But if we referred to the indications of the
CEI (Italian Episcopal Committee) for the lighting
of worship places, we could see that the
recommended illuminance values were between
50 and 150 lux for the general lighting,
and between 150 and 300 lux for the altar area,
so the measured values were always respecting
them. The result of the processing of the
measured data relating to three significant hours
of use of the environment is reported, by way
of example, in Table 1.
In particular, it was noted that on the worktops
the illuminance values were particularly low and
always much lower than 300 lx, therefore below
the limits suggested by the current standards;
the standard prescriptions concerning the
bottom area, to which an average illuminance
value not exceeding 100 lx was required, was
at least partially verified, or rather it was
in the presence of natural and artificial light.
A solid three-dimensional architectural model
of the environment was built, characterizing
all the materials, surfaces, and objects with the
measured and/or calculated thermo-physical,
optical, photometric, and colorimetric aspects.
Then, a lighting simulation model was defined,
using experimental data both of the internal
luminous climate, specifically the measured
illuminance and luminance values, and of the
external climate, or the sky and sun conditions,
the intensity of direct and diffused solar
radiation, and the index of sunshine.
The informational analysis of the simulation
results (on the information content of the light
signals) highlighted the distinct separation,
in terms of treatment and design of light,
between natural light and artificial lighting:
a differential demarcation that is present
in the very history of the lighting of this space,
between the former use a church and as the
nowadays use as a library. The lack of integration
and optimal combination between the natural
and artificial lighting sources can also be seen
from the renderings of the distribution and
uniformity of illuminance and of the luminance,
in the entire environment (Figure 7) and in each
zone (Figures 8-9). The lack of balance and
homogeneity in the distribution and uniformity
of the light is evident. The existing luminous
climate also produces a significant energy cost:
to be able to see and see well always have
energy implications. From the calculation of
annual energy consumption and costs, we can
deduce: a LENI value of 22-33 kW/m2 per year 9 ,
with a consequent annual maintenance costs
of 3,093 – 4,528 Euros and, therefore,
a consumption of 10,300 – 15,100 kWh/year.
When the light amount appropriate for
a correct vision is lacking, even in conditions
of simultaneous presence of natural and artificial
lighting, we can no more than note the same
1
SO 16331-1. 2012. Optics and optical instruments
-- Laboratory procedures for testing surveying
and construction instruments -- Part 1:
Performance of handheld laser distance meters.
2
UNI EN 12464-1:2011 Illuminazione dei posti di
lavoro. Parte 1.
3
UNI 11630:2016. Luce e illuminazione - Criteri per
la stesura del progetto illuminotecnico
4
CIE S023/E:2013 Characterization of the
10.00 am
Reading room
2.00 pm
Apse Reading room
6.00 pm
Apse Reading room Apse
Emin 6.43 1.41 6.59 1.4 6.05 1.38
Emax 245 138 248 141 245 127
141 79.2 143 80.8 135 72.1
Emin/Emedium
Emedium
0.046 0.018 0.046 0.017 0.045 0.019
Emin/Emax 0.026 0.01 0.027 0.01 0.025 0.011
Tab. 1 Illuminance values (lx) and correspondent ratios, measured in the different areas
qualitative use of light, or for a new design
approach that leads to shift our attention
focusing on quality, starting from the evaluation
of a correct quantity (of light, vision, and
perception), on the use value rather than on the
exchange one, thus operationally introducing
the second law of thermodynamics as read
by means of neg-entropy, or the informative
content of the light signals. This has led us to
develop an environmental experimentation
and monitoring method in constant reference
to the information content that light can deliver
(communicate). The analysis of the measured
experimental data was carried out considering
not only the compliance with the limit values
(the amount of light) suggested by the current
standards, also regarding the protection and
preventive conservation, but also the respect
to the finiteness of the usable negentropy flow
(the quality of light), coming from the Sun and
the Sky and from other sources of artificial light,
both necessary for the philological reconstruction
and the architectural reconfiguration of the
internal space of a church, which is today
a university library. The study of the present
state of the natural light and of the lighting was
extensive, demanding and complex, but it
allowed us to identify the information contents,
or the signals, and the critical points, as well
as the historical and philological characters
and elements. Designing light, and with light,
means transmitting information,
communicating, enhancing, making the space
usable, recovering the historical memory,
re-reading, re-interpreting, re-configuring and
re-transmitting this same space with the “Eyes”
of the knowledge and scientific thought that we
can afford today.
condition about the quality of light
and therefore a completely missing quality
of vision and perception. Natural light actually
carries information and has a high negentropy
content (informational and relational, 8 ):
it communicates the unmistakable presence
of a historical, liturgical, and ecclesiastical
function, as the semiosis of signs, ritual,
liturgical and philological symbols, which
translate into spaces made of light and shadows
that are typical of the architecture of the
ecclesia and the seminario.
Conclusions
With this research we propose a methodological
approach that allows us to trace the
fundamental bases for a lighting design project
that is energy-sustainable, but above all of
quality, in terms of content (information) and
communication. Negentropy is information;
it is the set of signals with transmitted
information content of which light constitutes
the transmission channel. Through the method
we propose, light and lighting are used,
interpreted, and read to process the information
signal (set of messages). In order to reach
with his lighting design project the quality and
informative communication of the “common
sense” – or what is perceived, experienced,
and felt by everyone and that everybody likes –,
it is sufficient for the lighting designer to share
the same code (transmission of information),
adding to the relational communication
a philological and content-rich hermeneutic
intervention, that is interpretative, to give and
rediscover the physical, cultural, historical,
and social sense, as well as in the code
(the transmission of information by light) as in
the contextual and extra-contextual network.
Therefore, the methodological approach we
propose allows us to obtain alighting project
that is “informational”, by possessing quality
in quantity, and also “relational”, being
it characterized by communication,
or the intersubjective transmission
of information (neg-entropy) that constitutes
the “common sense”.
The proposed method can be a useful support
for a lighting design project based on the
Performance of Illuminance Meters and
Luminance Meters
5
UNI/CEN TS 16163:2014. Conservazione dei beni
culturali - Linee guida e procedure per scegliere
l’illuminazione adatta a esposizioni in ambienti
interni
6
Corvi A., Frosali G., Paris E., Pelosi G., Viviani A..
Ingegneri & Ingegneria a Firenze. A quarant’anni
dall’istituzione della Facoltà di Ingegneria. Firenze
Acknowledgments
The authors thank Dr. Simonetta Pagnini,
Director of the Santa Marta Library, Dr. Paolo
Baldi, and all their staff for collaboration and
availability; Dr. Luca Fibbi of the LAMMA CNR
IBIMET Centre in Florence for having provided
all the climatic data necessary for this study;
Eng. Massimo D’Alessandro of Elettrotecnica
Nocentini srl for providing technical information
on the existing lighting fixtures.
University Press 2013.
Sura Al-Maiya, Hisham Elkadi. 2007. The role of
daylight in preserving identities in heritage
context. Renewable and Sustainable Energy
Reviews, 11, pp.1544–1557.
8
Brillouin L. Science and Information Theory.
Second Edition. Dover Books on Physics 2013.
9
UNI EN 15193-1:2017. Prestazione energetica degli
edifici - Requisiti energetici per illuminazione.
7
RESEARCH AND INNOVATION / LUCE 328
29