technical BRI
U.S. EPA's Homeland Security Research Program
(HSRP) develops products based on scientific
research and technology evaluations. Our products
and expertise are widely used in preventing, preparing
for, and recovering from public health and
environmental emergencies that arise from terrorist
attacks. Our research and products address biological,
radiological, or chemical contaminants that could affect
indoor areas, outdoor areas, or water infrastructure.
HSRP provides these products, technical assistance,
and expertise to support EPA's roles and
responsibilities under the National Response
Framework, statutory requirements, and Homeland
Security Presidential Directives.
Biological Inactivation Efficiency of HVAC
In-Duct Ultraviolet Light Devices
Background
One potential method of terrorism is the intentional
introduction of biological warfare agents (BWAs) into the
heating, ventilation, and air-conditioning (HVAC) systems
of target structures in order to distribute pathogenic
organisms. The introduction of BWAs into a building's
HVAC system could harm many people, depending on
the size of the building. This potential threat indicates a
need to identify and test devices that could be used to
destroy BWAs as they move through a building's air
handling system.
One category of technology that may meet this need uses
a configuration of ultraviolet (UV) lights that can be
deployed inside the building's air ducts. Short-wave
ultraviolet radiation in the "C" band (UV-C) has wavelengths of 200 to 280 nanometers. This type of
ultraviolet germicidal irradiation (UVGI) has been used for over 100 years to inactivate
microorganisms.
Early research in this area was directed at the control of highly infectious pathogens in medical
facilities. UVC was shown to be effective at killing Mycobacterium tuberculosis, the causative agent
of tuberculosis, and other bacteria including mycoplasma, as well as viruses and fungi.
In testing and evaluating homeland security related technologies, EPA provides unbiased, third-
party performance information that can supplement vendor-generated information. This information
is useful to decision makers in purchasing and applying the tested technologies. EPA's evaluations
are conducted in accordance with rigorous quality assurance protocols to ensure that data of
known and high quality are generated.
Bioaerosol Inactivation Devices
EPA has conducted evaluations on the ability of the following devices to inactivate bioaerosols
inside HVAC systems:
In-Duct System (Abracair, LLC)
ACP-24/HO-4 and AeroLogic Model AD24-4 (American Ultraviolet Corporation)
Bio-Fighter 4Xtreme, Model 21 (Dust Free)
ADPL-60-8 (Lumalier)
BioProtectorBP114i (Novatron, Inc.)
UV Bio-Wall 50 Outwardly Projecting Air Purifier (Sanuvox Technologies Inc.)
Model SE1 VO with GTS 24 Emitter (Steril-Aire, Inc.)
Altru-V V-Flex (Ultraviolet Devices, Inc.)
This document does not constitute nor should be construed as an EPA endorsement of any particular product,
service, or technology.
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Test Design
The nine UVC devices evaluated are designed to be mounted inside an HVAC system
to inactivate bioaerosols as they migrate through the air handling system. The devices were tested
separately in a laboratory-based test duct with state-of-the-art aerosol and microbiological
generation and measurement equipment.
The testing was conducted using one spore-forming bacteria, Bacillus atrophaeus (B. atrophaeus),
one vegetative bacteria, Serratia marcescens (S. marcescens), and one virus, Escherichia coli
phage MS2 (MS2 bacteriophage). The structural characteristics and susceptibility to UVC
inactivation make these reasonable surrogates for BWAs.
Each device was tested three times, once for each test microorganism. During testing, the test
microorganisms were generated and introduced into the test duct upstream from the installed
device. As air flowed through the duct, the bioaerosols passed through the device where they were
exposed to UVC.
Airborne Inactivation Efficiency
The ability of each device to destroy the bioaerosols as they passed through the test air duct is
reported as the airborne inactivation efficiency. The greater this percentage, the more effective was
the UVC device.
To determine the efficiency, samples of the bioaerosols were taken from the duct upstream and
downstream from the device. These samples were cultured, and the number of bacterial colony
forming units (CPUs) or viral plaque forming units (PFUs) were counted.
The efficiency of the device was then calculated as a percentage from the ratio of the upstream to
the downstream counts. This number is the percentage of microorganisms that did not survive
UVC exposure corrected for the number of microorganisms that died from the rigors of traveling
through the duct without being irradiated and for the number of microorganisms that did not
completely pass through the duct due to deposition on the duct walls.
The correction factor used for the inactivation efficiency was determined by conducting a test for
each microorganism without the UVC source in the device turned on. All nine devices were tested
in this fashion.
Performance and Results
All nine UVC devices were > 99 percent efficient at inactivating the vegetative bacteria.
• Three UVC devices were > 93 percent effective for all three microorganisms.
• Five devices had < 46 percent efficiency for inactivation of the spore form of the
bacteria
• Two devices had < 46 percent efficiency in destroying the virus.
The following table shows the airborne inactivation efficiencies of each device for each test
organism.
September 6, 2006
EPA/600/S-06/034
This document does not constitute nor should be construed as an EPA endorsement of any particular product,
service, or technology.
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UVC Device
Abracair, LLC
American Ultraviolet
Corporation ACP-24/HO-4
Atlantic Ultraviolet
Corporation AeroLogic
Model AD24-4
Dust Free Bio-Fighter
4Xtreme, Model 21
LumalierADPL-60-8
Novatron, Inc. BioProtector
BP114I
Sanuvox Technologies Inc.
UV Bio-Wall 50 Outwardly
Projecting Air Purifier
Steril-Aire, Inc. Model SE1
VO with GTS 24 Emitter
Ultraviolet Devices, Inc.
Altru-V
V-Flex
Lamps
12
4
4
1
8
6
5
6
12
Measured Dosage a
(pW-s/cm2)
447(376-550)
582(490-716)
295(249-363)
247(208-304)
3180(2678-3914)
> 42,342 (35,656 -
52,113)
16,439(13,843-
20,223)
19,826(16,696-
24,401)
7,651 (6,443-9,416)
Power (w)
6480-
6720
169
94
53
568
748
944
421
755
Airborne Inactivation Efficiencies (%)
Spore form of
bacteria
(B. atrophaeus)
6.9
9
0
4
40
>99.9b
93
96
71
Vegetative form of
bacteria
(S, marcescens)
99.8
>99.96 b
>99.8 b
99
>99.98b
>99.94b
>99.97 b
>99.96 b
>99.98 b
Virus
(MS2 bacteriophage)
59
75
46
39
82
>99.9 b
99
99
98
a The systems were run at 0.93 rrWsec (1970 CFM), except for the Novatron device, which was run at 0.14 rriVsec (300 CFM).
b These values are based on the upper 95 percent confidence limit for the mean downstream count of the test organism. There were
no downstream counts measured.
In addition to airborne inactivation efficiency, other attributes of each device were assessed. These
included dosage measurements, power consumption, single measurement intensity, pressure drop
across the device, and air temperature rise through the device. Homeland security research
studies using ultraviolet light are listed at this link.
For more information, visit the EPA Web site at www.epa.gov/nhsrc.
Technical Contact: Eric Koglin (koglin.eric@epa.gov)
General Feedback/Questions: Kathy Nickel (nickel.kathy@epa.gov)
September 6, 2006
EPA/600/S-06/034
This document does not constitute nor should be construed as an EPA endorsement of any particular product,
service, or technology.
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