Ventilation systems may in some cases be a major contributor to indoor air pollution. Several studies have shown that the pollution mainly originates from the filters. Microbial growth in the filters is seen as a cause for this pollution. The sensory pollution from a standard glass fiber filter and a glass fiber filter treated to inhibit microbial growth (both EU7) were compared. No clear pattern was found in the influence of the filters on the sensory air quality. The differences between the two tested filters were not significant.
Concerning artificial ventilation of interiors, microbial processes on air filters are assumed to cause pollution of the supply air with possible damage to the exposed persons' health. Therefore, the reaction of microorganisms on air filters was analysed in this project. The analysis focused on the influence of air temperature, relative air humidity, the filter medium and service life as determinants for microbial growth on air filters. The experiments showed that the parameters air temperature, filter medium and service life had no significant influence on microbial growth.
Recent concerns have been expressed with regard to emissions of glass fibers from heating, ventilation, and air conditioning (HV AC) systems. In this literature review, over 350 citations were found, of which 10 reported original measurements of glass fiber concentrations associated with the presence of fibrous glass duct lining or duct board, and two yielded sufficient data from which emission rates could be calculated.
Passive solar cooling for hot humid areas represents an important field for innovation, if we want to solve comfort needs in spaces (especially housing) designed to reduce economic, technical and health requirements. In urban areas or deep valleys and rain forests, which are common in most of the tropical equatorial countries, external breeze is not frequent and air speeds are too low to produce cooling, using a simple cross ventilation system. Since 1982 the author has developed new designs and constructions using passive solar techniques.
A nine-home field study was conducted to investigate the impact of mechanical air duct cleaning (ADC) methods on indoor air quality (IAQ) and system performance. ADC services were provided by the National Air Duct Cleaners Association (NADCA). Only mechanical ADC methods were evaluated. Surface treatments, such as biocides or encapsulants, were not part of the study. Pre- and post-ADC measurements were used to evaluate impacts.
Angle factors between a human body and rectangular planes are calculated by a numerical model. The method presented in this paper which predicts the thermal radiation field in a space, is based on a numerical integration method proposed in a previous paper. To confirm the validity of the calculated results, predicted angle factors for both standing and seated persons are compared with those from experiments. It was found that the predicted figures matched well with those from experiments except those between the human body and the front floor.
Fungal-contaminated air handling systems have been implicated as a source for the dispersal of spores into the indoor environment, potentially serving as a route of exposure to building occupants. Because quantitative data are lacking, this study was conducted to measure the dispersal of spores from fungal colonies growing on three types of duct material: galvanized metal, rigid fibrous glass ductboard, and fiberglass duct liner.
The new Guideline VDI 6022 contains hygienic standards for ventilation and air-conditioning systems. The requirements for the planning, design, operation and maintenance of ventilation and air-conditioning systems and their components are dealt with to ensure a hygienic condition according to the state of the art. The Guideline is subdivided as follows:
part 1 Offices and assembly rooms (published 07 /98)
part 2 Standards for Hygiene training (published 12/98 as a draft)
part 3 Factories (activities have been started 01/99)
In this study, the effect of duct cleaning on the indoor air quality and on the ventilation system hygiene in non-problem office buildings: was investigated. Six office buildings were selected from local duct cleaning companies' contracts. A questionary was distributed among the occupants prior to and after the duct cleaning. Also several air quality parameters were measured in outdoor air, indoor air,· and supply air and ventilation system hygiene measurements were performed prior to and after duct cleaning.
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