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Figure 2. Correlation between answers to questions Q.1. and Q.2. for each of the nine fabrics, obtained
from the questionnaires. Scores range limits are [0‐3] for question Q.1. and [0‐5] for question Q.2.
Figure 3. Normalized score for the visual contact with the outside for each of the nine fabrics.
4. Discussion
The first results clearly show the preponderant impact of the openness factor and color of the
fabrics on the visual contact. Comparison with the performance classes defined in the European
standard EN 14501 was investigated. Table 2 gives the list of all investigated fabrics with (combined)
normalized score ranked in ascending order, from the fabric with the worst visual contact to the one
with the best. Performance class according to the European standard EN 14501 is mentioned in the last
column of the table (0=very low; 5=very good). It is observed that the classification according to EN
14501 seems to overestimate the negative effect of the light color in the case of fabrics with low openness
factor. For example, light‐colored fabric N4 is classified as ‘low visual contact’ (class 1), showing a lower
performance than that of the dark‐colored fabric N3 (class 2), which does not correspond to the score
determined in this work. Moreover, fabrics with OF equal to 1% and 3% are treated in the same way in
EN 14501, while the observations made during this work show clear difference between both cases. The
classification according to the standard, even if it can be considered as a quite good first estimation, is
not able to capture the whole complexity of the reality.
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