measurement

This article shows results of air quality measurements (airborne moulds, microbes and particles) operated in summer and winter in an hospital in Japan.

Laser Doppler anemometry was applied to an axial fan. Results give access to a detailed knowledge of air flows, useful for optimizing the fan geometry.

Compact ventilation appliances appeared on the market for solar passive houses. They include a heat pump to transfer heat from ventilation exhaust air to fresh air and/or domestic hot water. This article is the second part of a serie of two. It continues to describe a model for simulating the operation and performance of such appliances which was developped to be used in the TRNSYS software environment. It compares the results of calculations with those of laboratory measurements.

The development of indoor air quality was studied in three newly finished buildings in Helsinki, Finland during the years 2000-2002. The concentration of volatile organic compounds (VOC), formaldehyde and ammonia, for which the Finnish Classification of Indoor Climate 2000 gives target values, in indoor air as well as the air exchange rate, relative humidity and temperature were determined for the newly finished buildings and 6- 12 months after the buildings had been taken in use.

The model estimations aimed at identifying the most important parameters that determine air change rate along with predicting the indoor radon concentration to be expected in new Dutch dwellings under different ventilation conditions.Measurements were compared to the model estimations. To increase infiltration and thus to decrease radon concentation, opening the air inlets and inside doors proved to be efficient.

A contaminated supply air system may have an adverse effect on indoor air quality. The aim of that study was to evaluate the effectiveness of different protective actions in achieving a clean supply air duct system on the one hand and to find out the location in the ductwork where most of the duct is accumulated. Measurements were made and presented in tables.
It appears that dust accumulation can be partly avoided by ducts protection during the whole of the construction transportation and storage phases and that no ducts with residual oil on the inner surface should be used.

In this article the author gives some guidelines and techniques to conduct IAQ investigations at low cost for school staff with small budgets : first he advises occupant interviews, followed by a physical survey of the premices. An IAQ toolkit at low cost can be prepared for a first level type of investigation.
Then a monitor data analysis can be made with the measurements of temperature, relative humidity and CO2.
Finally an hypothesis can be developed even with little background and small budget.
But particular problems may require an experienced consultant.

There is a relationship between geometric room parameters and the air flow patterns produced by mechanical ventilation systems. Experimental measurements of indoor air flows in a one-tenth sub-scale model room were made and compared to numerical simulations. The results show how obstructions can influence the air flow and contaminant transport in a room.

This paper presents the results of a field study on five HVAC duct systems in France. The principal objectives of this work were a) to evaluate the extent of duct leakage in those systems; b) to compare design and actual fan flow rates; c) to evaluate the thermal energy losses in the air ducts. The ductwork airtightness, measured by fan pressurisation method, was found to be in general well above the leakiest EUROVENT 2/2 class (class A), yielding unacceptable uncontrolled airflows. Fan airflow rates were measured with the constant injection tracer gas method.