Accuracy Of Dosimeters Research Articles

A Passive, Direct Reading, Length-of-Stain Dosimeter for Ammonia

A line of passive, length-of-stain dosimeters has been developed for ammonia, amines, carbon dioxide, carbon monoxide, chlorine, hydrogen cyanide, hydrogen chloride, hydrogen sulfide, nitrogen dioxide and sulfur dioxide. These were described in a previous publication. This paper deals with the calibration and accuracy testing of the ammonia (NH3) dosimeter. These dosimeters operate according to Fick's Law of Diffusion. For the NH3 dosimeter, this law can be modified to the form: 15S+S2=KCt, where S=stain length (mm), K is a constant, C=concentration (ppm) and t=time (hours). By experimentally determining K for each lot of tubes, the concentration corresponding to the stain length can readily be caluclated for a given exposure time within the applicable concentration range. The range of the NH3 dosimeter is from about 1 to 280 ppm. The accuracy of these NH3 dosimeters has been validated internally by using a technique described by DuPont. Accuracies of four recent lots were: ±16.3,19.7, 23.4,14.8%. The acc...

Method for determining complex operator noise exposures.

This procedure describes a field method for determining operator noise exposures that cannot be assessed from single sound level meter readings. Noise exposures that should be evaluated by this method are those characterized by time-varying operator position sound levels--sound levels that change by three decibels or more while the meter is being read. The method is based on statistical concepts and requires multiple readings for a sample period whose length is prescribed by the desired precision of the results. This new procedure compares well with the theoretical accuracy of the best dosimeters. The actual performance of the new method has been shown to be better than the actual performance of the dosimeters.