MCAS 120 NBC Air Filtration Product Summary
The
MCAS is a unique multi-chamber NBC air filtration unit designed to REMOVE OR
KILL all NUCLEAR-BIOLOGICAL-CHEMICAL AGENTS KNOWN. Pre-filtering and gas agent testing occurs in chamber one. Chamber two is for mechanical and chemical agent filtration. Chamber three is where air is exposed to ultraviolet radiation doses killing gaseous viruses, molds and bacteria. Chamber four is the blower chamber. It draws air through the whole filtration system and blows sterile air into the protected building.
Stage 1 Pre-Filter
The outside contaminated air
enters the MCAS at the pre-filter chamber consisting of a stainless steel
micronic mesh to remove large particles in the air that are 125 microns and
larger. The smallest particle that the human eye is able to see is 40 microns
in diameter. This pre-filter is removable and washable and greatly extends the
life of the next filtration stage. The gas agent test port allows allows a
visual inspection of the pre-filter to see if it is dirty and restricting the
air flow. This port also allows a common spray bottle to introduce a spray
mist of hypochlorite and water to make the pre-filter moist so contaminated
dust does not fly around during removal for cleaning.
 STAGE 2
AIR CONTAMINANT TEST PORT
The pre-filter chamber also
contains the GATP (Gas Agent Test Port) where the incoming air can be tested
for chemical agents using the standard ARMY M256A test kit (included). A 4
inch NPTM (national pipe thread male) plug is unscrewed and the test card lays in
this port and the plug is screwed in. Since the whole filter system is under
negative pressure there is no risk of contamination but rubber gloves are used.
Stage 3 HEPA
HEPA Filter
 Radioactive particles, some smoke, and biological agents can be
removed by using a HEPA filter. This filter works by a physical straining; removing dust that is so fine that it is not
visible to the human eye. The filter has 99.99% efficiency in removing
particles which are 0.3 microns in diameter (.000012 inches) and larger. A
micron is equal to .00004 inches or
4/100,000 of an inch. Although biological viruses range from .02 to .25 microns,
they are dispersed or carried by larger aerosol or dust particles which can usually
be removed by physical straining. The filter sleeve is designed to be compressed
from each end sealing against the gaskets. The compression is developed by a stainless
steel acme rod (acme threads can not be cross threaded) running through the
center of the filter sleeve. A plate nut on the one end of the acme rod
drives the end plate up against the opposite end plate of the filter sleeve.
This forms a complete and tight seal.
Contaminant
|
Particle Size -microns
|
Pollen
|
10-100
|
Human Hair
|
50-100
|
Plant Spores
|
10-50
|
Fly Ash
|
1-100
|
Fungal Spores
|
2-8
|
Insecticide Dusts
|
3-10
|
Anthrax Spore
|
1 x 4
|
Bacteria
|
0.1 - 50
|
Lung Damaging Dust
|
0.5 - 5
|
Tobacco Smoke
|
0.01 - 1
|
Burning wood smoke
|
0.2 - 3
|
Carbon Black
|
0.01 - 2
|
Fumes
|
0.001 -1
|
Viruses
|
.02 - .25
|
Stage 4 Carbon Filter
A
mechanical filter, such as a HEPA filter, is not able to remove
radioactive iodine gas. For this contaminant, an activated and impregnated
carbon filter must be employed. The carbon filter purifies the air by processes
called physical adsorption and chemical adsorption.
Physical
adsorption is a process where activated carbon is used to perform
a physical straining of contaminants, based on the molecular force, much like a
coffee filtering process but using a much finer filter. Carbon is used because
it has an extremely fine pore structure, much smaller than a HEPA filter, and
contains tremendous surface area. For some types of carbon, a volume of l
quart contains a surface area of 9 million square feet. This makes adsorption
efficient and practical.
Chemical
adsorption is a process where impregnated carbon is used in the filter. Impregnated carbon has
been treated with specific chemicals which have an affinity to attract and
thereby remove specific toxins or gases. There is a specific carbon to remove
radioactive iodine gas and the efficiency of removing the contaminant is based
on the amount of time the contaminant is in contact with the carbon. This
required period of time necessary to remove the contaminant is known as the residence
time. Radioactive iodine gas requires a residence time of 0.35
seconds.
