• Title/Summary/Keyword: air leakage

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Evaluation of Indoor Mold Exposure Level in dwelling Using DNA-Based Mold Assessment Method (DNA 기반 곰팡이 평가기법을 활용한 주택의 실내 곰팡이 노출수준 평가)

  • Hwang, Eun-Seol;Seo, Sung Chul;Lee, Ju-Yeong;Ryu, Jung-min;Kwon, Myung-Hee;Chung, Hyen-Mi;Cho, Yong-Min;Lee, Jung-Sub
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.28 no.4
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    • pp.382-392
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    • 2018
  • Objective: Allergic diseases such as asthma due to fungal exposure in houses have increased, and proper management is urgent. Mold can grow in the air, floor, walls, and other areas according to environmental conditions, and there are many limitations to the conventional methodology for examining fungal exposure. For this reason, the degree of fungal contamination is being evaluated by ERMI (Environmental Relative Moldiness Index), a quantitative analysis method proposed by the EPA. In this study, we compared ERMI values between water-damaged dwellings and non-damaged ones to evaluate the effectiveness of Korean ERMI values. We also explored the association of ERMI values with the level of airborne mold and characteristics of dwellings. Methods: Floor dust was collected after installing a Dustream collector on the suction port of a vacuum cleaner. The collected samples were filtered to remove only 5 mg of dust, and DNA was extracted using the FastDNA SPIN KIT protocol. Results: The ERMI values were found to be 19.6 (-6.9-58.8) for flooded houses, 7.5 (-29.2-48.3) for leaks/condensation, and 0.8 (-29.2-37.9) for non-damaged dwellings. The airborne concentration of mold for flooded, leakage or condensed, and non-damaged houses were $684CFU/m^3$, $566CFU/m^3$, and $378CFU/m^3$, respectively. The correlation between ERMI values and the levels of airborne mold was low (R = 0.038), but a weakly significant association of the ERMI values with the concentration of particulate matter ($PM_{10}$) was observed as well(R=0.231,P<0.05). Conclusions: Our findings show that the reference value using ERMI can be used to distinguish water-damaged and non-damaged dwellings. It is believed that ERMI values could be a promising tool for assessing long-term fungal exposure in dwellings.

Study for Failure Examples Involved to Spark Plug Assembling Part Damage, Timing Maladjustment and Alien Substance Insertion in Intake Valve Part on LPG Vehicle Engine (자동차용 LPG 엔진의 점화플러그 장착 부 손상, 점화시기 조정불량, 흡입밸브 부 이물질유입 고장사례 연구)

  • Lee, IL Kwon;Kook, Chang Ho;Ham, Sung Hoon;Kim, Sung Mo;Hwang, Han Sub;Jung, Dong Hwa;Moon, Hak Hoon;Lee, Jeong Ho
    • Journal of the Korean Institute of Gas
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    • v.25 no.2
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    • pp.22-27
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    • 2021
  • This paper is a purpose to study the failure examples for LPG vehicle. The first example, the researcher certified the incongruity phenomenon decreased engine power by ignition fire leakage because of spark plug threaded part damage assembling in cylinder head. The second example, the timing mark that accurately adjusting the camshaft and crankshaft position were twisted about 0.5 block each other. Finally, the researcher seeked the disharmony phenomenon as it couldn't set ignition timing. The third example, the researcher knew the failure phenomenon by interrupted the closing period for intake valve moving with air flow in the number 3 port of cylinder head as the foreign substance in cylinder head didn't remove. Therefore, the manager of a car has to thorough going inspect and the manufacture of a car must remove the cause of failure with quality assurance.

Evaluation of Freeze-Thaw Damage on Concrete Using Nonlinear Ultrasound (초음파의 비선형 특성을 이용한 콘크리트 동결융해 손상 평가)

  • Choi, Ha-Jin;Kim, Ryul-Ri;Lee, Jong-Suk;Min, Ji-Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.4
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    • pp.56-64
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    • 2021
  • Leakage due to deterioration and damage is one of the major causes of volume change by freezing and thawing, and it leads micro-cracking and surface scaling in concrete structures. The deterioration of damaged concrete accelerates with the chloride attack. Thus, in the detailed guidelines for facility performance evaluation (2020), the quality of cover concrete and the freeze-thaw (FT) repetition cycle were newly suggested for concrete durability assessment. The quality of cover concrete should be evaluated by the rebound hammer test and the FT repetition cycle should be also considered in the deterioration environmental assessment. This study suggested the application of fast dynamic based nonlinear ultrasound method to monitor initial micro-scale damage under freezing and thawing environment. Concrete specimens were fabricated with different water-cement ratios (40%, 60%) and air contents (1.5% and 3.0%). The compressive strength, rebound number, relative dynamic modulus, and nonlinear ultrasound were measured with different FT cycles. The scanning electron microscopy was also performed to investigate the micro-scale FT damage. As a result, both the rebound number and the relative dynamic modulus had difficulty to detect early damage but the proposed method showed a potential to detect initial micro-scale damage and predict the FT resistance performance of concrete.

