• Wind and Structures
• /
• 제9권4호
• /
• pp.297-313
• /
• 2006

The concentration of air pollution along roads is higher than the surrounding area because ventilation efficiency has decreased due to the high-density use of space along roads in recent years. In this study, ventilation efficiency around a heavily traffic road covered by an elevated highway and hemmed in along its side by buildings is evaluated using Visitation Frequency (VF, the frequency for pollutant to return to the objective domain) and Purging Flow Rate (PFR, the air flow rate for defining the local domain-averaged concentration). These are analyzed using Computational Fluid Dynamics (CFD) based on the standard $k-{\varepsilon}$ model. The VF and PFR characteristics of four objective domains are analyzed in terms of the changes in wind direction and arrangements of the fencing dividing up and down direction in the road center under the elevated highway. The resulting VFs are more than 1.0 for all cases, which means that pollutants return to the objective domain restricted by the elevated highway and side buildings. The influence of the arrangement of the buildings around the objective domain and the structure in the domain on the VF is substantial. In cases where there are no obstacles under the elevated highway, the local air exchange rate in the domain tends to be improved. Using these indices, the urban ventilation efficiencies between different urban areas can be compared easily.

• 한국환경과학회지
• /
• 제15권11호
• /
• pp.1011-1016
• /
• 2006

Recently, volatile organic compound(VOC) has been noted as a main cause of air pollution. VOC, with its toxic and offensive odor, is hazardous to health. Furthermore indoor, underground and hish-rise buildings are preferable living spaces. People spend more than 80% of the day indoor, so indoor air pollution is a matter of importance. In Korea, from 2004, 10 types of indoor pollutants in public facilities have been identified. However, there is no standard for individual VOC, so the regulation has not yet effectively been carried out. In this study, we have studied on the diffusion of Benzene in a room using a numerical analysis for various air-controlled conditions consisted of door, window and ventilation system. This study investigates spatial concentration distribution and time-history of room-averaged benzene concentration for several cases. The results of this study show that when the room is ventilated by a small fan only for 30 minutes, the average concentration of benzene is decreased a very little, thus the impact to human body would be serious compared to the case of natural ventilation by window and door, In the case of natural ventilation by window and door, if the wind speed is higher than 0.5m/s, it takes small than 4 minutes for benzene to spread to the target concentration of $1.2mg/m^3$.

• 한국터널지하공간학회 논문집
• /
• 제8권4호
• /
• pp.325-334
• /
• 2006

시계조절이나 설해방지 목적으로 설치되는 캐노피 구간 내에서의 기류유동특성의 이해는 정상환기 뿐만 아니라 비상시 대처방안 강구를 위한 요건이다. 또한 터널 방재시스템 설계를 위하여서는 종단구배, 평면선형, 단면크기 및 형태 등과 같은 터널의 다양한 특성이 화재확산에 미치는 영향에 대한 정량적인 이해가 필요하다. 본 연구에서는 국내도로터널의 전형적인 특성을 적용한 터널에 캐노피가 된 경우와 종단 및 선형구배, 단면적 및 형태, 곡선구간이 환기 및 화재확산에 미치는 영향을 CFD분석함을 목적으로 하였다. 분석결과 145m길이의 캐노피인 경우 50%정도의 개구율이 기류유동 패턴 및 환기효과면에서 가장 바람직하였다. 1.8km 터널내에서 20MW 화재발생시 종단구배는 풍속분포와 화재연 확산에 큰 영향을 미치며 제트팬$({\varnothing}1250)$ 4대를 가동한 경우 화재발생 후 5분 경과시 하류 40m지점 부근에서의 화재연 농도는 +2% 구배에서는 13% 감소, -2% 구배의 경우에는 20%정도 증가하며 또한 backlayering거리가 45m정도에 달한다. 직사각형 단면터널의 경우, 화재연 농도 및 풍속분포는 말굽형 터널과 비교하여 현저한 차이가 관찰되지 않는다. 3차선 터널에서는 이들 변수는 모두 감소하며 100초 경과시 50m 정도의 backlayering을 보이며 이후 서서히 감소한다. 곡선터널인 경우는 화재연의 확산이 느리며 100초 경과시 50m에 달하던 backlayering현상은 급격히 사라진다.

