Page 120 - ELEMENTS EUROPA (EN)
P. 120
116
HALLS FELT CEILINGS
STATEMENT OF THE ISSUE Out of necessity, the enforced system does not match the
system that underwent standardised and approved tests in terms
The idea is to build a ceiling with optimal acoustic absorption of acoustics, stability of and reaction to fire. New tests were
for talks to be clearly understood, positioned following the successfully made in approved laboratories for that very purpose.
coloured patchwork. The solution developed is based on a
standard system composed of 597 x 597 mm perforated steel ACOUSTICS
sheet square cassettes to which coloured felt is pasted. Much
equipment must also be inserted into the ceiling. The sound absorption quality of felt being insufficient in itself,
it was reinforced with a micro-perforated film placed on the
COLOURED PATCHWORK DESIGN perforated plaque the cassette is made up of. In some places, a
double film was even placed. This increases certain frequencies
Even though made up of adjoining squares and rectangles of being absorbed and makes the absorption spectrum more
various sizes and colours, Georges Meurant’s pattern complies regular so as to make talking clearer.
with strict constraints:
– all the lines shaping the squares and rectangles must be The glue pasting felt to the plaque absolutely must be
positioned on a 600 x 600 mm orthogonal basis, corresponding permeable to sound and a series of accelerated ageing tests
to the ceiling support modular dimension; proved necessary before choosing the appropriate product.
– each cassette is covered in monochromic felt;
– the number of colours is limited to 62. The mass and flexibility of the ensemble is sufficient to
address low frequency absorption demands through the mass-
FELT resilience-mass principle. As it happens, such demands are
moderate, as they concern understanding talking.
Wool felt is a natural and recyclable material; it is 1.4 mm thick
and pasted to the entire surface of the cassette and peripheral Acoustic performances of the new system are slightly
edges. inferior to the specifications prescriptions but the requested
reverberation times (between 0.75 s and 1.20 s according to the
halls volumes) were met thanks to wall dressing performance
proving better than initially planned.
ADAPTATION OF THE STANDARD PERFORATED METALLIC LOGISTICAL ASPECTS
PLATE SYSTEM
All 15 types of openings made in the cassettes, multiplied
Cassettes are fixed edge to edge by clipping in upside down by 62 colours, result in one thousand different cassettes, for
U-shaped supporting profiles. The extra felt layer in the place 30,000 or so cassettes. Each ceiling underwent complete
for these fixations makes using standard supporting sections layout and the installer designed some software producing
impossible. Larger sections have been prepared but there is too manufacturing sheets for each model, with stickers and
much friction between the felts: placing or removing a cassette wrapping grouping per 10-cassette lots (i.e. the number of
automatically causes the adjoining cassette to displace. After spots which can be reached from a given start position in the
several attempts, a solution was found. It comes in the shape of assembly scaffolding).
a small magnet, placed in each corner of a cassette, thus firmly
wedging the latter when the adjoining cassette is set in. The
supporting mesh is positioned in both directions so as to balance
the force pressure when placing the cassettes. This solution is
economical and its implementation is particularly easy, without
any need for tools.
