AIVC - Air Infiltration and Ventilation Centre

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air change rate

Predicting volatile organic compounds concentration in residential buildings (Part 2 : application of model)

Using the model developed in part 1 of this paper, the influence of material kinds, ventilation and air-cleaning device on VOC concentration in room is studied. The conclusion is that ventilation rate plays a very important role on VOCs concentration, but it affects little on VOCs emission rate.

Indoor climate and air quality in new offices: effects of a reduced air-exchange rate.

Describes an evaluation made of employee health complaints at a credit bank. A self-administered questionnaire determined the symptoms. The authors looked at ventilation effectiveness, contaminant concentrations and microclimate in relation to employee discomfort and health problems. Relatively high levels of carbon dioxide and bioaerosols were found, although temperature and humidity were normal. The authors suggest that an ineffective rate of room air exchange may be a significant factor.

Measurement and simulation of air exchange in the existing building.

This paper is based upon the results of measuring and simulating the air change in the single apartment of 5-storey multi-family dwelling. The technique of tracer gas concentration decay was applied to be able to assess the rate of air change. The building was used as normal by occupants so the results should be very accurate. The main aim of the research was to validate simulation methods used to predict infiltration. Multiven -the authors own program - was used to achieve this aim.

Development and field test of a demand guided coordination of heating and ventilation control systems in reconstructed blocks of flats.

Intelligent coordination of the thermodynamical and air ventilation processes can achieve the necessary compromise between comfort demands, necessary air exchange and low heating costs. A new user demand guided field bus based coordination of single room control and air change rate control is developed and tested for a commercial building automation system. A reconstructed block of 65 flats was used in the field test to show that the control strategy ensures the necessary air exchange in an energy-efficient manner.

New ventilation systems at select schools in Sweden - effects on asthma and exposure.

States that schools often have a low air change rate. The study attempted to find out if an improvement in school ventilation would lead to improved health in pupils. A questionnaire was set for 1476 primary and secondary school pupils in 39 schools. 100 classrooms were monitored. New ventilation systems were installed in 12% of the classrooms over the survey period, increasing air change rate and reducing relative humidity and occurrence of a number of airborne pollutants. The study found that reporting of asthmatic symptoms decreased in the schools with new ventilation systems.

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.

Air change rate measurement: the log/linear decay of tracer gas concentration with time.

A great deal of the literature on general ventilation expresses the adequacy of the volumetric flow rate of air in terms of the number of room air changes per hour. Although the concept of air change rate has very little relevance to the control of contaminants as it relates to the size of the room and not to the scale of the problem, the overall amount of air entering and leaving a workplace is of fundamental importance in assessing the quality of the working environment.

Natural ventilation analysed using dynamic simulation software.

The possibility of using natural ventilation for commercial buildings is increasingly being considered. To assist natural ventilation in these buildings atriums are often suggested for the building's design as well as mechanical systems providing low air change rates. To ensure that natural ventilation will meet today's comfort expectations the proposed design needs to be evaluated using dynamic simulation software.