The filter sleeve has two layers
of carbons. The first layer consists of activated carbon which removes
radioactive iodine gas generated from a nuclear explosion or nuclear power
plant accident. This filter makes it unnecessary to take Potassium Iodine to
block the absorption of radioactive iodine into the human thyroid. Iodine
tablets only work if they are taken 24 hours in advance of breathing the
radioactive iodine gas. The second layer of carbon is called Whetlerite/TEDA
Carbon and is specifically designed to remove chemical warfare agents. The
required resonance time is 0.35 seconds. Both carbons are designed for a
minimum of 0.4 seconds.
Burning
forests produce toxic gases such as: nitrogen oxides, benzene gas, toluene
gas, and carbon dioxide. Toxic gases produced from burning plastics and
industrial chemicals are known as pyrotoxins. These pyrotoxins are: nitric acid
gas, chlorine gas, chlorinated dioxin gas, hydrochloric acid gas, acrolein gas,
and sulfuric acid gas. These gases would be dangerous primarily in the
immediate blast area for a number of days. These toxins can be removed from
the fresh air supply using a carbon filter designed to remove acid gas. This
stage requires an impregnated carbon filter specifically designed to remove
these acid gases. Complete filtering requires a residence time of 0.35 seconds. 1
The activated carbon in the filter sleeve will filter out these acid gases.
A
chemical warfare filter functions like impregnated carbon in the radioactive
iodine gas filter. The particular carbon that must be used is called
"Whetlerite Carbon", meeting military specifications Mil-C-0013724C
(EA) Grades 1 to 4, and is used in military blast shelters. This carbon has
been impregnated with copper, chromium, and silver to specifically remove:
carbon sulfate gas, cyanide gas, phosgene oxime gas, mustard gas, phosgene gas,
cyanogen chloride, sarin gas, soman gas, VR-55 gas, VX gas, and other chemical
warfare agents. It is extremely efficient, lasts many years, and is very
expensive. Complete filtration requires a residence time of 0.35 seconds.
STAGE 5 POST CARBON FILTER
The
outside layer of the carbon filter sleeve contains a "post filter". When air is drawn through a carbon
filter, some very fine particles of carbon are removed and deposited outside of
the filter. Because they are extremely fine, they get into everything just by
air movement within the shelter or house; thus, they are easily inhaled. These
particles are called "carbon fines" and are contaminated and must be
kept within the filter. This is accomplished by using a micronic fabric on the
outside layer of the filter sleeve to contain the carbon fines within the
filter.
Stage 6 Ultraviolet Radiation
 Viruses
vs. Bacteria
Viruses
are tiny geometric structures that can only reproduce inside a living cell.
They range in size from 0.02 to 0.25 microns. When they are outside a living
cell they are dormant but when it enters a host cell, it begins to generate
more virus particles. Bacteria are one cell living organisms with an average
size of 1 micron that does not need a living host. Many bacteria are
beneficial to humans and necessary for the breakdown of organic wastes.
Killing Organisms
Many
viruses and bacteria are so small that they are not able to be filtered
physically by a HEPA or effectively adsorbed by the Carbon filter. Virtually
all biological warfare agents can be removed by filtering out what they are
carried on such as a dust particle or aerosol droplet. Viruses however, are
usually in the gaseous state and need to be killed by ultraviolet radiation (UVC)
or ultraviolet germicidal irradiation (UVGI) which is an ultraviolet light on
the C scale, specifically at a wavelength of 254 nm which does not generate
ozone. The amount of energy required to completely kill an organism such as a
virus, bacteria, mold, etc is called the Kill Energy which varies with each
organism. The ultraviolet light next to the filter sleeve stem develops
extremely high kill energy on the air flowing past this chamber to assure that
the kill rate is absolute. Exposure time is based on light intensity multiplied
by time. The exposure imposed on any organism in the MCAS-120 UV chamber is 17,227
uw/sec/cm 2. (microwatts/sec/square centimeter) Kill rates for
various organisms are listed below. Note that not all organisms are gaseous.
