Japan National Research Institute of Fire and Disaster

Tokyo, Japan

Japan National Research Institute of Fire and Disaster

Tokyo, Japan

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Naito H.,Chiyoda Corporation | Uendo T.,Tokyo Denki University | Saso Y.,Japan National Research Institute of Fire and Disaster | Kotani Y.,Tokyo Denki University | Yoshida A.,Tokyo Denki University
Proceedings of the Combustion Institute | Year: 2011

The roles of the physical, thermal and chemical effects of fine water droplets on extinguishment of diffusion flame subjected to high strain are quantified experimentally using a methane counterflow diffusion flame. Water droplets were generated by twin-fluid atomizers and ultrasonic mist generators. The distributions of water droplet diameter were measured by a PDPA and found to be nearly normal, with the number mean diameter ranging typically from 15 to 25 μm and the Sauter mean diameter from 25 to 30 μm. The limit of extinguishment was determined by the velocity gradient and the non-dimensional fuel-ejection velocity. The critical velocity gradient at extinguishment without water droplets was found to be 423 s-1. Introduction of water droplets into air stream resulted in reduction of the velocity gradient at extinguishment due to evaporation which causes the cooling and depletion of oxygen in the flame zone. The critical velocity gradient at extinguishment decreases with the increase of the surface area parameter, Σ, which is expressed by the ratio of mass fraction of water droplets to Sauter mean diameter. By a simple analysis, the lifetime of a droplet was compared with the residence time and it was found that there exists threshold below which droplets can be evaporated within the flame zone. PDPA measurement also showed that the water droplets with diameters larger than the threshold pass through the flame zone towards the stagnation plane. The threshold was found to depend on the velocity gradient. The maximum temperature measured by a thermocouple decreases with the mass loading of water droplets as well as the velocity gradient. However, the maximum temperature at extinguishment is rather independent of mass loading of water droplets and also of velocity gradient and the thermal effect is predominant in the extinguishment of the counterflow diffusion flame. © 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.


Suzuki T.,Japan National Research Institute of Fire and Disaster
Science and Technology of Energetic Materials | Year: 2014

Dinitrosopentamethylenetetramine, which was introduced in 1947, is a widely used chemical blowing agent in the rubber industry. One of important characteristics of dinitrosopentamethylenetetramine is that the decomposition proceeds by an exothermic reaction at relatively low temperature especially in contact with acidic materials. Dinitrosopentamethylenetetramine has been reported as being responsible for fire or explosion accidents. For example, a local newspaper in Dhaka in Bangladesh reported that a fire had occurred in a building in downtown and spread to neighboring buildings causing more than one hundred fatalities on 3 June 2010 and that dinitrosopentamethylenetetramine stored in the building had been one of the major causes of the spread of the fire. The thermal decomposition of dinitrosopentamethylenetetramine has been investigated for nearly half a century by a lot of researchers with many methods such as thermal analytical methods or sensitivity testing methods. The results of those investigations on decomposition, ignition, case histories of fire and explosion accidents, and safety measures are reviewed.


Koseki H.,Japan National Research Institute of Fire and Disaster
Energy and Fuels | Year: 2012

Recently proposed various solid biomass fuels are reviewed from a safety aspect, especially concerning the hazard of spontaneous ignition. Various types of biomass materials are proposed for use as fuel, such as RDF (refuse derived fuel) and wood chips. These fuels have high energy and potential to cause fires, explosions, or other incidents. Japan experienced many incidents with biomass materials, such as wood chips, coal-wood mixture, and organic rubble produced from destroyed houses by the great earthquake and tsunami in March 2011, in Japan. Organic rubble includes various organic materials and sometimes causes fire, and it may be able to be used for fuel of power plants. However, it is very difficult to extinguish fires of biomass fuel piles in storage facilities. Here, current studies on heat generation for these materials and a proposed evaluation test method for these new developing materials in Japan are introduced, which is to use high sensitivity calorimeters such as C80, or TAM, and gas emission test. Additionally, cause investigation work for post-earthquake fires by organic rubble, conducted by the author, is introduced. High sensitivity calorimeters can detect small heat generation between room temperature and 80 °C, due to fermentation or other causes. This heat generation sometimes initiated a real fire and produced some combustible gas, which may explode if fuel is stored inside silo or other indoor storage. © 2012 American Chemical Society.


