120 CFM
NBC Air Filtration System

A Nuclear, Biological, and Chemical air filter is a specialized wide spectrum filtration system that is made to draw air from outside a protected space and then use the filtered air to pressurize that space for collective protection (COLPRO).

We manufacture the Safe Cell NBC air filter in two sizes based on their system airflow output, measured in cubic feet per minute (CFM): 60 CFM and 120 CFM (this page) . Each shelter occupant needs at minimum of 5 CFM so we rate our 60 CFM Safe Cell at 12 occupants and our 120 CFM Safe Cell at 24 occupants.

The Safe Cell is offered by itself for installation in an unhardened safe room or as a complete system which includes everything necessary for installation in an underground hardened shelter: two blast valves, an overpressure valve, a backup hand crank, and an auxiliary blower to provide ventilation without filtration when there are no airborne threats. You can also purchase these items seperatley.

Shown with a user supplied battery and optional backup hand pump

120 CFM Safe Cell

Nuclear, Biological, and Chemical Protection
120 volt AC with 12 volt DC battery backup built in

This is the Safe Cell filtration system only – scroll down for the complete blast protected NBC air filtration system that includes blast valves

The ASR-200-AV-NBC Safe Cell is a positive pressure nuclear, biological, and chemical air filtration system.

It features an internal automatic switching power supply that will automatically switch to drawing power from a user supplied 12 volt battery if the power grid goes down. When the power comes back on, the power supply automatically switches back to AC power and recharges the battery.

NBC air filtration system - everything included

What’s Included with this filtration system

The Safe Cell comes with everything necessary to pull it from the boxes and install it in a safe room. If your room is sealed up, you will also need an overpressure valve. If you are installing it in a blast resistant shelter, you should also install blast valves.

  • One AC and DC capable Safe Cell with a complete filter bank that includes the two pre-filters, a nuclear grade HEPA particulate filter, and a warfare gas carbon adsorber.
  • Two wall mount brackets, two quick release clamps, two star nuts, and four lag screws.
  • One AC and one DC power cord.
  • One 60 inch chemical resistant flexible air intake hose.
  • One wall mount flange and gasket for the hose.
  • One hard copy of the installation and operation manual.

Prices, availability, and ordering

ASR-200-AV-NBC – $5,100, plus shipping

Call 541-459-1806 to place your order. We do final assembly and testing at time of order. We usually ship filter orders within one business day of the order being placed.

Shown with a user supplied battery

120 CFM Complete System

Nuclear, Biological, and Chemical Protection
120 volt AC with built in 12 volt DC battery backup capability.

Includes a 120 CFM Safe Cell, two blast valves, an overpressure valve, an automatic ventilation blower, and either a backup hand pump or a backup hand crank.

Everything you need to turn your underground shelter into a blast protected collective protection safe room!

Easy Installation
The two blast valves mount over the intake and outflow penetration pipes with the included concrete wedge anchors and heavy duty gasket. Once they are in place, the Safe Cell and the automatic ventilation blower are mounted where the flexible air intake hose can reach them both. This hose can be slipped right onto the intake blast valve, or plastic pipe can be used to plumb down from a ceiling mounted blast valve – as shown in the picture above. That’s it for the intake. On the outflow, the overpressure valve is slipped onto the outflow blast valve. That’s it. Everything goes together with nuts and bolts. Easy installation!

For a more detailed explanation – see the manual.

Shown here are the 60 CFM Safe Cell (exactly the same installation as the 120 CFM), a backup hand crank, two blast valves (one for the intake and one for the outflow), an overpressure valve, an automatic ventilation blower.

Also shown are some user supplied items: the deep cycle battery, a length of 4 inch, schedule 40 ABS plastic pipe with optional pipe clamps, and an extra length of hose on the top of the pipe.

Click on the image to enlarge.

120 CFM Safe Cell - what

What’s included with this kit

The 120 CFM complete system comes with everything necessary to pull it from the boxes and install it inside an underground shelter:

  • 1 AC and DC capable Safe Cell with a complete filter bank, includes a pre-filter set, a nuclear grade HEPA particulate filter, & warfare gas carbon adsorber.
  • 1 wall mount bracket, 2 quick release clamps, 2 star nuts & 4 lag screws.
  • 1 AC & 1 DC power cord.
  • 1 60 inch chemical resistant flexible air intake hose.
  • 1 emergency hand pump or an emergency hand crank.
  • 2 blast valves with gaskets, concrete wedge anchors, and a masonry drill bit.
  • 1 overpressure valve with both wall and ceiling adapters.
  • 1 automatic ventilation blower.
  • 1 hard copy of the installation and operation manuals.

Prices, availability, and ordering

ASR-200-AV-NBC-COMP-HC (with hand crank) – $6,600, shipping included
ASR-200-AV-NBC-COMP-BL (with bellows) – $6,965, shipping included

UPS Ground shipping is included. It is priced at hundreds less than the sum of the individual items – and with the free shipping, you will save about $800!

Call 541-459-1806 to place your order. We do final assembly and testing at time of order. We usually ship filter orders within one business day of the order being placed.

Filter Specifications

Envelope size: 15 inches (380 mm) x 26.88 inches (683 mm) x 31.25 inches high (794 mm)
Weight: 60 pounds (27 kg) with all of the filters installed
Blower output: 500 cubic feet per minute (14 cubic meters per minute)
System output: 120 cubic feet per minute (200 cubic meters per hour)
Noise level: 70 DB – A scale
Voltage: 110 to 240 volt AC (50-60 hertz) and 12 volt DC battery back up
Current draw: 2 amps at 110-220 volt AC, 9 amp at 12 volt DC
Fuse AC: 4 amp
Fuse DC: 15 amp
Power cords: US standard 110 volt AC grounded plug and a clip-lead 12 volt DC cord (battery)
Flexible hose: chemical resistant 60 inch (1.5 m) length by 5 inch diameter (127-mm)

Two piece polyester pre-filter that protects the HEPA from being loaded up with larger airborne particles. The first one is for large particulates, the second is for finer particulates.

