Andrezza Kyunmi Kim

Review of Recent Developments in Fire Detection Technologies

Progress in fire detection technologies has been substantial over the last decade due to advances in sensor, microelectronics and information technologies, as well as a greater understanding of fire physics. This paper provides a review of progress in fire detection technologies over the last decade, including various emerging sensor technologies (e.g., computer vision system, distributed fiber optic temperature sensor, and intelligent multiple sensor), signal processing and monitoring technology (e.g., real-time control via Internet) and integrated fire detection systems. Some problems and future research efforts related to current fire detection technologies are discussed.

A Review of Water Mist Fire Suppression Technology: Part II—Application Studies:

The progress on the research and application o f water mist technology in fire suppression has been substantial over the last decade. This paper, following our previous review o n water mist fundamental studies, reviews recent water mist applications for: the extinguishment of Class B spray and pool fires in machinery spaces, gas turbine enclosures, combat vehicles, and flammable l iquid storage rooms; the extinguishment of Class A fires in residential occupancies, marine accommodations and public spaces, heritage buildings and libraries; the extinguishment of Class C fires in electronic equipment and computer rooms; and the protection of aircraft onboard cabin and cargo compartments. Some new applications, such as the use of water mist for the extinguishment of Class K fires in commercial cooking areas; and the use of water mist as a possible total-ship protection method, as well as the use of water mist for the protection of heavy goods vehicle shuttle trains, are also reviewed. Up-to-date development of corresponding test and design criteria for the installation of water mist fire protection systems and for the evaluation of the capabilities and limitations of water mist for fire suppression in some application areas, such as machinery spaces, ships cabins and corridors, and turbine enclosures, are discussed.

Extinguishment of Cooking Oil Fires by Water Mist Fire Suppression Systems

A series of full-scale experiments were conducted in a mock-up commercial cooking area to study extinguishing mechanisms and effectiveness of water mist against cooking oil fires. The impact of water mist characteristics, such as spray angle, droplet size, flow rate, discharge pressure and type of nozzle, on the effectiveness of water mist against cooking oil fires was investigated. A series of oil splash experiments were also conducted to determine if the oil was splashed by water mist. In addition, the change in oil composition during heating and fire suppression was determined using Fourier Transform Infrared (FTIR) technique.The study showed that cooking oil fires were very difficult to extinguish, because they burned at high temperature and re-ignited easily due to changes in oil composition during heating and fire suppression. The water mist systems developed in the present work effectively extinguished cooking oil fires and prevented them from re-ignition. The spray angle, discharge pressure, and water flow rate were important factors to determine the effectiveness of water mist in extinguishing cooking oil fires.

Examination of the Extinguishment Performance of a Water Mist System Using Continuous and Cycling Discharges

We conducted a series of full-scale fire tests of a twin-fluid water mist system in an empty enclosure and in a simulated machinery space. During the tests, two water mist discharge modes, continuous and cycling, were used. We investigated the extinguishment performance of the water mist system using these two discharge modes under various fire scenarios, including different fire sizes, types, and locations, and different ventilation conditions. Test results showed that use of the cycling discharge substantially improved the effectiveness of the water mist system for fire suppression, in comparison to the continuous discharge. The corresponding extinguishing time and water requirement for fire suppression were significantly reduced, and some fires that could not be extinguished with the continuous discharge were extinguished with the cycling discharge. The improvement in fire suppression was attributed to high depletion and dilution rate of oxygen and the recurrent dynamic mixing generated by the cycling water mist discharge in the compartment.

Sprinkler Protection of Exterior Glazing

Previous investigations made into protecting glazing assemblies with dedicated sprinklers included protecting wide windows with multiple sprinklers, but they did not address protecting exterior glazing assemblies from external fire exposure with sprinklers. In addition to a summary of the previous work on protecting glazing assemblies with dedicated sprinklers, this paper describes the test set-up and discusses the test results that led to a sprinkler system recommendation for protecting exterior glazing assemblies from external fire exposures.

The Protection of Glazing Systems With Dedicated Sprinklers

Water spray is one method of protecting glazing exposed to fire. Research conducted at the National Research Councils National Fire Laboratory indicates that, under ideal con ditions, a window assembly, when protected by special sprinklers, will stay intact, and can obtain a fire resistance rating of 2 hours or longer. Experiments showed that there are several parameters related to sprinkler operation which affect the performance of the glazing assembly under fire exposure. This paper describes the test facility and discuss es the results of investigations conducted to determine the effect of the sprinkler activa tion time and sprinkler water flow rate on the effectiveness of dedicated sprinkler sys tems for protecting large glazing assemblies. The effect of the sprinklers on the average temperature and temperature gradient in the test room is also discussed.

Thermal Decomposition Products from Fire Suppression with HFC-227ea in an Electronic Facility

A study was undertaken to address concerns of corrosion in an electronic environment after fire suppression using HFC-227ea (C3F7H). Fire suppression using halocarbon agents, such as HFC-227ea, can produce thermal decomposition products, e.g., hydrogen fluoride (HF), which may cause corrosion in electronic equipment. In this study, full-scale experiments were conducted in a simulated electronic equipment room using six steel cabinets under various ventilation conditions. An in-cabinet cable fire was used in the tests as a fire source and HFC-227ea was used to suppress the fire. FTIR spectrometers were used to measure the gases in the cabinets and room. The test results showed that cabinet ventilation conditions affected fire extinguishment times in the cabinet, and therefore the amount of HF generation. In the open cabinet cable fire test, the concentration of HF was below 100 ppm in the fire cabinet. In the closed cabinet cable fire test, the maximum concentration of the HF reached 800 ppm in the fire cabinet. The migration of gaseous by-products from the fire cabinet to the adjacent non-fire cabinets was minimal. A large heptane pool fire test was also conducted in the simulated electronic equipment room; the maximum HF concentration in the room for this test reached 3900 ppm, slightly greater than the 3800 ppm within an open cabinet. However, peak HF concentrations of 1800 ppm and 500 ppm were observed within the ventilated and closed cabinets, respectively, during the heptane test.

Suppression of Pool Fires Using Halocarbon Streaming Agents

Handheld FM-200, FE-36, CF3I and Halotron I extinguishers with 2B:C, 5B:C and 10B:C ratings (or equivalent) were tested for extinguishing Class B heptane pool fires in small and large enclosures (45, 120 and 21000 m3). Test results showed that the Halotron I and CF3I extinguishers performed better than the FE-36 and FM-200 extinguishers. The concentrations of the halocarbons and acid gas by-products in the operator breathing zone and surroundings were measured during the tests. Measurements showed that the agent concentrations were below the levels that would pose life or health risk to the operator. The concentrations of acid gas by-products generated during suppression, however, were at dangerous levels in the small enclosures (45 and 120 m3). Heat flux towards the operator was also measured. Heat exposure presented a severe hazard to the operator during the pool fire suppression. Test results indicate some potentially hazardous conditions to an unprotected operator.

Fire Suppression with Inert Gas Agents

Total flooding fire suppression tests of pure argon (IG-01) and an inert gas mixture (IG-541) were conducted in a 121 m 3 compartment with simulated electronic- cabinet fires, wood-crib fires, liquid-pool fires and spray fires. Both agents extinguished the test fires by reducing the oxygen concentration in the compartment. Small fires were challenging to extinguish while large fires were easier to extinguish. The oxygen concentration in the compartment fell t o below 10% in some of the tests with large test fires. IG-541 was uniformly distributed throughout the compartment during the tests. The distribution o f argon became stratified during the tests.