Physico-chemical and microbiological measurements (temperature, humidity, CO2, CO, VOC, bacteria and fungi) were performed on indoor air of three schools near Paris (France). Results of measurements are given and analysed. Indoor air quality is better with mechanical ventilation than in operable windows classrooms. TVOC concentrations are much higher indoors than outdoors.
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.
CFD calculations and laboratory measurements in a full-scale model were carried out to assess the performance of a full transparent second skin façade intended to equip an office building, composed of very low solar energy transmittance glass, and being v
Field tests and a model allowed to study contaminant concentrations in a single family home in California operating with natural ventilation or with one of six mechanical ventilation systems (cyclic or continuous, multi-point or single-point exhaust). Continuous ventilation appears to be better for contaminant levels control.
Ventilation airflow rates and internal air distribution were measured in four poultry slaughter plants (250 to 775 workers), equipped with negative pressure ventilation systems (exhaust flow rate from 7.1 to 27.4 m3/s - no air intakes - supply air entering through various openings). Results lead the authors to recommend the installation of diffusers for makeup air supply, changes in the organisation of rooms to avoid contamination of one by the other and regular maintenance and cleaning of ventilation components.
This was a study of the relationship between mechanical ventilation and sick business syndrome in an office building with 1250 employees, where workers blamed the mechanical ventilation and indoor air quality for causing typical SBS symptoms such as nasal, eye, skin and mucous membrane irritations, lethargy and headaches). The building's mechanical ventilation rates were high.
A dynamic computer program was used to analyse the operation and performance of a thermal comfort controller for HVAC systems with forced-air ventilators. The software tool used was GEMS (Generalized Engineering Modeling and Simulation). Simulations indicated that when using a conventional thermostat, any form of mechanical ventilation is likely to increase the moisture content of the air inside a conditioned space in a cooing-dominated hot and humid climate. States that mechanical ventilators in this situation may contribute to indoor air quality problems of high moisture levels.
The study investigates the effect of mechanical ventilation and high-efficiency vacuuming on house dust mite numbers and allergen concentrations in dwellings of mite-sensitive asthmatics. Of forty houses, some received mechanical ventilation, some an HEVC, and some both, while a number acted as controls. The monitoring exercise lasted for twelve months. It was found that humidity was reduced in homes with mechanical ventilation and mite numbers reduced accordingly. Use of the vacuum cleaners enhanced the effect.
A move to mechanically ventilated low-dust mite affected, 'healthy' homes was investigated in relation to asthma control. Fourteen patients, allergic to dust mite allergens, were studied. Clinical improvements were significant in the patients, in contrast to the control patients. The study found a significant relation between reduction in medicine score and the fall in house dust mite exposure.
Thirty asthmatic patients were tested for exposure to house dust mites before and after moving to mechanically ventilated homes. There was found to be a significant reduction in house dust mite numbers after four months in contrast to the control group of 23 patients. A further reduction had occurred after 15 months. Air change rates increased from 0.40 ACH to 1.52 ACH. There was also a reduction in absolute air humidity.
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