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INDUSTRY
SUMMIT: DESIGN AND CONSTRUCTION
After Disaster
(enr.com
12/27/01)
By Nadine
M. Post
Craft comprehensive guidelines to assess
a facility's vulnerability and to assist owners in prioritizing
any security enhancements under consideration. Facilitate
research into improving the emergency performance of structures,
based on lessons learned from recent incidents. Approach security
design holistically and systemically, not in a vacuum.
Create an action plan for a concerted industry response to
individual disasters, natural or otherwise. Raise a unified
voice to educate and advise facility owners and managers,
building occupants and the general population about appropriate
responses to specific emergencies, especially concerning partial
or mass evacuation of compromised structures.
These are some of the calls to action proffered by a multidisciplinary
panel of public and private-sector construction professionals
at the plenary session on Design and Construction in the Aftermath
of Disaster. "As an industry, we need to unite to [meet] these
challenges," said James C. McKenna, vice president and general
manager of Turner Construction Co.'s New York Commercial Division,
New York City. "It is really an opportunity. We can't let
these [terrorists] do what they did to us without moving forward."
The hits on the World Trade Center and
the Pentagon, which filled the nation and the world with fears
of bioterrorism and other future attacks on the built environment,
catapulted civil defense and disaster control to the forefront
of design concerns. And though the experts agreed that much
can and should be done to reassess the vulnerability of infrastructure
and buildings, they also strongly cautioned against drawing
hasty conclusions about further fortifying structures against
heinous acts. "Our knee-jerk reaction as an industry is to
worry about fixing the buildings," said Ron Klemencic, chairman
of the Council on Tall Buildings and Urban Habitat, Bethlehem,
Pa., when civil defense should be the job of the federal government.
"Sept. 11 wasn't really about buildings, it was about terrorism
and airplanes," he maintained.
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| UNITY
Call issued for disciplines to band together for action.
(Photo by Michael Goodman for ENR) |
The sentiment was echoed by other participants.
Walker Lee Evey, program manager for the Dept. of Defense's
$3-billion Pentagon renovation, said: "We spend a lot of time
these days talking about what our response might be to a terrorist
act, what the targets might be, etc.," he said. "We're not
spending very much time trying to understand the nature [and
mindset] of our opponent. That's probably the first vulnerability
that we ought to address."
Robert Prieto, chairman of civil engineer Parsons Brinckerhoff
Inc., New York City, added: "On Sept. 11, the vulnerability
of infrastructure didn't change. Principally what changed
was our perception of the threats. We have to be careful that
we don't get trapped into designing for the last threat when
the next threat is out there."
Allen Rose, vice president of the special projects group of
Kansas City, Mo.-based engineer Black & Veatch, which is involved
in providing security for infrastructure, thinks the different
facilities across the nation "are not under any extraordinary
risk." But he added, "The aggressors will take extraordinary
risks to get to the particular facilities."
Consequently, "we're seeing a lot of partnerships formed now
that in the past really didn't exist," he said. "Water utilities
are talking to the National Park Service and the Forest Service,
trying to get support and buy-in for different prevention
and detection methods."
Prieto supports this approach: "You need to look at security
from a systemic standpoint, not from an isolated facility
standpoint," he maintained. On Sept. 11, "the security failing
was not at the World Trade Center or the Pentagon, it was
at an airport."
Hans A. Van Winkle, a major general and deputy chief of the
U.S. Army Corps of Engineers, advised all to beware of the
"learning enemy." Based in Washington, D.C., Van Winkle is
charged with overseeing a civil works program with an annual
appropriation of about $4.5 billion. Anytime one [security]
approach is taken, an enemy is going to spend a considerable
amount of time on "reconnaissance" to figure out how to get
around that approach, he said.
Attendees reiterated that the five-story Pentagon and the
twin 110-story towers of the World Trade Center sustained
their hits well, allowing thousands to escape. "The twin towers
performed heroically, given what was thrown at them," Klemencic
stressed, reemphasizing that the security breach was at the
airports. Klemencic is also president of structural engineer
Skilling Ward Magnusson Barkshire Inc., Seattle, a successor
firm to the original engineer for the World Trade Center.
Evey agreed. The Pentagon "performed magnificently," he said.
"Our building was hit by a [Boeing] 757 loaded with 20,000
gallons of jet fuel, [moving] at 350 miles an hour," said
Evey, yet only 125 Pentagon personnel, of 2,600 in the vicinity,
were killed.
With that stated, the consensus was that few owners were going
to require their buildings to be able to resist airplane attacks.
