The activity of radon daughters in high-rise buildings.
Abstract Forty measurements are reported in similar rooms in two high-rise buildings. The geometrical means for the concentration of radon daughters including and excluding the basement results, respectively, were 0.90 and 1.00 mWL, which is less than the quoted mean 2.0 mWL for 65 measurements in typical houses in the same city. The frequency distribution of these measurements shows a log-normal distribution. The concentrations did not depend on the distance from ground level but may depend on the ventilation rate of the room examined. The correlation between the concentration of radon daughters in WL in rooms above the first floor in the two high-rise buildings with the inverse of their ventilation rate were 0.73 and 0.67, respectively.
Comparison of various techniques for measuring natural ventillation in rooms
Various tracer gases were released into a room and the rate of decrease of their concentrations was used as a measure of the natural ventilation rate. Three different measurement instruments were used: an automated gas chromatograph, a gas sensor (for combustible gas), and a Geiger-Muller counter. The results of all three were in agreement. Complete mixing of all the tracers with the air inside the room required a period of at least 20min. The organohalogenated gases were found to affect the results of the gas sensor because of their strong adsorption on its detector surface. Despite stratification, of both tracer gas concentration and air temperature, there was no significant effect on measuement of natural ventilation rate.
Ground Fault Protection for Electric Utility Generating Station Medium Voltage Auxiliary Power Systems
Most generating station designs have medium voltage auxiliary power systems with low resistance grounded neutrals.1 In order to provide even higher reliability, the auxiliary power distribution system configurations supply increasingly redundant process equipment.