designer has several calculation methods available to comply, along with some ways to reduce the actual design wattage through control devices like occupancy sensors and lumen maintenance controls (see the sidebar on the facing page for a description of the Title 24 process).

For Hisham Barakat, a vice president and electrical engineer with consulting engineering firm Syska and Hennessy in Los Angeles, meeting Title 24 usually isn't a problem.

“I've rarely had a job that I've had a problem meeting Title 24,” Barakat said. “There are so many ways that you can do your calculations.”

Since Title 24 compliance is usually demonstrated at the plan check stage of design prior to construction, Barakat finds that often Title 24 is forgotten once the building is actually built.

“Title 24 rarely gets enforced beyond the plan check process,” he said. “The inspectors are rarely savvy enough to see how the actual installation meets the Code. It's just not followed up on as other codes are.”

For example, Title 24 mandates as one of its Mandatory Lighting Measures, that all buildings with more than 5,000 sq ft of conditioned space must have an automatic control to shut off the lights. Many buildings in California are now being built with complex lighting control systems that can shut down a building's lighting system based on a time schedule. Many of them offer an over-ride feature where occupants can flip a switch that will turn the lights on for additional time (usually two hours) before switching back into the pre-set schedule mode.

“People find those extremely annoying,” Barakat said. “I know of clients who have gone out and disconnected those over-ride switches. I understand why the Code requires it, but people are uncomfortable with it.”

With existing technology, there's only so much more Title 24 can do with electrical systems, Barakat said. He said he would like the standards to address more of the building envelope aspects, as well as appliances within the building. The standards don't give enough control credits, which can be used to reduce the amount of actual designed watts for dimming systems, he said.

Since its development in the early 1980s, Title 24 has frequently been changed to encourage the use of new technology. Originally written to allow compliance for lighting systems based on the T12 fluorescent lamp as opposed to inefficient incandescent lamps, the standards now focus on T8 fluorescent lamps, as well as the use of developing technology in lighting control systems and occupancy sensors.

Julie Glesne, a project manager with the lighting design firm Francis Krahe and Associates Inc., in Laguna Beach, Calif., said she always designs with the intent to beat Title 24, even when the project doesn't require it.

“It does its job in some respects,” Glesne said, “but in some respects, they are trying to force people to design responsibly and you can't. You can't force someone to design green.”

Glesne said a total building lighting control system is probably one of the best ways to manage lighting efficiently, but the systems come with a large price tag many owners are unwilling to pay.

“A lot of owners probably aren't realizing as much savings as they would like,” Glesne said.

And, Glesne said, some aspects of the standards don't always make sense.

For example, Title 24 mandates that in rooms larger than 250 sq ft, switching must be installed to control light fixtures that are within 15 ft of windows (what the standards call a “daylit area”) to allow those fixtures to be switched independently of the other lights in the room.

Glesne said sometimes that means a small room will have four or five switching zones, when a simple bi-level control system — allowing half the lamps in the room to be shut off — would make more sense.

One of the most striking changes in the standards made by the Energy Commission in January was the consideration of task lighting, long a missing element in the calculation of allowed and actual watts for different building types. Unless you had permanently installed fixtures, the standards did not take into consideration that many occupants bring their own task lights to plug into the wall. The new standards require that in office areas greater than 250 sq ft, 0.2W/sq ft must be included for task lighting in addition to the actual installed watts per square foot. Since the standards only allow 1.2W/sq ft to calculate the allowed watts for offices, this means that now only 1W/sq ft is allowed for non-task lighting.

However, the standard does allow some leniency, in that if you install a task lighting system that is less than 0.2W/sq ft, you can provide documentation to use the lesser value in your actual wattage calculations.

“We've always liked task lighting, but a lot of the aesthetes we work with don't like it,” said G. Michael Gehring, a principal with Kaplan Partners Architectural Lighting, Los Angeles.

A drawback to Title 24 for Gehring is the standard's emphasis on lighting the horizontal work surface without taking into consideration the need to light the vertical planes in a space.

“It's based on someone laying out two-by-fours in a space and saying that lights the horizontal plane,” he said.

And Gehring said the control credits for a typical office should be better, since you can only get a wattage credit of 10% for the installation of an occupancy sensor in an individual office.

“That means 90% of the time the lights are on and they aren't,” Gehring said. “No one has their lights on that much.”

He also sees room for the inclusion of a time factor in the standards, noting that there's a huge difference between an office occupied for 10 hours a day during the work week and a mall that may have lights on 24 hours, seven days a week.

“Of course, you don't want Title 24 to be too complex because you can't enforce it, and it's too hard to calculate,” Gehring said.

