month’s installment of the
ARCHITECTURAL RECORD / AIA
Continuing Education series contains valuable lessons from
the federal government’s approach to building security. Use
the following learning objectives to focus your study. After
reading the article, complete the questions and check your
answers. AIA members may fill in the self-report form and
send it in for two AIA Learning Units. —Mark Scher, AIA Director
reading this article, you will be able to:
Summarize the government's five levels
of building security classification.
Explain the GSA’s four areas of corrective
action for enhancing building security.
Describe general elements of secure
design for buildings with regard to perimeter, entry, interior,
and security systems planning; glazing; parking and access;
and building systems strategy.
The 1990s marked a flashpoint for architectural design and safety
in the workplace. The February 1993 bombing of the World Trade
Center in New York City obliterated the American public's sense
of immunity to large-scale domestic- and international-terrorist
attacks. The April 1995 bombing of the Alfred P. Murrah Federal
Office Building in Oklahoma City and the still-unsolved 1996 bombing
at Atlanta's Olympic Centennial Park heightened concerns about
security in public buildings and spaces. These national tragedies
permanently changed the way government and corporate clients locate,
plan, and design public facilities. As a result, security will
continue to be an essential criterion for planning buildings for
the foreseeable future.
strategies can most effectively minimize the loss of life and
property through integrated use of technology, operational policies,
and facility planning. Understanding the exact nature of what
may threaten a building is important, especially in the early
project development phases. From site selection and materials
specification to structural systems, every design decision may
someday be crucial to saving lives and preventing damage as a
result of an attack, accidental explosion, or natural disaster.
targets, and terrorism
anticipates targets, potential threats, and means of attack. The
goals are to protect people, buildings, products, services, equipment,
proprietary information, and often possessions and priceless artwork.
Most clients prefer not to publicize the threats they receive,
unless danger is imminent. Similarly, clients are reluctant to
discuss preventive security measures put in place. As a result,
the public rarely hears about potential threats unless a disaster
occurs. The biggest danger, suggests a former FBI official, may
come from loners or small antigovernment groups who can access
intelligence information and floor plans on the Internet.
are vulnerable to threats, exterior attacks, ballistic missiles,
and vehicle bombs--the last being the most destructive and easiest
to create. Chemical and biological threats are a growing concern,
particularly after the poisonous serin gas attack in the Tokyo
subway. Other threats include civil disobedience, mob or individual
acts of violence, package bombs, or unforeseeable events such
as fires, earthquakes, and gas-line ruptures. Given so many possibilities,
security experts admit they cannot predict or prevent all possible
scenarios, but they can recommend reasonable and prudent precautions.
of the Murrah building--which left 169 dead, 518 injured, and
$100 million in damages--prompted a comprehensive review of security
measures for all federal buildings. At the time of the explosion,
no security standards existed for federal buildings, says Anthony
DiGregorio, senior technical advisor at Applied Research Asso-ciates,
an Alexandria, Virginia, consulting firm specializing in industrial
security and protection. Immediately after the bombing, the U.S.
Department of Justice, under presidential directive, developed
federal standards on the ``hardening'' of buildings to explosives
and other potential domestic threats based on the findings of
the June 1995 report ``Vulnerability Assessment of Federal Facilities,''
known simply as ``The Marshals Report.'' As the principal owner
or landlord of the 1,300 federal buildings investigated, the General
Services Administration (GSA) was designated to coordinate security
standards and cost assessments.
team of security experts classified federal buildings into five
categories, or levels, based on facility size in square feet,
number of employees, and volume of public access. After continued
refinement of the draft report through 1997, the GSA Security
Design Criteria were accepted as the guidelines for ensuring public
safety at all federal buildings. The criteria will likely remain
in draft form, because an act of Congress is required to make
the larger the facility, the more employees, and the larger the
degree of public access, the greater the need for security. Most
federal facilities fall into one of the first four levels of safety
requirements, from level one, the lowest, to level four. Facilities
critical to national security, such as the Pentagon, have the
highest possible security classification, level five. A level-one
facility, for example, might not require an entry control system,
while a level-four facility would require electronic controls
with closed-circuit television (CCTV). A small facility with just
a few employees and a low volume of public contact may not need
much in the way of security, but some measures are required, such
as lighting with emergency power backup.
enforcement agencies often have their own security needs, and
the GSA cooperates with them in meeting these requirements. For
example, at the request of the FBI, the GSA directed that the
bureau's new 306,000-square-foot field office in Washington, D.C.,
receive facade and structural improvements to provide additional
blast protection at a cost of $5.9 million for construction and
$1 million for design fees. The total cost for the building was
$93.4 million, according to the GSA.
for improved security
The GSA's recommendations
apply to levels one through four for building design and construction,
security systems, operations, and equipment. Design and engineering
requirements fall into four general categories of corrective action
at perimeters, entries, interiors, and the security planning of
the overall facility.