Hatayama K.,Japan National Research Institute of Fire and Disaster
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2015

The Mw 9.0 2011 Tohoku, Japan earthquake tsunami damaged 418 oil storage tanks located along the Pacific coast of the Hokkaido, Tohoku, and Kanto Districts of Japan. A wide variety of damage was observed, including movement and deformation of the tank body, scouring of the tank base and ground, and movement or structural fracture of the pipe. In total, 157 of the 418 tanks were moved by the tsunami. By comparing the severity of damage with the inundation depth of the tsunami experienced by the oil storage tank, a fragility curve projecting the damage rate for plumbing is presented, and a rough but easy-to-use method of predicting tsunami damage to an oil storage tank from a given inundation depth is also presented: (i) for inundation depths of 2-5 m, tanks suffer damage to their plumbing, and small tanks (capacity < 100 m3) and empty larger tanks may be moved; (ii) for inundation depths of greater than 5 m, most tanks are moved. The validity of the previously-proposed tsunami tank-movement prediction method is first examined. A comparison of the method's predictions with the actual damage data from the 2011 Tohoku earthquake tsunami indicates a high hit rate of 76%. Copyright © 2015 by ASME.


Koseki H.,Japan National Research Institute of Fire and Disaster
Energies | Year: 2011

Various recently proposed biomass fuels are reviewed from the point of view of their safety. Many biomass materials are proposed for use as fuels, such as refuse derived fuel (RDF), wood chips, coal-wood mixtures, etc. However, these fuels have high energy potentials and can cause fires and explosions. We have experienced many such incidents. It is very difficult to extinguish fires in huge piles of biomass fuel or storage facilities. Here current studies on heat generation for these materials and proposed evaluation methods for these new developing materials in Japan are introduced, which are consistent with measurements using highly sensitive calorimeters such as C80, or TAM, and gas emission tests. The highly sensitive calorimeters can detect small heat generation between room temperature and 80 °C, due to fermentation or other causes. This heat generation sometimes initiates real fires, and also produces combustible gases which can explode if fuel is stored in silos or indoor storage facilities. © 2011 by the authors.


Hasegawa K.,Japan National Research Institute of Fire and Disaster
Chemical Engineering Transactions | Year: 2016

The Fukushima Daiichi Nuclear Power Plant, resulting from a massive earthquake, had the worst accident. Its causes are studied from safety culture and the inherent safety points of view. The matters that these fundamentals had not been embodied in the nuclear plants are as follows: priority of safety, seismic strengthening works, redundancy and diversity of subsystems, asymmetry failure mode; simplification and limitation of baneful effects on reactor cooling system, simplification of reactor building, attenuation and avoiding knock-on effect by miniaturizing reactor, tolerance toward leakage or melt-down at reactor pressure vessel, tolerance toward hydrogen gas generation, limitation of gas explosion effects, simplification of emergency countermeasures, and making status clear in emergencies. Therefore, the accident was triggered by the earthquake, but the escalation into an extremely significant accident was directly caused by a lack of safety principle and inherent safety designs. It must be more man-made than natural disaster. © Copyright 2016, AIDIC Servizi S.r.l.