• 한국환경보건학회지
• /
• 제32권5호
• /
• pp.387-397
• /
• 2006

This study was performed to investigate the characteristics of indoor air quality(IAQ) in 91 public facilities from September 2004 to March 2005 in the Honam province(Chonnam, Gwangju). The measured air pollutants are $PM_{10}$, formaldehyde(HCHO), CO, $CO_{2}$ and total suspended bacteria(TSB), the maintenance standard materials of IAQ management law established by ministry of environment in Korea(MOE). We also surveyed establishment and operation of ventilation equipment. It was measured $1.2m{\sim}1.5m$ on the floor between 8 o'clock AM and 7 o'clock PM. As the result, $PM_{10}$ and CO was showed the highest concentration, $188.89{\mu}g/m^{3}$, 8.67 ppm, at the indoor parking. The concentration of HCHO was the highest in large store and steamer room. The concentration was respectively $118.70{\mu}g/m^{3}\;and\;113.21{\mu}g/m^{3}$. The concentration of $CO_{2}$ was the highest at the reading room of the library on the condition of natural ventilation. The concentration of $CO_{2}$ was 1,816 ppm and higher than the IAQ standards established by MOE. The TSB was just measured in the hospital and silver town. It was the highest at the admission room of hospital. The concentration of TSB was $766CFU/m^{3}$. The public facilities of this study were not exceed each maintenance standards except $CO_{2}$ but it was surveyed that the management will be needed about some air pollutant according to target facilities.

• 한국축산시설환경학회지
• /
• 제6권1호
• /
• pp.1-14
• /
• 2000

The structural and environmental characteristics of typical pig houses in different growth phases were surveyed and analyzed. Based on the data for thirty nine selected farms in four provinces, Jeonbuk-do, Jeonnam-do, Gyeongbuk-do, and Gyeongnam-do, in the southern provinces, Korea, the goal is to eventually establish standard pig houses of sow and litter, nursery pigs, and growing-finishing pigs. The survey included farm scale, production specialization, structural dimensions of the houses and their ventilation systems, cooling and heating systems, and floor and pit systems related to manure collection. The survey showed 90∼98% of growing-finishing pig houses adopted the sidewall curtain systems. The sidewall curtain systems, although popular, is not well insulated which leads to excessive heating costs in winter. Regarding flooring and manure collection system of the house, 23∼35% of growing-finishing houses installed scraper systems with concrete-slat floors in Gyeongsang provinces while 52∼78% did in Jeolla provinces. The cause of a large variance in flooring between tow regions could not be academically pinpointed, rather it could be attributed to the advice of neighbors who leads local pig production circle. A general trend toward enlargement and enclosure of pig houses for all growth phases was gaining popularity in most regions in recent years. A steady shift to multisite operation from continuous operation was also observed to prevent a disease transfer. The structural design of a standard pig house with its environmental control systems including ventilation and heating/cooling system was suggested for further validation study. In-depth analysis of the survey data is presented in the Results and Discussion section.

• 한국축산시설환경학회지
• /
• 제5권1호
• /
• pp.1-15
• /
• 1999

The structural and environmental characteristics of typical pig houses in different growth phases were surveyed and analyzed. Based on the data for thirty six selected farms in four provinces, Gyonggi-do, Gangwon-do, Choongnam, and Chonbook, in Central Korea, the goal is to eventually establish standard pig houses of sow and litter, nursery pigs, and growing-finishing pigs. The survey included farm scale, production specialization, structural dimensions of the houses and their ventilation systems, cooling and heating systems, and floor and pit systems related to manure collection. The survey showed 90∼99% of growing-finishing curtain installation rate was lower by 10∼20%. The sidewall curtain system, although popular, is not well insulated which leads to excessive heating costs in winter. Regarding flooring and manure collection system of the house, there was quite a lot variability among provinces, with 30∼80% of the houses installing scraper systems with concrete-slat floors in comparison with 30∼60% using a slurry system. Gangwon-do and Choongbook Chungwoo-goon are the predominant regions that installed a scraper system. A general trend toward enlargement and enclosure of pig houses for all growth phases was gaining popularity in most regions in recent years. A steady shift to three site production from a lumped system was also observed to prevent a disease transfer. The structural design of a standard pig house with its environmental control systems including ventilation and heating/cooling system was suggested for further validation study. In-depth analysis of the survey data is presented in the Results and Discussing section.

