The air change rate in a single story office building was measured using atracer gas technique. The air change rate was determined by the rate of decay method using sulfur hexafluoride as the tracer gas. A total of eight tests were conduc
Describes validation of a simple technique for infiltration measurement in large, multicelled, naturally ventilated buildings by reference to a computer model study and by field measurements in two naturally ventilated office buildings. The salient features of the technique are: 1) a single tracer gasis used, 2) measurements need only be carried out in part of the building, 3) an initially uniform distribution of tracer is not needed, and 4) artificial mixing of the tracer with the internal air is not essential.
This study used a constant concentration tracer gas measurement system to measure the air infiltration rate of three modules simulating residential buildings in Canada. The results obtained were compared with computer predictions.
Air exchange rates were measured in the National Archives Building under various combinations of temperature and wind speed. The average air exchange rate under normal operation of the HVAC system was 0.9 h-1 for an average temperature difference.
This paper describes the procedures used in residences for rapid grab-sample and time-dependent measurements of the air-exchange rate and radon concentration: the radon source magnitude is calculated from the results of simultaneous measurements of these parameters. Grab-sample measurements in three survey groups comprising 101 US houses showed the radon source magnitude to vary approximately log-normally with a geometric mean of 0.37 and a range of 0.01 to 6.0 pCi/l/h.
The Aardvark automated system has been developed for continuously measuring the air-exchange rate and 222Rn (radon) concentration in an occupied residence. The air-exchange rate is measured over 90 min intervals by tracer gas decay using sulphur hexafluoride as the tracer gas.
Based on current concerns regarding indoor air quality and energy use, there is a need for in situ techniques for evaluating buildings' infiltration and ventilation characteristics. The U.S. National Bureau of Standards has developed and employed equipment and techniques for such evaluation. The measurement of whole building leakage and ventilation rates has been reported on previously. Additional procedures are presented here for a more complete evaluation of the ventilation system operation and the distribution of air within the building.
The typical infiltration load for a residential building has been found to range from one-third to one-half of the total space conditioning load. However, most infiltration measurements have been made on single-family houses.
The various meanings of ventilation efficiency are briefly summarised. The residual life time of a released tracer gas is chosen as the most meaningful and convenient basis for local efficiency measurements in large, occupied, mechanically ventilated buildings. Measurements were carried out in ten public swimming pool halls. Sulphur hexafluoride tracer gas was released from a 20 ml syringe at various locations around the pool hall and the integrated concentration with respect to time was measured at the exhaust air duct. This was extrapolated to infinite time using the measured decay rate.
Air infiltration flows into different zones of a building can be measured with the constant concentration technique by injecting a metered amount of tracer gas t o hold the concentration of the gas constant. The control and estimation algorithm used to calculate the injection rate is designed using classical transform and optimal estimation methods. The ability of the control algorithm to keep the concentration constant and to accurately measure time varying infiltration flows is demonstrated using digital computer simulations and laboratory experiments.
Login