Today's Architect has a tough decision to make when it
comes to choosing materials. There is steel and glass and
concrete and wood. What about fabric! Architectural Fabric
Structures are fast becoming a very common and visible part
of the built environment. No longer used for garden parties
and traveling circuses, these structures come in many new
forms and uses.
Fabric structures are being designed for as few as one
person as in a boutique resort hotel in the outback of
Australia, to covering 50,000 plus at the Super Bowl in
Houston, Texas. Fabric Structures are now also being
designed to cover animals as well like at Seaworld, Orlando
where these structures cover dolphins to prevent them from
sun burn (they get sun burn too?). And let's not forget
Man's newest best friend, the automobile. More and more,
the automobile has taken center stage where valet parking
attendants, airport parking owners and car dealers are
discovering the advantages of covering automobiles.
Fabric Structures are beings used as roofs, sails, walls,
lights, shades and even signs. With all these different
uses and forms, there are a variety of materials to choose
from depending on one's needs, budget and design.
The best way to determine which material to use is to see
what has already been used for the building type you are
considering.
If you are interested in structures such as tents or
umbrellas where the main objective is to provide temporary,
nomadic shelter, you are probably looking at vinyl
laminated or coated polyester.
If you are researching awnings and canopies, the options
are endless. You are most likely to hear words like acrylic
canvas and backlit fabrics and materials which you can
apply graphics to.
If shade is your primary concern, the buzz word is
structural mesh, high density polyethylene (HDPE),
perforations and percentage of light transmission.
For warehousing, industrial applications and temporary
buildings, a common term may be clear spans or
pre-engineered fabric building with materials that are mold
and mildew resistant like polyolefin.
The interior and lighting industry have their own variety
of fabrics where flame resistance, UL ratings and
percentage of reflectance are the most important issues.
Air and Tension Fabric Structures rely heavily on the
fabric's structural characteristics so tensile strength,
sound absorption and solar transmission play a major role
in their selection.
So, What material do you use?
Is your project near the water? Is it meant to last 20
years? Do you want to see it from afar or do you want it to
be dark inside at noon? These are all important questions
one should answer before you even start. Fabric Structures
have very few components. In most cases, it is just steel,
fabric, cables and hardware. The choice for each component
will most certainly affect the others. Other issues
include: span, size, availability, cost, codes, etc.
In most States, permanent, totally enclosed structures
require a "non combustible" or Class A/B rating according
to Building Codes. The most recognized and accepted
material used for Architectural Applications is Teflon
Coated Fiberglass or PTFE.
Recognized manufacturers include Saint Gobain, Verseidag,
FiberTech and Taconic. Teflon comes to the site brown like
a pair of khakis but bleaches to a milky white over time
(usually 4-8 weeks). The biggest problem with Teflon is
that it is stiff and brittle and must be handled very
carefully to avoid breaking the fibers. The best part is
its life span (25+ years) and its "self cleaning"
attributes.
Other "non combustible" materials include Silicon Coated
Fiberglass, Gore Brand Tenara Architectural Fabrics and
Ethylene tetra ethylene or ETFE.
Silicon has been out on the market for quite some time.
Unlike Teflon coated fiberglass which can be heat welded,
Silicon must be glued with a special adhesive. The
advantage of silicon over Teflon is its translucency, cost
and availability of colors. Gore Brand Tenara is also in
the "non combustible category". Its advantages include its
high translucency, long life span and it is more pliable
than silicon or Teflon so it can be used for retractable
structures.
ETFE is not really a fabric but a film presently being
promoted as an alternative to structural glass. It is
"green" friendly and is the new hot material to Architects
world wide today. It is being used in FIFA Stadiums in
Germany, the Olympic Games in China, being specified for
commerical buildings and retail and the choice for creating
artificial rainforests for zoos and Science Centers.