Facters Affecting Recurrence after Video-assisted Thoracic Surgery for the Treatment of Spontaneous Pneumothotax (자연기흉에 대한 비디오흉강경수술후 재발에 영향을 미치는 요인들)

  • 이송암;김광택;이일현;백만종;최영호;이인성;김형묵;김학제
    • Journal of Chest Surgery
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    • v.32 no.5
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    • pp.448-455
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    • 1999
  • Background: Recent developments in techniques of video-assisted thoracic surgery(VATS) and endoscopic equipment has expanded the application of video-assisted surgical procedures in the field of thoracic surgery. Especially, it will probably become the treatment of choice of spontaneous pneumothorax(SP). There is, however, a high recurrence rate, high cost, and paucity of long-term results. We report the results of postoperative follow-up and analyze perioperative parameters affected to recurrence, retrospectively. Material and Method: From march 1992 to march 1997, 276 patients with spontaneous pneumothorax underwent 292 VATS procedures. Conversion to open thoracotomy was necessitated in eight patients, and this patients excluded from the study. Result: The sex distribution was 249 males and 31 females. The mean age was 28.1 12.2 years(range, 15 to 69 years). Primary SP was 237cases(83.5%) and secondary SP was 47cases(16.5%). The major underlying lung diseases associated with secondary SP were tuberculosis 27cases(57.4%) and emphysema 8cases (38.3%). Operative indications included Ipsilateral recurrence 123(43.9%), persistent air-leak 53(18.9%), x-ray visible bleb 40(14.3%), tension 30(10.7%), contralateral recurrence 21(7.5%), uncomplicated first episode 8(2.9%), bilateral 3(1.1%), complicated episode 2(0.7%). Blebs were visualized in 247cases(87%) and 244cases(85.9%) performed stapled blebectomy. Early postoperative complications occurred in 33 cases(11.6%): 16 prolonged air-leak more than 5 days(four of them were required a second operation and found missed blebs); 5 bleeding; 5 empyema; 2 atelectasis; 1 wound infection. No deaths occured. The mean operative time was 52.8 23.1 minutes(range, 20 to 165 minutes). The mean d ration of chest tube drainage was 5.0 4.5 days(range, 2 to 37 days). The mean duration ofhospital stay was 8.2 5.5 days (range, 3 to 43days). At a mean follow-up 22.3 18.4 months(range, 1 to 65 months), 12 patients(4.2%) were lost to follow-up. There were 24 recurrences and seven patients underwent second operation and 6 patients(85.7%) were found the missed blebs. 12 perioperative parameters(age, sex, site, underlying disease, extent of collapse, operative indication, size of bleb, number of bleb, location of bleb, bleb management, pleural procedure, prolonged postoperative air-leak) were analyzed statistically to identify significant predictors of recurrence. The significant predictors of recurrence was the underlying disease[17.0%(8/47): 6.8%(16/237), p=0.038], prolonged postoperative air-leakage[37.5%(6/16): 6.7%(18/268), p=0.001], and pleural procedure [11.4%(19/167): 4.3%(5/117), p=0.034]. Blebectomy has less recurrence rate then non-blebectomy [8.2%(20/244) : 10.0%(4/40), p>0. 5]. However, this difference was not statistically significant(p=0.758). Conclusion: We conclude that it is important that we shoud careful finding of bleb during VATS due to reducing of recurrnece, and cases of no bleb identified and secondary spontaneous pneumothorax were indicated of pleurodectomy. VATS is a valid alternative to open procedure for the treatment of spontaneous pneumothorax with less pain, shorter hospital stay, more rapid return to work, high patient acceptance, less scar and exellent cosmetics. But, there is high recurrence rate and high cost, and than it is necessary to evaluate of long-term results for recurrence and to observate carefully during VATS.

