In the event of an emergency such as facility shutdown during process operation, the by-product gas must be urgently discharged to the vent stack to prevent leakage, fire, and explosion. At this time, the explosion drop value of the released by-product gas is calculated using ISO 10156 formula, which is 27.7 vol%. Therefore, it does not correspond to flammable gas because it is less than 13% of the explosion drop value, which is the standard for flammable gas defined by the Occupational Safety and Health Act, and since the explosion drop value is high, it can be seen that the risk of fire explosion is low even if it is discharged urgently with the vent stock. As a result of calculating the range of explosion hazard sites for hydrogen gas discharged to the Bent Stack according to KS C IEC 60079-10-1, 23 meters were calculated. Since hydrogen is lighter than air, electromechanical devices should not be installed within 23 meters of the upper portion of the Bent Stack, and if it is not possible, an explosion-proof electromechanical device suitable for type 1 of dangerous place should be installed. In addition, the height of the stack should be at least 5 meters so that the diffusion of by-product gas is facilitated in case of emergency discharge, and it should be installed so that there are no obstacles around it.

1. 서 론
2. 부생가스 폭발하한계 산정
    2.1 일반사항
    2.2 혼합가스의 폭발하한계 산정
    2.3 부생가스 폭발하한계 산정
3. 수소가스 폭발범위 산정
    3.1 수소의 물리·화학적 특성
    3.2 누출원(source of release) 목록
4. 폭발위험장소
    4.1 폭발위험장소의 범위 추정
5. 결 론
6. References

• 주종율(호서대학교 소방방재학과) | Joo Jong-Yul (Department of Fire and Disaster Prevention, Engineering)
• 정필훈(숭실사이버대학교 산업안전공학과) | Jeong Phil-Hoon (Department of Industrial Safety Engineering, Korea Soongsil Cyber University)
• 김상길(숭실사이버대학교 산업안전공학과) | Kim Sang-Gil (Department of Industrial Safety Engineering, Korea Soongsil Cyber University)
• 이성은(호서대학교 소방방재학과) | Sung-Eun Lee (Department of Fire and Disaster Prevention, Engineering) Corresponding author