But Sept. 11 was a wake-up call, offering a chance to reassess
the risks to the engineered environment. "It's really important
that we have a process to do that evaluation," said Van Winkle.
The Corps recently organized the multiorganization Infrastructure
Security Partnership for the purpose of creating such a process.
"It is our responsibility to make available the tradeoffs
between security, privacy, cost-benefit or risk-benefit type
of analysis, and personal freedoms and choices," Van Winkle
continued. Those in the con- struction industry "have to make,
to the best of our ability, those choices available to decision-makers"
and clients.
After performing risk assessments, a
major challenge facing the design community is to develop
performance levels for myriad structures, from infrastructure
to public, commercial and residential buildings. "Remember
the three R's of threat design," said Prieto. "Design to resist
the threat. Design to respond to the threat. Design to recover
from the threat."
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| UNDER
ATTACK Evacuation protocol should be situation-dependent.
(Photo by Tom Sawyer for ENR) |
"We've had an opportunity recently to
reexamine the design of many of our high-rise buildings, in
particular with regard to life safety, to egress and to structure,"
said Carl Galioto, a partner in the New York City office of
architect-engineer Skidmore Owings & Merrill. "We realize
it's necessary to step back from the prescriptive codes and
to examine the total building on an interdisciplinary basis,
on a performance basis. Everything is really linked. It's
the fire suppression systems with the building structure with
the fire protection system with the egress," he said.
Taking a holistic approach to design goes against the grain
of prescriptive codes. Participants were vehemently against
government-mandated security codes in general, let alone prescriptive
ones. In general, "the issue really is to design your systems
against the [specific] threat rather than trying to look at
a general design" for all buildings, said Martin Reiss, president-CEO
of Framingham, Mass.-based fire protection engineer, rja Group
Inc. And because each building, and each system, is different,
Reiss predicts that performance-based design is going to prevail
regarding life safety.
The prescriptive approach falls short, agreed all, because
it doesn't allow an integrated approach to design. For example,
current "prescriptive codes recognize and require certain
travel distances to exits," said Galioto, and are based on
evacuating the incident floor and the one above and below.
"They don't yet acknowledge the fact that...[after Sept. 11]
the tendency will be for occupants to want to evacuate the
entire building."
"We have to examine, and we have been examining...how long
it takes for the last occupant on the highest floor to leave
the building safely," he said, adding that clients now want
that kind of information.
Regarding egress, Prieto agrees that, in the short term at
least, the human tendency would be to flee an attack site.
But he stresses that in an event that involves weapons of
mass destruction, mass evacuation of a facility–for instance
a transit station–is often "exactly the wrong response. Sheltering
in place is the right response."
Experts agree there may be more deaths in the immediate affected
area, but fewer deaths outside, especially when the weapon
is nerve gas or another biohazard that can spread easily and
contaminate a bigger area.
"Many of these are pretty complicated issues" with no simple
solution, said WTC structural engineer of record Leslie E.
Robertson, president of the New York City-based firm that
bears his name.
For example, fire refuge floors in tall buildings, which allow
occupants to exit to a balcony area every 10 or 15 floors
to find fresh air, may work in some situations but not others.
"In the case of the World Trade Center, the presence of refuge
floors would probably have resulted in the death of thousands
and thousands of people," said Robertson. "And in the case
of atomic attack, that outside air might not be so great.
I think we have to think through the whole problem."
Jack B. Buckley, a mechanical-electrical consultant based
in Houston representing the American Society of Heating, Refrigerating
& Air-Conditioning Engineers Inc., Atlanta, agreed that refuge
floors, and other such fire-protection measures, can backfire
and need more research. "There have been places where things
have been opened up and the air–the smoke–has gone back into
a building from a fire below," he said. "Some of these refuge
areas have to be looked at. Maybe they ought to be inside
the building around the elevator area so that you can encapsulate
them in concrete," he suggested.
Reiss chimed, saying that: "By and large, today, the building
codes in the United States probably provide the safest buildings
anywhere in the world, as long as the [codes] are properly
implemented and the fire officials and building code officials
make sure buildings are built to those codes."
Industry leaders also advocate development of an action plan
for an orchestrated industry response to individual disasters.
"What we saw was the importance of this industry responding
on the 11th," said Prieto. "It should not have been ad hoc."
George J. Tamaro, senior partner of geotechnical engineer
Mueser Rutledge Consulting Engineers, and leader of the effort
to evaluate the post-Sept. 11 stability of the trade center's
70-ft-deep basement structure, said: "One of the problems
we had immediately after the incident was obtaining suitable
documents to caution the fire and police departments and emergency
services personnel against the danger spots."
