Indoor and Built Environment

The effects of light on health can be divided into three sections. The first is that of light as radiation. Exposure to the ultraviolet, visible, and infrared radiation produced by light sources can damage both the eye and skin, through both thermal and photochemical mechanisms. Such damage is rare for indoor lighting installations designed for vision but can occur in some situations. The second is light operating through the visual system. Lighting enables us to see but lighting conditions that cause visual discomfort are likely to lead to eyestrain. Anyone who frequently experiences eyestrain is not enjoying the best of health. The lighting conditions that cause visual discomfort in buildings are well known and easily avoided. The third is light operating through the circadian system. This is known to influence sleep patterns and believed to be linked to the development of breast cancer among night shift workers.

There is still much to learn about the impact of light on human health but what is known is enough to ensure that the topic requires the attention of all those concerned with the lighting of buildings.

In spite of concerns by some, chrysotile or white asbestos continues to be used throughout much of the world although several countries have questioned its safety and a number of them have decided to ban its use for any purpose. The reason is largely because the commercial exploitation over a century ago was carried through with little regard for health and safety through ignorance of possible health effects. Poor working conditions with high airborne fibre levels produced a high level of disease. No effects were noted in people exposed to chrysotile at low fibre levels and recent studies have confirmed this lack of effect. However, concern regarding the early mistakes persists to the present time, the subject has become politicised and in 2007 the Korean government banned further use of chrysotile cement. This high level action affects the attitudes of the public, building owners, and occupiers. There is overwhelming evidence that low level exposure has no adverse health effects and that there is a practical threshold. Whether or not the Korean government ever rescinds the ban the fact remains that abatement and replacement of existing chrysotile materials because of a fear of very low level exposure is incompatible with sustainable building practices.

The design and management of the indoor environments of buildings should foster ‘‘health and wellbeing’’. Buildings affect the health of occupants in many ways, for example, through building related illnesses, sick building syndrome and allergy, and environmental health problems. The principal causes of sick buildings in the majority of cases are related to microbial effects and emissions of volatile organic compounds (VOCs) and formaldehyde from building materials or products used in buildings. Lighting and inadequate ventilation, particularly in airtight buildings are also important factors. New and refurbished buildings where there has been inappropriate use of materials could lead to high indoor concentrations of VOCs and formaldehyde, odours, and adverse effects on occupants. Indoor air quality management and investigation of sick buildings are complex issues, requiring multidisciplinary investigations and environmental monitoring. This paper considers the requirements for investigation of sick buildings with a particular focus on emissions of VOCs and formaldehyde in indoor environments, including examples of the causes and odour effects. Some guidelines for assessment of exposure risks are also included.

This paper considers the requirements for investigation of sick buildings including some guidelines for assessment of exposure risks with a particular focus on dampness, proliferation of moulds, and dispersion of fungal spores in indoor environments. Building pathology, indoors air quality management and management of bio-deterioration, and health problems in buildings are complex issues requiring multi-disciplinary investigations and environmental monitoring. Lack of maintenance, chronic neglect, and building defects leading to water ingress, condensation, and dampness in the building fabric will often produce proliferation of pathogenic toxic moulds, and other microbial and biological effects that could cause allergic response in sensitive people and generally lead to ‘‘sick buildings.’’ A general guide has been provided by this paper for environmental assessment of toxic moulds in indoor environments, including a suggested guideline for assessing the threshold levels for fungal spores in indoor air.

A three-dimensional simulation on biological pollutant concentrations in a hospital isolation room with ultraviolet (UV) light devices has been carried out using computational fluid dynamics software, Fluent 6.3. The effects of the positions of the UV lamps, light intensity, and ventilation rates on the microorganism removal efficiency were examined by this study. The UV light intensity in the air flow domain was obtained with the modified P-1 model. Numerical results showed that the airflow could be very complicated in the room. Two different arrangements of the UV lamps were considered and the microorganism removal efficiency with the UV devices set on the wall was shown to be higher than that set in the corner of the room. The microorganism removal efficiency was shown to increase with an increase in the light intensity. Ventilation could enhance the microorganism removal efficiency, but would reduce the disinfection efficiency.

