• Fire Science and Engineering
• /
• v.21 no.4
• /
• pp.1-11
• /
• 2007

This study aims to investigate, review, and summarize the definition, development, and applications of "percent agent in pipe", "percent of agent in pipe" which is used as a key factor in testing and evaluating the performance of gaseous fire extinguishing agents, including Halon 1301 and $CO_2$. This study also analyzes and compares the local and international standards on testing and evaluating the performance of gaseous fire extinguishing systems, as well as the results of system performance tests conducted as a part of performance evaluation and approval programs for gaseous fire extinguishing systems, especially, Korean Gaseous Fire Extinguishing System Performance Approval Program called KFI Approval. Percent agent in pipe was defined first in NFPA 12A, Standard on Halon 1301 Fire Extinguishing Systems, dating back to the 1970's. After the phaseout of Halon 1301 systems in 1994 in the developed countries, the percent agent in pipe has been widely used in Halon 1301 alternative clean agent fire extinguishing systems, both halocarbon clean agent systems and inert gas clean agent systems, as an essential criterion to assure the system design accuracy, determine the limitations and performance of a system, and to predict the system performance results accurately, especially, in association with their system flow calculations. Underwriters Laboratories has their own standards such as UL 2127 and 2166 applying percent agent in pipe in testing and evaluating the performance of clean agent fire extinguishing systems. As a part of a system performance test and approval program called KFI Approval System, Korea also has started to apply the percent agent in pipe as a key factor to test, evaluate, and approve the performance of gaseous fire extinguishing systems, including both high and low pressure $CO_2$ systems, from the early 2000's. This study outlines and summarizes the relevant UL and KFI standards and also describes the actual test resultant data, including the maximum percents of agent in pipe for gaseous fire extinguishing systems. As evidenced in lots of tests conducted as a part of the system performance test and approval programs like KFI Approval System, it has been proven that the percent agent in pipe may work as a key factor in testing, evaluating, and determining the limitations and performance of gaseous fire extinguishing systems, especially compared with the hydraulic flow calculations of computer design programs of gaseous fire extinguishing systems, and will remain as such in the future. As one thing to note, however, there are some difficulties in using the unified percent agent in pipe to determine the maximum lengths of pipe networks for gaseous fire extinguishing systems, because the varying definitions used by some of the flow calculations (not in accordance with NFPA 12A definition) make it impossible to do any direct comparison of pipe lengths based on percent agent in pipe.

• Fire Science and Engineering
• /
• v.26 no.6
• /
• pp.1-6
• /
• 2012

There are specific indications about additional gas for the unencloseable openings of the carbon dioxide extinguishing systems. But there are no indications for other gas extinguishing systems including clean agent extinguishing systems only have the principle when it need, apply it. Therefore, this study suggested applying the equation of additional gas for the unencloseable openings of the carbon dioxide to all of the other fire suppression gas that we are use.

• Journal of the Korean Society of Safety
• /
• v.23 no.6
• /
• pp.95-99
• /
• 2008

Halon was known as a cause of the ozone layer destruction. In 1987, it was designated as one of the ozone-layer-destroying materials in the Montreal Protocol. Therefore substitutes of Halon agent has been developed including inert gas extinguish system, which is one of the most widely used fire extinguishing system. This study intended to increase the efficiency of inert gas extinguishing agent by using inert gas additives. As IG-541 shows high extinguishing power, the experiment was performed to measure the effects of gaseous additives to it. Cup-burner fire extinguishing apparatus was used with n-Heptane fuel. Among many of pure inert gaseous agents, Helium showed the most excellent extinguishing power. When Helium was added to IG-541, fire extinguishing power was increased and the concentration of oxygen in chimney also risen. By adding Helium to IG-541, the effectiveness of inert gas fire extinguishing system is able to be increased.

• Fire Science and Engineering
• /
• v.32 no.5
• /
• pp.22-33
• /
• 2018

The amount of halogen clean fire extinguishing agents has been increased by the excellent features of extinguishing, adaptability and no residue. On the other hand in situations without a hazard assessment and safety standard of agents, chemical accidents by the agents occurs frequently. This study was performed to propose the halogen clean agents' regulatory exposure limit and safety standard including the quantitative ventilation system with gas leak monitoring, hazard recognition and optimal personal protection selection through a literature review and experimental research.

