faces of the future - Illuminating Engineering Society

esearch
BY JENNIFER A. VEITCH
M A T T E R S
In a previous column (March
2008), I wrote about laboratory
experiments that showed
the benefits of individual, personal
control over lighting. These
experiments showed that giving
people the opportunity to choose
their own local lighting levels
enables them to create conditions
closer to their personal preferences.
Working in one’s preferred conditions
leads to a more positive mood
and to better satisfaction with lighting.
In experiments supported by
the Light Right Consortium (www.
lightright.org), having individual
control over lighting seemed to
improve motivation over the workday;
people without control showed
a drop in motivation from morning
to afternoon. Today, I can update
you on our progress in studying
these effects in the field.
When writing the final report for
the Light Right Albany experiments,
the team concluded that laboratory
investigations of the effects
of light distribution and individual
control had reached the end of their
usefulness (Boyce, et al., 2006;
Boyce, Veitch, Newsham, Myer, &
Hunter, 2003). To demonstrate the
overall organizational benefits of
high-quality, energy-efficient lighting
in offices would require a field
study in a functioning work setting.
Our team at NRC-IRC has now
completed that study, with funding
from the Light Right Consortium.
The investigation was designed to
achieve two objectives:
1. To replicate the results of the
Light Right Albany experiments in a
functioning work setting.
2. To extend the model developed
from the Albany data to organizational
effectiveness outcomes.
RESEARCH DESIGN
The project was designed around
a linked mechanisms map (Figure 1).
As in the Albany experiments, each
concept in the linked mechanisms
map had at least one associated
measurement.
The experimental design was a
naturally occurring field experiment
in an organization that has undertaken
a major renovation of three office
buildings, involving both furnishings
and lighting. Individual floors in all
buildings will be renovated in phases
over several years. During the study
period (May 2008-September 2009),
both old (pre-renovation) and new
(post-renovation) conditions existed
in the buildings. The old lighting
consisted of recessed paraboliclouvered
luminaires (similar to the
Base Case condition in the Albany
experiment 1), and the new lighting
consisted of workstation-specific,
individually controllable, suspended,
direct/indirect luminaires (similar
to the Dimming Control condition
in the Albany experiment 1).
Furnishings also changed with the
lighting (from teal (dark) to off-white
(light)), except for four floors in one
building that have had the new lighting
for several years and that are
keeping their medium grey panels.
All of the buildings had large windows
on all orientations. Figure 2
shows examples of the old and new
lighting and furnishings.
All occupants of the three buildings
were asked to complete an
online questionnaire on three occasions
during the study, in May-June
2008, June 2009 and September
2009. Each time, the questionnaire
included questions and tasks to
assess the individual-level concepts
in the linked mechanisms
map. Each measurement wave
included a site visit by the research
team, during which the physical
conditions in selected locations
were measured, with photometric
measurements both by day and by
night (electric lighting only). Some
of the participants moved to newly
renovated offices between the first
and second measurement waves;
others had already moved to new or
newly renovated spaces before the
first wave; and others did not experience
any office design or lighting
changes during the study period.
As is evident from the photos,
the three luminaire and furnishing
combinations created markedly
different visual conditions. (There
were also three variations in the
operation of the workstation-specific,
direct-indirect luminaires, which
resulted in different proportions of
indirect illumination, but these were
small in comparison to the difference
between workstation-specific,
direct-indirect lighting and recessed
parabolic louvered luminaires.)
All the measured locations met or
exceeded IES recommendations for
work-plane illuminance. The offices
26 www.ies.org