Unit Objectives

Explainthe five possible protective actions 
for a building and its occupants.

Comparefiltration system efficacy relative 
to the particles present in CBR agents.

Explainthe key issues with CBR detection.

Identifythe indications of CBR 
contamination.


Unit VIII: CBR Measures

Units I-VI covered the Risk Assessment 
Process

Units VII and VIII explain Explosive Blast, 
CBR Agents, and their effects

Units IX and X demonstrate techniques for 
site layout and building design to counter or 
mitigate manmade threats and similar 
technological hazards


CBR Measures: An Overview 

..Protective Actions for Buildings 
and Occupants
..Air Filtration and Cleaning 
Principles and Technology
..CBR Detection and Current 
Technology
..Non-Technology CBR 
Contamination IndicationsFEMA 426, Chapter 5 is based on best practices for 
safeguarding building occupants from CBR threats. This 
module is organized into four sections :
SOURCE: SENSIR TECHNOLOGIES

CBR Terrorist Incidents Since 1970

1984 
Botulinum1972 
Typhoid00959085807570November 1995Radioactive CesiumDecember 1995RicinJune 1996 
Uranium1992 CyanideMarch 1995 RicinApril 1995 
SarinApril-June 1995Cyanide, Phosgene, 
Pepper SprayFebruary 1997 
Chlorine14 Injured,
500 EvacuatedJune 1994 
Sarin7 Dead,
200 InjuredMay 1995 
PlagueApril 1997 
U2351984 
Salmonella200 Injured1985 
CyanideMarch 1998Cesium-1372001AnthraxMarch 1995 Sarin

What is the CBR Threat Today?
POTENTIALIMPACTPROBABILITY/LIKELIHOODNUCLEARWEAPONIMPROVISEDNUCLEARDEVICERADIOACTIVEMATERIALCHEMICAL AGENTOR TOXICINDUSTRIALCHEMICALBIOLOGICALAGENT

Why Would Terrorists Use CBR?

..Available and relatively easy to manufacture
..Large amounts not needed in an enclosed space
..Easily spread over large areas
..Potential for mass casualties
..Strong psychological impact
..Overwhelms resources
..Difficult to recognize (contagious or spread by victims)



CBR Sources

•Laboratory/commercial•Industrial facilities•Foreign military sources
..At least 26 countries possess 
chemical agents or weapons
..10 countries are suspected to 
possess biological agents or 
weapons•Medical/university research facilities 
•Nuclear facilities•Home production

Limitations of CBR Materials

•Targeted dissemination is difficult•Delayed effects can detract from impact•Counterproductive to terrorists’support•Potentially hazardous to the terrorist•Development and use require timeand expertise

Chemical Agents:

Characteristics and Behavior

•Generally liquid (when containerized)
•Normally disseminated as aerosol or gas
•Present both a respiratory and skin contact hazard 
•May be detectable by the senses (especially smell)
•Influenced by weather conditions


Subway riders injured in AumShinrikyosarin 
gas attack, Tokyo, March 20, 1995. 
(AP Photo/ChikumoChiaki ) 

Classes of Chemical Agents

Chemical Warfare AgentsChokingAgentsBloodAgentsBlisterAgentsLethalNerveAgentsIncapacitatingandRiot ControlIndustrial ChemicalsWarfare Agents

Industrial chemicals 
previously used as 
chemical warfare agents

Industrial Chemicals

Text Box: Aeration, cyanide kit
Comparative Toxicity

0100200300400500600ChlorinePhosgeneHydrogen CyanideParathionMustardSarinVX

How Much Sarin Does it Take?

Text Box: 33 g (1 shot glass)
Chemical Agents Key Points

•Chemical agents are super toxic
•Relative toxicity: industrial chemicals < 
mustard < nerve
•Normal states are as a liquid or a vapor
•Inhalation hazard is of greatest concern



Biological Warfare Agents



Classes of Biological Agents

BacteriaVirusesToxinsFEMA 426 -Appendix C contains a CBR glossary and 
characteristics of biological agents

Text Box: Antibiotics and vaccines
Viruses

Text Box: Vaccine, supportive therapy
Toxins

Note: There are numerous naturally-occurring toxins.

For our purposes, we will group them into two categories. 

Text Box: Supportive oxygenation
and hydration
Biological Agents Key Points

Onset of symptoms 

Potentially contagious

Signs and symptoms 

Protection 

Treatment



Nuclear/Radiological Materials

Improvised Nuclear DevicesNuclear PlantsRadiological Dispersal Device

Ionizing RadiationAlpha particlesBeta particlesGamma raysNeutronsThere are also non-ionizing types of radiation –fluorescent lights, lasers, and microwaves. In 
these examples, the radiation can cause burns, but it does not cause molecular change or 
ionization

Common Radiation Exposures

Average annual exposure360 mrem per yearChest x-ray10 to 30 mremFlight 0.5 mrem every hourSmoking 1.5 packs per day16,000 mrem per yearMild radiation sickness*200,000 mremLethal dose* 450,000 mrem* single acute exposureChronicAcute

Health Hazards in an Incident

•Exposure to radiation source (external)
•Contamination (possible internal and/or external)




Protection from Radiation Exposure

Time

Distance

Shielding

AlphaBetaGammaNeutronpaperleadbookwater

CBR Detection

SOURCE: BAE SYSTEMSSOURCE: BRUKER DALTRONICS
Text Box: ?
CBR Incident Indicators



CBR Protection Strategies

Protective Actions:

•Evacuation
•Sheltering in Place
•Personal Protective Equipment
•Air Filtration, Pressurization, and 
Ultraviolet Light
•Exhausting and Purging



Evacuation
..Determine airborne hazard source --internal or external
..Determine if evacuation will make things better or worse
..Assembly should be upwind, at least 1,000 feet away, 
and three different locations (A, B, C plan)
..In most cases, existing plans for fire evacuation apply –
follow through -exercise

Sheltering in Place

A building can provide substantial protection against 
agents released outside if uptake of contaminated air can 
be halted or reduced and/or if uptake of fresh/filtered air 
can be increased.

