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Buildings
Building for a Secure Future: Bioterrorism
(enr.com
and archrecord.com - 3/25/02 issue)
By Mary B. Powers, and Nadine M. Post, with Andrew G. Roe, ENR
Simple measures that can protect the inhabitants
of a building or users of critical infrastructure from chemical
and biological attack are becoming routine since the Sept. 11 terrorist
attacks and the subsequent anthrax outbreaks. Many building owners
and developers are demanding that design criteria for their projects
include security master plans. And those in charge of protecting
infrastructure are working out protocols to protect water, wastewater
and other systems. These include risk assessments to determine how
much security is truly needed.
Threat and vulnerability assessments analyze everything as a system,
not just "what can be done to protect," contends Keith
Henson, director of security services for Lockwood Greene, Spartanburg,
S.C. "We start at the basics to determine what the asset is
and what the threat is." An office building is a higher risk,
for example, if corporate officers are there regularly.
The U.S. Army Corps of Engineers is charged with protecting the
armed forces, including civilian employees, from chemical, biological
and nuclear attacks in military buildings. Each military installation
is responsible for designing its own buildings.
The Corps' Construction and Engineering Research Laboratory in
Champaign, Ill., is developing a software tool to ensure that architects
can understand the threats and design buildings to a certain threshold
of protection. "The software will include ‘wizards' that
will allow users to evaluate such complicated issues as computational
fluid dynamics without knowing what that is," says Jim Miller,
a mechanical engineer at the lab.
The Corps expects the software to familiarize designers with various
materials as well. Some building materials are almost impossible
to clean, for example, while others only need to be wiped down.
Other high-tech materials, such as carpet that can neutralize contaminants,
are under investigation.
The laboratory is participating in a program run by the Defense
Advance Research Program Agency to develop buildings that are immune
to chemical, biological and radiological attacks. "The thrust
is to develop and demonstrate technologies that actively resist
attacks," says Miller. They will test various response modes
such as filtration and neutralization.
VULNERABLE
The Corps is also looking at how best to protect water treatment
infrastructure. Plans include development of dynamic models of distribution
systems that could tell officials how long they have before a biolgical
agent reaches a critical facility.
More importantly, the model helps officials identify all access
points to the system, says Vincent Hock, the Corps' project leader
for infrastructure. Water towers, well heads, manholes and fire
hydrants are not typically secure, and are considered the most vulnerable
points of a water system. "Preventing physical access is most
important," he says.
Many public utilities are not waiting for government directives.
In February, the Metropolitan Water District of Southern California
(MWD) authorized $5.5 million for additional protection of its facilities
and drinking water supplies. The district will upgrade its automated,
remote water-quality sampling and analytical capabilities, as well
as purchase additional contaminant monitoring equipment and instrumentation
and beef up physical security at water filtration plants.
"We asked the board to authorize this expenditure now, rather
than wait for the passage of one of several federal and state bills
on security measures that may provide funding for increased security
costs for water agencies," says Ronald R. Gastelum, MWD's CEO.
"While we hope for eventual reimbursement, we spend this money
on critical security programs with no regrets."
One advantage of U.S. systems is that they still chlorinate water
to disinfect it. "It is one of the single most effective killers
of bioactivity," says Hock. Super chlorinating is a low-tech
way and easy way to kill biological agents.
Dilution keeps chemical contamination from being much of a threat
to water systems. "It's difficult to add enough of a chemical
contaminant to be a threat," says Ed Wetzel, vice president
of Montgomery Watson Harza, Pasadena, Calif. However, there is no
way to guarantee that a water system is 100% safe, he says. As with
buildings, the beginning point for protection is assessing the vulnerability
of the system.
LOOKING AT RISK
The U.S. Dept. of Energy's Sandia Laboratory in New Mexico has developed
risk assessment methodology for dams, transmission systems and water
systems. Company executives are trained and certified by the lab.
"We think it gives us a leg up," says Wetzel, especially
since Congress is considering requiring all public agencies to assess
vulnerability using the Sandia methods.
The most fundamental method of reducing risk to water systems
is deterrence, stresses Wetzel. "It's important to slow intruders
down enough to give the response team time to catch them before
they do something," he says.
MWH has formed an alliance with McLean, Va.-based research and
engineering consultant Science Applications International Corp.
to help its clients with such deterrents. "SAIC knows which
systems to put in, and we know how to install them in water facilities,"
Wetzel says.
For buildings, Henson lists four basic methods of protecting assets:
modifying daily routines of building facilities and maintenance
personnel; changing the security force; installing physical barriers;
and adding electronic surveillance systems. "The simplest protection
from any threat is distance," he says.