Ultraviolet
Radiation Dangers
UV
radiation does have two dangers. When exposed to bare skin it will produce a
sunburn (radiation burn) and it is also damaging to the human eyes and can
result in conjunctivitis (inflammation of the mucous membranes). When changing
the bulbs, the UV light must be turned off to avoid these dangers. On the side
of the MCAS housing is a visual site glass to visually verify if the ultraviolet
light is on. This glass sight port is thick enough to prevent any appreciable
radiation negatively affecting nearby occupants.
AMOUNT
OF GERMICIDAL SHORTWAVE (254nm)
ULTRAVIOLET
RADIATION NECESSARY FOR
COMPLETE
DESTRUCTION OF VARIOUS ORGANISMS
Bacteria
|
UV Dose
uw/sec/cm2
|
Bacteria
|
UV Dose
uw/sec/cm2
|
Agrobacterium lumefaciens 5
|
8,500
|
Pseudomonas
aeruginosa (Environ.Strain)
1,2,3,4,5,9
|
10,500
|
Bacillus anthracis 1,4,5,7,9 (anthrax veg.)
|
8,700
|
Pseudomonas aeruginosa (Lab. Strain) 5,7
|
3,900
|
Bacillus anthracis Spores (anthrax spores)*
|
46,200
|
Pseudomonas fluorescens 4,9
|
6,600
|
Bacillus megatherium Sp. (veg) 4,5,9
|
2,500
|
Rhodospirillum rubrum 5
|
6,200
|
Bacillus megatherium Sp. (spores) 4,9
|
5,200
|
Salmonella enteritidis 3,4,5,9
|
7,600
|
Bacillus paratyphosus 4,9
|
6,100
|
Salmonella paratyphi (Enteric Fever) 5,7
|
6,100
|
Bacillus subtilis 3,4,5,6,9
|
11,000
|
Salmonella Species 4,7,9
|
15,200
|
Bacillus subtilis Spores 2,3,4,6,9
|
22,000
|
Salmonella typhimurium 4,5,9
|
15,200
|
Clostridium tetani
|
23,100
|
Salmonella typhi (Typhoid Fever) 7
|
7,000
|
Clostridium botulinum
|
11,200
|
Salmonella
|
10,500
|
Corynebacterium diphtheriae 1,4,5,7,8,9
|
6,500
|
Sarcina lutea 1,4,5,6,9
|
26,400
|
Dysentery bacilli 3,4,7,9
|
4,200
|
Serratia marcescens 1,4,6,9
|
6,160
|
Eberthella typhosa 1,4,9
|
4,100
|
Shigella dysenteriae - Dysentery 1,5,7,9
|
4,200
|
Escherichia coli 1,2,3,4,9
|
6,600
|
Shigella flexneri - Dysentery 5,7
|
3,400
|
Legionella bozemanii 5
|
3,500
|
Shigella paradysenteriae 4,9
|
3,400
|
Legionella dumoffill 5
|
5,500
|
Shigella sonnei 5
|
7,000
|
Legionella gormanil 5
|
4,900
|
Spirillum rubrum 1,4,6,9
|
6,160
|
Legionella micdadei 5
|
3,100
|
Staphylococcus albus 1,6,9
|
5,720
|
Legionella longbeachae 5
|
2,900
|
Staphylococcus aureus 3,4,6,9
|
6,600
|
Legionella
pneumophila (Legionnaire's
Disease)
|
12,300
|
Staphylococcus
epidermidis
5,7
|
5,1200
|
Leptospira canicola-Infectious Jaundice 1,9
|
6,000
|
Streptococcus faecaila 5,7,8
|
10,000
|
Leptospira interrogans 1,5,9
|
6,000
|
Streptococcus hemolyticus 1,3,4,5,6,9
|
5,500
|
Micrococcus candidus 4,9
|
12,300
|
Streptococcus lactis 1,3,4,5,6
|
8,1200
|
Micrococcus sphaeroides 1,4,6,9
|
15,400
|
Streptococcus pyrogenes
|
4,200
|
Mycobacterium tuberculosis 1,3,4,5,7,8,9
|
10,000
|
Streptococcus salivarius
|
4,200
|
Neisseria catarrhalis 1,4,5,9
|
8,500
|
Streptococcus viridans 3,4,5,9
|
3,1200
|
Phytomonas tumefaciens 1,4,9
|
8,500
|
Vibrio comma (Cholera) 3,7
|
6,500
|
Proteus vulgaris 1,4,5,9
|
6,600
|
Vibrio cholerae 1,5,8,9
|
6,500
|
Molds
|
UV Dose
|
Molds
|
UV Dose
|
Aspergillus amstelodami
|
77,000
|
