scope:

NPR 2949 describes a general method to determine the concentration of toxic vapours or gases in workplace atmospheres, using gas diffusive sampling with a sorbent tube, thermal desorption and gas chromatography. The standard applies to the determination of the concentration of toxic vapours or gases in workplace atmosphere, using a sorbent tube containing an adsorbent suitable for the matter concerned, which can be desorbed thermically. The field of application is determined by the diffusion debt, which in turn depends on the diffusion coefficient for the matter to be determined and on the styling of the adsorption tube.