security is essential to prevent either a moving or stationary
truck bomb attack. The next generation of new federal courthouses,
now under design or construction, will integrate landscaping,
site planning, and parking controls with more visible security
measures, including CCTV monitoring, lighting with emergency backup,
and physical barriers or bollards. Standoff distance is a term
used to describe the limiting of vehicular access through street
is critical at federal courthouses and other facilities containing
criminal justice agencies, although individuals may view any building
that is a symbol of authority as a target. Thus, the location
and design of main entrances, loading docks, mail rooms, and utility
mains is of particular concern. At main entrance lobbies, magnetometers,
such as those used at airports, and electronic detection devices
can identify deadly weapons and explosives.
years, the threat of mail bombs has prompted greater security
in mail rooms and more thorough package screening. Loading docks
and shipping and receiving areas are also potential targets for
larger package explosives or vehicle bombs and are places where
an intruder may try to illegally enter a facility. To minimize
potential damage, delivery areas should not be located near mechanical
areas or underground. Other entry precautions include installing
intrusion-detection systems and upgrading current life-safety
standards. Many buildings--even in the private sector--now use
sign-in procedures for delivery people and packages while limiting
their access with CCTV entry controls, secure access to utility
mains, and heavy-duty locks at higher-risk facilities.
addresses design and construction materials. Street-level retail
spaces in government buildings are also carefully evaluated. At
the new Ronald Reagan Federal Building in Washington D.C., shops
are located on a lower-level arcade near the public spaces and
security increases in upper levels of the building.
include employee identification; controlling visitor circulation;
limiting access to building-control centers; and providing emergency
power, computer, and phone lines to critical systems. The GSA
also evaluates child-care center locations in federal buildings.
Future planning will include the hardening of some day-care centers
and site assessments to mitigate potential threats by moving them
away from high-risk areas.
includes assessing the specific risks of the various federal agencies--such
as the FBI and the Bureau of Alcohol, Tobacco and Firearms. During
site selection and planning, consideration is given to whether
these agencies belong in an open, multitenant office building
or in their own building, located where dangers are minimal.
there is a fine line between informing design professionals on
planning safety design standards and aiding those seeking to circumvent
these measures. For that reason, the GSA divulges information
about the design criteria on a need-to-know basis to those involved
in federal projects. Some architectural firms contacted to discuss
how the security measures apply to federal courthouses in various
design stages declined to comment or provide photographs, on the
advice of the GSA.
Security Design Criteria
Wade Belcher, architect in charge of the security design standards
at the GSA Public Building Service in Washington, D.C., ``few
buildings have been completed with designs based on the security
criteria. Many buildings have had components from the criteria
included through retrofit projects; however, most have chosen
not to disclose what the elements are.'' Nevertheless, private-sector
security experts, architects who specialize in justice facilities,
and structural engineers specializing in blast design, who are
familiar with the GSA security criteria, can offer insight into
security design measures applicable to many building types.
The main goal
of the GSA security criteria is to save lives and prevent injury.
Secondary goals are to protect federal buildings and assets. The
security criteria provide a performance-based approach to various
building systems and components, from window glazing to structural
systems. In the event of a major terrorist or criminal act, structural,
mechanical, electrical, and life-safety criteria are aimed at
facilitating safe evacuation and rescue.
address security concerns while considering cost parameters and
acknowledging an acceptance of risk. Officials recognize that
federal buildings should not be fortresses or bomb shelters, but
rather buildings that are open, accessible, and well woven into
the community fabric.
assessment is required at the early stage of each federal project.
Risk factors may be as diverse as a building's symbolic importance
if it is a highly visible landmark or its function if it is considered
vital to national interests (such as a national monument, an air
traffic control center, or the White House, for example). Other
factors to be assessed include the overall effects of an attack,
including death and injury, property damage, and workplace interruptions.
Costs associated with repairs and replacement are also considered.
Designs should allow for the ability to increase security in response
to a heightened or temporary threat, such as at a federal courthouse
during a high-profile trial. More costly or inconvenient measures,
such as prohibiting parking, may be implemented as needed.
should follow a tiered defense system, with zones of security
starting at the building perimeter and decreasing toward its core.
The tiers include the standoff distance in front of the building,
building exterior walls, the screening-and-access control area,
and safe interior areas for valuable assets. Each building system
should support an interdisciplinary approach to mitigate risk
and reduce casualties, property damage, and loss of critical functions.