Oospora lactis 1,3,4,6,9
|
11,000
|
Aspergillus flavus 1,4,5,6,9
|
99,000
|
Penicillium chrysogenum
|
56,000
|
Aspergillus glaucus 4,5,6,9
|
88,000
|
Penicillium digitatum 4,5,6,9
|
88,000
|
Aspergillus niger (breed mold) 2,3,4,5,6,9
|
330,000
|
Penicillium expansum 1,4,5,6,9
|
22,000
|
Mucor mucedo
|
77,000
|
Penicillium roqueforti 1,2,3,4,5,6
|
26,400
|
Mucor racemosus (A & B) 1,3,4,6,9
|
35,200
|
Rhizopus nigricans (cheese mold) 3,4,5,6,9
|
220,000
|
Protozoa
|
UV Dose
|
Protozoa
|
UV Dose
|
Chlorella vulgaris (algae) 1,2,3,4,5,9
|
22,000
|
Giardia lamblia (cysts) 3
|
100,000
|
Blue-green Algae
|
420,000
|
Nematode Eggs 6
|
40,000
|
E. hystolytica
|
84,000
|
Paramecium 1,2,3,4,5,6,9
|
200,000
|
Virus
|
UV Dose
|
Virus
|
UV Dose
|
Adeno Virus Type III 3
|
4,500
|
Influenza 1,2,3,4,5,7,9
|
6,600
|
Bacteriophage 1,3,4,5,6,9
|
6,600
|
Rotavirus 5
|
24,000
|
Coxsackie
|
6,300
|
Tobacco Mosaic 2,4,5,6,9
|
440,000
|
Infectious
Hepatitis 1,5,7,9
|
8,000
|
0
|
0
|
Yeasts
|
UV Dose
|
Yeasts
|
UV Dose
|
Baker's Yeast 1,3,4,5,6,7,9
|
8,1200
|
Saccharomyces cerevisiae 4,6,9
|
13,200
|
Brewer's Yeast 1,2,3,4,5,6,9
|
6,600
|
Saccharomyces ellipsoideus 4,5,6,9
|
13,200
|
Common Yeast Cake 1,4,5,6,9
|
13,200
|
Saccharomyces sp. 2,3,4,5,6,9
|
17,600
|
1. "The Use of Ultraviolet Light for Microbial
Control", Ultrapure Water, April 1989.
2. William V. Collentro, "Treatment of Water with Ultraviolet Light -
Part I", Ultrapure Water, July/August 1986.
3. James E. Cruver, Ph.D., "Spotlight on Ultraviolet Disinfection",
Water Technology, June 1984.
4. Dr. Robert W. Legan, "Alternative Disinfection Methods-A Comparison
of UV and Ozone", Industrial Water Engineering, Mar/Apr 1982.
5. Unknown
6. Rudolph Nagy, Research Report BL-R-6-1059-3023-1, Westinghouse Electric
Corporation.
7. Myron Lupal, "UV Offers Reliable Disinfection", Water
Conditioning & Purification, November 1993.
8. John Treij, “Ultraviolet Technology”, Water Conditioning &
Purification, December 1995.9. Bak Srikanth, “The Basic Benefits of
Ultraviolet Technology”, Water Conditioning & Purification, December 1995
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STAGE 6 BLOWER
 The centrifugal air
blower is a high pressure reverse curve motorized impeller located at the end
of the filter housing after the ultraviolet light to create negative pressure
inside the filter housing. This blower pushes filtered air into the protected structure.
If the air leaving the structure is restricted, the structure will be
positively pressurized preventing contaminating agents from penetrating the
house. See the MCAS 120 Operator’s Manual for weatherizing the protected
structure.
MCAS-120 INSTALLATION
The MCAS can be placed in a
basement, or mechanical room or anywhere the distribution duct can reach other
rooms. The MCAS-120 will protect to an 18,000 ft 3 structure that is
properly weatherized for infiltration leaks.
Inlet air is
taken from outside the house using the stainless steel intake manifold that is
supplied with the MCAS 120. This requires drilling a 6 inch diameter hole
through an outside wall.
