The study compares on 30 ventilation systems an hygienic factor determined from conditions at air intake (including moisture before and after drainage, porosity and contamination) and microbiological analysis of air. The aim is to identify ventilation systems potential risk for indoor air contamination.The study has shown a clear relationship between the microbiologic and the hygienic conditions; i.e. dry and clean intakes are less likely to be microbially contaminated. The method seems to identify potential problems, which could be confirmed by a microbiological study.

This study presents a literature review on oil residues on HVAC components. A sampling of oil residues by filter contact method and analysis by infrared spectroscopy method have been developped. Amounts of oil residues on surfaces of components varied a lot (<10 mg/m to 700 mg/m) but were significantly correlated to odour intensity. Cleaning of oil residues from the duct surfaces with typical cleaning methods is very difficult and it is better to deliver from the manufacturer components free of oil residues.

The study monitored two similar ventilation systems with fine filters during a few months, one operating continuously, one only during day time. Air, surface and filter material samples were taken to evaluate the extent of microbial contamination with viable fungi and bacteria. Filter and air of the permanent system,with higher relative humidity, were less contaminated by microbes and the contamination was more evenly spread in the filter.

A two-years old filter was placed in a ventilation system recirculating the air in an experimental space. Via glass tubes air was extracted to an adjacent room to allow a panel to evaluate the sensory load after facial exposure, without entering the space. The sensory pollution load of the filter determined from full exposure was approximately 7 times lower than when determined after facial exposure. Even though, used filters may still be important sources of indoor air pollution.

In an environmental lab with a panel of 30 women exposed 4 hours, comfort and health have been detremined both with a used or a new filter present in the ventilation system. All other environmental parameters were kept constant. A used filter in a HVAC system can have a negative effect on both the immediate perception of the indoor air quality and on perceptions and health-related symptoms. However, the annoyance experienced through the sensory system may have amplified the intensity of symptoms.

CFD simulations and measurements were used in isothermal air-conditioned space of a gymnasium. Different airflow patterns due to different supply air were simulated. Results obtained are correct considering the complexity of boundary conditions.

Design of thermal and air environment for large spaces is often realised with CFD simulations but due to measurement difficulty there are few cases in which results are compared after construction. This study uses a simple method for visualizing air currents and for estimating distribution of air movements with balloons.

The study characterised the mixing of tracer gas in three ventilation systems with two different airflow rates (totally outdoor air).The test procedure is presented and errors are calculated and compared.

The Moravian library's atrium in Brno (Czech Republic) is eight stories high. Ventilation is a combination of mechanical supply by nozzles in each gallery and a natural stack effect in the atrium from bottom to top. CFD has been used for design.

Measurements of metabolic carbon dioxide concentration made in four classrooms in two schools are reported for both occupied and unoccupied periods. Measurements were taken for approximately one week in each classroom during the unheated season and the time-varying ventilation rates estimated. The results of the experiments show CO2 concentrations that are far beyond the guideline value of 1000 ppm (the maximum concentration during the occupied period was 3756 ppm). Calculated air supply rates vary from unacceptably low levels, to rates that are in line with guidance.