Higher air intake capacity with optimum
Statutory provisions governing
the reduction of sound emissions from industrial buildings have
been tightened considerably over the last decade. These requirements
can be met by using sound absorbing slabs, which considerably reduce
the aerodynamic surface Aw.
An extensive research and testing programme, supported by measurements,
each performed by independent institutes, forms the basis for the
development of gravity roof ventilators which deliver a sound reduction
index value (R'w) without the use of sound absorbing slabs of up
to 24 dB. As a result of pressure drop minimisation, the relatively
high sound reduction values do not significantly reduce the coefficient
of discharge Cv0.
When sound reduction requirements are higher, sound absorbing slabs
with aerodynamic cladding on the flow approach side are used. The
high coefficient of discharge Cv0 value of GAL ventilation
components means that an above-average coefficient of discharge
Cv0 value is still attained for the system as a whole
in combination with sound absorbing slabs.