• Journal of the Korea Institute of Building Construction
• /
• v.4 no.1
• /
• pp.97-103
• /
• 2004

In case of a fire in road or railway tunnel it is always necessary to keep the escape condition as good as possible. Most of the victims of major fires in tunnels are because they couldn't leave the tunnel in time and were trapped by smoke, or rescue teams couldn't reach the place of the accident due to low visibility and high temperature. In spring 2003 a comprehensive field experiment was undertaken in a large scaled tunnel in Youngin City to test the effectiveness of a new water spray curtain system, designed to the air qualify inside of a tunnel in case of fire during passenger's escape to safe routes, In order to control the smoke propagation, fixed water sprayed nozzles were used to make water curtain system, which can be installed or hanging water piping line below ceiling. The experiment was accompanied by an extensive measurement campaign in order to measure temperature dropping effect and flow conditions as well as CO concentration for various water sprayed curtains produced by sprinkler heads or water spray nozzle. Eventually comparison analysis were undertaken to investigate the performance of water curtains under fixed water pressure. Therefore most effective water curtain system was presented on the basis of water droplet size in long tunnel.

• Fire Science and Engineering
• /
• v.17 no.4
• /
• pp.124-130
• /
• 2003

This research focuses on analysis of a interaction fracture of various glasses due to contact of water sprayed curtain on hot glass surface with high temperature produced from convective heat source near glass wall. A large scaled experimental test was done in order to find the range of the glass surface temperature to be able to cause the breakage of the glasses when water droplets reach on the hot surface. This paper shows the allowable temperature of the glass surface for prevention of the cooling down breakage before water curtain droplets contact the surface. Allowable Temperature if $250^{\circ}C$ for the tempered glass but general glass is very relatively low. Therefore if the water curtain spray system was adequately activated by a thermal detector installed below ceiling adjacent glass wall with water curtain nozzle system, all hot glass would not break out by cooling water droplet's contact on the hot surface due to convective heat released by adjacent fire source near the glass wall.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.33 no.12
• /
• pp.81-90
• /
• 2017

This study was conducted to investigate the thermal environment status of nursery rooms in workplace daycare centers in Jeju and propose measures to improve their indoor physical thermal environment. For this purpose, measurements were performed in the winter indoor physical environment of 51 nursery rooms in 11 workplace daycare centers and a psychological evaluation survey on the thermal environment of nursery rooms was conducted for 70 nursery teachers. The investigation was carried out over 11 days in January 2017. The results are as follow. The average indoor temperature of the nursery rooms was $21.3^{\circ}C$($18.7-23.8^{\circ}C$) and the indoor temperatures of 47 nursery rooms (92.9%) were higher than the environmental hygiene management standard for domestic school facilities ($18-20^{\circ}C$). The average relative humidity was 33.9% (16.4-56.0%), and 37 nursery rooms (86.3%) showed a lower average relative humidity than the standard (40-70%). The average absolute humidity was $9.1g/m^3$ ($4.7-13.6g/m^3$), which was lower than the standard for preventing influenza ($10g/m^3$). When the indoor temperature and humidity of the nursery rooms were compared with international standards, it was found that 85% or more of the 51 nursery rooms maintained appropriate indoor temperatures, but 40-50% of the nursery rooms maintained a low humidity condition. Therefore, they need to pay attention to maintaining the appropriate humidity of the nursery room to keep the children healthy. The average indoor temperature of the nursery rooms showed a weak negative correlation with the average relative humidity. The indoor temperature had a significant effect on the relative humidity: a higher indoor temperature resulted in lower relative humidity. Regarding the fluctuations in the average indoor temperature of the nursery rooms during the day, in daycare centers that used floor heating, the indoor temperature gradually increased form the morning to the afternoon and tended to decrease during lunch time and the morning and afternoon snack times, due to ventilation. The daycare centers that used both floor heating and ceiling-type air conditioners showed a higher indoor temperature and greater fluctuations in temperature compared to the daycare centers that used floor heating only. In the survey results, the average value of the whole body thermal sensation was 3.0 (neutral): 32 respondents (62.7%) answered, "Neutral", Which was the largest number, followed by 21 respondents (30%) who answered, "Slightly hot" and 17 respondents (24.2%) who answered, "Slightly cold." Twenty-nine respondents answered, "Slightly dry," which was the largest number, followed by 28 respondents (54.9%) who answered, "Neutral" and 10 respondents (19.6%) who answered, "Dry." The total number of respondents who answered, "Slightly dry" or "Dry" was large at 39 (56.4%), which suggests the need for indoor environment management to prevent a low-humidity environment. To summarize the above results about the thermal environment of nursery rooms, as the indoor temperature increased, the relative humidity decreased. This suggests the effect of room temperature on the indoor relative humidity; however, frequent ventilations also greatly decrease the relative humidity. Therefore, the ventilation method and the usage of air conditioning systems need to be re-examined.

