PR1995

Three different examples illustrate the possibilities offered by the use of tracer gas methods for detailed airborne moisture transport studies in building. The first one concerns an individual dwelling with severe condensation problems, the second one gives an example of statistical data collection of humidity related parameters in 18 apartments and the last one focuses on the evaluation of the amount of water evaporating from the building materials of a recently built low energy dwelling and on the energy consumption required for drying the construction.

Thirty-one independent fan pressurization measurement series were performed on seven apartments in three family housing buildings at Fort Riley, Kansas, using four protocols. The tests followed procedures in new or revised fan pressurization standards by the International Standards Organization (ISO), American Society for Testing and Materials (ASTM) and Canadian General Standards Board (CGSB). In addition, the effect of interzonal flow was considered. The three standards gave similar results.

This paper describes a method which aims to generate an overall view of multizone building air flow by integrating methods for bulk air flow analysis, air flow field analysis, and building thermal analysis. This has been achieved by implementing a computational fluid dynamics approach within the ESP-r building energy simulation environment which already incorporated a model air flow network approach. The current state of the method is demonstrated by a case study. The main conclusion from this is that the integrated method is very promising.

Approved Document (AD Part F1) of the Building Regulations [1] for England and Wales identifies trickle ventilators as an option for providing natural background ventilation in commercial buildings. This paper reports the results of a field measurement study carried out at BRE during the winter of 1994/95 to assess the effectiveness of trickle ventilators. Two occupied office rooms were equipped with trickle ventilators and measurements were carried out for a fortnight period in each office, with the ventilators closed during the first week followed by a week with them open.

Dynamic insulation has been used in non domestic buildings for 20- 30 years in order to reduce the heat loss and to bring preheated air into the buildings. Dynamic insulation means a construction where the air is being forced through the insulation, usually from the colder outside air into the heated building. The Norwegian Building Research Institute has been engaged to evaluate 12 row houses, with dynamic insulation used in the roof, which has been built in the Oslo area. 4 of the houses were monitored over a period of time.

The Building Research Establishment is currently investigating the impact of various radon remedies at a radon affected test house. Tests aim to assess how different ventilation strategies affect indoor radon levels and the building environment. Those examined include natural underfloor ventilation, mechanical underfloor ventilation (supply and extract), and whole house pressurisation. The test house has a suspended timber floor with an inaccessible underfloor space and is typical of much of the UK housing stock except for indoor radon levels regularly in excess of 1000Bqm^-3.

In order that sampling points may be strategically located, it is desirable to have knowledge of the spatial variation of ventilation eflectiveness parameters prior to measuring them using tracer gas sampling techniques. The research described in this paper is being carried out to establish a tracer gas sampling strategy as well as to facilitate the prediction of ventilation effectiveness parameters. The procedure developed requires the division of the internal space into a large number of cells and, by the application of CFD, the mass flow rates between adjacent cells to be established.

In this paper, we investigate the potential of an aerosol-based technique to significantly reduce the leakiness of residential air distribution systems (ADS). The first part is dedicated to a short review of theoretical analyses of particle transport and deposition in an ADS as well as particle removal in the leaks. The purpose of this review is to pre-determine the ranges of the flow rates, pressure differentials and miscellaneous characteristics of the particles that would allow plugging of the leaks in a relatively short time.

A computer program has been developed to predict the wind pressure coefficients Cp on facades and roofs of block shaped buildings. The program is based on fits of measured data, including wind shielding by obstacles and terrain roughness. Main advantages of the program are: - it needs no expertise of its users on wind pressures; - the input is simple. It exists of building and obstacles coordinates and orientations; - generating Cp values for ventilation model calculations needs no separate action.

There is an increasing concern at the possible health effects of fine suspended particulate (aerosol) upon human health, particularly in the urban environment. Aerosol infiltrating indoors may arise from transport, power generation and natural sources. Aerosol also arises from indoor sources, through cooking processes for example, and from animal dander. In zones within a building, within which the air is reasonably well-mixed, the levels of aerosol will depend upon the ventilation rate and the rate of deposition on indoor surfaces.