Outlet air exits the structure
through infiltration leaks in the house and the supplied stainless steel air
outlet manifolds. Infiltration occurs through the perimeter of doors, windows,
electrical boxes on outside walls and ceilings, and anywhere air can penetrate
and navigate around a hole or fixture. The one inch diameter air outlet
manifolds are installed high on the wall to vent heat and spent air. The
valves on the outlet manifolds are adjusted to maintain at least 0.1 inch water
gage static pressure inside the structure.
BATTERY BANK
The battery bank is composed of
eight 130 amp hour deep cycle marine 12 volt lead acid batteries connected in
parallel. Terminal fuses are used to protect the batteries. They are
maintained in a fully charged state by a 30 amp Smart battery charger.
Although very little hydrogen gas is generated because the charge per cell is 0.626
amps, which is well below the 2.5 amp/cell threshold, traces of hydrogen gas
are vented to the outside of the building by a 12-volt blower and hose from the
top of the battery bank to the outside of the building. A stainless steel battery
gas vent manifold is supplied to be installed on the protected building
exterior wall.
MCAS 120 Location and Hook-up
- One 6 inch air inlet duct
- One 6 inch air outlet or duct
- One 1 inch battery vent hose
- One 115 VAC power cable
The MCAS 120 should be located in
a place where AC power is available and where the air intake manifold can be
installed on a vertical wall and the sterile air can be supplied to a central
location in the house. The maximum temperature for the unit is 120 oF.
Uncrating the MCAS 120
- Remove the wooden slats on the
cover of the crate.
- Remove 50 feet of 6 inch
diameter duct hose
- Remove the four filter sleeves
50 lbs each
- Remove the filter chamber 150
lbs
- Remove the wires connecting the
batteries together.
- Remove the eight batteries 70
lbs each.
- Remove the fiberglass battery housing
40 lbs
Assembling the MCAS 120
- Place the battery housing in
place
- Place all 8 batteries in the
battery housing.
- Connect all the positive wires
and all the negative wires
- Connect the quick connectors to
the circuit breaker panel
- Lay the filter chamber on the
battery housing
- Remove the blower housing cover
using wrenches
- Remove the plate nut
- Slide two of the filter sleeves
into place with the rod in the center of the housing.
- Screw on the plate nut and hand
tighten
- Rebolt the blower housing cap
using the stainless bolts.
MCAS 120
SPECIFICATIONS
Air blower life....................................................... 60,000
hours
Air blower type..................................................... 8-in
dia. Rev curve centrifugal 12-V, 21 watt
Air blower volume................................................ 120
cfm @ 0.5 in S.P. W.G.
Air filter................................................................. HEPA
99.99% @ .3 u
Air filter-carbon-activated
residence time........... 0.4 sec
Air filter-carbon-Whetlerite
residence time.......... 0.4 sec
Air filter post carbon............................................. .3u
Air inlet manifold.................................................. Stainless
for vertical wall
Air outlet manifold................................................ stainless
(6) for vertical wall
Assembly time..................................................... 30
min to install filter sleeves
Batteries............................................................... 8-130
amp hour deep cycle LA marine 12V
Battery housing.................................................... structural
fiberglass
Battery vent manifold.......................................... stainless
for vertical wall
Capacity............................................................... 18,000
ft3 with sealed building
Circuit Protection................................................. magnetic
circuit breakers and terminal fuses
Duct..................................................................... 6
inch diameter 50 ft supplied
Duration-blower 24hr/day ................................... 16
days
Duration-blower and light 24
hr/day..................... 7 days
Electrical meter.................................................... voltage
and amp/hr digital
Electrical power................................................... 2
amps AC for battery charger
Filter Chamber..................................................... structural
fiberglass
Flame spread....................................................... 25-50
Type II, ASTM E84
Shipping weight.................................................... 800
lbs.
Shipping dimensions............................................ 30
x 78 x 46 in crated
Ultraviolet Light.................................................... 254nm
12 VDC
Ultraviolet Radiation
dose.................................... 17,227 mw/sec/cm 2
SEE MCAS 120 OPERATOR’S
MANUAL FOR COMPLETE INSTALLATION AND OPERATION INSTRUCTIONS.
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