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ASSIST Application Design Metric Guides

Overview

The Alliance for Solid-State Illumination Systems and Technologies (ASSIST) has developed short design guides providing an overview of the main lighting characteristics that are important for different applications. Specifically, these guides suggest alternative ways to evaluate and compare LED solutions with traditional lighting technologies. The suggestions focus on how application metrics and benefit metrics can be used and contrasted to typical light source or luminaire metrics (e.g., luminous efficacy [lm/W]) when assessing the effectiveness of different lighting options at meeting the design objectives. Additional resources are provided for further reading.

Metrics Background

Application metrics are methods that measure the application efficacy of a particular lighting system. In general, application efficacy is concerned with how well a lighting system delivers light to where it is needed and is specific to the application and its task area. The basic concept can be augmented to conform to the photometric requirements of a task, for example light levels and uniformity. Application efficacy is in direct contrast to the traditional metric of luminaire system efficacy, which is specific only to the luminaire and does not consider the application. ASSIST has implemented the application efficacy concept in a number of its recommended metrics, as a means to appropriate comparisons among all lighting technologies serving a given application.

Benefit metrics consider what factors are important in an application and how a light source (LEDs in this case) can provide those benefits using metrics other than those traditionally considered. These benefit metrics may include spectral effects on visibility, brightness, color rendering (beyond CRI), light source color appearance, perception of safety, flicker perception, illuminance uniformity, and more.

Summary Poster (2015) PDF

Publications

Parking Lot Lighting PDF
This guide is meant to assist lighting designers, owners and operators in identifying appropriate metrics for quantifying the benefits of parking lot lighting relative to the costs, and in doing so, maximize the value of the specified lighting system.

Roadway Lighting PDF
This guide is meant to assist lighting designers, owners and operators in identifying appropriate metrics for quantifying the benefits of roadway lighting, including issues of scene brightness, photopic illuminance and visual efficacy.

Health Care Lighting PDF
This guide is meant to assist lighting specifiers in identifying appropriate metrics for illumination design in health care environments. Metrics in addition to conventional quantities such as photopic illuminances should be considered in these locations for issues like color quality and non-visual effects. These application issues and benefit metrics are discussed, with pointers to appropriate resources provided.

Retail Lighting PDF
This guide identifies appropriate metrics for quantifying the benefits of retail lighting, including application efficacy, color quality, and methods for using color to increase the visual appeal of displays while reducing power density.

Industrial Lighting PDF
This guide identifies ways to achieve maximum benefits in industrial lighting, including visibility, safety, and visual comfort.

Application Metrics Background

Application metrics are methods that measure the application efficacy of a particular lighting system. In general, application efficacy is concerned with how well a lighting system delivers light to where it is needed and is specific to the application and its task area. The basic concept can be augmented to conform to the photometric requirements of a task, for example light levels and uniformity. Application efficacy is in direct contrast to the traditional metric of luminaire system efficacy, which is specific only to the luminaire and does not consider the application. ASSIST has implemented the application efficacy concept in a number of its recommended metrics, as a means to provide appropriate comparisons among all lighting technologies serving a given application.

For more information on application efficacy and metrics, see the following publications:

Narendran, N., J.P. Freyssinier, J. Taylor, T. Dong, and R. Capó. 2010. Application efficacy for comparing energy demand in lighting applications. Tenth International Conference on Solid State Lighting, August 1- 5, 2010, San Diego, CA, Proceedings of SPIE 7784: 77840L.
Full-text PDF

Taylor, J. 2010. An application approach to achieving success with LEDs. Lighting India 5(2): 48-55.
Full-text PDF

Freyssinier, J.P., J. Taylor, D. Frering, and P. Rizzo. 2009. Considerations for successful LED applications. Proceedings of ChinaSSL2009, 6th China International Forum on Solid State Lighting, October 14-16, 2009, Shenzhen, China, pp. 206–209.
Full-text PDF

Narendran, N., J.P. Freyssinier, Y. Zhou, and J. Taylor. 2009. ASSIST recommends: Striving for application-specific evaluation methods. Proceedings of the 2009 International SSL Standards & Measurements Workshop, 6th China International Forum on Solid State Lighting, October 14, 2009, Shenzhen, China,
pp. 22–26.
Summary pdf logo | Full-text PDF

Narendran, N., J.P. Freyssinier, and J. Taylor. 2008. LED luminaire performance: changing traditions can set the right expectations. LEDs Magazine 18: 33-39.
Full-text PDF (Requires free site registration)

ASSIST recommends: Recommendations for Testing and Evaluating Luminaires Used in Directional Lighting PDF 

ASSIST recommends: Recommendations for Evaluating Parking Lot Luminaires  PDF 



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