• 한국안전학회지
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• 제33권5호
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• pp.51-59
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• 2018

It is difficult to determine the outdoor toxic level of hazardous chemicals that are leaked in the building, since there are no efficient ways to calculate how much percentage of the leaked chemicals is released into the outdoor atmosphere. In address to these problems, we propose a reasonable box model that can quantitatively evaluate the mass rate of the indoor chlorine leakage into the outside of the building. The proposed method assumes that the indoor chlorine leakage is fully mixed with the indoor air, and then the mixture of the chlorine and indoor air is exfiltrated into the outside of the building through effective leakage areas of the building. It is found that the exfiltration rate of the mixture of the chlorine and indoor air is strongly dependent on the temperature difference between inside and outside the building than the atmospheric wind speed. As compared with a conventional method that uses a vague mitigation factor, our method is more effective to evaluate the outdoor toxic threat zone of the chlorine that are leaked in the building, because it can consider the degree of airtight of the building in the evaluation of the threat zone.

• 한국안전학회지
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• 제30권4호
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• pp.14-19
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• 2015

The purpose of this paper is to study the correlation application that electrical fire causes occurs for overcurrent and leakage current signals in the indoor wiring. In the order to purpose, the causes data of overcurrent, or leakage current of electrical fire are drawn out referring to past studies, consulting with experts and experimental data. The correlation application was then applied with fuzzy logic of intelligent technique. To check the reliability and performance of the correlation application, modified center of area(CoA) was adopted to calculate the possibility that electrical fire occurs, whose value was then compared to the results. The chance of electrical fire calculated is higher when two causes of fire are put into the CoA of the correlation application of this paper than that of when each cause is separately put into the CoA. The correlation application developed in this study enables better analysis on possible electrical fire due to overcurrent, or leakage current and provides managers with the possibility of electrical fire so that they can better manage at a time of overcurrent, or leakage current.

• 대한건축학회논문집:구조계
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• 제34권1호
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• pp.61-68
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• 2018

Recently, concentration of fine and ultra-fine particulate matter(PM) has been increased in KOREA. The increase of PM in KOREA is due to increase of domestic industries and yellow dust from china. PM is known to cause diseases such as dyspnoea, asthma, arrhythmia. Since PM is harmful to human, KOREA Ministry of Environment(ME) warns people to stay indoors when the outdoor PM concentration is high. However, prior studies has shown that indoor PM concentration can be relatively high when outdoor PM concentration is high due to infiltration of PM into buildings though leakage areas. In this study, airtightness, indoor and outdoor pressure difference and PM 2.5 & 10 concentration were measured in an apartment complex to observe PM infiltrating into building. Field measurement was conducted in newly-built apartment buildings to avoid the influence of indoor PM which can be generated by residents. The airtightness test was conducted to identify the leakage areas of the apartment, such as electric outlets and supply/exhaust diffusers. The airtightness test result showed that the air leakage area of the building was dominant in buildings envelop. According to indoor and outdoor pressure difference measurement result and PM concentration measurement result, it can be concluded that outdoor PM can infiltrate into indoor by leakage areas when wind is blown toward the apartment. As a result, pressure difference formed by the external weather condition and architectural characteristics such as the airtightness in building can influence PM to infiltrate into buildings. In further studies, I/O ratio, stack-effect, infiltration and penetration factor will be considered.

• KIEAE Journal
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• 제3권3호
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• pp.43-50
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• 2003

Nowdays the apartment is a main type of modernized residential buildings. According to the improvement of construction techniques and functions of windows and doors, recent apartments are enhanced air tightness of windows, doors and building envelopes. As Infiltration is decreased and natural ventilation is reduced, energy could be saved in winter. However, indoor air quality is bad. The air Infiltration of a building could be enlarged by physical actions, such as building designs, constructions and reduction of air tightness which is caused by aging. This research analyzes and measures with KNS-4000P (Sapporo air tightness measurement) the air tightness of the high rise apartments which is recently constructed and not occupied yet. With depressurization method, the KNS-4000 installed on the window and the indoor air-leakage was measured. At that time, Air come out from the edge of the windows and doors because of the pressure differences between indoor and outdoor. We measure the amount of the air as effective air leakage areas. This method of depressurization takes less time to measure than other methods and is less affected from other conditions. We measured infiltration of total 56 household, 29 households S apartment (total floor area : $64.42m^2$) in Balan and 29 households D apartment(total floor area : $78.21m^2$) in Chonan. As a result of the field measurements at October 2003, normalized leakage area of D apartment in Cheonan was $2.05cm^2/m^2{\sim}3.49cm^2/m^2$ (average: $2.77cm^2/m^2$) and normalized leakage area of S apartment in Balan is $1.23cm^2/m^2{\sim}1.68cm^2/m^2$ (average: $1.5cm^2/m^2$).

