Because of the lack of valid information regarding the influence of bends on the thermal and hydraulic performance of flues, a series of preliminary experiments were conducted using a full-scale Perspex rig. Analysis of the results and observations enabled the development of a methodology capable of determining the reduction of flow rate arising from the presence of bends. The analysis has also shown that existing quasi-steady-state methods used for the design of these flue systems are valid.

A literature search was undertaken to assemble and interpretthe-best available· data that can be used for perfonning multizone airflow modelling in mid and high rise apartment buildings. The best currently available data is presented and areas where further field testing research is required are identified. A multizone airflow modelling software tool was used to provide an analysis of ventilation related energy issues in a newly constructed 10 story high-rise apartment building.

Pressure testing techniques have long been used in the laboratory on building components such as windows, for example, to ensure that rain will not penetrate them under windy conditions.

The effects on pressure loss of the separation and orientation of closely coupled duct fittings in RVAC systems were investigated using computational fluid dynamics to analyse the pressure distribution in a system containing two 90° bends in two common configurations; an S bend and a U bend. Fittings that are separated by less than 8 to 10 hydraulic diameters· of the duce behaved in very different ways depending upon the orientation of the fittings in relation to one another.

Researches into natural ventilation characteristics of courtyard buildings have been carried out extensively in climates very different from tropical climate. Nevertheless, courtyards have been incorporated for centuries in traditional shop houses and also adopted in many modern commercial buildings in tropical countries such as Singapore. This paper discuses a study to investigate the natural ventilation characteristics of courtyard buildings in Singapore. Four typical courtyard buildings are examined.

Features of natural wind and artificial airflow are related to human thermal sensation. Based on the existing records of natural wind and artificial air movement, their turbulent intensity of velocity fluctuation, energy spectra. probability distribution of velocity are compared and analyzed.

Indoor environment required for kitchens in a big hotel in Hong Kong wa described. Local regulations and design guides for ventilation systems in kitchen including exhausts were briefly reviewed. In addition, effluents from cooking were discussed. Environmental parameters including air temperature, air speed and relative humidity in U1e kitchen of a coffee shop in n horel were studied. Better ventilation designs for the kitchens are proposed. Further, immediate actions to be taken are recommended.

Ventilation requirements for vehicular tunnels in the Hong Kong Special Administrative Region are discussed. For vehicle emissions, carbon monoxide is considered to be important for vehicles running on petrol engines, and suspended particulates for diesel engines. Other environmental control parameters are temperature, air speed and air pressure. Codes, regulations and design guides for ventilation systems are reviewed. Different ventilation designs adopted in local vehicular tunnels are described.