scope:

NPR 2950 describes a gneral method to determine the c oncentration of toxic gases and vapours in workplace atmosphere, using gas diffusive sampling with a dosemeter, which immediately gives an indication of the concentration of the matter under determination by a change of colour when reacting within a suitable reagent. The pre-standard applies to the determination of the concentrations of volatile matter in workplace atmosphere, making use of dosemeters in which the air penetrates by diffusion and which contain an adsorbent suitable for the matter concerned, impregnated with a reagent; the pressence of the matter concerned is immediately made visible by a change of colour.