• Journal of the Korean Institute of Gas
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• v.25 no.3
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• pp.27-38
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• 2021

We devised the system to automatically shutdown the boiler and to fundamentally block the harmful gases, including carbon monoxide, into the indoor when the exhaust system swerves: (1) The discharge pressure of the exhaust gas decreases when the exhaust pipe is disconnected. The monitoring system of the exhaust pipe is implemented by measuring the output voltage of APS(Air Pressure Sensor) installed to control the amount of combustion air. (2) The operating software was modified so that when the system recognizes the fault condition of a flue pipe, the boiler control unit displays the fault status on the indoor regulator while shutting down the boiler. In accordance with the ventilation facility standards in the "Rules for Building Equipment Standards" by the Ministry of Land, Infrastructure and Transport, experiments were conducted to ventilate indoor air. When carbon monoxide leaked in worst-case scenario, it was possible to prevent poisoning accidents. However, since 2013, the number of indoor air exchange times has been mitigated from 0.7 to 0.5 times per hour. We observed the concentration exceeding TWA 30 ppm occasionally and thus recommend to reinforce this criterion. In conclusion, if the flue pipe fault detection and the indoor air ventilation system are introduced, carbon monoxide poisoning accidents are expected to decrease significantly. Also when the manufacturing and inspection steps, the correct installation and repair are supplemented with the user's attention in missing flue, it will be served to prevent human casualties from carbon monoxide poisoning.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.5-11
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• 2002

In this study, new development of natural ventilation window was accomplished to control environment of greenhouse with no use of farced ventilation during hot season. The ventilation effect of developed ventilation window was investigated in experimental greenhouse which was designed using side wall panel and folding type panel fur natural ventilation. Folding panel type ventilation window was designed to open upper part of the side wall and top of the roof using two hinges which are located bottom of the side wall and the roof panel to grab one side of each panels and guide the other side along with the guidance rail. Developed ventilation window has top ventilation part with maximum moving distance X=ι (1-cos$\theta$)=848.5 mm and side ventilation part with maximum moving distance Y=ι/2 $\times$sin$\theta$=1,184.4 mm at 45$^{\circ}$ of theoretical opening angle. It took 4.5 minutes to open roof vent fully and temperature at 1.2 and 0.8 m height decreased after 1 minute from starting opening and became equilibrium state maintaining 3-4$^{\circ}C$ difference after 2 minutes from complete opening. Air exchange rate was 15.2~39.3 h$^{-1}$ which was more than 10~15 h$^{-1}$ of continuous type and Venlo type greenhouse. The descent effect of temperature by ventilation windows was two times higher than Venlo type greenhouse.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.609-622
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• 1997

Nitrogen dioxide $(NO_2)$ has been regarded as one of the main elements among air pollutants, and we measured $NO_2$ levels of near gas range, kitchen, living room and outdoor on 489 apartments in Pusan area. $NO_2$ were sampled by using Palmes tubes (diffusion tube sampler) during August 16-25, 1995 (summer) and January 15-29, 1996 (winter), respectively. Authors wanted to know comparison of $NO_2$ levels in summer and winter, $NO_2$ levels categorized by variables, and variables affected to $NO_2$ levels. According to this study, we conducted to establish the degree of indoor-outdoor air pollution of urban apartments in Korea and methods to reduce indoor air pollution. The results of this study were summarized as follows: 1) Mean $NO_2$ levels of near gas range, kitchen, living room, and outdoor were $25.9{\pm}10.0ppb,\;23.3{\pm}8.0ppb,\;19.9{\pm}6.1ppb,\;and\;19.0{\pm}6.0ppb$ in summer, and $34.5{\pm}16.8ppb,\;28.2{\pm}13.4ppb,\;25.3{\pm}12.5ppb,\;21.8{\pm}9.8ppb$ in winter, respectively. 2) Mean $NO_2$ levels according to the floor levels were not significantly different in summer, and in winter, $NO_2$ levels were decreased as the floor levels were increasing, but those were increased above 16th floor. 3) Variables showing significant correlation(p<0.05) with $NO_2$ levels were as follows; Summer: floor level, family size, number of family during a meal, number using gas range during rice cooking per day, and natural ventilation. Winter: floor level, family size, number of person who have been respiratory disease in a house, number of family during a meal, total number of meals, and number using gas range during rice or side-dish cooking per day. 4) We suggest that the methods of reducing indoor $NO_2$ levels are ventilation during cooking, complete combustion, decreasing number and time of cooking, and substitution of fuels.