These included seven-level-deep shafts; weak floor slabs unable
to support fire vehicles and heavy equipment; intake pipes,
6 to 7 ft in diameter, connected directly to the Hudson River
and pouring water into the site; and more. All these structures
and services had to be identified and secured, said Tamaro.
"One of the little hobby horses I'm riding," he continued,
is to provide facility owners, in advance, with cartoons showing
locations of utility lines and shutoff valves. These simple-to-read
drawings, which would include information on securing a facility
post-incident, should also be made available to public safety
personnel, suggested Tamaro.
The situation at the Pentagon proves Tamaro's point. "We were
fortunate at the Pentagon in that we had current drawings
and doubly fortunate that our offices were not located in
the flight path of the projectile," said A.S. "Mack" McGaughan,
executive vice president and southeastern division manager,
amec Construction Management Inc. amec is in charge of the
renovation of the Pentagon's Wedge One, much of which was
slammed by the plane on Sept. 11.
Evey suspects that most fatalities in the Pentagon occurred
in the fire that ensued, not from the plane's impact. He and
others are therefore focusing on simple measures to improve
egress during a fire. "We've learned a lot of things already
that don't require huge changes to the code, and they aren't
terribly expensive," he said.
Take over-the-door exit signs. In a smoke situation, the signs
can't be seen by people crawling on their hands and knees.
"If you stand up you'll be in a smoke cloud that will kill
you in 30 seconds, and you can't see your hand in front of
your face anyway," said Evey. The signs need to be near the
floor.
Others concurred that fire, not terrorism, remains the most
serious and common danger to building occupants. "The issue
is really providing egress for people," said Reiss. "Depending
upon the type of building, you may have to build in certain
redundancies." For that reason, the 452-meter-tall twin Petronas
Towers in Kuala Lumpur, Malaysia, considered targets by the
owner, have redundant life safety systems. For example, the
fire alarm system has three control stations, said Reiss.
Regarding retrofitting buildings against biohazards, "there's
been discussion in various [publications] about what people
are going to do to the air-conditioning systems," said Buckley.
Suggestions range from cutting off outside air to relocating
fresh air intake vents.
The suggestions "concern myself and other members of ASHRAE,"
said Buckley. For instance, sometimes when outside air is
cut off in a high-rise, the stack effect increases, which
is a negative.
Buckley cautions that solving one problem often creates another.
Finding broadly applicable solutions to existing buildings
is not easy when there are so many buildings and so many different
air-handling systems, he maintains.
Consequently, ASHRAE has organized a study group to look into
hazards, including such things as bombs internally and externally,
and biohazardous material. The findings will be presented
in January at ASHRAE's annual meeting in Atlantic City, N.J.
Blast specialist Todd Rittenhouse, managing partner of the
structural division of engineer Weidlinger Associates, New
York City, is most focused on protecting buildings surrounding
the primary target of an attack. "Our bigger concern has been
collateral damage" to proximal structures, he said. "In Oklahoma
City, 250-odd buildings were damaged," he reminded participants,
referring to the terrorist bombing of the Alfred P. Murrah
Federal Building in 1995. "In the World Trade Center area,
[more than] 300 buildings were damaged."
Rittenhouse thinks owners of buildings surrounding target
buildings need to be advised by designers as to measures they
can take to protect their facilities, including installing
laminated glass.
Prieto agrees. "Collateral damage is a major issue. You may
have a perfectly fine low-profile building, but it's sitting
across the street from a high-profile target. From a security
standpoint, this requires "individualized analysis," he said.
Two years ago, there was a formal analysis done for an attack
involving weapons of mass destruction in a public transit
facility, said Prieto. "The threat defined at the time was
not the transit station as the target, but the transit station
in the vicinity of a high-profile building or symbol," he
added.
"The analysis identified four priority transit stations from
a security standpoint," Prieto said. The first two were the
World Trade Center station and the Pentagon station. "The
other two, fortunately, have not been attacked," he added.
At the round table, there was a call for stronger industry
participation in public policymaking, and not simply regarding
security. "The question is, why have we, as public servants,
as private groups, as associations and industries, not been
able to provide the leadership" to get the message out that
our infrastructure is deteriorating? asked Van Winkle. "We
seem to be concerned about a terrorist threat" but not about
the infrastructure crumbling through inattention.
This needs to change, he said, and Sept. 11 also provides
opportunity for that. It's something that goes way beyond
civil defense and disaster control.
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