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| Particulate Sampling Filters |
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Of the more than 2,200 airborne hazards listed in the SKC Guide to Air Sampling Methods, over 500 are collected by filters. About 80% of a filter surface is porous. An air sampling filter may contain millions of pores smaller than the diameter of a human hair (which is about 30 microns) or even cigarette smoke (about 0.5 micron). Pore size, like the filter itself, depends on the application requirements. All SKC filters are manufactured following strict tolerances to meet NIOSH, OSHA, and EPA specifications.
For our complete listing, see our online catalog section containing filters and
filter accessories here.
Air Sampling Filters
Preloaded Filters
About Filter Materials and Applications
- Mixed Cellulose Ester (MCE) for metals, welding fumes, asbestos, and other
fibers.
- Polyvinyl Chloride (PVC) for silica, chromates, and gravimetric analysis of
respirable and total dusts.
- Teflon (PTFE or Polytetrafluorethylene) for PM10, pesticides,
acid aerosols, and solvents.
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- Fiberglass for gravimetric analysis of pesticides, isocyanates, and air
pollutants.
- Quartz, heat-treated to remove trace organic impurities; for monitoring
trace levels of organic pollutants.
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If sampling in high humidity conditions, it is important to know the water
sorbing characteristics of the filter medium you are using. Moisture sorption by
the filter or the cassette is one of the most common causes of weight
instability in weight-type analyses. Using hydrophobic materials can reduce
water sorption problems, however, these materials may not be suitable for some
applications. Use the following information as a general guide to the water
sorbing characteristics * of various filter
materials and cassettes.
Very Low Moisture Sorption
- PVC membrane
- Aluminum cassette
- Stainless steel cassette
Low Moisture Sorption
- Glass fiber filter
- Quartz fiber filter
- Teflon (PTFE) membrane
- Polycarbonate membrane
- Greased Mylar impaction substrate
- Greased aluminum foil impaction substrate
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High Moisture Sorption
- Cellulose fiber
- Cellulose ester membrane
Very High Moisture Sorption
- Polyurethane foam (PUF)
- Polystyrene cassette
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* Filter coatings and manufacturing variables
also affect water sorbing characteristics.
- Use only the filter material and pore size specified by the method
- Place the cassette inlet in a downward position
- In gravemetric filter determinations, do not overload the filter
- For respirable dust, use a cyclone.
For inhalable dust, use the IOM sampler.
- Closed-face filter sampling requires a 2- or 3-piece cassette with the inlet
section in place and only the small sealing plug removed.
- Open-face filter sampling requires a 3-piece cassette with the inlet section
removed
- When support pads are specified, place the pad behind the filter so that the
air passes over the filter first.
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Custom Filters Available
For specific applications, SKC will manufacture filters to meet your specific
requirements. Contact your SKC representative for more information.
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