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Recently, display cases in museums have improved in airtightness.On the other hand, there is a risk that artifacts in display cases may be exposed to chemical gases if there is gas emission from the interior materials used in the display cases. Also it is thought that gas concentration increases with time. However, change in gas concentration in display cases has not been made clear until now.To confirm such a change,it is necessary to repeat gas sampling in a specific time cycle and to keep the display cases closed during test period. But if the cases are kept closed, confirming change in gas concentration is difficult since measuring devices cannot be easily set or removed.In order to solve this problem,a display case was made for environmental testing and gas concentration was measured. This paper reports the change in acetic acid gas concentration in the display case as confirmed by measurement. It also compares the acetic acid emission rate of the interior materials obtained from the measurement of the display case and that obtained from chamber test. As a result, it was found that there was little difference in emission throughout the experiment. Gas concentration obtained by the measurement was corrected by removing the effect of gas sampling. This corrected gas concentration was consistent with that obtained through prediction formula based on initial gas concentration. In addition, emission rate of the interior materials obtained by chamber test and by the present measurement was similar. From these results, it was found that it is possible to predict change in gas concentration in display cases by obtaining initial gas concentration and that chamber test is an effective method to estimate gas concentration in display cases. |