Mould growth can deteriorate indoor air quality in buildings. To alleviate problems in the built environment, accurate understanding of the risk factors associated for mould infestation is required. This study aimed at identifying the key risk factors that could affect mould growth on interior surfaces in residential buildings in Korea. Both the physical characteristics of buildings and the behaviour of occupants were recognised as key concerns. A questionnaire survey had been conducted randomly on a national basis for this research. The questionnaire included building-related factors, and occupants’ activities and behaviour. A total of 314 completed questionnaires were collected and processed for statistical analysis. The association of mould growth with locations and types (apartments, multiplex houses, and detached houses) of the residential buildings were tested. The relationships between mould growth and activity factors, for example, bathing, washing clothes, and opening windows were also considered. Apartments were shown to be more vulnerable to mould growth in comparison to other types of residential buildings. The results were compared with findings from other regions in the world to further understand the effects of these key factors.

Controlling or avoiding direct sun beam shining into the interior is a key criterion for consideration in most architectural daylighting designs. This treatment is mainly intended to attenuate the adverse glare and contrast associated with direct sunlight and to lessen the negative contribution of direct sunlight on the cooling load. Window shades are commonly used in Korea to reduce heat gains in the form of direct beam radiation, particularly in summer. Very often they consist of non-movable structures, such as overhangs, vertical fins or composition of both, forming eggcrate-type systems, and ideally should be designed by incorporating these methods. One of the simplest sunlighting controls is Venetian blind. It plays a role in excluding direct sunlight but reflecting light to rear interior, while still allowing a view to exterior. The blinds also go far toward improving uniformity in illuminance. External shading devices are much more effective than internal shading devices. However, it is not popular because of cost, maintenance, and esthetic reasons. We developed an experimental configuration of external shading device, providing better performance of shading and view. A series of simulations and measurements have verified the differentiated advantages in illumination and building energy consumption by using this system.

Building occupants can enjoy a healthy and comfortable indoor environment and use less cooling energy if sufficient natural ventilation is available in their dwellings. Assessing the natural ventilation performance of building designs requires modelling of the external wind environment, the natural ventilation rate and the thermal environment in individual rooms, and reduction in the use of air-conditioning equipment. These are complicated processes. A practical approach for assessing the natural ventilation performance of residential building designs is presented in this paper. The method includes prediction of wind pressures upon window openings in the building façade by computational fluid dynamics simulation, natural ventilation rate prediction using a flow network simulation model, and indoor free-float temperature and air-conditioning energy-use predictions using a building heat transfer and an air-conditioner performance simulation programme. Additionally, the method includes a simplified statistical approach to deal with the random variations in the speed and direction of the wind. This method has been applied to assess the natural ventilation performance of a standard public housing block design widely used in Hong Kong, taking into account when the wind wing walls were incorporated into the building façade and when the separation distances among the building blocks were widened by 25% and 50%.

This study was performed to determine the heating energy savings and carbon dioxide reduction that would result from turning off ondol heating in housing units in Korea. Lowering the room temperature and intermittent heating of a room are effective methods for reducing heating energy consumption. These techniques were proven in our previous studies by modelling simulations. To confirm the simulations schedule controllers, which automatically turned off the ondol heating in the living room and kitchen from 10 pm to 6 am, were installed at the hot water distributor in five households. The heating gas used in each of the housing units was measured over a period of 5 years, with and without the schedule controllers. We found that approximately 30% of gas consumption, mainly used for heating, can be saved compared to turning on the appliance during the night.

In terms of lighting for the built environment, both providing healthy light and eliminating harmful components of light are the key factors for consolidation and for health promotion. The ingredients of daylight are exceedingly complicated and are classified by the wavelength of light. Ultraviolet (UV) light, wavelength between 400 nm—10 nm, is more energetic and will penetrate more readily through obstacles than visible light. In spite of all their positive uses, UV rays are very harmful for anyone who spends a large amount of time in the sun without proper protection. Glass and film manufacturers produce optically functional glass panes to control UV and infrared rays of sunlight. In order to curb excessive penetration of UV rays, optically functional glasses have been proposed and the performance assessments of the glazed materials have been measured and reported in this paper. Various pair-glasses consisting of UV control glass and the conventional are manufactured and evaluated, providing the photometric data in terms of wavelength. In conclusion, UV protection glass is more effective in controlling UV rays of natural light. Obviously, clear glass treated with UV protection film would provide excellent control of UV penetration and a pair of clear and UV protection glass treated with UV protection film should be recommended; this achieves 96.7% UV protection performance from natural light.

