Abstract
The evaluation of dust in communication machine rooms is becoming more and more important because of the increasing numbers of optical devices in information communication. To carry out airborne dust evaluation more cheaply and easily, a method for separating “dust collecting” and “dust evaluation” was adopted. A method for automatically exchanging samples was examined in the collecting function. Moreover, a handy optical method was examined in the evaluation function.
The main examination results are listed as follows:
(1) We enabled airborne dust information to be recorded in the dust collecting filter for long term fixed periods using an “Airborne dust environmental recorder”.
(2) The optical reflection method was examined as a method for evaluating dust. We found a very strong correlation between the amount of dust in the filter and the brightness index. The correlation coefficient was 0.961.
(3) The relation between the amount of suck flow and the correction coefficient of the recorder was clarified. By using this correction coefficient, it is possible to calculate the amount of dust from changes in the brightness index in the filter. The width of the data change in this recorder was estimated to be±5% or less from the simultaneous evaluation results of five recorders.
(4) As a result of setting up the recorder in three NTT machine rooms and the simultaneous evaluation of dust in the environment, it was shown that airborne dust in the environment was significantly different in various parts of the same building. Moreover, it was shown to easily judge the relative superiority or inferiority of airborne dust in the environment.