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Surgical Treatment of Pulmonary Aspergillosis (III) (폐 국균증의 외과적 치료(제 3보))

  • 정성철;김우식;배윤숙;유환국;정승혁;이정호;김병열
    • Journal of Chest Surgery
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    • v.36 no.7
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    • pp.497-503
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    • 2003
  • Pulmonary aspergillosis usually results from the colonization of the existing lung lesions by chronic pulmonary diseases, such as tuberculosis. Most cases of pulmonary aspergilloma have been treated surgically for many years because it is a potentially life-threatening disease causing massive hemoptysis. Here we reviewed our results from the last 10 years. Material and Method: We reviewed 31 cases surgically treated from Aug. 1992 to Jul. 2002. retrospectively. This investigation is designed to illustrate the peak age incidence, sex ratio, chief complaints, preoperative study, anatomic location of operative site, postoperative pathologic finding and postoperative complications. Result: The peak age Incidence laid in the 3rd and 4th decade of 20 cases (64.5%). The most common complaint was hemoptysis in 27 cases (87.1%). The 31 cases had a history of treatment with anti-tuberculous drugs under impression of pulmonary tuberculosis. The 19 cases (61.3%) showed the so-called “Air-meniscus sign” on the preoperative chest X-ray. In the 31 cases (100%) on the chest computed tomography. as a preoperative diagnostic modality, positivity was shown in 37.9%, 83.3% was shown on the fungus culture of sputum for Aspergillus, serum immunodiffusion test for A. fumigatus, respectively. The anatomical location of aspergilloma was mainly in the upper lobe in 19 cases (61.3%) and the majority of cases were managed by lobectomy. The postoperative pathologic findings showed that 31 cases (100%) were combined with tuberculosis. The postoperative complications include empyema, prolonged air leakage, remained dead space, postoperative bleeding and these numbers of cases is 3 cases (9.7%), 2 cases (6.45%), 2 cases (6.45%), 1 case (3.23%), respectively. one case was died postoperatively due to massive beeding, and asphyxia. Conclusion: Compared with the previous study, there is no significant difference in results. Preoperative chest computed tomography and immunodiffusion test were more commonly available and showed high positivity. Operations often became technically difficult because of pleural space obliteration, indurated hilar structures, and poor expansion of the remaining lung, which were more prominent in the patients with complex aspergillosis. In such cases, medical treatments and interventional procedures like bronchial artery embolization are preferred. However, cavernostomy is also recommanded with few additional morbidity because of its relatively less invassiveness. Early surgical intervention is the recommended management for patients with simple aspergilloma considering the Row surgical mortality and morbidity in recent days.

Outpatient Chest Tube Management with Using a Panda Pneumothorax Set with a Heimlich Valve (Panda Pneumothorax Set with Heimlich Valve에 의한 외래에서의 흉관 관리)

  • Choi, Soon-Ho;Lee, Mi-Kyung;Ryu, Dae-Woong
    • Journal of Chest Surgery
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    • v.42 no.4
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    • pp.497-501
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    • 2009
  • Background: Prolonged air leakage and pleural fluid drainage from a chest tube may delay removing the chest tube after a patient undergoes video-assisted thoracoscopic wedge resection and the patient is otherwise ready for discharge. We reviewed 37 outpatients patients who were being managed with a postoperative chest tube (a Panda Pneumothorax set with a Heimlich valve). Material and Method: From January 2005 to December 2007, 294 patients underwent video-assisted thoracoscopic wedge resections & pleurodesis. Of them, 37 patients met the criteria for outpatient chest drainage management with using a Panda Pneumothorax set with a Heimlich valve. The patients received written instructions, and they demonstrated competence with using the Panda system. The patients returned for chest tube removal after satisfactory resolution of their air leak and pleural fluid drainage. Result: The patients discharged with a Panda pneumothorax set had a longer duration of hospital stay (mean: 10.3$\pm$1.7 days, range: 11 to 17 days) as compared with the patients without a Panda pneumothorax set (mean: 6.2$\pm$1.5 days, range: 4 to 7 days). The chest tube was removed successfully from the patients with a Panda pneumothorax set at an average of 9.8$\pm$1.6 days (range: 9$\sim$18 days) after discharge. There were no major complications. Four patients experienced minor complications. Thirty six patients (97.3%) experienced uneventful and successful outpatient chest tube management. Conclusion: Successful postoperative outpatient chest tube management with using the Panda set was accomplished in 36 selected patients. This program resulted in a substantially reduced hospital cost and enhanced patient satisfaction by allowing earlier discharge.

