John Park Davies, managing director of IKON Aluminium Systems, explores the important role louvres play in
improving the performance and aesthetics of UK buildings and why geing the correct specification is vital.
Far too often, louvres are left until the
end of a build; a forgotten product that
must be sourced and installed within
a limited time frame. Yet louvres are,
in fact, an integral feature of the building
envelope, offering both performance benefits
and aesthetics, and should form an important
part of the specification process.
Poor specification can lead to poor
performance, not just of the system but across
the entire building; from rainwater ingress
and restricted ventilation to wasted energy.
Louvres can improve the energy-efficiency of a
building by increasing airflow and optimising
natural ventilation but if they are incorrectly
specified or located, the opposite effect can
occur, creating resistance to airflow and making
a building less energy efficient.
For optimum performance, architects and
specifiers must specify a louvre system which
balances performance, e.g. water ingress and
airflow, with aesthetics.
Traditionally, louvre systems have been based
on free area – calculated by measuring the clear
BUILDING PRODUCTS | MAY 8
distance between the blades and multiplying
it by the width of the louvre panel, or the
height if the blades are arranged vertically.
However, with developments in louvre design
and the increasing demand for improved
water protection, the limitations of louvre
specification, based on free area alone, have
been realised. Free area can be affected by bird
and insect mesh, structural supports and most
importantly, it doesn’t factor-in how air flows
through the louvre.
Louvre specification needs to progress
and move away from free area and consider
other critical factors, including the location
and exposure of the louvres, site orientation,
prevailing weather conditions and the potential
of wind-driven rain.
These factors should then be balanced with
the required airflow, acceptable pressure drop
and level of water penetration, before finally,
considering the building’s exterior design along
with the position and aesthetics of the louvres.