English

In USA, after the 2001 bioterrorist attack, filtration efficiencies have been evaluated at three US. Postal Service (USPS) facilities. New ventilation and filtration systems (VFSs) including HEPA filters were used to provide an optimal filtration efficiency (at least 99,97 %). In this paper the techniques used for measurement of particle concentration are described (use of optical particle counters GRIMM Type) and the results presented.

Thanks to a right air filtration strategy a good IAQ does not have to cost more. Advances in air filtration allow the development of systems that provide superior IAQ with a reduction of energy costs. HVAC filters play an important part in the removal of airborne contaminants, and protect the HVAC equipment from dust. They provide a cleaner and greener air.

Ventilation rates and main parameters related to IAQ have been tested in some office buildings and residential houses whom occupants complained about the bad indoor air quality. Based on the test results and regulations, some suggestions were made such as elimination and control of the emission of pollutants at their sources , installation of local exhaust ventilation facilities, proper design and construction of the air conditioning and ventilation systems, use of air cleaners, public education.

One strategy to secure the release of hostages held by terrorists, is to release an anaesthetic agent through the ventilation system. But it is not so easy to apply. The demand concerning the right amount of anaesthetic needed must be analyzed, along with the specific place in the building where it is required. A model has been made formulated to find the most appropriate strategy for this kind of emergency ventilation. The results are presented and recommendations given for applying the model in practice.

The aim of that study was to establish a methodology to quantify the ozone emission rate from electronic air cleaners, along with the ozone decay parameter. For that experiment 3 different portable ionisation-type air cleaners were used . The leakage rate of the stainless steel environmental chamber was measured by a tracer decay gas method. The results and conclustions are presented.

The most recent initiative taken by the Hong Kong SAR government to improve IAQ in various facilities is fan IAQ certification scheme for offices and public places. This paper outlines the key elements of the scheme , discusses the suitability of the IAQ criteria, and identifies the difficulties in meeting the prescribed measurement protocols.

Stacks can enhance the natural ventilation of buildings. They can drive ventilation in floors where there is little heat load. In this paper, the use of stacks for second ventilation has been investigated with laboratory experiments and supporting quantitative models. Results and conclustion are presented.

Do multiple solutions of natural ventilation exist in complex buildings and what are the physical mechanisms that can lead to a such existence ? To answer that question the authors have examined a simple one-zone building with four openings using the simple macrocospic method of thermofluid modelling and have made a simulation of the four-opening building with a conventional network modelling computer program .
The results show a good agreement between the predicted ventilation flow rates by the network modelling method and the simple analytical solutions.

The evaluation of a quantitative method for culturing particles on HVAC filters is the aim of this research. Two phases for that study : first, a case study comparison of two HVAC filters from a building with a history of IAQ concerns and secondly remediation efforts in the same building. This limited study has been carried out for prelimimary assessment of the use of a filter quantification method to evaluate relative airborne fungal load.

This paper studies particle diffusion of a wide range of particle sizes compared with the diffusion of passive contaminant under the same conditions. A numerical model was validated then simulation of diffusion of particles in 2 different clean rooms was made. The results show that ventilation mode, particle source location and air exchange rate have an influence on the particle distribution.