Guidance for
Protecting Building Environments
from Airborne
Chemical, Biological, or Radiological Attacks
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THIS
DOCUMENT IDENTIFIES ACTIONS that a building owner or manager can
implement without undue delay to enhance occupant protection from an
airborne chemical, biological, or radiological (CBR) attack. The
intended audience includes building owners, managers, and maintenance
personnel of public, private, and governmental buildings, including
offices, laboratories, hospitals, retail facilities, schools,
transportation terminals, and public venues (for example, sports arenas,
malls, coliseums). This document is not intended to address single
family or low-occupancy residential housing (less than five family
units). Higher risk facilities such as industrial facilities, military
facilities, subway systems, and law enforcement facilities require
special considerations that are beyond the scope of this guide.
The
likelihood of a specific building being targeted for terrorist activity
is generally difficult to predict. As such, there is no specific formula
that will determine a certain building’s level of risk. Building owners
must make their own decisions about how to reduce their building’s risk
to a CBR attack. These decisions may be aided by a comprehensive
building security assessment. Many government and private organizations
have identified resources that provide insight into building security
assessments. The reference list at the end of this document will help
the reader obtain this information.
No building
can be fully protected from a determined individual who is intent on
releasing a CBR agent. The recommendations in this guide will not
preclude injuries or fatalities in the event of a CBR release. .
However, facility owners and managers can transform their buildings into
less attractive targets by increasing the difficulty of introducing a
CBR agent, by increasing the ability to detect terrorists before they
carry out an intended release, and by incorporating plans and procedures
to mitigate the effects of a CBR release. Some of the references listed
in the back of this document can provide information on how to recognize
if a CBR release has occurred. These recommendations focus on airborne
releases of CBR agents* in quantities capable of being easily
transported by a few individuals. Protection from other types of attacks
such as explosions, building collapses, and water supply contamination
require much different measures and are not addressed in this document.
The
recommendations set forth in this document are not intended to be a
minimum requirement that every building owner and manager should
implement for every building. Rather, the decisions concerning which
protective measures should be implemented for any building should be
based on several factors, including the perceived risk associated with
the building and its tenants, engineering and architectural feasibility,
and cost.
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*Note:
References to a release of CBR agent in this document will always refer
to an airborne CBR release.
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Terrorism
events have increased interest in the vulnerability of U.S. workplaces,
schools, and other occupied buildings to CBR threats. Of particular
concern are the airflow patterns and dynamics in buildings, specifically
in the building heating, ventilating, and air conditioning (HVAC) systems.
These systems can become an entry point and a distribution system for
hazardous contaminants, particularly CBR agents. Building owners need
reliable information about how they can (1) modify their buildings to
decrease the likelihood or effects of a CBR incident and (2) respond
quickly and appropriately should a CBR incident occur. Comprehensive
guidance is needed in several areas, including:
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How to
modify existing buildings for better air protection and security.
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How to
design new buildings to be more secure.
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What
plans building managers should prepare in advance to help them make
effective decisions in the midst of a CBR incident.
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While more
comprehensive guidance is being developed, this document focuses on the
shorter-term goals of identifying those protective actions that you can
take immediately. But it recognizes that some recommendations may not be
feasible for you or in all situations.
In
initiating any plan to modify building system design or operation, an
important first step is to understand these systems: How were they
intended to operate? How do they currently operate?
Getting to
know your building may best be handled by conducting a walk-through
inspection of the building and its systems, including the HVAC, fire
protection, and life-safety systems. During this inspection, compare the
most up-to-date design drawings available to the operation of the
current systems.* This step may require, or benefit from, the assistance
of qualified outside professionals. Without this baseline knowledge, it
is difficult to accurately identify what impact a particular security
modification may have on building operation. While it is important to
understand how the existing building systems function, the systems need
not operate per design before you implement security measures. A partial
list of items to consider during your building walk-through includes:
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*Note: If sufficient questions or surprises arise from
the building walk-through, an independent evaluation by a qualified HVAC
professional should be used to establish a useful baseline.
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The
recommendations can be divided into four general categories: (1) things
not to do; (2) physical security; (3) ventilation and filtration; and (4)
maintenance, administration, and training. Some of these items, such as
securing mechanical rooms, may be started prior to your completing the
recommendations in the "Know your building" section. Items within each of
the four categories are listed in the order of priority. Items considered
to be highly critical are identified by “***” next to the number. As you
review these recommendations, consider their potential implications upon
the contract language necessary for existing and future service contracts.
A brief discussion of the four categories and some commonly considered
recommendations follow.
