Program for the 2007 Joint Meeting Technical Day

U.S. and Canadian National Committees of the CIE

 

Thursday, October 18, 2007

Ottawa, Ontario

Measurement of Spectral Irradiance in the UV

Arnold Gaertner, PhD

National Research Council of Canada Institute for National Measurement Standards

In response to the increased scientific and commercial requirements for accurate UV measurements in fields such as environmental monitoring and air and water purification systems, the NRC-Institute for National Measurement Standards (INMS) has established a strategic initiative for the Photometry and Radiometry (PAR) Group to develop improved UV scales for the measurement of optical sources and detectors. I will present some of our recent work in the PAR Group toward the establishment of a spectral irradiance scale in the UV range from 200 nm to 350 nm. Two important components are the calibration of a high temperature blackbody source as a primary optical source and the transfer of UV calibrations between deuterium lamps. I will discuss some of the problems involved in these measurements, with an emphasis on the calibration of deuterium lamps.

 

Measurement of LEDs and Solid State Lighting

Yoshi Ohno, PhD

Optical Technology Division, National Institute for Science and Technology (NIST)

The US Department of Energy is starting an EnergyStar program for high performance SSL products, with  minimum requirements for lm/W and CRI.   This necessitates standard test methods as well as a laboratory accreditation program for measurement of SSL products.  NIST is developing NVLAP program for SSL products and leading efforts to develop ANSI standard on chromaticity of SSL products and IESNA standard on electrical and photometric measurement of SSL products.  NIST is developing calibration services and standards required in these measurement procedures.  Measurement of high-power LEDs is also a problem.  CIE 127:2007 (Measurement of of LEDs) does not address the thermal issues of high-power LEDs.  The current industry practice to measure LEDs at Tj=25 degrees C (using pulsed operation) does not meet the industry needs.  NIST is developing a standard method in which LEDs are measured under realistic thermal conditions.

 

The CIE and Mesopic Photometry

Werner Adrian, PhD, Professor Emeritus

University of Waterloo

As the spectral sensitivity of the eye changes below photopic luminance levels, we need to know these changes. In 1963, the CIE recommended a set of curves for preliminary use. This prompted reinvestigations to provide a firm basis for mesopic photometry. This led to  a DIN (German) Standard in 1982.  Applications of the  "equivalent luminance Leq " , as the CIE termed it, to visual functions are shown.

 

Development of Guidelines for Mid-Block Crosswalk Lighting

Ron Gibbons, PhD

Lighting and Infrastructure Technology, Virginia Tech Transportation Institute

Pedestrian crossings pose significant illumination challenges due to the complexity of the visual task, involving urban scenes and moving vehicles and pedestrians.  Development of lighting guidelines for this context is therefore difficult.  Mid-block crosswalks offer a less complex setting than intersections and therefore were chosen as the context for developing new approaches to formulating illumination guidelines.  Digital imaging is being used to test visibility under and range of low light conditions.   The methods are explained.

 

Modeling Color Appearance of Glazing Systems Under Daylight Conditions

Mojtaba Navab, PhD

Taubman College of Architecture and Urban Planning, University of Michigan (Ann Arbor)

Architects and lighting designers often use glass samples to evaluate the outdoor color or appearance of buildings from the exterior or interior under different daylight conditions.  However, there are limits on the number of samples that can be ordered and on the range of viewing conditions. This paper describes results of computer simulation and modeling of color appearance of glazing systems compared with physical assessment. The optical properties of selected coatings and substrates were measured and compared under real sky conditions.  Portable instrumentation and field assessment protocols were developed to obtain the glazing system optical properties to be used as an input to computer visualization of glazing systems. Basic glazing constructions such as monolithic, double, triple, laminated, were included in all the testing and simulation. More complex glazing constructions, such as double laminated, were tested at full scale to better evaluate phenomena such as inter-reflections.  The results of this study will accelerate decision-making and contribute to better criteria for glazing systems.