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.27-31
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• 2018

Classification of explosion hazard areas is very important in terms of cost and safety in the workplace handling flammable materials. This is because the radius of the hazardous area determines whether or not the explosion-proof equipment is installed in the electrical machinery and apparatus. From November 6, 2017, KS C IEC-60079-10-1: 2015 will be issued and applied as a new standard. It is important to understand and apply the difference between the existing standard and the new standard. Leakage coefficients and compression factors were added to the leakage calculation formula, and the formula of evaporation pool leakage, application of leakage ball size, and shape of explosion hazard area were applied. The range of the safety factor K has also been changed. Also, in the radius of the hazardous area, the existing standard applies the number of ventilation to the virtual volume, but the revised standard is calculated by using the leakage characteristic value. In this study, we investigated the differences from existing standards in terms of ventilation and dilution and examined the effect on the radius of the hazard area. Comparisons and analyzes were carried out by applying revised standards to workplaces where existing explosion hazard locations were selected. The results showed that even if the ventilation and dilution were successful, the risk radius was not substantially affected.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.183-190
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• 2011

This study investigated the emissions characteristics of air freshener using small emission chamber method. The emission of VOCs from air freshener were determined in the small chambers in the temperature (25, $30({\pm}1)^{\circ}C$), relative humidity ($50{\pm}5%$), ventilation rate (0.3, 0.5, ($0.8({\pm}0.005)/hr$), and sample loading factor ($1.4{\sim}551.0g/m^2$) in this study. The emission tests from air freshener for sample loading factor resulted in TVOC emission rates of $0.7{\sim}64.4mg/m^2{\cdot}h$ after 5 hours. For most target VOCs such as limonene, ${\alpha}$-pinene and linalool, higher temperature and ventilation rate levels exhibited increased emission rates.

• Journal of The Korea Institute of Healthcare Architecture
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• v.20 no.1
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• pp.7-14
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• 2014

Purpose: In this study, we performed ventilation simulations for a standard isolation ward including three intensive care rooms, one anteroom(buffer room), and its recommended ventilation equipments. The purpose of this study is to predict outflow of pathogenic bacteria from patient breath to verify the reliability and the safety of the isolation ward. Methods: We suppose three scenarios of the movement of medical staff. The leakage of patient's breath to out of the ward is predicted in these scenarios using CFD simulations. Results: The patient's breath leakage rate to out of the ward in scenario 1 according to room air changes per hour(ACH : 6 and 12) is predicted to be 0.000057% and 0.00002%, respectively. The patient's breath leakage rate to out of the ward in scenario 2 according to room air changes(ACH : 6 and 12) is predicted to be 0.00063% and 0.00019%, respectively. The patient's breath leakage rate to out of the ward in scenario 3, which is the worst case(6 room air changes) is predicted to be 0.1%. Implications: Through the ventilation simulation like that in this study, the reliability and the safety on isolation performance of various plan of isolation ward are predicted quantitatively.

• Journal of dental hygiene science
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• v.8 no.1
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• pp.35-42
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• 2008

This survey was compared and analyzed about the primary factor that dental office's working environment effect on physical subjective symptom and based on self-filling survey, 656 dental hygienists on July through August 2006, and analyzed using descriptive statics, ANOVA and Multiple Regression Analysis. The result of satisfaction degree of hospital working environment was pretty low about office air condition. Most people have complained that office's air quality makes it difficult to their work and mentioned that they were sore and dull all over the back, shoulder, and neck. The odor is major factor to be satisfied with office environment. Proper ventilates the way open the window more often was essential to maintain fresh indoor air quality and keep the extraction materials by separator and sealing tightly for remove the odor. Other factors were temperature, lighting fixture, ventilation facilities, and freshness of air. Dental hygienist was unsatisfied with hospital air condition and this polluted air condition was the cause of physical subjective symptom in work place. Furthermore, this research would be applied for improvement of working environment by decreasing of indoor air pollution.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.55-61
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• 2007

This paper has been conducted to estimate cooling capacity of the dehumidification tower using hot water from a solar water heating system as a energy source of regeneration process when the dehumidification and drying system is applied to room cooling. A solar water heating system was operated and indoor temperature distributions were simulated according to weather conditions when the concerned solution was used to dehumidify room air in the dehumidification tower. Through this simulation researches we found th following results ; It was found that air velocity through supply and return diffusers should be controlled because it can cause uncomfort in dwelling area. It was found that in the sunny morning temperatures of dwelling area 1 and 2 are higher than those of dwelling area 3 and 4. In this research all the calculation results of heating and cooling system supported by solar water heater have confirmed that its cooling capacity could not reach PMV 0, thermal comfort.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.176-182
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• 2009

In the present study, a numerical simulation for the diffusion of hydrogen jet in a enclosure was performed to aid the leakage test of the hydrogen for the safety of the hydrogen vehicle. The temporal and spatial distributions of the hydrogen concentration in the test chamber are predicted from the present numerical analyses. Flammable region of 4-74% and explosive region of 18-59% hydrogen by volume was identified from the present results. Factors influencing the diffusion of the hydrogen jet were examined to evaluate the effectiveness of forced ventilation for relieving the accumulation of the leaked hydrogen gas in the chamber, which include location of open windows, size of leakage nozzle, and leakage rate among others. The distribution of the concentration of the leaked hydrogen for various cases can be used as a database in various applications for the hydrogen safety.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.238-247
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• 2005

This study was to analyse participant's satisfaction according to the visiting purpose and experiences on the exhibition service, and also to suggest guideline for new standard evaluation in the operating exhibition service. The implications are as follows; firstly, surrounding environment showed significantly for merchandising & information participant's, and also stay cost & tourism service showed up general visiting purpose participant's. Secondly, it was showed significantly a place for refreshment, fire equipments, and ventilation & heating/air conditioning on the exhibition service. Third, government & exhibition authorized person should provide best environment through satisfaction factors in the exhibition service.