• Fire Science and Engineering
• /
• v.33 no.4
• /
• pp.77-82
• /
• 2019

Fire extinguishing systems are essential equipment in all indoor facilities to address unexpected fire scenarios, and appropriate fire extinguishing agent should be used depending on the place and object to protect. Among these, gaseous fire-extinguishing systems are used to protect electronic equipment. Therefore, inert gases that do not undergo chemical reactions are used mainly in those systems. On the other hand, recently, owing to the high integration of electronic equipment, there are some cases, in which large noise generated from gaseous systems damage the electronic equipment. In this study, numerical analysis of the discharge noise with various nozzle contraction angles was carried out to improve the gas fire extinguishing system. Numerical analysis was carried out using ANSYS FLUENT ver 18.1. The causes of the noise were elucidated using the swirl distribution. The noise level of the modified model was reduced by approximately 6 dB compared to the reference model, which is similar to the result of a previous study, confirming the validity of the method.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.7
• /
• pp.939-944
• /
• 2018

Clean fire extinguishing agents refer to chemical that can replace Halon 1211 and Halon 1310 according to the Montreal Protocol fermented to protect the Earth's ozone layer. In Korea and abroad, system standardization and performance evaluation of clean fire extinguishing agents are being carried out. This paper proposes an optimal nozzle shape by modeling and numerical analysis of various nozzle shapes based on general clean fire extinguishing system. The ejection speed of the nozzle can be improved by studying three - dimensional modeling of the nozzle for two shapes, Type A and B. Flow analysis was performed on the two types of nozzles and the gas velocity and pressure distribution were measured with different nozzle diameters. It was confirmed that the jetting speed was changed at the nozzle outlet according to the number and diameter of the nozzle holes. The flow rate increased with increasing the pressure regardless of the nozzle hole diameter. Based on the results obtained from the experiment, the K-factor value was deduced. Finally, a nozzle with a 12-hole structure with a 5-mm nozzle hole was proposed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.12
• /
• pp.74-79
• /
• 2017

The fire extinguishing performance of hybrid nozzle systems is improved by injecting an extinguishing agent concentrically into the target site and, in this study, water mist is used as a water curtain to confine the droplets of the agent. In this study, we numerically investigated the effect of the foundation angle and injection pressure on the performance of a hybrid nozzle by evaluating the mean radius of the volume fractions of the agent and water mists. An experiment involving a water mist nozzle was carried out to validate the numerical method and then the droplet behaviors, e.g., stochastic collision, coalescence and breakup, were calculated with 2-way interaction Discrete Particle Modeling (DPM) in the steady state for the hybrid nozzle system. The mean radius of the water mists increased by about 40 %, whereas that of the agent decreased by about 21 %, when the injection pressure was increased from 30 bar to 60 bar. In addition, the mean radius of the agent increased by about 24 % as the foundation angle of the hybrid nozzle head increased from $30^{\circ}$ to $60^{\circ}$. As a result, it can be inferred that the injection angle and pressure are important factors for hybrid water mist designs.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2002.05a
• /
• pp.21-29
• /
• 2002

With regard to the personnel safety and other safety when the gas suppressants are discharged into the area where occupants exist, the short term and long term effects to the health of people are discussed mainly with the Carbon dioxide agent and Halon Replacement agents system. To gain the benefits of CO2 extinguishing systems while minimizing risk to people serious attention must be given to personnel safety in the design, installation, and maintenance of CO2 systems. Training of personnel is essential. A major factor in the use of a clean agent fire suppressant in a normally occupied area is toxicity. While all halocarbon agents are tested for long-term health hazards, the primary endpoint is acute or short-term exposure, The primary acute toxicity effects of the halocarbon agents described here are anesthesia and cardiac sensitization. For inert gases, the primary physiological concern is reduced oxygen concentration.