Factors influencing effectiveness of ultraviolet germicidal irradiation for inactivating airborne bacteria: air mixing and ventilation efficiency.

As a result of the recent resurgence in tuberculosis incidence, there has been increased interestin using ultraviolet germicidal irradiation (UVGI) of room air to reduce exposures toinfectious agents. This paper presents results of experimental studies investigating how airmixing and ventilation influences the efficacy of UVGI for inactivating airborne bacteria.Tracer gasSFGand tracer particles generated by nebulization of a- salt solution were injected into a full-scale room. The particles simulate an aerosol carrying an infectious agent generated by persons coughing or sneezing.

A field experiment on indoor consistency distribution of combustion gas by ventilation performance of range hood.

In apartments of Korea, exhaust-only hood system is commonly installed for kitchen ventilation. However, as to resident's increasing complaints recently due to poor indoor air quality and hood noise, a careful review regarding kitchen ventilation system came to be in need. This paper presents a research that was conducted to improve ventilation problems in the existing kitchen of apartments. For this purpose, a field test has been carried out to examine the effect of range hood's exhaust airflow rates, and makeup air inlet's settings on kitchen ventilation efficiency.

Indoor air quality in museums and historical buildings in St Petersburg and in north-west region of Russia.

This presentation deals with the problem of achieving stable microclimate in old buildings ofSt Petersburg - such as churches, museums and palaces. Characteristic traits of such buildingsare rather thick envelops which as a rule accumulate large quantities of heat or cold. Themajority of these buildings are equipped only with central water heating and are naturallyventilated.Experimental study of microclimate in buildings of this kind proves that during cold season(with average temperature -10C) the relative humidity there will be about 30-35% and less.

Displacement ventilation forming at different air flow rates.

The paper presents the results of the tests of two-zone airflow pattern forming in a room with displacement ventilation where various heat sources and various airflow rates were tested. The position of the interface layer between the zones was determined experimentally - on the basis of tracer gas concentration measurement and on the way of calculation - on the basis of the plume model above a point heat source complemented with experiment. The following heat sources were used: a plume simulator, a desk lamp, a computer, a round plate and a human body.

Servicing the Millennium Dome.

With a diameter of 320m, and a height of 50m the Millennium Dome is one of the World's largest enclosed spaces, probably the largest among those intended for public use. This paper briefly discusses some of the Building Services issues involved in the design and construction of the Dome, concentrating on the ventilation, and heating/cooling of the building. Buro Happold are the engineers for the Dome responsible for Structural, Building Services, Fire and Access Engineering of the main structure and many of the exhibitions within it.

Individual thermal comfort control with desk-mounted task / ambient conditioning (TAC) systems.

Three very different task/ambient conditioning (TAC) systems were investigated in a climate chamber. Two desk-mounted TACS, the “Personal EnvironmentalModule” (PEM), intended for US offices, and the “ClimaDesk” (CDESK), intended for European offices, were compared experimentally with a floor-mounted unit, the “Task Air Module” (TAM). All three provide some individual control of cooling, while PEM and CDESK also provide individual control of heating.

A study on the characteristics of indoor environment and comfort in office building with underfloor air-conditioning (UFAC) system.

During the last decade, an increasing interest in Underfloor Air-Conditioning (UFAC) systems has emerged. This is due mainly to an increased demand from employees for a greater control over their working environment. And the building and its engineering systems not only have to be designed to achieve the high standards of environmental control at economical cost, but also thermal comfort is an important factor that influences occupants' satisfaction with the indoor office environment.

Ventilation efficiencies of task/ambient conditioning systems with desk-mounted air supplies.

In laboratory experiments, we investigated the ability of two task/ambient conditioningsystems with air supplied from desk-mounted air outlets to efficiently ventilate the breathingzone of heated manikins seated at desks. In most experiments, the task conditioning systemsprovided 100% outside air while a conventional ventilation system provided additional spacecooling but no outside air. Air change effectiveness (i.e., exhaust air age divided by age of airat the manikins face) was measured.

Ventilation, energy and IAQ impacts of mechanical ventilation in a US dwelling.

Based on concerns about indoor air quality and trends towards tighter envelope construction,there has been increasing interest in mechanical ventilation of residential buildings in the UnitedStates. This paper reports on a situation study of indoor air quality, ventilation and energyimpacts of several mechanical ventilation approaches in a single-family residential building Thestudy focuses on a two-story house in the northwestern United States and employs themultizone airflow and contaminant dispersal model CONTAM96.

Thermal and ventilation characteristics in a room with underfloor air-conditioning system.

It is the objective of the present paper to investigate indoor environmental characteristics ofan office building with an underfloor air conditioning system. Thermal conditions in the roomwere monitored including horizontal and vertical temperature distributions, supply andexhaust air temperatures, and globe temperature. Indoor air quality was investigated bymeasuring carbon monoxide, carbon dioxide and airborne particulate. Velocity distributionsaround a floor air terminal, and thermal comfort around a supply air terminal were alsoinvestigated.

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