• 한국대기환경학회지
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• 제18권5호
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• pp.373-381
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• 2002

Benzene, Ethyl-benzene, Toluene and Xylene (BTEX) can be released to a groundwater in case of the oil leakage from underground storage tank of a gas station. These chemicals are found to contribute to the total inhalation risk from contaminated indoor air. This study presents the assessment of a human exposure to such chemicals released from the groundwater into indoor air. At first, a 2-compartment model is developed to describe the transfer and distribution of the chemicals released from groundwater in a house through showering, washing clothes, and flushing toilets. The model is used to estimate a daily human exposure through inhalation of such BTEX for adults based on two sets of exposure scenarios. Finally, a sensitivity analysis is used to identify important parameters. The results obtained from the study would help to increase the understanding of risk assessment issues associated with the indoor pollution by BTEX released from contaminated groundwater.

• KIEAE Journal
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• 제10권4호
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• pp.81-86
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• 2010

The main sources of the new house syndrome(sometimes it called sick building syndrome) are a concentration of formaldehyde (HCHO) and a concentration of total volatile organic compounds(TVOC). I had field measurements of indoor air quality in the apartment unit at medium-size cities(Y city, C city). I measured indoor air temperature, HCHO concentration in 16 units, TVOC concentration in 6 units and air tightness in 7 units. And I measured outdoor air quality, HCHO concentration and TVOC concentration. Mean concentration of HCHO was $357{\mu}g/m^3$(2006 standard=$120{\mu}g/m^3$), mean concentration of TVOC was $3,092{\mu}g/m^3$ and mean effective air leakage area was 193 cm2. There was a close relation between the indoor air temperature and HCHO concentration, between the indoor air temperature and TVOC concentration. Air tightness also had relation.

• 설비공학논문집
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• 제20권1호
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• pp.26-34
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• 2008

Heat recovery ventilator(HRV) is recommended to improve indoor air quarlity (IAQ) and energy conservation in apartment houses. Recently, in Korea, HRV is produced from many manufacturers. However, there have been not so many experiences to apply HRV in apartment houses and verification on the performance such as heat exchange efficiency, carry-over rate, internal leakage, etc. have not been carried out sufficiently. So in this study, fan performance, heat exchange efficiency, air leakage, internal exhaust leakage, external leakage and sound level of HRV were examined for selected HRV models under domestic and international standard. Results of performance test, there were need to improve latent heat exchange efficiency and sound level of HRV.

• 한국가스학회지
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• 제27권4호
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• pp.12-18
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• 2023

독성 가스 누출 사고 발생 시 인명 피해를 최소화하기 위해서는 사고 시나리오에 따른 적절한 대피 방법이 사전에 수립되어야 한다. 본 연구에서는 동일 누출 조건에서 건축물의 방향과 산업단지 위치가 실내 농도 증가와 실외 확산에 미치는 영향을 살펴보고 효과적인 대피 기준을 마련하였다. 또한 이러한 기준을 바탕으로 화학사고 인명 피해 최소화라는 관점에서 건물을 건설할 때 건물 방향에 대한 기준도 마련하였다. 건물의 방향이 누출 방향에 대해 정면, 측면, 후면인 경우에 대해 전산 수치 해석을 수행하였으며, 그 결과 건물 창문이 누출되어 오는 방향과 마주보고 있을 때의 실내 오염농도가 반대편에 창문이 있을 때의 실내 오염농도와 비교하여 120배 정도 높게 나왔다. 또한, 급격한 실내 농도 증가율로 동일 시간에 실내 공간이 2배 이상 독성 가스 물질로 가득하게 되었다. 이러한 현상은 건물 창문이 정면에 위치한 경우 창문 주위의 압력 차와 속도 저하로 건물 주위에 독성 가스가 정체하게 되는 것으로 나타났다. 본 연구 결과를 바탕으로 최적 대피를 위한 건축물 방향 기준을 설정한다면 화학사고 발생 시 주민들의 피해를 최소화하는 데 도움이 될 것으로 판단된다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.454-458
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• 2008

This article describes an interference reduction scheme for Mobile WiMAX in an indoor environment. The feasibility of user deployed femtocells in the same frequency channel as an existing macro cell network is investigated. One of the important requirements for co-channel operation of femtocells such as auto-configuration and self optimization are discussed. In femtocell deployments, leakage of the pilot signal to the outside of a house can result of the higher number of mobility events caused by passing user of macrocell. This interference effect can be minimized by reducing the pilot power using proper scheme. This paper introduces existing auto-configuration method of power control and proposed interference reduction scheme using power control for Mobile WiMAX in an indoor environment.

• 조명전기설비학회논문지
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• 제22권12호
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• pp.95-100
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• 2008

기존의 누전차단기는 병렬아크에 대해서 차단을 실패하거나 차단시간이 결어지는 결함이 있었다. 본 논문에서는 저압 옥내배선 계통에서 병렬아크를 모의하여 기존 누전차단기의 차단특성을 분석하고, 병렬아크 검출에 적합한 공심형 전류센서와 신호변환회로를 설계하여 기존 방식의 누전차단기에 적용하였다. 제안한 방식은 병렬아크의 발생위치와 관계없이 누전차단기를 동작시켰으며, 차단시간은 아크가 발생한 위상에 따라 $1.74{\sim}8.3[ms]$의 범위로 기존 차단기에 비해 약 5배 빠른 특성이다.