Things not to do
More than
anything else, building owners and managers should ensure that any actions
they take do not have a detrimental effect on the building systems (HVAC,
fire protection, life safety, etc.) or the building occupants under normal
building operation. Some efforts to protect the building from a CBR attack
could have adverse effects on the building's indoor environmental quality.
Building owners and managers should understand how the building systems
operate and assess the impact of security measures on those systems.
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***1.
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DO NOT
PERMANENTLY SEAL OUTDOOR AIR INTAKES. Buildings require a steady
supply of outdoor air appropriate to their occupancy and function.
This supply should be maintained during normal building operations.
Closing off the outdoor air supply vents will adversely affect the
building occupants and likely result in a decrease in indoor
environmental quality and an increase in indoor environmental quality
complaints.
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***2.
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DO NOT
MODIFY THE HVAC SYSTEM WITHOUT FIRST UNDERSTANDING THE EFFECTS ON THE
BUILDING SYSTEMS OR THE OCCUPANTS. This caution directly relates to
the recommendation that building owners and managers should understand
the operation of their building systems. If there is uncertainty about
the effects of a proposed modification, a qualified professional
should be consulted.
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***3.
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DO NOT
INTERFERE WITH FIRE PROTECTION AND LIFE SAFETY SYSTEMS. These systems
provide protection in the event of fire or other types of events. They
should not be altered without guidance from a professional
specifically qualified in fire protection and life safety systems.
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Physical Security
Preventing
terrorist access to a targeted facility requires physical security of
entry, storage, roof, and mechanical areas, as well as securing access to
the outdoor air intakes of the building HVAC system. The physical security
needs of each building should be assessed, as the threat of a CBR attack
will vary considerably from building to building. For example, the threat
to a large corporate headquarters may be considered greater than the
threat to a small retail establishment. Some physical security measures,
such as locking doors to mechanical rooms, are low cost and will not
inconvenience the users of the building. These types of measures can be
implemented in most buildings. Other physical security measures, such as
increased security personnel or package x-ray equipment, are more costly
or may inconvenience users substantially. These measures should be
implemented when merited after consideration of the threat and
consequences of a terrorist attack. Building owners and managers should be
familiar with their buildings and understand what assets require
protection and what characteristics about the building or its occupants
make it a potential target. By first assessing the vulnerabilities of
facilities, building owners and managers can address physical security in
an effective manner. While the identification and resolution of building
vulnerabilities will be specific to each building, some physical security
actions are applicable to many building types. These include:
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***1. |
PREVENT
ACCESS TO OUTDOOR AIR INTAKES. One of the most important steps in
protecting a building’s indoor environment is the security of the
outdoor air intakes. Outdoor air enters the building through these
intakes and is distributed throughout the building by the HVAC system.
Introducing CBR agents into the outdoor air intakes allows a terrorist
to use the HVAC system as a means of dispersing the agent throughout a
building. Publicly accessible outdoor air intakes located at or below
ground level are at most risk—due partly to their accessibility (which
also makes visual or audible identification easier) and partly because
most CBR agent releases near a building will be close to the ground
and may remain there. Securing the outdoor air intakes is a critical
line of defense in limiting an external CBR attack on a building. |
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Relocate
outdoor air intake vents.
Relocating accessible air intakes to a publicly inaccessible location
is preferable. Ideally, the intake should be located on a secure roof
or high sidewall. The lowest edge of the outdoor air intakes should be
placed at the highest feasible level above the ground or above any
nearby accessible level (i.e., adjacent retaining walls, loading
docks, handrail). These measures are also beneficial in limiting the
inadvertent introduction of other types of contaminants, such as
landscaping chemicals, into the building.
Extend
outdoor air intakes.
If relocation of outdoor air intakes is not feasible, intake
extensions can be constructed without creating adverse effects on HVAC
performance. Depending upon budget, time, or the perceived threat, the
intake extensions may be temporary or constructed in a permanent,
architecturally compatible design. The goal is to minimize public
accessibility. In general, this means the higher the extensions, the
better—as long as other design constraints (excessive pressure loss,
dynamic and static loads on structure) are appropriately considered.
An extension height of 12 feet (3.7 m) will place the intake out of
reach of individuals without some assistance. Also, the entrance to
the intake should be covered with a sloped metal mesh to reduce the
threat of objects being tossed into the intake. A minimum slope of 45°
is generally adequate. Extension height should be increased where
existing platforms or building features (i.e., loading docks,
retaining walls) might provide access to the outdoor air intakes. |
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Medical Air Solutions,
Inc.
©
1999-2012 Medical Air Solutions, Inc. All rights reserved. 
