As California progresses towards its energy efficiency and decarbonization goals, section after section of the building industry is being overhauled. The belt is tightening this code cycle in several substantive ways, and nonresidential lighting is one of the areas feeling the pressure. As Jim discusses (see “2019 Nonresidential Performance Method is not a Magic Bullet”), nonresidential lighting power density (LPD) allowances are being ratcheted down from the level of fluorescent technology to all LED technology under 2019 code. This means that, first and foremost, designers need to be embracing all LED and layered lighting designs now, if they haven’t already done so.
Here’s a table comparing 2016 and 2019 Complete Building LPD allowances from the Energy Code Ace class on “Decoding What’s New: Let’s Talk 2019 Title 24 Part 6” for nonresidential, high-rise multifamily and hotel/motel buildings:
While the majority of nonresidential lighting projects we see at Gabel are new high-rise multifamily building where lighting is only one of the components we incorporate into the whole building performance method, we have also had the pleasure over the past few years to work on a slew of lighting alteration projects using the prescriptive method. This is a common scope of work, as buildings from big box stores to apartment complexes with amenity spaces replace their lighting regularly for maintenance.
California’s Energy Code covers these lighting alterations to ensure that improvements to existing building stock do not increase energy use. However, many of these projects proceed without considering the Energy Code. They miss the potential for energy savings to avoid dealing with the headache of compliance analysis. At Gabel Energy, with the support of Energy Code Ace, we are encouraging lighting alteration compliance by developing consulting relationships with contractors, giving them tools to help understand code requirements, and advocating for their needs when it comes to code development. With this approach, we hope to make compliance less painful and energy savings more accessible to the industry.
Important Considerations for Lighting Alterations
I am going to briefly cover indoor lighting code requirements to highlight some important considerations for lighting alterations.
There are two areas to consider when it comes to lighting energy use. The first is the rated power of the system, which sets the ceiling on how much energy can be used at any given time. The second is the control scheme, which ensures lights are only on when they are needed. The following sections of California’s Energy Code regulate lighting power density and mandatory controls:
- Section 130.1 covers mandatory indoor lighting controls. These include area (on/off), multi-level (dimming), and shut-off (timer or occupancy sensor) controls in addition to demand response and daylighting controls.
- Section 140.6 covers indoor lighting. It directs us to remain below a certain lighting power density per lighting occupancy to comply with the power limits.
- Section 141.0(b)2I specifically addresses indoor lighting alterations, and gives exceptions both to controls and to lighting power densities for alteration projects.
There are a few things we have learned that become important in lighting alteration projects and that distinguish these projects from new construction:
- Lighting Power Density (LPD): Calculating LPD typically requires floor plans. This causes potential issues with lighting alteration projects, where floor plans may not be in the budget to be drawn up, and original floor plans may not be available or may no longer be accurate. The alteration section of code allows for wattage compliance to be achieved by reducing the wattage of the altered fixtures rather than by LPD, allowing for an audit to be sufficient to determine compliance. However, in the upcoming code cycle, this compliance method is limited to buildings 5,000 ft². or less. This means, for a large number of the typical lighting retrofit projects out there, that this option is no longer available as of January 1, 2020. Instead of allowing this to boot projects back to the noncompliance/unpermitted wing of the world, Gabel is hoping to fill the gap by proving audit tools to contractors that incorporate room area measurements. This way, floor plans may not need to be drawn up.
- Controls: For existing buildings, the mandatory lighting controls of Section 130.1 can be extremely cost prohibitive. However, lighting alteration code Section 141.0(b)2I and Table 141.0-F define situations when fewer controls are required as long as the total installed wattage meets certain percentages lower than the total allowed wattage from Section 140.6. This means contractors need to design systems that meet these criteria. See the Lighting Alteration table from “Decoding What’s New: Let’s Talk 2019 Title 24 Part 6” for details:
- Design/Product Availability: Typically, designing lighting systems that are better than code is possible because the code is aligned with ASHRAE and LED technology. Most people are using LED technology these days, and also projects don’t need as much wattage as is allowed per code. However there are a few pitfalls designers may run into that bump up the wattage and unbalance the delicate equation required to meet controls exceptions. I am going to list out a few wattage reduction rules of thumb:
- Custom fixtures bump up your LPD.
- We are looking at the total rated wattage of the fixture, not the lamp being used. Hardwired fixtures are preferable.
- Layered lighting design is the path to lowering LPD.
In conclusion, lighting alterations remain a hefty portion of projects out there, and though compliance with code is complex, designing compliant systems can be simple and cost effective.
Article written by Ari Usher, Energy Analyst
First published in the Gabel Energy Summer/Fall 2019 Newsletter