Security should be considered in all decisions, from trash receptacle
placement to the design of redundant electrical systems. Critical
functions and life-safety systems should be located toward the
inside of the building, away from the exterior, where they are
more vulnerable to explosions.
the facility should be access-controlled, and surface parking
should be controlled with appropriate perimeter barriers; handicap
accessibility must be maintained. Magnetometers and X-ray equipment
should be integrated into the entrance lobbies. Egress lighting
should have emergency power backup. Emergency power units should
not be co-located with primary power units, as they were at the
World Trade Center, where a single underground explosion disabled
both power sources.
planters, street furniture--should be considered as a means of
lending a building added protection where only a minimal setback
from the street is available. A given facility's individual security
requirements should be considered when deciding whether to limit
direct pedestrian and vehicular access to the building. It is
essential to evaluate shipping and receiving areas for potential
location in a remote area of the facility. The selection of glazing
and fenestration materials should be evaluated based on their
performance when subjected to lateral forces.
use of site planning, perimeter definition, sight lines, and lighting
can eliminate the need for awkward engineering solutions that
might result in less-than-pleasing buildings.``The challenge to
architects is to provide an inviting community environment and
deal with physical security. These are not contradictory and can
enhance one another,'' says Ed Feiner, FAIA, chief architect for
the GSA. ``Physical imagery is important. The most successful
federal buildings are `transparent'--the security elements are
in place, but they are not visible to the public.''
``The GSA evaluates each potential threat individually. There
is no cookbook to solve all problems; every building is different.
The security criteria attempt to define how a solution should
perform in any given situation, rather than establishing hard-and-fast
rules that can't be tailored to specific needs.''
begins during property and site selection. ``The GSA prefers sites
with some breathing room,'' says Feiner. ``Not a buffer zone--that's
for a fortress. Historically, small city courthouses are set on
a lawn on a hill, to create an icon with a grand civic presence
for the public. The GSA wants to achieve that image and derive
security benefits at the same time.''
Even in an
urban setting, standoff distance is used to address vehicular
traffic and reduce the exponential effect of a car bomb. For example,
the new Brooklyn Federal Courthouse project included an experimental
program to combine art and architecture by inviting artists to
work with structural engineers. The goal is to put the best face
on necessary security requirements, with less intrusive, visually
interesting perimeter security devices, nonstructural elements,
The blast at
Oklahoma City's Murrah Federal Office Building resulted in many
lessons for future construction of federal facilities, especially
relating to glazing, life-safety issues, and structural systems,
notes Don Porter, AIA, partner at HLW International, in New York
City, and project manager for the Brooklyn Federal Courthouse.
the explosion at the Khobar Towers, an American military housing
compound in Dharan, Saudi Arabia, provided information on how
glass shatters during a blast. Window film was scheduled for installation
but had not been applied at the time of the explosion. Most of
the fatalities in Oklahoma City and Dharan resulted from shards
of glass, which flew as far as 100 feet into the building.
The GSA and
manufacturers have studied and tested several types of glass,
security window film, and other materials under test explosions.
Glazing with protective film may be effective in some cases, but
blast experts claim that more testing is required to generate
conclusive data. ``The data is lacking on how best to protect
windows and curtain-wall construction,'' Porter says. ``There
is no empirical data on the effects of blasts and no agreement
on what works best--glazing, films, and window frames--especially
in retrofits. We can't do a 100 percent job on security--then
we'd just end up building a bunker--so there are compromises involved.''
glass has some problems with spontaneous failure, but experts
say it performs better in a blast environment than float or annealed
glass; when shattered, it produces small cube-shaped projectiles
with significantly higher breaking strength than pieces of float
glass. Laminated glass, which consists of a layer of film laminated
between two pieces of glass, tends to stick to the laminating
film and stay in window frames when broken. This reduces the number
and velocity of flying fragments. During failure, float glass
creates large, sharp-edged shards resembling knives and daggers,
experts say. For window assemblies to stay in place, the glazing,
mullions, and anchors must be able to resist blast pressures enough
to transfer loads to the adjacent structure.
designers have been addressing issues of enhanced security for
state and county projects for a while now. ``The federal guidelines
raise the requirements to another level. There is no total answer
to the best approach,'' says Don Dwore, AIA, principal and director
of the justice facility group at Spillis Candela & Partners,
in Coral Gables, Florida. Typically, security comprises 4 to 5
percent of a courthouse project's construction costs, Dwore estimates,
and perhaps 3 percent or less for county projects. At the $22
million Charlotte County Courthouse in Pensacola, Florida, approximately
$400,000 was spent on security measures.
secure buildings, parking, and a secure path to their chambers.
They don't want to be shot and killed on the way to work,'' Dwore
observes. ``When assessing property, street setbacks are important.
Raising courthouse functions well above street level, use of wide
stairs, ramps, hardened building elements, bollards, and landscaping
can prevent vehicles from causing further damage to secure areas.