• 한국환경보건학회지
• /
• 제46권3호
• /
• pp.344-352
• /
• 2020

Objectives: Much attention has been paid to indoor air quality. Ventilation within schools is important because of indoor air quality and its effect on health and learning performance. In this study, we evaluated the carbon dioxide (CO₂) concentrations and ventilation rates in schools. Methods: This study measured the concentration of CO₂ in elementary, middle, and high school classrooms over six months. The seasons during the study were summer, fall, and winter. Sensor-based monitoring was used and the basic characteristics of the classroom were investigated. The body surface area of the students was used to calculate the CO₂ generation rate, and the air change per hour (ACH) was evaluated using mass balance modeling. Results: The average CO₂ concentration measured in most schools exceeded 1000 ppm. The ventilation rates varied from season to season. Compared to the recommended ventilation rate of 4.9 ACH, the roughly 3 ACH calculated in this study indicates that most schools possessed insufficient ventilation. Conclusions: The concentration of CO₂ in school classrooms could be an indicator of indoor air quality and can affect students' learning ability. In this study, CO₂ concentrations exceeding the standard indicate a lack of ventilation along with problems with indoor air quality. Therefore, appropriate improvements are needed to overcome these problems.

• 한국생활과학회지
• /
• 제18권2호
• /
• pp.509-522
• /
• 2009

This is a basic study to improve air quality of school classrooms in winter time. The purposes are to check indoor thermal and air environment in school classrooms during winter and to analyze influencing factors on indoor environment. The measurements of students' physical elements with questionnaire surveys were carried out in a total of 6 classrooms. As a result, this research shows that the temperature of one classroom was below indoor thermal standard level, three classrooms had lack of heat, and two classrooms are heated much, which induce relatively low humidity. All of 6 classrooms had lack of ventilation, being high level of $CO_2$ concentration and 2 classrooms are in condition of high PM10 concentration. The majority of students(76%) answered that the cause of their 'heated space syndrome' is because of the lack of ventilation. Students' opening windows for ventilations is hardly carried out at normal times, except that indoor temperature is over standard. That is, we can suggest one of solutions, which is to enable students to operate heating and ventilating system by themselves according to students' physical condition.

• 한국축산시설환경학회지
• /
• 제20권4호
• /
• pp.177-182
• /
• 2014

This research was conducted to grasp the present condition of environmental management relating to Korea detector dogs that performed their duties such as detection and lifesaving. We directly conducted a survey throughout visit to five government agencies. In environmental management case, average length and width of kennels were 1.78 m and 3.50 m, respectively. Types of floor were searched as coating cement, tile, ucrete and concrete. Most of government agencies ventilated kennels using ventilation fan systems with natural ventilation. But there were differences between government agencies in frequencies of the sanitary management items. On the other side, major diseases of the German shepherd breed as a major detector dog were in order of arthritis, measles, earache, and dermatosis. And their daily training time was average 4 hours. Finally, it is thought that these results could be used as a basic data of standard breeding management manual of Korea detector dog.

• Advances in environmental research
• /
• 제3권3호
• /
• pp.253-281
• /
• 2014

The quest for enhanced thermal comfort for dwellings encompasses the holistic utilization of improved building fabric, impact of weather variation and amongst passive cooling design consideration the provision of appropriate ventilation and shading strategy. Whilst thermal comfort is prime to dwellings considerations, limited research has been done in this area with the attention focused mostly on non-dwellings. This paper examines the current and future thermal comfort implications of four different standard construction specifications which show a progressive increase in thermal mass and airtightness and is underpinned by the newly developed CIBSE adaptive thermal comfort method for assessing the risk of overheating in naturally ventilated dwellings. Interactive investigation on the impact of building fabric variation, natural ventilation scenarios, external shading and varying occupants' characteristics to analyse dwellings thermal comfort based on non-heating season of current and future weather patterns of London and Birmingham is conducted. The overheating analysis focus on the whole building and individual zones. The findings from the thermal analysis simulation are illustrated graphically coupled with statistical analysis of data collected from the simulation. The results indicate that, judicious integrated approach of improved design options could substantially reduce the operating temperatures in dwellings and enhance thermal comfort.