This introduction
briefly summarizes the role of facade engineer.
Façade engineering is increasingly taking place
in an array of specialized skills needed to complete building. A facade was
always an important mark of the
individuality of an architect and owner but never before have facade components
been so complex.
A lot of attention is paid to design, therefore
some sophisticated facade projects are more complex than entire buildings and of greater
value. The façade may account for 20% of the total cost of a building and be the
greatest factor in determining the whole life cost energy maintenance and
replacement.
Façade design leads to the improvement of the
quality and comfort of buildings through the use of better materials and
processes, coordinated and intelligent design and the development of intelligent
façades.
The role of a facade
engineer is to help an architect to
accomplish his or her artistic vision by proposing a relevant means to achieve
the desired effect without any negative impact.
It seems to be the common rule that the later
he joins the team, the tougher his task is.
Some major goals may be determined, but
the list varies depending on specific project requirements. For example; the
airport development priority may be noise protection, on the other hand a
pharmaceutical facility program will put stress on air tightness of partitions
in order to produce hermetic environment inside. The sanitary conditions play a
greater role in hospitals, gastronomy, etc.
Goals:
· accommodation of all building
functions,
· safety (fire, security)
· indoor climate (temperature and its
gradient, moisture, air movement)
· waterproofing
· micro and macro biological control
· noise reduction
· seismic protection
· construction economy
· installation feasibility
A facade engineer also diagnoses faults of existing
building envelopes. This invaluable field experience helps in designing and
consulting new constructions.
There are
two major local factors: climate and law, which are in most cases the decisive
factors and they play a large part in shaping the building form, as it was
observed in history. The more innovative and outstanding form of building
designed by architect the weaker it potentially might be. Only truly excellent
design would survive the probe of time.
Below I give an illustration of the importance
of climate:
Most developed countries have moderate climate.
It is common that in winter the ground freezes to 1 - 1,5m (3'-4" - 5'-0") in depth.
Many popular
building materials and systems introduced in warm climates prove useless in cold
and moderate climates because they are prone to freeze-thaw cycle damage.
Shallow foundations, small building additions,
stairs and sidewalks are lifted by frozen soil. A design shall provide their
separation from deeper founded constructions by control joints.
The natural daily and annual extreme
temperature span (~150 degrees.C) causes significant temperature stresses:
contraction and expansion of external building materials and joint movements,
therefore the proper design of joints is a challenging task.
Oxygen and sun radiation as well as many other
factors degrade many building materials. Specific materials features and
properties must be taken into consideration and serious thought has to be given
to the choice of building materials. Many materials cannot be used on outer
surfaces without the protective coat of paint or impregnation (wood) or
anodicoxidation (aluminum). Some of new developed materials have no aging data
available. A well known example is PVC plastifiers migration. Another condition is the galvanic action
between two different metals (like copper and steel) which, if carelessly connected,
leads to quick deterioration by corrosion.
Large humidity pressure differences on the
outside and inside leaf of a building envelope lead to undesired condensation
inside partitions, damage building tissue, render improperly sealed
thermoinsulation useless and may lead to further biological corrosion. Wind
driven rain may penetrate internal sheathing and cause periodical leaks.
The pressure of wind and heavy snow cause
structural challenges. The means of support and the layering of the arrangement
can totally change the appearance of the façade. Safety is essential to assure
protection of human life.
Noise protection is a growing concern in
traffic conditions in large cities and around airports.
The heating energy savings are essential where
the protection of the environment and the rising costs of fuel play an
increasingly important role. External
envelopes and these of internal partitions which separate rooms of different
temperatures shall be carefully designed to reach the required thermal
resistance (R). The balance of energy of a whole building must be kept low to
achieve "a long mileage" effect.
Architects and engineers in Europe have developed the
intelligent facade design- among others introducing double facades, which
passively control the internal environment causing energy savings and
significant acoustical comfort improvement.
Also see my presentation about Facade Design Principles.