Gas Sampling
The maintenance, servicing, and also the dismantling of old buildings and facilities constructed with halogenated pollutants such as PCBs (e.g. in silicone sealants), but also accidents in which PCDDs, PCDFs, or other pollutants were released, today require constant monitoring of the concentrations of these hazardous substances in indoor and ambient air. Suitable sample preparation is required for the isolation and enrichment of these substances, which are usually only present in trace amounts. For many years, reversible adsorption of these pollutants on specially cleaned PU foam filters (PUFs) has been established for this purpose. This procedure is also specified in various US EPA, ASTM, and DIN methods.
We produce these PU foam filters in numerous sizes from 8 x 31 mm to 100 x 135 mm from the two common PU materials GA 3035 (standard material with a density of 30 kg/m3) and SH 100 (lower density of 20 kg/m3). The filters are offered both uncleaned and cleaned according to VDI method BGI 505.47 (formerly ZH 1/120.47). In this process, the PU foam filters are extracted with toluene for 24 hours and then with acetone for 24 hours, so that production-related impurities are removed and blank values are reduced accordingly. Other dimensions and cleaning methods are also available on request. By purchasing the cleaned filters, which are supplied in flat bags made of aluminum composite foil or, for a small surcharge, in amber glass screw-top containers with a PTFE-coated sealing washer, depending on the customer’s requirements, the user is spared the cumbersome and time-consuming preparation and can concentrate fully on the actual measurement.
As an alternative to PU foam filters, glass tubes filled with Florisil are also suitable, which are recommended by the PCB guideline NRW, among others, as a suitable means of sampling indoor air. We produce these glass tubes and offer them in the usual high quality: with 8 mm ID for sampling up to 5 L/min and with 12 mm ID for sampling up to 10 L/min.
