Commercial Architecture July/August 2016 - (Page 60)
High-In-The Sky Safety
Passive fire-containment system supports the
building enclosure for One World Trade Center.
Linking New York City's Tribeca neighborhood to
IMPEDING FIRE PROGRESS
the Financial District and standing 1,776 ft. high, the
Passive fire-containment systems hinder a fire's spread
104-story, 2.6-million-sq.-ft. building is home to busi-
in part by addressing the three key paths that allow fire
nesses operating in industries ranging from finance to
to spread vertically at the building exterior perimeter. A
publishing to real estate and international commerce.
first path of fire propagation occurs when the void be-
Its dramatic, shimmering form blends geometric shapes
tween the floor slab and the exterior curtain wall is left
and prismatic glass to create a stunning visual that re-
unprotected, permitting flame and hot gasses to spread
flects light in myriad ways throughout the day.
up through the joint.
owering above a city renowned for its skyscrap-
more risks than a life-safety system that incorporates de-
ers, One World Trade Center stands as the
tection, active, and passive elements.
tallest building in the Western Hemisphere.
While the building's design is breathtaking, One
A second path of vertical fire spread is not as com-
World Trade Center also evokes awe due to its location-
monly understood. Typically, the building materials
standing at the very site where the Twin Towers once
used to construct a building's curtain wall are made of
stood. Given the location's painful moment in Ameri-
low-melt and heat-sensitive materials. If the spandrel
can history, it is not surprising that the building facts
panel is not properly protected, fire can cause an early
posted on its website mention, "life-safety systems far
failure of the curtain wall, allowing fire to propagate up
exceed NYC building code."
and through the curtain-wall cavity.
Whether specifying building materials for a marquee
Finally, a third path of fire propagation-although
project such as the World Trade Center or a lower-profile
not a requirement of the building codes and ASTM
building, the building community evaluates three ele-
E2307-demands consideration when it comes to deliv-
ments when specifying life-safety systems. Detection
ering the maximum level of safety in a high-rise struc-
systems include alarm systems such as smoke and heat
ture. Referred to as leapfrog, this path of fire spread oc-
detectors. A second element focuses on active systems
curs when fire breaks out the vision glass on the floor of
that suppress a fire. Sprinkler systems are the most com-
fire origin. When the vision glass is broken, flame and
mon suppression systems used in buildings.
hot gasses can escape and lick up the exterior face of the
A third life-safety element is compartmentation, also
curtain wall. Eventually, the vision glass on the floor
referred to as a passive approach to fire containment.
above breaks, allowing fire to re-enter the building
Unlike active systems that are dependent upon an "on"
through the window opening. The fire will continue to
jump from floor to floor using this path.
fire-containment systems feature no activating device.
Thermafiber Firespan 90 curtain wall and Thermafi-
Therefore, the passive approach promises to always work
ber Safing mineral-wool insulation from Owens Corn-
once the system is correctly installed. Passive systems
ing, Toledo, OH, were used in One World Trade Center
also play a key role in containing a fire to a room of ori-
to deliver fire-containment barriers between a fire source
gin, delaying its spread, and adding precious time for
and the building's floor slab perimeter and curtain wall.
occupants to evacuate or take refuge in a safe zone.
New York's One World Trade Center was built with life-safety systems that
far exceed the building code. Passive fire containment plays a large part.
COMMERCI A L A RCHI T EC T URE
In addition, Thermafiber Impasse mineral-wool-in-
As passive fire-containment systems slow the spread
sulation hanger system uses a stepwise technique of
of fire, firefighters have an opportunity to enter the
overlapping components during installation to lock the
building and extinguish the fire while it is still manage-
Firespan curtain wall insulation materials in place. The
able. In conjunction with a building enclosure's curtain
Firespan 90 insulation is secured to the aluminum fram-
wall, perimeter fire-containment systems are designed to
ing of the exterior curtain wall. This protection is an
prevent the spread of flame and hot gases at the void
important part of any building's design because the lon-
created where the exterior curtain wall bypasses the
ger the curtain wall insulation stays in place, the longer
floor assembly. History has borne out that relying on
it can help provide protection to the building's alumi-
just one or two life-safety elements is associated with
num framing, thus maintaining the structural integrity
Table of Contents for the Digital Edition of Commercial Architecture July/August 2016
Cigar Factory Embarks On A New Life
Windows & Door Products
Historic Renovation Includes Geothermal
Church Sings Praises Of Condensing Boilers
HVAC & Plumbing Products
Raising The Roof On Historical Bath House
Two Paws Up For Rubber Floors
Library Blends Stone And Glass
Lighting For The Future
Lighting & Electrical Products
Building Technology Products
Commercial Architecture July/August 2016