Outdoor Lighting Power Allowance (LPA)2016 CASE Report Topics
The Outdoor Lighting Power Allowance (LPA) values in Title 24 are subject to change as new technologies (in particular, light source technologies that increase lamp efficacy) become available to the market. As a result, the LPA values have continued to slowly move downward over time in response to these technological advancements, most recently for Pulse-Start Metal Halide (PSMH) technology.
LED light source technology is advancing rapidly, and the raw lamp efficacy of LED light sources are rapidly improving beyond that of both PSMH (the current baseline standard), and High Pressure Sodium (HPS) light sources. The lumen package efficacy is anticipated to exceed PSMH and HPS in several years. Further, the efficiency of LED luminaires is typically significantly higher than either PSMH or HPS luminaires. LED luminaires will exceed combined HID source luminaire efficacy sometime in late 2014 or 2015. (DOE 2013) Finally, LED luminaires can deliver light more uniformly to the target area, which will result in further savings opportunities.
In addition, LED light source technology has a variety of operational advantages over either PSMH or HPS, including:
- much longer life expectancy (in some cases beyond 100,000 hours)
- better lumen maintenance at a given age of operation
- very good dimming efficacy curves
- a large range of dimming capability (down to 10% in most cases)
- rapid level changes that accommodates sensor integration
- instant re-strike for On-Off-On switching capability
- preservation of source color characteristics over full dimming range
As a result, LED is rapidly claiming a large portion of the exterior lighting market, and the market adoption of LED is anticipated to accelerate as the cost of LED products continues to decrease.
This measure intends to replace PSMH light sources with LED as the basis for the calculation of Lighting Power Allowances (LPA) for all exterior applications where it is technically feasible to do so.
At no point in this LPA adjustment will the lighting design criteria be changed. This basis of design has been established by the Illumination Engineering Society (IES) in a variety of sources and mapped as part of the previous Title 24 Outdoor Lighting Case Studies (CASE 2007). This matrix of design criteria was reviewed to ensure that no specific recommendations have changed, and therefore, no changes are needed to the illuminance criterion that establishes the LPA values.
Further, two specific applications have been identified that require attention. There currently is no allowance mechanism for lighting associated with ATM locations in Outdoor Lighting. This lighting is currently exempted from the code through an exception in 140.7(a). ASHRAE 90.1-2013 includes an allowance for this, and it is possible to establish a reasonable allowance for ATM locations and insert this allowance as a line-item into the tables of LPA values.
The other application requires some clarification in the language, but will require no additional LPA values established. This is lighting for tunnels and other covered pathways that would not normally be interpreted as Non-Sales Canopy applications. In this circumstance, the proposal is to add language including them in the Non-Sales Canopy category.
Several stakeholder meetings and CEC staff workshops were held regarding the Nonresidential HVAC Economizer Modifications building energy efficiency topic. The list of past meetings and hearings can be found here. If you would like to receive email updates on this CASE topic, click the link below.