Fires In Japan Research Articles

Study of Effectiveness of CO and Smoke Alarm in Smoldering Fire

Introduction One of the main causes of home fires in Japan is smoking in bed, and carbon monoxide poisoning and suffocation account for a high proportion of cause of death in bedding fires [1]. In this study, using a full-scale building model, a smoldering fire initiated with a lighted cigarette placed still on cotton bedding was reproduced. The COHb concentration (blood COHb concentration) inhaled into a human body and the density and concentration behavior of smoke and CO alarms were compared by monitoring the change in the CO concentrations while smoldering fire. Early detection of fires and effects on a human body were discussed based on the data and the effectiveness of a smoke and CO alarm placed on an indoor wall was examined. Experimental In this study, single function CO gas sensor modules and smoke and CO alarms equipped with photoelectric smoke detectors and electrochemical CO sensors were arranged in a full-scale building model, as shown in Figure 1. Smoldering fire was caused in cotton bedding using a cigarette as a source of fire, and the COHb concentration of an expiratory position and the smoke densities and the CO concentrations of smoke and CO alarms placed on walls were examined. The laboratory was W2.12 ×D2.58 × H2.42 m and a set of cotton bedding was arranged. The source of the fire was set almost at the center of the laboratory and the CO sensor modules were arranged at the pillow, in the bedding, and on the upper part of the bedding (L1-300～L5-400), and on the lower part of the ceiling (L1-2120～L5-2120). Also, smoke and CO alarms (A1～A4) were placed 300 mm off the ceiling on the four walls of the laboratory. The CO concentration outputs and smoke density outputs at each measuring point were collected per 5 seconds using data loggers. After the lighted cigarette (MEVIUS SUPER LIGHTS) was placed still, each measured data was being continuously monitored. Also, based on the CO concentration data from the CO sensor modules surrounding the bedding, the COHb concentration accumulated in a human body was calculated. Result and Conclusions Each CO concentration data from the CO sensor modules placed 400 mm above the lower part of the mattress, in the bedding, and at the expiratory position were extracted as representative data (Fig.2). The CO concentration right above the fire point started rising 50 seconds after the cigarette was placed still, sharply surged to a high concentration level over 1000 ppm at 440 seconds. The CO concentration under the coverlet also suddenly surged a bid later than the one right above the source of the fire, exceeding 1000 ppm at 350 seconds. For the CO concentration at position near the pillow as expiratory position, the rise of CO concentration was confirmed 380 seconds after the cigarette was placed still and the concentration exceeded 1000 ppm at 1240 seconds. Figure 3 shows it is sufficiently possible to detect CO on the wall’s position since it was found in the comparison of the data of the CO sensor module near the ceiling and the smoke and CO alarms on the laboratory walls that the trends of CO concentration were similar in terms of the ways of rising and the concentration values. In this experiment, assuming a respiratory position of a sleeping person, the COHb concentration accumulated through breathing based on the CO concentrations of the upper part of the bedding (L2-300～L5-400) and the CO concentrations and smoke densities of the alarms placed on the walls were compared. Here, the smoke and CO alarms were set to at 10%/m for smoke and 100ppm for CO. Figure 4 shows the relationship between the CO concentration and smoke density values of A2 which responded last among the alarms placed on the walls and the COHb concentrations of the pillow position was related to these data. It was found that the CO alarm detected 280 seconds faster than the smoke alarm. The COHb concentration at the pillow position in the case of this extremely dangerous situation was calculated and it was found that the concentration was 15.1% when the smoke alarm went off. From the results above, it has been confirmed that the CO detection function of a CO and smoke alarm placed on a wall enables people to evacuate well in advance and the alarm is effective in early detection of fire.

Study of Effectiveness of CO and Smoke Alarm in Smoldering Fire

One of the main causes of home fires in Japan is smoking in bed, and carbon monoxide poisoning and suffocation account for a high proportion of cause of death in futon smoldering fires. In this study, using a full-scale experiment room model, a smoldering fire initiated by a lighted cigarette placed still on cotton bedclothes was reproduced. The carboxyhemoglobin “COHb” concentration in the blood was compared by monitoring the change in the carbon monoxide “CO” concentrations inhaled into the lung during smoldering fire in a full-scale experiment room model. Early detection of fires and effects on a human body were discussed based on the data and the effectiveness of a CO and smoke alarm placed on an interior wall was examined. As a result, it has been confirmed that the CO detection function of a CO and smoke alarm placed on a wall enables early detection of fire effectively.

Study of Effectiveness of CO and Smoke Alarm in Smoldering Fire

Study of Effectiveness of CO and Smoke Alarm in Smoldering Fire

Experimental study on vulnerabilities of Japanese-style tile roof assemblies to firebrand exposures.