The majority of fabric structures being considered today
are for uses which do not require complete enclosure. That
means, they are most likely "open air" or do not require a
Class A rating. Class C is the most common rating and NFPA
701 is the most accepted certificate for most Fire
Marshals. Vinyl coated polyester (PVC) is the most common
material used on the market today.
What's not to like. The material comes in a variety of
colors, strengths, weights, thickness, perforations,
translucency and textures. The material is pliable and
stretches quite nicely. You can find material with 10, 12
and even 15 year warranties. You can find material that is
50 to 100" wide so you can have few, fewer or the fewest
amounts of seams.
Manufacturers include Ferrari, Mehler, Naizil, Seaman and
Verseidag, to name a few. These are the names most seen on
Specifications, which means that these companies are
directly marketing and assisting the Architect in the early
stages of the design.
PVC comes in a variety of top finishes: acrylic, PVDF and
PVF film. There is much debate about top finishes but all
manufacturers agree that they are needed to protect the
base fabric from UV degradation, water and wind. Frankly,
it's all about the coatings. PVF is a film applied to the
main fabric while acrylic and PVDF are coatings. Both PVF
and PVDF claim to be "self cleaning" or provide the base
material with a much cleaner and maintenance free surface
but both require additional work in the shop which may be
unknown to the Architect. Both top of the line PVF and PVDF
require that the top coat or film where two panels are to
meet be grinded off in order for them to be RF welded. This
is time consuming and requires great care in order to keep
the seams clear of dirt, model and mildew. There are
"weldable" PVDF but their warranties are not as long as the
high tech top coats.PVC Structures love graphics and
provide a great backdrop for projected images.
Today, more and more fabric structures are being designed
for shade only. Structural mesh and perforated fabrics are
being specified because of the need for shade, the need to
allow the elements to go thru the material and the need for
a space to "see thru and be seen". The material most often
used is high density polyethylene (HDPE). Manufacturers
include Multiknit, Coolaroo and Shadetex. This material is
a higher grade mesh than what one would see at a home
improvement warehouse or at an outdoor furniture store.
HDPE is used for playgrounds, areas requiring hail
protection, schools, day care centers as well as theme
parks and spaces of public assembly. Mesh is hot so you can
stay cool. Mesh comes in colors, fire rated and with
different perforations. It has a life span of 8-10 years
and in most cases lowers the size and loads on the
structural system and foundations because it takes less
wind.
If you want to keep it simple, then work with materials
which do not rely on their structural characteristics for
its stability. These materials are usually clad on a frame.
The materials are usually vinyl laminated polyester,
acrylic coated canvas, and materials with a light topcoat.
Sunbrella is a common brand name. The material has less
technical information available for applying them to fully
engineered lightweight structures but when used as a
cladding on a frame, they offer many opportunities to the
Architect. One can apply graphics to the material, bring
texture to the surface or make something truly unique.
If you want to look at materials for interior application,
look no further than the industrial fabric industry and
Theatrical Drapery. There are lightweight PTFE materials
used for ceilings in dome stadiums, PVC fabrics are used
for interior tensioned fabric sculptures while theatrical
drapery materials from companies like Rosebrand and Dazian
are used for a softer look. Spandex/Lycra is another common
material used for transforming temporary and permanent
spaces but require the material be fire treated prior to
fabrication.
Lastly, it doesn't hurt to dream about the future of
architectural fabrics. The wish list would include "Smart"
fabrics, fabrics that change color according to weather,
light or mood. Fabrics made with optic and photovoltaic
fibers, materials with longer life spans, higher tensile
strength, improved self cleaning, higher translucency and
environmentally friendly.
The future of Architectural Fabric Structures depends on
the continuing effort of manufacturers to improve its
existing products and to introduce new materials.
----------------------------------------------------
Samuel J. Armijos, AIA is Vice President of USA Shade and
Fabric Structures and author of Fabric Architecture:
Resources for shade, signage and shelter. He resides in
Fairfield, NJ with his wife and two children.
http://www.fabricarchitect.com
No comments:
Post a Comment