Changes of characteristics of livestock feces compost pile during composting period and land application effect of compost (축분 퇴비화과정 중 특성변화와 축분퇴비 이용효과)

  • Jeong, Kwang-Hwa;Kang, Ho
    • Journal of the Korea Organic Resources Recycling Association
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    • v.9 no.1
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    • pp.56-64
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    • 2001
  • Composting of livestock feces is economic and safe process to decrease the possibility of direct leakage of organic pollutants to ecosystem from commercial and environmental point of view. This study was conducted with three different experiments related to composting of livestock feces. The purpose of experiment 1 was to investigate changes of characteristic of compost pile during composting period by low temperature in cold season. To compare composting effect of experimental compost pile and control pile exposed in cold air, experimental compost piles were warmed up by hot air until their temperatures were reached at $35^{\circ}C$. Sawdust, Ricehull and Ricestraw were mixed with livestock feces as bulking agent. The highest temperatures of compost pile during composting period were in sawdust, rice hull, rice straw, and control were $75^{\circ}C$, $76^{\circ}C$, $68^{\circ}C$, $45^{\circ}C$ respectively. Moisture content, pH, C/N and volume of compost were decreased during composting period. Experiment 2 was carried out to study utilization effect of compost by plant. A corn was cultivated for 3 years on fertilized land with compost and chemical fertilizer. The amount of harvest and nutrition value of corn were analyzed. In first year of trial, the amount of harvest of corn on land treated with compost was lower by 20% than that of land treated with chemical fertilizer. In second year, there was no difference in yield of com between compost and chemical fertilizer. In third year, the yield of com on land fertilized with compost was much more than that of land fertilized with chemical fertilizer. The purpose of experiment 3 was to estimate the decrease of malodorous gas originating from livestock feces by bio-filter. Four types of bio-filters filled with saw dust, night soil, fermented compost and leaf mold were manufactured and tested. Each bio-filter achieved 87-95% $NH_3$ removal efficiency. This performance was maintained for 10 days. The highest $NH_3$ removal efficiency was achieved by leaf mold on the first day of operation period. It reduced the concentration of $NH_3$ by about 95%. Night soil and fermented compost showed nearly equal performance of 93 to 94% for 10 days from the beginning of operation. The concentration of hydrogen sulfide and methyl mercaptan originating for compost were equal to or less than $3mg/{\ell}$ and $2mg/{\ell}$, respectively. After passing throughout the bio-filter, hydrogen sulfide and methyl mercaptan were not detected.

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Comparison of VATS with Thoracotomy for the Treatment of Spontaneous Pneumothorax (자발성 기흉의 치료에서의 비디오 흉강경 수술과 개흉술의 비교)

  • 김문수;김영태;김기봉;김원곤;성숙환;김주현
    • Journal of Chest Surgery
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    • v.32 no.3
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    • pp.294-298
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    • 1999
  • Background: Video-assisted thoracoscopic surgery(VATS) has been established as a new method for treatment of spontaneous pneumothorax. We compared the clinical results of VATS with those of thoracotomy performed during the recent 5 years. Material and Method: We analyzed 126 patients whose medical records were available among the 154 patients who underwent operations for spontaneous pneumothorax from 1992 to 1996. The mean age was 27.1 years(15 to 75 years). 87 patients were operated on by VATS(Group A) and the other 39 by thoracotomy(Group B). The mean follow-up period was 14.7 months. Result: The operation time was shorter in group A than in group B(90.6${\pm}$38.6minutes: 117.2${\pm}$58.9minutes, p<0.05). The duration of postoperative hospital stay was shorter in group A than in group B(6.7${\pm}$4.2: 9.4${\pm}$3.3 days, p<0.05). The amount of analgesics(nalbuphin HCl, ketoprofen) used postoperatively were 2.4${\pm}$2.8 ampules in group A, which is less than the 6.5${\pm}$5.6 ampules in group B(p<0.05). The number of staples used in group A was smaller(2.7${\pm}$1.3 in group A, 1.76${\pm}$1.1 in group B, p<0.05). The duration of chest tube indwelling(4.3${\pm}$4.0 days in group A, and 5.6${\pm}$3.0 days in group B, NS), the recurrence rate(13.8% in group A, 2.6% in group B, NS), and the duration of air leakage(1.3${\pm}$3.3 days in group A, and 1.0${\pm}$2.5days in group B, NS) were not statistically different between the two groups. Conclusion: The application of VATS for the treatment of spontaneous pneumothorax has brought in better clinical results(shorter operation time, shorter hospital stay, less pain, and better cosmetic merits) than the thoracotomy without increasing any morbidity. However no advantages in recurrence rates and duration of postoperative air leakages are revealed.