Large-caliper trees on site can keep vehicles at a safe remove
from the building.''
is now integral to building and life-safety systems. Experts recommend
that mechanical systems include gas detectors and the capability
to keep biohazards out of fresh-air intakes, especially at research
and lab buildings.These should be located where unauthorized access
will be minimized as well.
should not branch off from the main water-supply line at a point
where they would be vulnerable to failure if there were an accident.
Similarly, water mains and pumps should be plumbed so that if
a break occurs in the main, there is an alternate way to get water
to the pumps. Building-utility areas must be secured by controlled
access. Fire stairs and areas of refuge and escape should not
empty into main lobbies or loading docks because these are areas
of high potential risk for an explosion, and evacuating people
through them could cause injuries and panic. Exit stairs are much
more easily rerouted during the conceptual design phases than
lines, telecommunications, and electrical power should be routed
separately rather than run through a single duct. Main electrical
feeds should not enter buildings at potentially vulnerable locations,
such as loading docks, receiving areas, and main entrances. Redundant
systems, if located remotely, also provide a level of protection.
If one system malfunctions, the other can replace it.
The World Trade
Center bombing in an underground public parking garage caused
several floors to collapse, destroying the chiller plant and the
backup emergency generator system. Primary and secondary systems
were located side by side, not remotely. ``Public underground
parking should not be located near critical building systems,
backup generators, or gas meters,'' observes William Daly, managing
director of Kroll-O'Gara Company, a New York City security, investigative,
and risk-management firm that was a consultant to the Port Authority
of New York and New Jersey for the World Trade Center after the
disaster. ``Such areas require compartmentalization, and their
walls should be strengthened with steel plates to deflect explosions.
Locating emergency systems above grade is better to avoid flood
damage, but if they should catch on fire on upper floors, extinguishing
the flames is very difficult.''
bombing, underground parking has been limited to prescreened tenants.
Deliveries must be preauthorized and may be received only at checkpoints
from those with identification.
automated-access controls in office buildings reflect new technology,
says Daly. Biometrics electronically read the contours of hands
for identification. Retina scanning, fingerprinting, and proximity-card
access systems are user-friendly methods to screen pedestrian
is a relatively new area for commercial and civilian buildings,
and there are several points of view on the subject. Some federal
agencies want to enhance vulnerable portions of their building
by localizing blast resistance, or hardening, says David Kossover,
P.E., a New York City structural engineer and blast expert. In
contrast, the British don't recommend hardening their civilian
buildings but assume there will be a certain amount of damage.
They concentrate on mitigating partial or total building collapse
and on improving the blast resistance of the exterior glazing.
Others claim that reinforced-concrete and steel buildings with
well-detailed connections often withstand pressures and vibrations
from explosions and do not sustain extensive permanent damage.
They also admit it is not possible to design a bombproof building
that will survive undamaged and guarantee few injuries. Instead,
limiting damage and human injury is best achieved through good
design, not necessarily through localized blast-design techniques.
This debate will most likely continue in the years ahead.
enhance buildings may also make them more vulnerable to attack.
Windows and atria provide openness and daylight but also contradict
blast-mitigation objectives, asserts engineer Tod Rittenhouse,
blast expert and principal of Weidlinger Associates, a New York
City consulting engineering firm. Blast-mitigation strategies
permit significant localized damage while preventing catastrophic
collapse. Casualties immediately near a blast may be unavoidable,
but by preventing progressive collapse, further fatalities may
does not apply to blast resistance, because earthquakes and explosions
affect buildings differently. Blasts usually affect a relatively
small geographic area around a building's perimeter, while earthquakes
move the entire building. When a building is hit by a bomb, damage
generally occurs to its skin, floors, and interior walls. These
areas are not designed to transfer blast loads to a building's
frame, so they may tear away, leaving the structural frame intact.
Even though a structure may not be damaged by a seismic event,
in a blast, permanent deformation of columns and girders (see
sidebar, page 146) may occur in areas near an explosion.
The GSA's current
enthusiasm for the design-build method of project delivery raises
concerns that some aspects of security design will be diluted
during budget reviews. ``As government agencies move from traditional
design-bid-build to alternatives like design-build, it will be
interesting to see how security criteria will be value-engineered
and applied,'' says John Sporidis, senior vice president of HDR
Architecture, in Alexandria, Virginia. ``When projects go the
design-build-developer route, we must pay attention to ensure
that the integrity of the design is not compromised and nothing
By all accounts,
Americans haven't seen the last terrorist attack on public- or
private-sector buildings. Clients--and the public--will continue
to demand comprehensive yet unobtrusive security responses from
the design and construction industries. It is also essential that
research continue to find the most appropriate building materials
that can withstand a host of attacks, accidents, and disasters.
The challenge ahead is to seamlessly integrate life-safety and
security measures with aesthetic building design. Security need
not be incompatible with good design--and the use of prudent precautionary
measures may save countless lives and millions upon millions of
dollars in damages.