tracer gas

Measurement method for ventilation effectiveness, more specifically, for contaminant removal effectiveness with a point source corresponding to infector is analysed in this study with tracer gas measurements and infection risk calculations. Ventilation effectiveness is needed in infection risk-based ventilation design to take into account air distribution methods deviating from fully mixing. Tracer gas measurements were conducted with two source location in six non-residential spaces.

Building air infiltration rate is required as an important input in the calculation of building heat loss. Tests to directly measure infiltration rates are complex and time-consuming to perform, and are therefore usually substituted with an airtightness test as a more efficient alternative. An empirical ratio, or sometimes an infiltration model, is then used to predict the building infiltration rate from the measured airtightness value. For instance, in the United Kingdom the building air permeability measured by a steady pressurisation test and reported at 50 Pa

Measuring ventilation rates in occupied dwellings is challenging but represents the conditions that occupants experience. This paper explores the constraints of existing methods when measuring the ventilation rate of occupied buildings and proposes a new method addressing some of them.  

Air infiltration contributes to a heat loss typically representing up to one third of the heating demand of a building. The building airtightness, also quantified as air leakage, is the fundamental building property that impacts infiltration. The steady (de)pressurization method (blower door) is the widely accepted standard process for measuring building air leakage. However, this method requires the enclosure to be pressurised to a typical range of 10-60 Pa, which is not physically representative of the pressures experienced by buildings under natural conditions.

In order to provide patients with a high quality indoor environment and ensure a pleasant working place for medical care personnel, thermal environment and indoor air quality are regarded as two of the most important requirements. 

Using natural ventilation is effective to save energy, and it is essential for energy conservation and decreasing running cost [1]. However, in office buildings located in where mid- to -high-rise buildings are densely distributed, the way of ensuring stable ventilation is very important matter of natural ventilation system. In this research, we focus on the ventilation performance of an office building where the natural ventilation system is introduced by utilizing the buoyancy force through a ventilation shaft.

From the energy point of view, buildings should be as tight as possible. But lack of ventilation will result in high level of indoor pollutants, which is harmful for occupants. Numerous studies find that lack of ventilation could cause symptoms for occupants, which are characterized by World Health Organization as Sick Building Syndrome.

Door operation and the subsequent passage of occupants through the doorway can cause containment failures in hospital isolation rooms. Typically hinged doors are used between the isolation room and anteroom/corridor in healthcare facilities. However, sliding doors can reduce door induced airflows through the doorway and hence effectively reduce the contaminant outflow during the door operation.

Air change rate is often used as an important characteristic of indoor environmental quality, which significantly impacts human health. However, easy, effective, real-time and low-cost air change rate measurements in naturally ventilated resident buildings are still a huge challenge. This paper presents a method based on the release of a stable rate of the tracer gas CO2 given off by solid CO2 (dry ice) in an insulated box.  In theory, the dry ice will sublime at a constant rate as long as there is sufficient dry ice in the box.

The article presents the results of our research, which was realized under a cooperation project between the University of Pécs, Hungary and the University of Osijek, Croatia. The aim was to gather 50 Pa ACH, air tightness and spontaneous ACH information of residential houses by the Croatian and Hungarian border. The budget of the project allowed approximately 50 tests for each university; these summarized results are presented together with correlations found between the results.