Plans to develop and improve a regional residential environment based on current residential and acoustic environments have been developed. A survey of the residents of Mokpo, a port city located on the south-western tip of the Republic of Korea, examined the relationship between the respondents’ residential and acoustic environments and their awareness of their sound environment. Ambient sounds were categorised as: (a) work/mechanical noise; (b) natural environment sound; (c) living environment noise; (d) maritime environment sound; (e) traditional environment sound; (f) water environment sound; and (g) regional environment sound. This categorisation was found to be affected by factors such as sex, age, and educational background. The ambient sounds found most satisfying were identified as (e) and (g), in this order, which confirmed the importance of the acoustic environment in residential regions. The existential value of sound in the environment was also evaluated by re-categorising the sounds into another set: (a) traditional sound; (b) traffic noise; (c) regional vitality sound; (d) nature sound; (e) construction work sound; (f) rural environment sound; and (g) train and mechanical sound. These groups were found to be affected by age, educational background, region, and utility. The (c),(d), and (e) sounds, in particular, showed a stark difference in perception: the first two were rated as ‘‘better to be present’’ by respondents from the new downtown area, whereas the construction work sound was viewed ‘‘positive’’ by respondents from the old downtown area. The results confirmed the need for more balanced urban development planning.

This study investigated methods of optimizing the operation of photovoltaic (PV) integrated shading devices to attain their maximum benefits to indoor spaces and occupants. A shading device consisting of multiple adjustable louvers coated with PV cells was examined. A motor adjusted the blind angle of the louvers. Sensors measured the available sunlight and daylight levels. The operation of the motor was controlled by a computer based on measured climatic conditions. In developing optimal operation methods, fire energy, thermal, lighting, and visual factors were considered: shading effect, energy production from the PV cells, indoor daylight levels, visual comfort, and thermal comfort. In our control methods, visual comfort supersedes any other physical factors. This is based on the fact that visual comfort is the most important factor in office environments. Thus, it was regarded as the first-order factor in the PV integrated shading control. The performance of a PV integrated louver-type shading device was examined in terms of energy production, light transmission, and visual comfort.

The purpose of this study was to investigate both the sleep environment and sleep quality in bedrooms. It was also to reveal the relationship between sleep environment and sleep quality, and to study its seasonal changes in winter, spring, and summer. The subjects for this study were 24 women who lived in apartments in Seoul and its environs. We conducted two groups of measurements. One group considered elements of the sleep environment: mean radiant temperature, air temperature, relative humidity, carbon dioxide (CO₂) concentration, illumination, and equivalent noise level. The other looked at elements of sleep quality: the apnea— hypopnea index, and inspiratory flow limitation (as %FL), which were measured simultaneously while subjects were asleep. Results showed first, that people were exposed to a variety of problems when asleep, related to their sleep environment such as too low or high air temperatures, or relative humidity and high CO₂ concentrations. Second, these were seasonally dependant and people slept best during spring, then winter, and then summer. Third, the effect of the sleep environment on sleep quality varied with age.

The use of natural lighting has the potential for improving both the energy efficiency and indoor environmental quality in buildings. A light-pipe system can bring natural light to spaces that would otherwise not be able to benefit from the advantages of daylight penetration. This paper presents the monitoring results of a light-pipe system that was installed in a window-less space of a building located in Korea. Indoor illuminance distributions and concurrent outdoor illuminance were monitored at a 1 s interval over a period from April 2009 to May 2009. The results demonstrated the effects caused by the amount of clouds, solar altitudes and external total illuminances; on both the daylighting performance of the light-pipe system and the indoor illuminance distributions of the space. The findings of this study indicated that the light-pipe system could be an effective tool particularly for introducing daylight indoors, even under overcast sky conditions in Korea.

A light-pipe system can introduce daylight into the deeper building interiors, thus potentially displacing the requirement for electrical lighting. For the light-pipe system to be widely used in Korea, it is important to quantify its daylighting performance with due consideration regarding the effects imposed by the local climate conditions. This paper reports the development of a model to predict the daylighting performance of a light-pipe system used in Korea. This model study was based on the monitoring data obtained from a window-less space in which the light-pipe system was installed. The model can predict indoor illuminance distributions and daylight penetration factors as a function of outdoor illuminance, solar altitude and the amount of cloud present. Comparisons were made between the predicted and the monitored data obtained from the study; and also between predictions given by the developed model and other existing predictive models. The comparisons have provided validation of the newly developed model and that the predicted results were robust and reliable.

