2.4.2
Pre-filter and Post-filter
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NOTE: Post filters are required by ASME N 509, are
located downstream of adsorbers for carbon fines
collection, and used for non-military applications.
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The [pre-filter] [pre-filter and post-filter] shall be extended, dry media
type, [100 mm 4 inch deep] [150 mm 6 inch deep] [300 mm 12 inch deep], with
an average atmospheric dust-spot efficiency of 95 percent based on ASHRAE
52.1. Initial resistance at [_____] m/s feet/second shall not exceed
[_____] pascals inches wg.
2.4.3
High-Efficiency Particulate Air (HEPA) Filter
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NOTE: Frames constructed of plywood are usually
used in applications where disposal of filters is by
incineration.
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HEPA filters and frames shall meet the materials, design, inspection,
fabrication, quality assurance, and nameplate marked as specified in ASME
AG 1, Section FC. HEPA filters shall have a 99.97 percent efficiency with
a 0.3 micron diameter particle size as determined by the dioctyl phthalate
(DOP) test method in accordance with IEST RP-CC-001.3. HEPA filters shall
be qualified and labeled in accordance with UL 586. HEPA filters shall
have the indicated capacity and pressure drop for clean filters. Filter
frames shall be [Type II - stainless steel sheet, Type 304] [Type IV
plywood] construction as defined in ASME AG 1, Section FC. The HEPA filter
media shall be manufactured in accordance with ASME AG 1, Section FC.
Filtration media frames shall have an integral perimeter gasket seal.
Initial resistance at [_____] m/s feet/second of filter face area shall not
exceed [_____] pascals inch wg.
2.4.4
Carbon Adsorber
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NOTE: To remove all chemical warfare agents(
included in FM 3-9) from an air stream use
impregnated ASZM-TEDA carbon media. To remove
chemical agents that only have low volatility (vapor
pressure less than 1,000 pascals) use activated
carbon conforming to ASME AG 1. Many toxic
industrial chemical vapors are not effectively
removed by ASZM-TEDA carbon.
Commercial carbon adsorbers are typically designed
for 500 scfm when configured as a single stage
system; however, designs for various air flow
capacities 165 to 354 sL/s (350 to 750 scfm) are
available as indicated in the table below.
Adsorber Air Flow Rate
Nominal Adsorber
Single Stage,
Dual Stage,
Depth, mm (inches)
L/s (cfm)
L/s (cfm)
355 (14)
177 (375)
354 (750)
SECTION 15860A
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