air velocity

Describes a study of the emissions from five commonly used building products: three floor coverings - PVC, floor varnish on beechwood parquet and nylon carpet on a latex foam backing; an acrylic sealant and a waterborne wall paint on gypsum board. Small scale test chambers were used over 50 days. A sensory panel was used to assess odour intensity and VOCs were measured. Emissions were studied under two or three different area-specific ventilation rates.

Thermal comfort in ventilated spaces depends mainly on air temperature, air speed and turbulence intensity. Mean air speed is commonly measured with omnidirectional hot sphere sensors, whereas directionally sensitive measurement instruments and CFD-simulations normally give the mean velocity vector. The magnitude of the mean velocity vector in turbulent room air flows can be much lower than the mean air speed due to different time averaging processes. This paper studies the difference both experimentally and theoretically as a function of turbulence intensity.

For natural ventilation of rooms there is a wide range of possibilities with regard to the selection of window type, size and location. A bottom hung window mounted near the ceiling is often used as it has proved to work well with regard to draught risk and thermal comfort in the room. However, there is a need for more detailed information on the performance of this and other types of windows to make it possible to use improved design methods for natural ventilation systems.

In this study the instantaneous temperatures and velocities close to a diffuser for displacement ventilation have been recorded by using whole-field measuring techniques. The air temperatures were measured indirectly by the use of a low thermal mass screen in conjunction with infrared thermography. The measuring screen was mounted parallel to the airflow, acting as a target screen. By using the thermal images the size of the near zone was also calculated. To determine air movements a whole field method called particle streak velocimetry (PSV) was used.

The paper presents a ventilation comfort chart that has been developed under Thailand climate and using Thai volunteers. 183 male and 105 female college-age subjects were exposed to different thermal conditions in order to investigate the effect of air velocity on thermal comfort in ventilated "non-conditioned" spaces. To this end commercial electric fans were used to control the air velocity near the subjects. The air velocity varied between 0.2 and 3 m/s. Room conditions varied between 26°C and 36°C (D.B.T.) and 50-80% relative humidity.

This paper presents results belonging to a larger investigation on low velocity indoor air jets. The experiment is undertaken in a climate room where an isothermal air jet is issued from the centre of one lateral wall. Measurements are performed with a single fiber film probe, and with Particle Streak Velocimetry system. With Particle, Streak Velocimetry has been developed a three dimensional analysis of the instantaneous velocity field. With the use of fiber filmprobe, the fluid-dynamics of the jet flow is explored in terms of mean longitudinal velocity, and relative turbulence intensity.

The aim of the research was to find out the indoor climate conditions in Finnish commercial kitchens by measurements and inquiries. Twelve kitchens were selected from the Helsinki metropolitan area. The measurements concentrated on thermal conditions. On the average thermal conditions in measured kitchens are not fully satisfactory and they varied considerably between the kitchens. Thermal conditions within kitchens varied also depending on the workplace. Heat stress harmful to health was only found in two kitchens.

Recommendations for the characteristics of anemometers that will ensure accurate velocity measurements are specified in the present standards. Recent research shows, however, that the requirements in the standards are based on incorrect assumptions and are insufficient to perform draught discomfort assessment that meets the accuracy requirements for human comfort specified in the indoor climate standards.