 

Task Lighting Effects on Office Worker Satisfaction and Performance, and Energy Efficiency

Guy Newsham, PhD

National Research Council of Canada Institute for Research in Construction

This presentation reports on two experiments conducted in a mockup office.  In the first, participants worked for a day under one of two lighting designs1) ceiling-recessed parabolic luminaires and 2) the same parabolic ambient lighting with the addition of an angle-arm task light.  Participants had no control over the lighting until the afternoon, when they were offered dimming control over the ambient parabolic lighting; participants with task lighting were also permitted to move the arm location.  During the day participants performed a variety of simulated office tasks and completed questionnaires on mood, satisfaction, and discomfort.  There was no main effect of lighting design on questionnaire outcomes, however, task lighting was associated with performance improvements on some tasks.  Participants' preferred ambient light output remained the same in the task lamp scenario.  The second experiment followed up on this point.  Ambient lighting was provided by ceiling-recessed, parabolic luminaires and participants were given a variety of options for task and ambient lighting.  Increasing task lighting did reduce chosen ambient light output, but the reduction in lighting power was small, and only about the same as the power drawn by the task light.  Results suggested that participants did not dim ambient lighting further because they preferred to maintain illumination on non-task surfaces, and to avoid extreme luminance ratios.

 

Energy Saving Lighting Control Systems for Open-Plan Offices: a Field Study

Anca Galasiu, MSc

National Research Council of Canada Institute for Research in Construction

We conducted a field study in a deep-plan office building equipped with suspended direct-indirect luminaires located centrally over cubicle workstations. In order to reduce lighting energy use, the luminaires employed integral occupancy sensors and light sensors (daylight harvesting), as well as individual dimming control accessed through occupants' computer screens. Data were collected from 86 workstations over a year to examine the energy savings and power reduction attributable to the use of controls. An awareness campaign that used e-mail reminders to encourage the occupants to use the individual control feature of the lighting system was also conducted. Results indicate that the lighting system generated substantial energy savings and peak power reductions compared to a conventional fluorescent lighting system installed on a neighboring floor.  The energy savings by control element (e.g., daylighting, occupancy) are reviewed. The light sensor savings were, as expected, higher in perimeter workstations, and would have matched the performance of the occupancy sensors with some modifications to the control parameters. The average daily peak power demand for lighting was also substantially reduced.

 

Links Between Office Lighting Appraisal and Organizational Outcomes

Jennifer Veitch, PhD

National Research Council of Canada Institute for Research in Construction

The most frequently-asked question related to lighting quality research is “What can it do for my company’s productivity?” Field and laboratory research is demonstrating that providing good-quality lighting influences the bottom-line by influencing employee satisfaction. Most would agree that a high-quality lighting installation provides good task visibility and contributes to the attractiveness of the space. In two experiments in a simulated office space, temporary office personnel worked under one of six lighting conditions for a day. Combined results from two statistical approaches show that people who perceived their office lighting as being of higher quality rated the space as more attractive, reported more pleasant mood, and showed greater well-being at the end of the day. Direct-indirect lighting and personal control were favoured. Such a system was favourably rated by employees in a field study with a long-term installation. Moreover, satisfaction with lighting influenced overall environmental satisfaction, which in turn favourably influenced job satisfaction, increased organizational commitment, and reduced the intent to turnover.

 

Daylight 1-2-3: A New Daylighting/Energy Analysis Program

Christoph Reinhart, PhD

National Research Council of Canada Institute for Research in Construction

Daylight 1-2-3 is a non-expert design analysis tool that supports daylighting-related design decisions in commercial buildings during the initial design and design development stages. The tool predicts the daylighting and energy performance of sidelit and/or toplit private offices, open plan offices, and classrooms. The tool’s main objective is to help design professionals with interest in - but no expert knowledge of - daylighting to develop climate-responsive daylighting design concepts; to optimize façade/ roof layout and orientation with respect to daylight and energy use; and to quantify energy savings from occupancy sensors and/or photocell controlled dimming.