• Fire Science and Engineering
• /
• v.31 no.5
• /
• pp.37-43
• /
• 2017

Domestic sandwich panel buildings are widely used on walls and roofs of factories and warehouse facilities. Factory and warehouse facilities have high fire load and rapid spread of fire due to their use characteristics, leading to large fires. Due to the characteristics of materials, walls and roofs are collapsed, resulting in life damage and property damage. In this regard, this study examined domestic and international standards of sprinkler facilities to prevent ignition of sandwich panel walls. Also, in order to check whether the fire was prevented by installing the head on the wall of the sandwich panel, the fire test was carried out with 10 cm, 60 cm, and 120 cm from the wall along the sprinkler head installation standard of domestic fire safety standards. As a result of the fire test, it was confirmed that the sandwich panel was prevented from igniting when the head of water pressure 0.1 MPa and water quantity K-80 was installed. According to the separation distance, it was impossible to measure the temperature at 10 cm, but at 60 cm, At the maximum temperature of $525^{\circ}C$ and 120 cm, the maximum temperature of the wall of the sandwich panel was measured as $276^{\circ}C$. As a result of the fire test, considering the fire point of 450 degrees Celsius in the fire test of the sandwich panel, the distance from the sandwich panel wall to the combustible is more than 120 cm.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.4
• /
• pp.619-625
• /
• 2019

It is difficult to design because of the plug-holing phenomenon in which the amount of smoke discharged from the vertical vent is smaller than the designed amount of smoke. In this study, the effect of cross-sectional area ratio of tunnel and natural ventilation and heat release rate of fire source on plug-holing phenomenon occurring in natural ventilation system was experimentally analyzed. In the experiment model reduced to 1/20 size, the aspect ratio of the tunnel and the vertical vent was fixed, and the influence on the plug-holing phenomenon was confirmed by varying the sectional area ratio of the tunnel and the vertical vent. Experimental results show that the plug-holing phenomenon is caused by the comparison of the smoke boundary layer temperature with the temperature in the vertical vents, and the flow and temperature distribution characteristics under the vertical vents are changed as the cross-sectional area ratio of the tunnel and vertical vents increases. The plug-holing phenomenon is affected by the cross-sectional area ratio between the tunnel and the vertical ventilation. The greater the cross-sectional area ratio, the greater the probability of plug-holing.

• Journal of the Korean Society of Safety
• /
• v.21 no.3 s.75
• /
• pp.73-80
• /
• 2006

Generally beam design depends on the yielding and maximum strength of each member varying with its section shape. Web plate of H-shape beam has not been substituted with glass plate, because it is known that its strength and heat properties are different and it is limited to substitute the existing steel web with glass element. Ceiling height of each room should be decreased with more than 60-80cm due to the beam. Differently from this condition, glass web beam has a good point to see through it and sunshine can be penetrate into the other size especially when it is installed as of outside wall. And also, it can be safer due to controlling room inside easier, if the strength is applicate. This study is to show some applicability after finding out the properties using the test. The test members with a size of $1,600{\times}200{\times}300{\times}9mm$ being SS41 rolled steel having THK 9mm flange while having 8,10mm and reinforced glass 12mm thickness is bonded with epoxy bond under the condition of temperature $28^{\circ}C$, humidity 50%, bonding power 24Mpa. It is show reinforced glass has 5 times of fracture stress more than the common glass but $50{\sim}150%$ difference between these 2 kinds of glass was shown. Reinforce glass did not support the original upper flange after fracture but the common glass did the upper flange after unloading. Generally reinforced glass is stronger than the common one but the common glass having a part of crack on it, compared with reinforced glass having the overall fracture could be more useful in case of needing ductility.

• Journal of the Korean Society of Safety
• /
• v.31 no.6
• /
• pp.25-31
• /
• 2016

This paper has analyzed the structure, applicable regulations and the resistance characteristics of insulation ring type of CSST (Corrugated Stainless Steel Tubing for Gas). With the flammability test conducted in accordance with KS C IEC 60811-1-1, the evaluation of insulation resistance, temperature characteristics, and reliability has been conducted. An insulation ring type CSST consists of protective coating, tube, nut, insulation ring, packing, socket, and ball valve. Connecting an insulation ring type CSST to gas tubings for gas appliance is not permitted, moreover, the product shall be installed inside a sleeve pipe in case of buried installation such as the ceiling. Damages on protective coating and tube were detected when fire was applied to the test sample with a portable torch for 60 seconds. The insulation resistance of a normal product was $49.59M{\Omega}$, while that of the product completed the flammability test reduced to $9.21M{\Omega}$. The mean insulation resistance within the confidence Interval of 95% using the mini tap program 17 was $49.59M{\Omega}$ and the mean insulation resistance within the confidence interval reduced to $9.21M{\Omega}$. In the normal distribution analysis of 95% confidence interval, the value-P of the normal product was stable at 0.075 and AD(Anderson-Darling) statistic value was turned out to be 0.063, which is very normal, and the standard deviation was analyzed as 0.2586. The value P of the product completed the flammability test resulted in 0.005, the AD was 1.355 and the standard deviation reduced to 0.07908.

