American SafeRoom

Complete Filter Replacement Set


These replacement filters are of the highest quality. They are all easily replaced by using simple hand tools (two Crescent wrenches) and a suitable receptacle such as a plastic bag to place to old filter in. For more information about how to replace the filters, please see the Safe Cell manual.

All of these filters come with the Safe Cell:

The pre-filters are designed to extend the life of the HEPA filter by trapping both large and small particles. The first filter is the roughing filter with an average efficiency of 25 to 30 percent when tested in accordance with ASHRAE 52.1. The roughing filter extends the life of the intermediate filter or pre-filter and reduces its change frequency. The second filter is the intermediate filter with an average efficiency of 80 to 85 percent when tested in accordance with ASHRAE 52.1.

The HEPA filter
The nuclear grade HEPA filter is a special filter we have made just for our application.Each HEPA filter is individually tested to MIL-STD-282 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 an individual serial number.

Every HEPA filter is individually DOP tested: 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 deg/C), low temperature environment of (-3 deg/C). UL also subjects the HEPA filter cell to a spot flame test of (954 deg/C).

  • Media: Water repellant glass micro fiber 99.97% True HEPA cell type (A)
  • Cell Side Material: Fire retardant particle board
  • 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 placard for the Safe Cell


Carbon adsorber
The nuclear grade war gas adsorber is a block sieve adsorption filter cell consisting of two containment medias and a center block of blended granual nuclear grade war gas carbon and ASZM-TEDA.

This special blend of two kinds of activated carbon adsorbs warfare gases and radioactive iodine in order to meet the requirements of US Army Corps of Engineers ETL 1110-3-498 standard for war gas removal.

Carbon blend specifications:

  • Activated impregnated NUK-TK TEDA Nuclear grade TEDA for removal of radio active iodine
  • ASZM-TEDA copper-silver-zinc-molylebeunm-triethylenediamine

Critical standards that we meet or exceed:

  • ASTM D 2854-1996: industry standard test method for apparent density of activated carbon
  • ASTM D 2867-1999: industry standard test method for moisture in activated carbon
  • ASTM D 3802-1997: industry standard test method for ball-pan hardness of activated carbon
  • ASTM D 3467: activity for CCL - 60% minimum
  • ASTM D 2862/D5158: particle size: 4X8 Mesh U.S.
  • ASTM D 3838: pH aqueous extract - 9.2 minimum
  • ASTM D 3466: ignition temperature 330C
  • ASTM D 3803: radioactive iodine removal
  • Impregnated with 2.1 Potassium iodide, 3.1% TEDA
  • EA C 1704-1992: chemical research development and engineering
    center purchase


How long will a set of filters last?
That's sort of a loaded question. Room air filter manufactures can know with some certainty what their filters will be challenged with. With NBC filters, the challenge is unknown.

We saw on 9-11-2001 a few inches of fine dust on the streets of New York. Any particulate filter will quickly clog if it is fed that amount of dust. On the other end of the spectrum, a light dusting of fallout won't do much to the filter. In fact, particulate filters (pre-filters and the HEPA) actually filter better as they load up. The particulates that they catch act to increase the area of the filter. The down side is that as the filter loads up, it puts out less airflow.

The carbon adsorber is a different situation. It does not adsorb gases better as it loads up. It uses a process called adsorption to attract and hold gas particles on the surface of the carbon. It does not care what kind of gas it is adsorbing - that is why we like to see the filter buttoned up with the shipping caps until it is needed. Water vapor is a true gas that loves to adsorb to the carbon graduals. And when the carbon loads up, the only feedback is that the carbon adsorber increases in weight very slightly. If you had a very accurate scale, you could measure the adsorber before and after and tell if it's had it's life used up.

We tell people that our filters will last "one event." That is, if you have a mushroom cloud on the horizon or a nuclear plant releasing radiation upwind, that is an event. When you receive the all clear, then it is time to take the entire Safe Cell off the wall, take it outside, remove the old filters, and install new ones. Notify your local hazmat team about the contaminated filters

Our supplier keeps keep more than adequate stock of them for normal sales, but we cannot anticipate the demand when there is a nuclear event. The best way to ensure you have replacement filters is to order them when you order your Safe Cell.

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