Obvious measures, such as moving an air intake from ground level
to the roof to make access more difficult or locating a "sensitive"
building in the most secure area of a campus, are usually the least
expensive.
But the most obvious measures are not always the best. The American
Society of Heating, Refrigerating and Air-Conditioning Engineers
Inc., Atlanta, concerned about opportunists pushing their wares,
issued an eight-page "initial" directive in January that
cautions against taking action without proper counsel (ENR 1/21
p. 12).
"We have to take time to figure out if [owners] need to do
anything different to operate their buildings as safely as possible,"
said William J. Coad, ASHRAE president, at the organization's winter
meeting in Atlantic City, N.J.
For existing buildings, ASHRAE recommends that owners first familiarize
themselves with their buildings and building systems. They should
then check that the building is performing as intended. Finally,
they should not make any changes without understanding the consequences.
The ASHRAE report counsels not to "close outdoor air intake
dampers or otherwise block ventilation paths...change the designed
airflow patterns or quantities; and...modify the fire protection
and life safety systems without approval of the local fire marshal."
Mechanical engineers caution building owners that changing things
in an existing building might solve one problem while creating another.
For example, roof air intakes may be more difficult to reach than
street-level intakes, but they are not intruder-proof either and
must be guarded or secured against biohazards. Additionally, closing
off air intakes can reduce a system's ability to purge contaminants.
Components and systems that should be studied go beyond the heating,
ven-tilating and air conditioning, says ASHRAE. Areas of refuge,
building shell and duct tightness, and fire protection and safety
should also be considered. The organization also advises owners
to develop a preparedness plan for "extraordinary incidents"
against the building.
In advising that doing nothing may be the best course, ASHRAE
is primarily addressing commercial building owners. For more specialized
building types, such as laboratories that house chemical and biological
agents, designers are adding more security than ever.
The 350,000-sq-ft emerging virus laboratory at the Centers for
Disease Control and Prevention in Atlanta, likely to contain the
most dangerous pathogens, will be protected by its location, says
George Chandler, CDC's facilities planning officer. "We have
a setback zone for certain buildings, away from pedestrian routes
and roads," he says.
But the laboratory's campus master plan, developed long before
Sept. 11, already had addressed security, Chandler says. "It
didn't take the World Trade Center; Oklahoma City was enough,"
he says, referring to the 1995 bombing of the Alfred P. Murrah Federal
Building. Besides setbacks, CDC looked at such protective measures
as guard post and security camera placement and safety windows.
High-risk buildings require expensive protection from chemical
or biological agents, such as duplicate security command posts and
sophisticated heating, ventilation and air-conditioning systems
with negative or positive pressure. But simpler measures can protect
lower-risk buildings. Two examples are moving the mailroom off site
or installing a stand-alone HVAC system. Taking security to the
next level would mean adding a negatively pressurized duct system
to suck harmful agents into a filtering system, say engineers.
HVAC COSTS
Other vulnerable areas, such as building lobbies, also could be
equipped with stand-alone HVAC systems that do not recirculate return
air through the entire building. "The cost…becomes acceptable
if it limits the disruption of the building," says Terry Gillick,
vice president of technology, Syska Hennessy Group, New York City.
Most biological agents are between one and five microns in diameter.
Anthrax, for example, is 2.5 microns. High-efficiency particle air
(HEPA) filters in HVAC systems will filter out particles down to
0.3 microns. "That's very expensive, and the units must be
oversized to get enough air flow," says Gillick.
Expense generally limits HEPA use to high-security federal facilities.
Health- care facilities often install prefilters and use HEPA units
as a final filtration system.
The U.S. State Dept.'s specifications mandate 100% filtration
of the air in U.S. embassies overseas for chemical and biological
agents. That added measure of security adds at least 5% to ventilation
system costs, says Gillick. Ultraviolet-C emitters can destroy bacteria
in ductwork, but the technology is not yet widely available. By
and large, HVAC system protections are low-tech, "but the threat
is complex," says Gillick. Most systems cannot give early warning
of contamination. "It's a problem the military has grappled
with," he says. There are systems, but they are large and cumbersome
and hard to deploy.
Not everyone agrees that protecting buildings and infrastructure
is worth the effort. "Terrorists are more likely to look at
food or beverage distribution for raw casualties," says Eric
Croddy, senior research associate at the Monterey Institute of International
Studies, Monterey, Calif. Equipping hospitals with rapid diagnoses
and detection will save more lives than building fortresses, he
says. "Castles never held out anyone that wanted in badly enough,"
Croddy adds.
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