• Fire Science and Engineering
• /
• v.19 no.1 s.57
• /
• pp.70-89
• /
• 2005

Fire scenarios in a space $20.0m\;\times\;4.0m$ floor and 3.0m high were simulated by using computational fluid dynamics program (FDS 4.0.3) to investigate the effect of the combined operation of both sprinkler and vent systems, which are installed for cooling and blocking smoke which propagates beneath the ceiling of a horizontal corridor, on the temperature and smoke density of it. It was shown that the combined operation both sprinkler and vent systems was more effective than each operation for cooling and blocking smoke, the number of operating sprinklers was two because of corner effect of wall, and over-installed sprinklers deteriorated the effect of cooling and blocking smoke. This study showed that the case of two sprinklers and vent flow rate $3.0m^3/s$ in fire scenario was the most effective for cooling and blocking smoke. It was confirmed that the smoke downdrag occurs in operating sprinkler system, and the more smoke droplets produced by increasing fire size, the greater smoke downdrag occurred.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2011.04a
• /
• pp.334-339
• /
• 2011

이 연구에서는 내화천장구조 재료의 고온 열특성을 파악하여, 건축물 화재시 천장구조에 대한 보다 정확한 화재성상예측을 위한 실험적 자료로 제시하고자 한다. 건축물의 화재성상 예측은 내화설계 시 반드시 필요하며, 화재성상예측을 위해서는 화재하중, 작용외력, 안전계수 및 설계용 정수의 합리적인 설정이 중요하다. 화재하중 및 작용외력 등은 건축물의 부재가 지니는 하중조건에 대한 화재시의 부재 안정성 예측에 관계되는 부분이며, 설계 시 필요한 데이터 중 내화천장구조 재료의 고온 열특성 값은 화재발생 구획의 화재온도가 주요 구조부재에 전달되는 정도를 예측할 수 있는 인자로 볼 수 있다. 따라서 내화천장구조 재료의 고온 열특성 값 설정은 화재발생 공간의 온도범위($20{\sim}1000^{\circ}C$)에 걸쳐 평가 및 분석되어야만 정확하고 신뢰성 있는 화재발생 예상 공간의 부재 온도 및 안전성 분석이 가능하다. 이에 국내 건축구조물에 사용되고 있는 대표적인 내화피복 재료인 방화석고보드, 텍스, 암면에 대해서 $20^{\circ}C{\sim}900^{\circ}C$까지의 열전도율을 측정하였다. 실험결과 방화석고보드와 텍스의 경우 약 0.15 W/m K까지 일정하게 증가하였다. 암면의 경우 약 $700^{\circ}C$까지는 방화석고보드나 텍스에 비해 열전도율이 낮게 나타났지만, $800^{\circ}C$ 지점부터 용융 및 탄화가 진행되면서 열전도율이 급격히 상승하는 것으로 나타났다.

• Journal of the Korean Solar Energy Society
• /
• v.40 no.1
• /
• pp.25-33
• /
• 2020

It has been reported about the energy saving performance of UFAD(under floor air distribution) system and NPC(night purge cooling) system respectively which are applied for commercial buildings. However, when two systems are used at the same time, the effect of heat transfer from floor plenum to slab may vary depending on the operating conditions of NPC. In this study, cooling energy demands were analyzed for building models with UFAD and NPC by using TRNSYS 17 program. UFAD was applied as a cooling system of the base building model, and the cooling energy demands were compared for 64 cases in which the operating time, supply airflow rate, and outdoor air temperature(T_o) of NPC. As a result, it was confirmed that the cooling energy demands were reduced to 30 ~ 80% level compared to UFAD alone, and in particular, the energy demand was reduced in proportion to the supply airflow rate or the operating time while T_o was 16 ~ 20℃. However, when T_o was 22℃, the increase in the supply airflow rate or the operating time results in a disadvantage in terms of cooling energy demands. In addition, the cooling energy demands for UFAD+NPC model were analyzed by applying weather data from three regions with different average outdoor air temperatures. As a result, the cooling energy demand of operating NPC only when T_o was below 20℃ was reduced by 27% compared to that of operating NPC continuously for 8 hours.