Tracer gas sorption in and permeation through building materials influence tracer gas ventilationmeasurements. Therefore, it is important to have knowledge about these processes.The permeation of three commonly used tracers (SF6, N2O and the PFT C6F6) through untreatedgypsum board has been experimentally investigated. The result shows that all three tracers diffusereadily through this material (diffusion coefficients in the order of 1 10.-6 m2/s). Caution shouldtherefore be exercised when using tracer gas measurements in rooms with walls of gypsum boardor other porous materials.

Ventilation is the most effective procedure to reduce indoor air pollutant. Volatile organiccompounds (VOCs), which cause health related symptoms, are often detected in the indoorenvironment. The way of ventilation should be decided depending on the level of VOCs. Thelevel of VOCs and ventilation rate are usually measured individually. This study will proposea simple method to measure both the ventilation rate, by perfluorocarbon tracer gas technique(PFT), and VOCs concentration immediately by using a single sampler.

Natural ventilation is a prevailing way to relieve the indoor thermal environment against warmand humid climate. The field measurement of the thermal performance of a model house withnaturally ventilated double skin walls compared with a conventional insulated model housewas carried out. Only the gap between the double skins is ventilated, while the indoor of theconventional model is ventilated mechanically.

This paper describes the unsteady terminal and presents its characteristics gained fromexperiment. The experimental results showed that the fan-coil unit tested in the experimentwas able to provide fluctuating airflow and the velocity curve of supply airflow wasconsistent with the control signal very well. The spectrum of supply airflow is similar to thespectrum of natural wind if the control signal simulating natural wind provided. The supplyair temperature is changed when the airflow is changed.

Mixing ventilation and displacement ventilation were compared in an intervention study inclassrooms. Particles, cat allergen and CO2, were measured in classroom air at different levelsabove the floor, during regular lessons. With mixing ventilation, the particle concentrationtended to decrease with height, with a stronger gradient occurring for larger particles. Withdisplacement ventilation, the particle concentration increased with height, except for particles>25 m. The displacement system thus tended to have a slight upward displacement effect onmost of the particles.

The thermal environment in vehicles varies greatly. The interaction of the cabin thermalenvironment, created by the HVAC system, the outdoor conditions as well as the occupants,is rather complex.In this regard, in order to improve occupants comfort, we thought of locally differentiatingthe parameters which influence peoples satisfaction.

The influence of uniformly distributed cooling load is investigated on the air velocity in theoccupied zone. The experiments have been carried out in a scaled test room of 6 6 2 mwith a scale factor 1:1.5. The room is equipped with nine vortex inlets. The inlets areuniformly distributed; every inlet supplies a cubical volume to remove the maximum possiblecooling load with a minimum airflow rate. The air supply rates based on floor area are set to30 m/(h m2). The cooling load generated by mannequins is uniformly distributed and variesbetween 0 and 180 W/m2.

Natural controlled ventilation is often ignored when buildings are designed. It is importantthat architects, property developers both commercial and residential, designers, engineers andthe general public be aware of guidelines (readily available) for proper indoor air quality.Mechanical engineers should realize that introducing supplemental fresh air ventilation intoheating, ventilating and air conditioning (HVAC) systems aids in improving indoor air qualityand often maximizes the efficiency of the HVAC systems.

This paper is about the application of active stack system to enhance natural ventilation inpublic housing in Singapore. About 86% of the population is staying in high-rise publichousing, known as Housing and Development Board (HDB) flats, which is designed fornatural ventilation. The main objective of this work is to assess the status of naturalventilation in a typical 4-room HDB flat using scaled model in the wind tunnel, and todevelop an effective active stack system to enhance natural ventilation in the flat.

This paper investigates the effect of ventilation on mould growth in a typical Japanese bathroom byuse of the fungal index which indicates the growth rate of a mould, Alternaria alternata S-78. Thebathroom was set in an artificial climate where the temperature and relative humidity (RH) werekept constant. The temperature, RH and fungal index in the bathroom were measured under severalventilation methods after taking a bath.