Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p59
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 59/117)
Character Range: 510663–513673

long-term near-continuous emission monitoring is undertaken.
    * Buildings — because of the usually limited surface area of coverage, flux chambers may not measure the actual flux into a built structure, especially if there is preferential access to the structure. Also, air-movement conditions within the chamber may not reflect natural room conditions in a structure – leading to overestimation or underestimation of fluxes depending on relative pressure differentials inside and outside a chamber.
More detailed information can be found in Davis et al. (2009a), Baker et al. (2009) and Hartman (2003).

9.5              Sample collection and analysis
Source: Davis et al. (2009a)
Samples for analysis may be collected using a range of media which include sorbent tubes (charcoal or multisorbent), Summa canisters, Tedlar® bags, glass vials, and syringes. Standard operating procedures should be developed for sample collection and any variations to the procedure (for site conditions or equipment limitations) fully documented.

It may be possible to carry out a field screening assessment of the contaminants present using a PID, FID or other handheld detector, providing the instrument detection limits are sensitive enough to measure concentrations at levels relevant to health risk assessments. For field screening, soil vapour samples may be collected via a vacuum (evacuation) chamber into a Tedlar® bag or similar and the meter connected directly to the Tedlar® bag.

Commonly used active and passive collection methods are discussed in the following sections, while more detailed information can be found in Davis et al. (2009a).

    9.5.1          Active methods

9.5.1.1         Sorbents
Sorbent materials, packed into tubes, typically comprise activated carbon and/or a range of multi-sorbent materials (one or more different sorbent media may be present in each sample tube). Vapour samples are collected by drawing air (using pumps) at a calibrated rate through the tube over a specified period of time. The flow rate and sampling volume are dependent on the sorbent media used, the range of target chemicals and the required limit of reporting. The reporting limit is determined by the volume of air drawn through the sample tube, the adsorbent and analytical method used, and the potential for high concentrations (requiring dilution of the sample during analysis).

Sorbent tubes have a maximum capacity which may be exceeded in circumstances where the source concentrations are high and/or the sample volume drawn through the tube is large. A control section of the tube, analysed separately to the sample section, indicates whether breakthrough has occurred (i.e. whether the capacity of the tube has been exceeded). If the tube capacity is exceeded, the reported concentration will under-represent the actual site conditions.

9.5.1.2         Canisters
Whole air samples can be collected using specially prepared canisters (Summa canisters) which are sent to the field under vacuum and