Improvements to ventilation systems for the purpose of saving energy may also affect the provision of good air quality. Measurement of ventilation effectiveness may be used to determine whether or not good fresh air distribution and satisfactory contaminant removal has been achieved in a specific case. However, for such measurements to be useful, it is necessary to establish recommended values of the parameters and to check the reliability of the measurement procedures. This paper is concerned with the second of these problems.

This paper describes a laboratory model for the testing and validation of tracer gas measurement techniques. Previous attempts at experimental validation have often been limited to two zones, or a particular measurement strategy, or a particular range of flows. The model consists of four zones, each of 1m³ internal volume. The zones are connected so that all possible inter-zone flow paths exist. The flow down each path is driven by a pump and monitored by a flow meter. A control panel enables any combination of interzone flows to be set, within the capacity of the pumps.

The equivalent leakage area algorithm is used to illustrate the use of statistical simulations to predict distributions of infiltration and energy loss for buildings. The important parameters in the model are: leakage at 50 Pa pressurisation, indoor and outdoor temperature, leakage in the ceiling and the floor, wind speed, building height and shielding class. Most of these parameters are not known accurately. In the statistical method we assumed for each a distribution based on measurement or good guess.

The traditional description of a flow system with a multicell model, Vc(t)=Qc(t)+p(t), may sometimes be to restrictive. The multicell theory require measurements, or reconstruo tion, of the tracer concentrations in a number of perfect and immediate mixed cells. Often, using of mixing fans and closing doors between cells are necessary to comply with the theory. Another, very usefil and more general description of a flow system is through the weightingfinction. Unlike the multicell model this is not an internal model, but only an input- output model and it is thus less informative.

One of essential problems of the present research related to building analyses is air flows determination. Air flows not only cause energy consumption but also influence air quality parameters, specially in a multizone (and high) buildings. Thepaper presents the main assumptions of the newly developed simulation method. The major departures are addressed which distinguish this alternative method from other multizone models.These include the principles of dividing a dwelling house into zones and the accomplishment of the simulation.

The paper presents a proposal of numerical procedure for air flow simulation in multi-zone buildings (up to 100 zones). This procedure can work with 1 hour time-step according torequirement of TRNSYS-a well-known modular system simulation programme. Co-operation between TRNSYS and my own programme is analysed, taking a typical Polish 5-storey dwelling house as an object of simulation. The proposed numerical procedure can also be run as an independent programme calculating the ventilation air flow, air change rate and heat losses due to infiltration.

In occupational hygiene the common practice is to use dilution ventilation (MIXVENT) which ideally requires perfect mixing. Increasingly, however, displacement ventilation (DISPVENT) is being applied; ideally this involves fresh air displacing contaminated air without mixing. Keeping MIXVENT as a reference the approach of intervention was used to estimate the potential of DISPVENT for improving environmental conditions in a garment sewing plant. Air exchange efficiency of MIXVENT came to 49%. DISPVENT improved the efficiency to a level of 57%.

The first part of this paper describes a detailed study of the flow of aerosol particles through large openings and the second part describes deposition characteristics of aerosol particles in a single-zone chamber lined with different types of materials, e.g. aluminium foil and carpet. Tracer-gas and aerosol particles were injected into a naturally ventilated room and their concentrations with time were monitored. The room was fitted with a number of windows which allowed examination of single-sided ventilation.

The use of sulphur hexafluoride (SF6), nitrous oxide (N2O) or carbon dioxide (CO2) as tracer-gases have been examined for the measurement of airflow in a two-zone environmental chamber. A series of measurements were carried out to examine airflows through a doorway under natural convection, forced convection and combined natural and forced convection. Results were compared with those predicted using the MULTIC computer program.

This paper is concerned with measurement of airflow in ducts using an active (pumped) sampling system. The system is capable of sampling tracer gases using either tubes packed with adsorbent or sample bags. A perfluorocarbon tracer (PFT) was injected into the ducts using thermostatically-controlled heating blocks. The samples were collected and analysed using a thermal desorber/gas analyser system. Laboratory and field testing of airflow in ducts was carried out. A large office building was studied for measurements of ventilation rate, ventilation efficiency and air quality.