AIVC - Air Infiltration and Ventilation Centre

Search form

EBC

You are here

Home

mechanical ventilation

Mechanical ventilation in office buildings and the sick building syndrome. An experimental and epidemiological study.

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.

Thermal comfort controller for HVAC systems with mechanical ventilators.

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.

Mechanical ventilation and high-efficiency vacuum cleaning: a combined strategy of mite and mite allergen reduction in the control of mite-sensitive asthma.

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.

Clinical efficacy of reduction in house-dust mite exposure in specially designed, mechanically ventilated "healthy" homes.

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.

House-dust mite exposure reduction in specially designed, mechanically ventilated "healthy" homes.

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.

Dynamics of airborne fungal populations in a large office building.

Documents a study of airborne fungal concentration in a newly constructed building on the Gulf coast. States that fungal concentrations indoors were consistently below those outdoors, and samples did not clearly indicate contamination in the building, although visible growth was evident in the ventilation system. Concludes that the intrusion of most of the outdoor fungal aerosol is prevented by modern mechanically ventilated buildings, and that even extensive air sampling may not give the whole picture.

Effect of a new ventilation system on health and well-being of office workers.

Examines the effect of a new, individually controlled ventilation system on employee symptoms. Two groups of employees were studied in one office building with mechanical ventilation, with one group the control. Individual control of the workspace ventilation was given to the intervention group. The new system gave higher air velocities, more variable temperatures, and higher concentration of airborne dust and fungal spores. Nevertheless, after four months, employees reported fewer symptoms.

Nasal patency and biomarkers in nasal lavage - the significance of air exchange rate and type of ventilation in schools.

Describes a study carried out in order to examine the relationships between the ventilation rate and the type of ventilation system on one hand, and objective nasal measures on the other. The method was to carry out a standardised investigation which included acoustic rhinometry and nasal lavage at a school. 279 persons at 12 primary schools in Sweden were invited and 84% participated.

The quality of mechanical ventilation systems in Belgian office buildings: findings of field research, analysis and opportunities for improvement.

The aim of this paper is to identify the weak points in nowadays ventilation installations in Belgium and to discuss energy performance approach of buildings as a way to solve many of the ventilation related problems.

Air toxics in a new Australian dwelling over an 8-month period.

Outlines a 'healthy house' design for suburban Australia. The design incorporated a tight building envelope and a ducted mechanical ventilation (and heat recovery) system, providing a minimum ventilation rate of 0.35 air changes per hour. Partial filtration and dehumidification of the air was also included. Low-VOC building materials were chosen. Total volatile organic compound (TVOC) concentrations were approximately 4,000 microgrammes per m3 just after construction, decreasing by a double-exponential model to 300 microgrammes per m3 by eight months, which is good.

Pages