Roof assemblies are known to be vulnerable to firebrands in urban and wildland-urban interface fires. In the 2016 urban fire in Japan (Itoigawa-City Fire), at least 10 structures were ignited by firebrand showers and three of these structures were ignited by firebrand penetration under tile roof assemblies. In this study, the vulnerabilities of Japanese-style roof tile assemblies to firebrand exposures were investigated by using a continuous-feed firebrand generator with applied nominal wind speeds of 6 m/s and 9 m/s. It was observed that Japanese-style roof tile assemblies were more vulnerable than concrete flat, concrete profile, and terracotta flat roof tiles for applied wind speeds of 6 m/s. When the experiments were performed with debris placed underneath the roof tiles, penetrated firebrands ignited debris. Flaming ignition was observed under 9 m/s where flame was observed to protrude from the tiles in an effort to reach necessary oxygen for combustion.

Large Urban Fires in Japan: History and Management

Wildland fires and wildland–urban interface (WUI) fires quite often become the focus of discussion among fire researchers whenever large outdoor fires are the topic, especially because of their global occurrence and their potential for causing serious damage. But at the same time, large urban fires have been occurring in Japan especially after major earthquakes or with high winds, at densely built urban area consisting of old wooden houses. Normally, fire spread is caused by three mechanisms: flame, radiation, and firebrands, especially in the cases of wildland fires, WUI fires, and large urban fires. And what is common between WUI fires and large urban fires is structure–structure fire spreading. In Japan, “Taika” (large urban fire) is a fire when the total burnout floor area is 33,000 m2 or more. The present paper first discusses the history of large urban fires in Japan, then examines the national standard regulations for fire safety in Japan aimed at mitigating the damage caused by those fires. Finally, an overview of current scientific research in methods of controlling urban fires in Japan is provided. This paper compiles such impotent information on large urban fires in Japan, which is the novelty and merit in this work. Furthermore, the contents in this paper will be contributing to the progress of new project ISO/TR 24188 on “Large outdoor fires and the built environment—Global overview of different approaches for standardization”, at ISO/TC92/WG14 “Large outdoor fires and the built environment”.

Physics-based urban fire spread simulation coupled with stochastic occurrence of spot fires

This paper presents the development and validation of physics-based urban fire spread simulation coupled with stochastic occurrence of spot fires. When a fire occurs in densely-built wooden residential area, the fire easily spreads to adjacent buildings because of the narrow distance between buildings. Although the fire in weak winds is usually extinguished by firefighters before developing into large-scale fires, the fire in strong winds sometimes overwhelm the firefighting capability because of the occurrence of spot fires. Numerous firebrands that are released from burning buildings travel a long distance by strong winds and cause new fire ignitions far from the burning buildings, which are referred to as the spot fires. Actually, firefighters have suffered from the spot fires in the past great urban fires in Japan, such as the Itoigawa fire in 2016. From such an experience, there have been calls for the use of urban fire spread simulation in planning of firefighting operation in strong winds. Therefore, we have been developing a physics-based urban fire spread model including the stochastic occurrence of spot fires. Here, in order to validate the model, we numerically simulated the fire spread in wooden residential area in Itoigawa City using Monte Carlo method and compared the calculated results with the fire damage in 2016. From the calculated results, we concluded that the proposed model could reasonably explain the number of spot fires that occurred in the Itoigawa fire, and could simulate the urban fire spread conservatively in terms of the fire spread rate.

Comparative Analysis of Post-Earthquake Fires in Japan from 1995 to 2017

Post-earthquakes fires are high-consequence events, which may cause extensive damage once occurred. However, their nature has not been fully investigated as they are low-frequency events at the same time. A questionnaire survey was conducted for the fire services that corresponded to post-earthquake fires in their areas of jurisdiction in recent years, and outline data on fires following nine earthquakes was collected. A database containing information on 665 fires following 11 earthquakes in Japan from 1995 to 2017 was constructed by integrating survey data into an existing database of fires following the 1995 Kobe and 2011 Tohoku earthquakes. Through this database, the features of post-earthquake fires were comparatively analyzed from the viewpoint of types and causes of fire, ignition, fire spread in urban areas, firefighting activity, fatalities, and damage to fire safety equipment systems. The result shows that electrical is increasing in proportion in comparison with the earlier earthquakes among several causes of ignition; about 70% of all ignitions following major earthquakes occurred within a day from the shaking; and the average time required for fire engines to discharge water after ignition increased by 8–25 times in comparison with the ordinary cases. Quantitative correlations for the rate of ignition, $$ r $$ , cumulative relative frequency of ignition, $$ f $$ , and virtual travel speed of fire engines, $$ v_{FF} $$ , that can be used for the risk assessment of post-earthquake fires were also developed. This comparative analysis provides a comprehensive perspective on the issues of post-earthquake fires that have formerly been analyzed fragmentally and construct a technical basis for the future studies.