Indoor air quality (IAQ) is an important public health issue. Driven by rising energy costs, buildings are increasingly built or renovated to be air tight to reduce unwanted heat loss. In consequence the air quality levels in such buildings are degraded. This study presents a wireless sensor network for monitoring IAQ in buildings. Comprised of various IAQ sensors, this network is capable of measuring IAQ levels at various locations within a building simultaneously. The network is integrated with the heating, ventilation, and air-conditioning systems in the building to ensure acceptable air quality in interior spaces. Using the sensor network, various indoor air pollutants (CO, CO₂, VOCs, and airborne particles) can be measured in spaces that house potential sources of pollutant production. When measured pollutant levels are higher than acceptable, the network will alarm indoor occupants, trigger activation of the building’s climate control equipment, exhaust polluted air, and bring in fresh air from the outside. The ultimate aim of this study is to implement the sensor network throughout various building types. To this end, an affordable, low-cost, wireless IAQ controller that can be easily installed avoiding the need for costly wiring was developed.

This paper discusses the development of a new structural composite hybrid system that is able to replace a conventional residential structural system in which space is partitioned using concrete walls. The new structural system consists of structural tees and wide flange steel beams, with the bottom flange and/or portion of the web partially encased in pre-cast concrete, which is then mechanically anchored by headed stud shear connectors both to the bottom flange and the web of the structural tees. In composite frame built apartments, materials known to be heavy carbon dioxide (CO₂) emitters can then be either excluded or reduced with consequent reduction in CO₂ emissions. This study has investigated 36 selected multi-residential apartment buildings of linear shape to compare the CO₂ emissions of the new composite hybrid and conventional multi-residential apartments. The CO₂ emissions resulting from the composite hybrid apartments were reduced to approximately 75—80% in comparison to the emissions occurring from the construction of conventional load-bearing wall apartments. This was achieved by reducing the main sources responsible for CO₂ emission.

Accessibility is the most important element for creating a successful and robust environmental condition to enhance community vitality and health. In the era of diversity where all residents need to be respected, finding the optimal group in providing shared spaces is essential for satisfying residents to the greatest extent. Shared spaces considered here are those for general residents and for the elderly residents. In this context, this study intended to compare space arrangement preferences of three different age groups for creating a community with diverse shared facilities. Online questionnaire survey was conducted to collect data from residents in their 30s, 40s and 50s; and individual interviews of residents in their 60s and 70s. F-test and MDS with PROXSCAL method were carried out to achieve spatial map where various shared spaces were allocated in the most adequate way. As a result, the spatial configuration preferred by the three age groups was found to be different and details of those differences were identified. These results from scientific empirical analysis will be useful to explore a community agreement; providing solutions for the community location that would satisfy the potential users to the greatest extent, thereby promoting a socially integrated community for all ages.

Discomfort glare from bright luminaires or windows is not a simple matter but consists of a complex relationship between a number of factors. The objective of this study was to investigate the effect of the background luminance on discomfort glare in relation to the size of the glare source. An experiment was conducted with observers. In the experiment, the change in the discomfort glare, depending on the change in the background luminance, was measured using different sizes of glare sources. Seven sizes of steradian of the glare source were selected and five levels of background luminance were chosen for the experiment. The results showed that the higher the background luminance, the smaller the observer’s degree of discomfort glare. The exponent of background luminance changed clearly into different patterns in relation to the sizes of the glare source. A new mathematical formula has been developed by this study to determine the exponent of the background luminance for use in the range from 0.0003 to 5 sr of the glare source. The use of this formula would extend the application limit of the current unified glare rating formula from the current limit of 0.1 to 5 sr. Using the formula, the change in the background luminance would have no impact on the discomfort glare, in case when the glare source occupies the entire visual field.

The utilisation of underground spaces has been receiving more attention in Korea in recent years. However, due to continuous complaints of environmental quality from would-be occupiers, the developers must identify the possible negative aspects that could potentially relate to the physical characteristics of underground spaces to alleviate the impacts. This research aims to determine the sustainable design guidelines for underground developments in relation to the visual environments. At the first stage, the study focused on the evaluation of the already-built examples to assess the problems that exist in the underground spaces of high-rise offices recently built in Korea. The visual aspect in terms of illuminance and the human responses with regard to naturally occurring lighting in the underground environment are the issues of major concern. A series of model simulation has provided the advance configurations for the commonly used sunken structures. The study has also proffered skylight systems as a better sustainable solution for the underground development.

Building energy management systems (BEMS) have commonly been applied to minimise building operation costs through effective building management. Our approach was to find a new method by which building information could be applied to ubiquitous sensor networks. A new BEMS framework to minimise energy consumption in building facility management and utilise energy optimally was devised. A sensor location model was constructed based on the concept of defining the minimum activity area dependent on furniture boundaries. Semantic location of the usable area relative to architectural components was first introduced to deliver high-level context to the sensing environment. A Gong-BEMS solution has been developed to demonstrate how spatial information can be constructed and exploited in the building energy management process.