The
Oklahoma City bombing in 1995 had already changed our perceptions about
security in public buildings. 9/11 horrified us and mobilized an even
greater response. But knowing that something must be done hasn’t
made the doing of it any easier. Simply put, while we need and want
protection from the world’s maniacs, we don’t want to live
or work in bunkers.
These attacks have served as challenges to everyone in the AEC community.
Creating appropriate responses - balancing security with cost, aesthetics,
accessibility, and other factors - has been an exacting task for many
professionals.
In June, NIST, the National Institute of Standards and Technology
(which has no regulatory authority), published a new set of 30 recommendations
resulting from investigation of the WTC collapse. It suggests nationwide
adoption of certain standards and codes instead of relying on the regionally
-specific code hodgepodge currently in effect. The recommendations
(see http://wtc.nist.gov for details) are divided into several categories
including - structural integrity, fire resistant materials, fire protection
systems, evacuation methods, emergency response systems, policy improvements,
and education.
The puzzle contains three primary pieces: A) Controlling Access by
potential attackers;
B) Creating a structure that can withstand attack; and C) Saving lives
if an attack occurs.
The challenge for landscape architects has been to design aesthetically
pleasing external barriers and methods of controlling access, while
not creating traffic jams for those who are there legitimately, including
elderly, handicapped, or emergency personnel. Architects make so many
decisions which are essential ingredients for security - about circulation,
access methods and redundancy, compartmentalization, and building materials
to name a few.
Engineers have focused on how best to augment and harden the structural
aspects to handle new blast loads, prevent fire damage, and improve
essential building components such as elevator shafts and stairwells.
They are also working on methods of collapse mitigation - one method
ties a building together vertically and laterally so that loads within
a building might be redistributed if primary structural supports are
damaged.
Under development: Lighter weight construction materials with outstanding
strength and less combustibility; new methods and materials for improving
fire-proofing; and carbon fabric wrapping of structural elements to
increase strength. New wireless and nano-technology will also become
standard ingredients in future buildings – both for monitoring
and controlling essential systems. After the attack on the Pentagon,
smoke from the damaged section was cut-off from the rest of the buildings
by remote control, using a system which was on trial at the time.
An estimated 80% of the 168 killed in Oklahoma’s explosion died
not from the blast itself, but from glass and other falling debris.
Tremendous advances have been made in fenestration and curtain wall
manufacture as a result. Safety films can both bind glass together
and also provide solar control to deal with comfort and energy issues.
Various innovative window ‘catchers’ designs keep entire
windows, or walls, from becoming deadly projectiles. Contrary to instincts
that rigid is better, curtain walls are now in use (for instance in
the new Time Warner building in NYC) that can take a considerable amount
of force by bending without breaking.
The dilemma of how to evacuate a building in the event its primary
means of egress are unusable is a foremost safety issue. Based on our
experience at the WTC collapse, stairwells are being resized and in
many cases separate stairwells are now created for emergency personnel.
Keeping them clear of smoke is also obviously essential…and not
easy.
Our basic premise that elevators are unusable in event of an emergency
is now being challenged. ASME has a task force working on methods and
material needed to keep them safely running. This would make a tremendous
difference! Cutting-edge secondary evacuation systems such as automatic
harness-based lowering devices, mass-evacuation carriages that deploy
from a buildings rooftop, and even inflatable slides are also being
developed.
One of the difficulties facing professionals: open sharing of solutions
is problematic. How can we share solutions among professionals without
also sharing with potential terrorists? Another difficulty is the age
old problem of how to predict exactly what will be needed tomorrow.
Changing attack methods are sure to require changing solutions. It
truly requires a united effort.
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