ventilation

This paper deals with an experiment made in a rest room located in the living quarter of a Norwegian oil platform in the North Sea. The project was to get an area for the non-smokers with no odour of cigarette fumes : a non smoker could then sit next to a smoker when placed upstream the airflow.
It was decided to install a variable air volume (VAV) system regulated via a general air quality sensor.The sensor was located adjacent to the exhaust slot nearest to the non-smoking area.

For the protection of workers against the excessive radiation heat, local ventilation is used . But the distribution of locally supplied air has to be designed so as not to interfere with the production process. The design of a local air supply ( air shower) is based on operational measurements of thermal conditions realised on the working place of operators.
The analysis of the the operators'heat stress was made by using the WBGT-index (Wet Bulb Globe Temperature index)

The paper describes the test procedure and sums up the criteria for the air handling components and systems defined in the Finnish guideline for ventilation equipment Test methods, such as a measuring method of mineral fibres released into airflow, and a method for measuring the odour threshold of processing oils have been added to the guideline.The experience from the labeling system has been very positive .

In order to identify the complex flow located at the breathing zone of a seated person exposed to the airflow coming form a PVS (personalized ventilation system) two techniques are used and compared : the PIV ( a two-dimensional particle image velocimeter) and the LDA (laser doppler anemometer) technique with a single point measurement, given by a cross section of laser beams.
The PIV technique appears a very interesting tool in studies aiming at identifying airflow in rooms or around objects.

Model experiments were conducted to know the airflow in a room equipped with a ceiling multi-cone diffuser A comparison between the results of CFD and the model experiments has been done.

The main objective of this paper is to describe methods for characterising air diffusers for CFD simulation of the room airflows. As a basis of work, a circular diffuser was used for working out and testing those methods.

Part 1 of this paper gives first an outline of the experiment (full-scale measurement of the air velocity carried under isothermal condition), then discusses the 2 modeling methods - the BOX method and the P.V. method - used for CFD simulation.The results of calculations with the 2 methods showed good agreement with the experimental data.

Using the model developed in part 1 of this paper, the influence of material kinds, ventilation and air-cleaning device on VOC concentration in room is studied. The conclusion is that ventilation rate plays a very important role on VOCs concentration, but it affects little on VOCs emission rate.

The study used CFD to examine reactions between ozone and terpenes in a room under 4 conditions. The study indicates that chemical reactions can significantly alter the concentration of air pollutants, an imperfect mixing may result in reactant and product concentrations significantly different from those predicted by the model that assumes fully mixed conditions.

The methods for estimating or calculating the noise reduction in ductwork are described. Information is given about noise propagation in straight circular or rectangular ducts and in ducts with diameters changes, bends, elbows or junctions. Noise reduction by air diffusers, filters, coils, is also presented, as well as noise emission by ducts walls.