Brad Hutchinson, a principal at the Los Angeles lighting design firm Visual Terrain, also finds some aspects of Title 24 too limiting for his work, although he considers the standards to be a positive influence on the industry. Even when designing systems outside of California, Hutchinson still adheres to the principles of Title 24.

“My approach to the design is still the architectural program and the marketing program,” Hutchinson said, using a restaurant as a common example. “A restaurant is very difficult to light correctly and I don't want to use a lot of compact fluorescent fixtures in there.”

If he finds that his design isn't meeting Title 24, he would either re-think his approach or add some control systems to gain some credits.

“I see it as a goal and, in terms of lighting design, a fine goal to reach or beat,” he said.

Florence Cahn Turner, who works in specification sales for Prudential Lighting Products in Los Angeles County, has seen Title 24 change over the years and foster advances in lighting technology. She said the lighting industry has been slow to adopt new, more efficient lighting fixtures because California has been the only state demanding it.

“Once the rest of the country realizes they also have this energy problem, that's likely to change and I think that's good,” Cahn Turner said.

Cahn Turner cites changing attitudes about what constitutes good lighting as having a significant effect on Title 24.

“If you accept the fact that emergency lighting is 1 footcandle minimum and good office lighting is 50 footcandles and you translate that into watts per square foot, then there is a line where you have to stop,” she said. “But we used to say 65, 70 or more footcandles was good office lighting, but it no longer is.”

And, Cahn Turner suggests, lighting technology is always changing.

“If you think about the T5 lamp, that came as a big surprise to people who thought the T8 was the be-all and end-all,” she said.

In the past, she says, a linear fluorescent fixture with two lamps would have to be at 6 ft to 8 ft on center to be effective, whereas new fixture technology — using such innovations as the T5 high output lamp — has allowed on-center spacing to increase to 10 ft and sometimes 12 ft to 15 ft on center, thereby reducing the amount of fixtures used and saving resources.

Cahn Turner predicts that in the near future designers will probably see the most change in the lighting industry in the introduction of efficient lamp sources like high-intensity discharge lamps, which will have better color rendering. This will allow them to be used in more applications. She also thinks lenses will play a larger role as new optical systems in lenses give alternatives to conventional parabolic louvers.

“I think Title 24 has pushed us to use the new things,” she said, adding that Europe has always been ahead of the United States in accepting new lighting technology. As Title 24 developed and was rewritten to include the T8 lamp, most buildings in the U.S. were still being built using T12 lamps. “If the T8 lamp hadn't already been in Europe, where would we have been?”

Russell Fortmeyer is an electrical engineer for Arup, Los Angeles.

How does Title 24 work? A brief guide to the ins and outs of Non-Residential Title 24
  1. The standards have built-in mandatory design measures. These include requiring that all lights, except those for emergency purposes, be switched in some fashion; bi-level switching (every other light fixture, or individual lamps in each fixture); separate control of lighting within 15 ft of a window; and that buildings with more than 5,000 sq ft of conditioned space require an automatic means of shutting off the building's lighting.

  2. The allowed lighting power, in watts, is calculated using one of four methods:

    The Complete Building Method is used mainly when a building is built or totally renovated. In this case, a single lighting power allowance (in watts per square foot) regulates the entire building. For example, a school allows you to design up to 1.4W/sq ft.

    The Area Category Method allows you to break up a building's functions into specific areas, such as conference rooms, lobbies, hallways and offices, in order to maximize the allowed lighting power for all of your spaces.

    The Tailored Method is similar to the Area Category Method, only you are dealing with individual rooms, as opposed to types of spaces, and you include consideration of the actual task being performed in that room.

    The Tailored Method also includes allowances for retail and display lighting, which takes into account lighting used to light walls and inside display cases.

    The Performance Approach is used when the designer uses a computer program certified by the California Energy Commission to prove the building meets its allowed budget.

  3. After steps 1 and 2, you have your allowed watts. Concurrently, you need to count all of the fixtures installed on the project and the total actual power in watts of those fixtures. If this Actual Lighting Power is less than the Allowed Lighting Power, then you comply. If not, you would go to step 4.

  4. The standards allow you to gain credits for installing certain non-mandatory controls in your building.

    For example, if you install an occupancy sensor in a room of more than 250 sq ft, you can multiply that room's actual lighting power by the lighting adjustment factor (in this case, 10%) to find your control credit. If you have 200W installed in that room, you would have a credit of 20W that you could now subtract from your Actual Lighting Power total until you meet the Allowed Lighting Power and, hence, comply.

  5. Finally, all of this information must be compiled onto official documents and submitted for plan check by the designer.

  6. The full Title 24 can be accessed at this Web address:

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