38 JULY/AUGUST 2017 LEDSMAGAZINE.COM
education | HUMAN-CENTRIC LIGHTING
The new Holla comprehensive school near Telemark, Norway opened for the 2016 school year with LED-based lighting inside and out, including
tunable-white lighting in class and group
rooms. The tunable lighting is considered
human-centric lighting (HCL) or what is
sometimes referred to as lighting for health
and wellbeing. The spectrum can be set to
boost alertness at times, for instance, during
an exam, or for a relaxed environment at
other times. The school hopes the system will
improve learning and also help students sleep
better at night. The solid-state lighting (SSL)
project further included other standard LED
fixtures with fixed spectrum indoors and out.
Glamox Luxo Lighting supplied the lighting products for the school. The company
specializes in lighting products for schools,
healthcare facilities, retail, hospitality,
and commercial and industrial buildings.
HCL capabilities are offered in a number of
Glamox luminaires. The company relies on
the DALI (digital addressable lighting interface) platform for control and supports control components and systems from a number
of third parties such as Tridonic and Helvar.
The C90-R family of luminaires used in the
Holla teaching rooms have the HCL capabil-
ity (Fig. 1). The recessed 2×2-ft, troffer-style
fixtures have a planar optic that delivers uni-
form light across the surface. The HCL ver-
sion of the fixture can produce light across
the spectrum of 2500K CCT to 7000K CCT —
from warmer than incandescent lamps to a
very cool color temperature. The luminaire
design closely tracks the black-body locus
across that range. The luminaires also deliver
excellent color rendering with CRI above 90.
And the school feels that such high CRI will
further enhance the learning experience.
Given the control system involved, a teacher
or school administrator could potentially set
the CCT and dim level of the installed light-
ing to any desired configuration. Lumen out-
put ranges to 4616 lm. But the installation
has been customized to enable simple adjust-
ments of the lighting for the typical modes
that might come into play on a daily basis.
The Standard setting for most activities
configures the lighting to 3500K. Teachers have a DALI panel in each room to turn
lights on or off and to adjust the dim level.
The Standard setting is designed to deliver
horizontal illuminance of 300 lx on a plane
0.75m above the floor — desk level.
Energy and focus
The system also includes Energy and Focus
settings. First, let’s discuss the photometric
characteristics, which are the same for both
settings, and then we will consider the differ-
ent ways in which the two settings are applied.
The lighting design took into account
the concept called cylindrical illuminance
and often abbreviated Ez. The Ez metric
is a value in lux that represents the mean
value of vertical illuminance on a cylinder.
Requirements for cylindrical illuminance
have been defined in the European standard
EN 12464-1:2011 for indoor workplace lighting, and for sitting workers that calculation
is based on a height of 1.2m from the floor —
typical head height. The school system delivers Ez of 350 lx at 1.2m and a CCT of 6500K
in the Energy or Focus modes.
The Energy setting is managed by the
building management systems (BMS) to
which all of the SSL products are linked.
The BMS enables the Energy setting auto-
Norwegian school installs tunable
LED lighting to enhance learning
A human-centric lighting project is intended to improve learning performance and sleep patterns for
students, explains MAURY WRIGHT, and the lighting design also optimizes cylindrical illuminance.
FIG. 1. Classrooms are primarily lit by Glamox C90-R troffers with tunable-white