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Surgical Treatment of Congenital Cystic Lung Disease (선천성 낭성 폐질환의 수술적 치료)

  • Wi, Jin-Hong;Lee, Yang-Haeng;Han, Il-Yong;Yoon, Young-Chul;Hwang, Youn-Ho;Cho, Kwang-Hyun
    • Journal of Chest Surgery
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    • v.41 no.3
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    • pp.335-342
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    • 2008
  • Background: Congenital cystic diseases of the lung are uncommon, and they share similar embryogenic and clinical characteristics. But they are sometimes vary widely in their presentation and severity. Therefore they are often difficult to make different diagnosis each other, and all require surgical treatment. Material and Method: From 1993 to 2006, 38 patients underwent surgical procedures under these diagnostic categories in the Depart. of Thoracic and. Cardiovascular Surgery, Busan-Paik Hospital, College of Medicine, Inje University. And we retrospectively reviewed these patients' charts for clinical presentations, surgical procedures, pathologic findings and postoperative morbidity and mortality. Result: There were 22 males and 16 females, ages ranged from 1 month after birth to 51 years and mean age was 20.8 years. The main symptoms were 19 fever, cough, sputum production due to recurrent infection, 7 dyspnea, 8 chest discomfort, 4 hemoptysis, but eight patients were asymptomatic. Computed tomography was chosen as diagnostic modalities and available for operation plan for all of patients. For all the cases, surgical resection were performed. Lobectomy was performed in 28 patients, simple excision (resection) in 8 patients, segmentectomy or wedge resection in 2 patients. There were 10 pulmonary sequestrations, 15 congenital cystic adenomatoid malformations (CCAM), 11 bronchogenic cysts, and 2 congenital lobar emphysemas. They all were confirmed by pathologic exams. The complications were 6 wound disruption or infection, 2 chylothorax, 1 ulnar neuropathy, but all of them were resolved uneventful. There was no persistent air leakage, respiratory failure, operative mortality and recurrence. Conclusion: We performed immediate surgical removal of congenital cystic lung lesions after diagnosis and obtained good results, so reported them with literature review.

Efficacy of 12 Fr. Closed Thoracostomy Drainage in Management of Primary Spontaneous Pneumothorax (12 Fr. 흉관삽입술을 이용한 원발성 자연기흉의 치료)

  • 박상현;지현근;김응중;김건일;박종운;신윤철
    • Journal of Chest Surgery
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    • v.37 no.12
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    • pp.983-986
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    • 2004
  • Background: The indications of closed thoracostomy drainage in management of primary spontaneous pneumothorax is well known, but there is no special specification for the size to be inserted. Recently, various minimally invasive operational techniques have been introduced and researched. According to the trend, we tried to ascertain the efficacy of 12 Fr. chest tubes instead of the existing 24 Fr. chest tubes. Material and Method: Patients who were younger than 30 years old and diagnosed as primary spontaneous pneumothorax and treated with closed thoracostomy drainage were enrolled in this study. We retrospectively compared group A who were drained with 24 Fr. chest tubes from January to May 2003 with group B with 12 Fr. chest tubes from November 2003 to April 2004 on procedure time for closed thoracostomy drainage, duration of chest tube drain, duration of hospital stay, complication, and recurrence. Result: The male to female ratio was 16 : 3 in group A and 18 : 2 in group B. The mean age of patients of group A was 21.7$\pm$4.0 and group B was 20.0$\pm$3.7. The mean procedure time for closed thoracostomy drainage in group A (21.6$\pm$2.9 minutes) was significantly longer than group B (10.8$\pm$1.9 minutes)(p < 0.05). The mean duration of chest tube drain was 3.8$\pm$ 1.7 days in group A and 4.3$\pm$2.2 in group B, and the mean duration of hospital stay was 5.6$\pm$1.9 days in group A and 5.2$\pm$1.5 days in group B. There was no complication in both groups and 6 cases in group A (35%) and 5 cases in group B (25%) were operated because of recurrence and persistent air leakage. In conclusion, there was no statistical difference except for the procedure time for closed thoracostomy drainage between two groups. Conclusion: We concluded that there were no significant differences in efficacy between 12 Fr. chest tube and 24 Fr. chest tube in closed thoracostomy drainage for primary spontaneous pneumothorax and we found advantages of 12 Fr. chest tube in shortening procedure time because of easy and simple techniques.