The amount of protection varies with:

..How tight the building is
..Level of exposure (dose x time)
..Purging or period of occupancy
..Natural filtering



Personal Protective Equipment

SOURCE: BROOKDALE INTERNATIONAL SYSTEMS INC (CANADA)

SOURCE: MINE SAFETY APPLIANCES COMPANY (USA)
SOURCE: BARDAS CHILD PROTECTIVE WRAP (ISRAEL)

Text Box: Aftermath of Tragic Events 
FEMA 426, Figures 5-5 and 5-12: Bag Filter and HEPA Filter; Commercial 
Air Filtration Unit, p. 5-12 and 5-22

Air Filtration and Pressurization•Requires modifications to HVAC and electrical 
systems –significant initial and life-cycle costs•Introduces filtered air at a rate sufficient to produce 
an overpressure and create an outward flow through 
leaks and cracksSOURCE: TRION INCORPORATED

Two Types of Collection Systems: 

Air Filtration and Cleaning

•Particulate air filtration
..Principles of collection
..Types of particulate filters
..Filter testing and efficiency ratings
•Gas-phase air filtration
..Principles of collection
..Types of gas-phase filters



Air Contaminant Sizes



SOURCE: FLANDERS CORPORATION

Pleated Panel Filters 

Various Filter Types

Carbon Filters 
HEPA Filters 
FEMA 426, Figure 5-9: Charcoal Filter Beds (center), p. 5-17SOURCE: FLANDERS CORPORATIONSOURCE: AMERICAN FILTER

ASHRAE Standards

FEMA 426, Table 5-1: Comparison of ASHRAE Standards 52.1 and 52.2, 
p. 5-12


ASHRAE Standards

FEMA 426, Table 5-1: Comparison of ASHRAE Standards 52.1 and 52.2, 
p. 5-12


Inside Versus Outside Releases

Outside Release

•Keep people inside building
•Reduce indoor/outdoor air exchange –close dampers
•Shut off air handling systems and equipment that moves air 
–HVAC, exhausts, combustion, computers, elevators
•Close all windows and doors
•Once the outdoor hazard has dissipated
..Open all doors and windows
..Turn on all fans, including purging systems



Inside Versus Outside Releases

Inside Release

•Turn off all air handling equipment if no special stand-
alone systems installed
•If special systems installed, i.e. mailroom
..Place air handling system on full (or 100% outside air) to 
pressurize the space around release room
..Turn off all air handling supplying release room 
•Consider activating fire sprinklers in release room if 
toxic chemicals involved
•Evaluate evacuation routes for contamination
•Evacuate building in accordance with emergency plan



Exhausting and Purging

Basic Principles:

•Use ventilation and smoke/purge fans to remove airborne 
hazards
..Use primarily after an external release plume has 
passed
..Selectively use for internal release –may spread 
contamination further
•Purging should be carefully applied
..Primarily when agent has spread throughout building



HVAC System Upgrade Issues

•What is the threat? Toxic Industrial Chemicals, 
particulate, gaseous, chemical, biological?
•How clean does the air need to be and what is the 
associated cost?
•What is the current system capacity?
•Is there filter bypass and how significant is air infiltration 
into the building envelope?
•Will improved indoor air quality offset upgrade costs?
•Is system maintenance addressed?



Economic Issues to Consider

Initial Costs

..Filters, housing, blowers 
..Factors including flow rate, contaminant 
concentration


Operating Costs

..Maintenance, replacement filters, utilities, waste 
disposal


Replacement Costs

..Filter life (factors include continued concentration 
and particle size distribution, flow rates, etc.)



Access to 

Outdoor Intakes

FEMA 426, Figure 3-8, Example of Protecting Outdoor Air Intakes, p. 3-36 and

Figure 3-11, Example of Enclosing Existing Vulnerable Air Intake, p.3-38



Ultraviolet Germicidal Irradiation

All viruses and almost all bacteria (excluding spores) are 
vulnerable to moderate levels of UVGI exposure

FEMA 426, Figure 5-10: UVGI Array with Reflective Surfaces, p. 5-19

UV lamps resemble ordinary fluorescent lamps, but are designed to emit 
germicidal UV

Infiltration and Bypass

Infiltration
..Building envelope 
tightness and ventilation 
control are criticalBypass
..Filters should be airtight
..Check gaskets and 
seals
..Periodically check

Things Not to Do

•Outdoor air intakes should not be permanently 
sealed.
•HVAC systems (includes filter upgrades) should 
not be modified without understanding effects 
on building systems or occupants.
•Fire protection and life safety systems should 
only be modified after careful analysis and 
review.



Things to Do

•Have a current emergency plan that addresses 
CBR concerns
..Exercise plan
..Revise plan based upon lessons learned
•Understand your HVAC building vulnerabilities
•Conduct periodic walk-through of system for 
evidence of irregularities or tampering
•Recognize that there are fundamental 
differences among various CBR events



Summary

•CBR threats are real and growing.
•Industrial chemicals are readily available.
•Military chemicals require specialty expertise.
•Most buildings provide a reasonable level of 
protection.
•Inside versus outside building release determines 
evacuation and other reaction decisions.
•Develop an emergency plan and ensure it works.



Unit VIII Case Study Activity

Chemical, Biological, and Radiological (CBR) Measures

Background

Purpose of activity: check on learning about the nature of 
chemical, biological, and radiological agents

Requirements

•Refer to Case Study and FEMA 426
•Answer worksheet questions