Iwata Y.,Japan National Research Institute of Fire and Disaster
Science and Technology of Energetic Materials | Year: 2013

A differential adiabatic calorimeter is newly developed as the calorimeter which can estimate the thermal decomposition hazards of chemicals in the adiabatic condition that the phi-factor is equal to one. It is regarded that the adiabatic temperature rise measured by its calorimeter does not depend on the sample mass experimentally. There is a possibility that it becomes to the useful tool to estimate the hazards of the self-reactive substances. However, its propriety of the data measured by its calorimeter is not so known and familiar in the field of the hazardous evaluation of chemicals. In this report, the measurement results by its calorimeter are investigated with di-tert butylperoxide (DTBP). DTBP is one of the self-reactive substances and used as standard sample of the ARC. Activation energy of DTBP in the thermal decomposition is obtained and is compared with the literature value. The property of DTBP decomposition is investigated by the measurements data. In addition, its calorimeter is applied to the evaluation of the thermal decomposition hazards of the other self-reactive substance. N,N′-dinitroso pentamethylene tetramine (DPT) is one of the blowing agents which is high reactive material. DPT became the cause material of some fire accidents in the past In this report the heat onset temperature and the activation energy of DPT are measured in the adiabatic condition. The decomposition reaction is discussed on the basis of the measurements data.


Hatayama K.,Japan National Research Institute of Fire and Disaster
Earthquake Spectra | Year: 2015

The Mw 9.0 2011 Tohoku-oki tsunami damaged 418 oil storage tanks and moved 157 of them. Using data on the severity of damage and the maximum inundation depth of the tsunami, a fragility curve representing the damage to oil storage tank plumbing is presented in this paper: P(η) = φ ((ln η - 1.02)/ 0.574), where P is the damage rate, η is the maximum inundation depth in meters, and φ is the standard normal cumulative distribution function. The existing method of predicting the movement of tanks exposed to a tsunami is validated by comparing the predicted damage with actual damage data from the 2011 tsunami. The accuracy (hit rate) is 76%. © 2015, Earthquake Engineering Research Institute.


Hatayama K.,Japan National Research Institute of Fire and Disaster
NCEE 2014 - 10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering | Year: 2014

The Mw9.0 2011 off the Pacific coast of Tohoku, Japan earthquake tsunami damaged 418 oil storage tanks, and 157 of these tanks were moved by the tsunami. Using data on the severity of damage and the maximum inundation depth of the tsunami, a fragility curve representing the damage caused by the tsunami to oil storage tanks' plumbing is presented in this paper: P(η) = Φ((lnη -0.98)/0.48), where P is the damage rate, η is the maximum inundation depth in meters, and Φ is the standard normal cumulative distribution function. The existing method of predicting movement of tanks exposed to a tsunami is validated by comparing the predicted damage with actual damage data from the 2011 tsunami; the accuracy (hit rate) is 76%.


Iwata Y.,Japan National Research Institute of Fire and Disaster
Chemical Engineering Transactions | Year: 2013

A differential adiabatic calorimeter (DAC) was recently developed as the calorimeter which can estimate the thermal decomposition hazards of chemicals in the adiabatic condition that the phi-factor is equal to one. Its calorimeter can measure thermal properties of sample regardless of heat capacity of the sample container. There is a possibility that it becomes to the useful tool to estimate the hazards of the selfreactive substances. The adiabatic temperature rise measured by its calorimeter does not depend on the sample mass experimentally though the adiabatic investigation strongly commonly depends on sample mass. However, its propriety of the data measured by its calorimeter is not so known and familiar in the field of the hazardous evaluation of chemicals. In this report, the measurement results by its calorimeter were examined with di-tert-butyl peroxide (DTBP)/toluene solution. DTBP is one of the self-reactive substances and used as standard sample of the ARC (accelerating rate calorimeter). In addition, the property of DTBP decomposition was investigated by the measurements data of the differential adiabatic calorimeter. As a result of measurements, the measurement results implied DTBP reacted with toluene as the problem of DTBP. In order to solve these problems, it was proposed to use pentadecane as solvent because pentadecane was not so volatile and active in the range of the measurement temperature. The experimental results suggested the DTBP decomposition process depended on DTBP concentration. The activation energy and heat of reaction obtained by the DAC was almost the same as literature values. In addition, the data of heat rate and the pressure rate without the sample mass and solvent effects were obtained in the thermal decomposition of DTBP. © 2013, AIDIC Servizi S.r.l.

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