Increasing interest is attributed to the problem of the accumulation of organic vapours emitted from indoor building materials due to an effective insulation of buildings with low ventilation rates. A measurement technique for determining emission rates using a 1 m3 laminar flow test chamber is described.

Airflow rates are directly affected by the amount of open area and consequently by the inhabitant behavior with respect to window opening. In this paper, a stochastic model using Markov chains, developed at the LESO to generate time series of single-window opening angle is modified to generate multiple window openings. It is based on data measured by the TNO Delfton 80 identical, 16 openings dwellings located at Schiedam (NL). The model is then validated by a comparison of the real andgenerated data.

A new handbook, describing in details the measurement techniques which could be used to better understand the infiltration and ventilation in buildings is presented. This handbook results from the cooperation between Annex 20 and Annex 5 of the IEA ECB program. It presents the techniques for detecting and measuring as well the air leakages as the air flows in buildings and inventilation systems. Methods related to ventilation efficiency and effectiveness, like the measurement of the age of air, are also described.

A "HESCO"-type diffuser was selected as an example for the validation exercise in the IEA Annex 20 project (Air flow pattern within buildings). It consists of 84 small round nozzles that are arranged in four rows in an area of 0.71 m x 0.17 m. With the same effective area, the diffuser is simulated by 1, 12, and 84 simple rectangular slots and by the momentum method. In the momentum method, the supply air momentum is set to be that of the 84 small round nozzles. The simulation of the diffuser is incorporated in the airflow computation in a room.

This report describes tracer gas measurements of the local mean age of air at different locations within an office room. These results are used to assess the distribution of fresh air atdifferent depths, and to give guidance on the depth over which single-sided ventilation is effective.

This article discusses the application of tracer gas methods to industrial hygiene investigations. It introduces the basic concepts necessary to understand the application of tracer gas methods to particular airflow and contaminant movement measurements. It provides an overview of existing methods which can be used to obtain quantitative data on a variety of airflow and contaminant movement related questions which often are of interest to the industrial hygienist.

The methods available for the measurement of air infiltration and air movement in large industrial halls are restricted by the size of the building and the nature of the operations which take place within it. Single tracer decay measurements are the easiest to perform and this paper examines the possibility of extracting useful information from them. Using a multi-zone representation of the building volume, the properties of tracer decay curves are considered, and the ease of extraction infiltration and air flow data examined by means of simulations.

The passive perfluorocarbon method (PFT-method) has been successfully applied in ventilation measurements in rooms. The method is, in principle, also applicable to air flow measurements in ventilation ducts. There are, however, several problems in applying a passive sampling technique in a duct. First, the concentration of the tracer may not be uniform through the cross-section of a duct. Second, the velocities in a duct are normally an order of magnitude higher than in a room.

Tracer gas tests were conducted on a five-storey apartment building to determine the air and contaminant flow patterns within the building. The test method involves the injection of a small amount of tracer gas, SF6, into a selected location to create a single source and monitoring the tracer gas concentrations at locations throughout the building. Based on the rates at which the tracer gas concentrations change at various locations, the air and contaminant flow patterns within the building can be determined. Several such tests were conducted.

The possibility of unacceptable internal air pollution levels can cause concern at the design stage given the potential for cross contamination between building exhausts and ventilation intakes is there. The complexity of airflows around buildings, however, makes it extremely difficult to predict the contamination levels at the intake locations. This paper reports a wind tunnel technique using a model of a proposed building to determine the pollutant levels expected at various inlet locations due to the re-ingestion of noxious emissions from its two stacks.