HEPA particulate filter
Protects personal against fallout particles, toxic aerosols, and biological warfare agents.

The nuclear grade media furnished in these filters is certified to meet the requirements of the: Israeli Ministry of Defense and the U.S. Army.

MIL-F-51079D as required in the US Army document for:
Design Of Collective Protection Shelters To Resist Chemical, Biological and Radiological (CBR) Agents, Us Army Corps of Engineers ELT 1110-3-498 24 Feb. 1999.

EN 1822-1-1998 High efficiency air filters: Classification,
Performance testing and marking.

Media Water repellant glass micro fiber 99.97% true HEPA type (A).
Cell Side Material Fire retardant particleboard
Separators Aluminum
Bond: Polyurethane foam
Gasket Material Neoprene (RE43E1)
Gasket Location Both sides
Factory Test Certified 99.97% (DOP)
UL 866 Label Required

HEPA filter cell
As developed by the Atomic Energy Commission and used in nuclear power stations, hospitals and bio-containment laboratories.

Guaranteed Performance
Each HEPA filter is individually tested before it leaves the factory, your assurance that it meets rated efficiency. The penetration and actual airflow rate are indicated on the label. Each filter is also assigned a serial number.

DOP Test
This has been the industry standard test method for many years. It is conducted using a forward light scattering photometer. The HEPA is challenged with 0.3 micrometer particles of dioctyl-phthalate (DOP). By measuring the upstream and downstream concentration of these particles, the HEPA filter cell efficiency can be calculated.

Underwriters Laboratories Classification UL 586
This classification to insure that each HEPA filter cell is individually tested at the factory. Additionally, representative HEPA filter cells are tested by UL to ensure that they provide their rated HEPA level filtration, after being subjected to the following conditions of a high moisture environment of (90% R.H.), a high temperature environment of (371 degrees Celsius), low temperature environment of (-3 deg/C). UL also subjects the HEPA filter cell to a spot flame test of 954 degrees Fahrenheit.

Activated carbon filter for protection against war gases
The nuclear grade war gas adsorber is a block sieve filter cell consisting of two containment medias and a block of nuclear grade war gas carbon.

It is effective in the removal of the following war gases:
Hydrogen cyanide
Mustard gas

NUK-TK Nuclear Grade Carbon Specifications
12 inches (304 mm) x 24 inches (608 mm) x 6 inches (152 mm) high.

Carbon, activated impregnated TEDA copper-zinc-molylebeunm-triethylenemelamine

1. ASTM D 2854-1996 Standard test method for apparent density of activated carbon
2. ASTM D 2867-1999 Standard test method for moisture in activated carbon
3. ASTM D 3802-1997 Standard test method for ball-pan hardness of activated carbon
4. ASTM D 3467 Activity for CCL: 60% minimum
5. ASTM D 2862/D5158 Particle size: 4 x 8 Mesh U.S.
6. ASTM D 3838 pH aqueous extract: 9.2 minimum
7. ASTM D 3466 Ignition temperature 330 Celsius
8. ASTM D 3803 Radioactive iodine removal
9. Impregnate 2.1 Potassium iodide, 3.1% TEDA


Occupancy ratings

The ASR-200-AV-NBC produces 120 cubic feet per minute (CFM) of filtered air supply sufficient for 24 adults. This 5.0 CFM per occupant is based on the first ASHRAE standard that is excerpted below. The Israeli standard of 3.5 CFM per occupant is also useful in determining the absolute upper end of your shelter occupant capacity.

In order to insure sufficient airflow rate and overpressure state in a particular installation the guidelines specified in the installation manual and test kit must be followed.

Some installations require larger unit sizing based on the size and construction type of the room rather than the number of occupants. Please do not hesitate to contact our technical support department with any questions. We highly recommend adherence to local building codes.

ASHRAE Handbook 1985 Fundamentals Volume
Section IV Load and Energy Calculations

Chapter 22 Ventilation and Infiltration

(TC 4.3, Ventilation Requirements and Infiltration)

Page 22.1 Minimum Outdoor Air Supply Rates:
ASHRAE Ventilation Standard 62-1981,1 defines minimum outdoor air supply rates for various types of occupancy. These rates have been arrived at through a consensus of experts working in the field. As shown in Eq. (2), a minimum rate of 5 cubic feet minute per person for sedentary activity and normal diet holds the Co2 level in a space 0.25% under steady state conditions.

While normal healthy people tolerate 0.5% Co2 without undesirable symptoms and nuclear submarines sometimes operate with 1% Co2 in the atmosphere, a level of 0.25% provides a safety factor for increased activity, unusual occupancy load or reduced ventilation.

Environmental Control for Survival 11.1-11.24
Page 11.4 Vitiation Factors:
Carbon dioxide concentration should not exceed 3% by volume and preferably should be maintained below 0.5%. For a sedentary man, 3 cfm (1.4 l/s) per person of fresh air will maintain a Co2 concentration of 0.5%.

American Safe Room provides free air filtration and component blast protection shelter consultations. Contact our Sales Manager at 541-459-1806 or send a plan view drawing of your shelter to sales@AmericanSafeRoom.com or FAX it to 503-212-6695.