[Diffusion indicator tubes for hydrogen chloride]

In order to define the mean shift exposure of workers in the environment of hydrogen chloride, we could use, besides long-term colorimetric tubes also colorimetric tubes on the principle of diffusion, named also passive monitors. Experiments are performed on different reactionary principles and recipes of indicator compositions for hydrogen chloride: with pH-indicators as bromphenol blau, dimethyl yellow and benzopurpurine 4B, and also reactions for discoloration of silver chromate or lead sulfate. The successful variants are metrologically evaluated by means of gas generating device for calibration gas mixtures. Special attention is given to the accuracy of the results at different air humidity. Recipes with minimum effect of the air humidity on the results are developed and is proved, that concentrations of hydrogen chloride could be significantly measured, also at higher humidity of the examined air of those given in the literature.