Quantifying Wind-Driven Firebrand Production from Roofing Assembly Combustion.

Large outdoor fires present a risk to the built environment. Examples often in the international media reports are wildfires that spread into communities, referred to as Wildland-Urban Interface (WUI) fires. Other examples are large urban fires including those that have occurred after earthquakes. Firebrands are a key mechanism on how rapidly fires spread in urban fires and WUI fires. An experimental protocol has been developed to ignite full-scale roofing assemblies and quantify the degree of firebrand production during the combustion process. As wind is an important factor in firebrand generation, the experiments were conducted under a range of wind speeds at the Building Research Institute's (BRI) Fire Research Wind Tunnel Facility (FRWTF). A further unique aspect of this work is the experimental results are compared to firebrand size and mass distributions collected from an actual large-scale urban fire in Japan. Results of these experiments demonstrate that when only oriented strand board (OSB) is applied as sheathing, a significant number of firebrands collected from roofing assemblies were less than 1 g and 10 cm2. It was also observed that experiments on individual building component firebrand generation provided useful insights into actual urban fire firebrand generation.

Characteristics of Firebrands Collected from Actual Urban Fires.

The characteristics of firebrands collected from a recent urban fire in Japan are described. Specifically, this fire broke out from a Chinese restaurant in Itoigawa-city, Niigata, Japan on December 22nd 2016. On the day of the fire, strong winds resulted in rapid fire spread. With the presence of an average wind speed of 9 m/s, the fire quickly spread, resulting in the damage of 147 structures, with 120 of 147 destroyed. The fire was extinguished more than 30 hours later. During the fire, firebrands were observed and 10 spot fires were reported. After the fire, investigations were performed and firebrands were collected from the burn site. The size and the mass of firebrands were measured and compared with the available literature data. It was observed that more than 60 % of the collected firebrands had less than 0.10 g mass and 2.0 cm2 projected area and the size and the mass of firebrands were independent of the location. The size and the mass of firebrands from this fire were similar to those from another urban fire under similar wind speed and were also compared to those produced from a firebrand generator. The firebrand data set presented here provided valuable insights into how firebrands are generated from structures in actual urban fires. Finally, the description on how a firebrand generator may be used to produce firebrands similar to urban fires yields an important advancement to begin to study such complex phenomena in the laboratory.

八本松トンネル火災事故に関する一考察

On March 17th, 2016 a fire accident happened at the Hachihon-matsu Tunnel in Hiroshima Prefecture. In this paper, the accident is described in detail as well as the facilities in the tunnel. In the latter half of the paper discussion leads to the safety standards for tunnel fires in Japan, which should be revised in the near future. Stress is put on the disaster psychology, which has to be taken into account in designing an escape scenario of the passengers in tunnel fires.

Fires and Recoveries Witnessed by the Dutch in Edo and Nagasaki: The Great Fire of Meireki in 1657 and the Great Fire of Kanbun in 1663

Kaji to kenka ha Edo no hana (Fires and fights are the highlights of Edo) is a famous phrase to illustrate that fires plagued the city of Edo (now known as Tokyo) during the Tokugawa period (1603–1868). Fires seem to have been considered not only terrible disasters, but also a symbol of a busy, active metropolis. The same is true in other early-modern Japanese cities, particularly those facing the Pacific Ocean or the East China Sea, such as Nagasaki.The geographical setting of these two cities, among others, is one of four factors that contributed to many of the fires in Japan. The winter monsoon from the north or northwest caused by the Siberia anticyclone is steady and powerful from December to February, and the first summer monsoon from the south, called haru ichiban (the first wind of spring) in March or April is also quite strong. During these months, the combination of dry air, strong winds, and individual fires set to keep homes warm create fire hazard conditions. Even today, the season when most fires occur is winter.As Edo lies in the center of the Kanto plain, there is nothing to prevent strong winds. Between 1601 and 1867, there were 1,798 fires in Edo, including 49 large fires, whereas Osaka experienced only six large fires and Kyoto nine. Although it is open to the sea on the south-west, Nagasaki is surrounded by mountains, so the winds blow from the north-east to the south-west. There were smaller fires in Nagasaki, which is a smaller city than Edo, but the number of incidents was still high. Nagasaki suffered from 232 fires during the period 1633–1868, including those that occurred in suburban areas.

Estimates of carbon emissions from forest fires in Japan, 1979–2008

Emissions from forest fires directly affect the global and regional carbon cycles by increasing atmospheric carbon as well as affecting carbon sequestration by forests. We have estimated the release of total carbon, carbon-based trace gases (CO2, CO, CH4) and non-methane hydrocarbons (NMHC) emitted from forest fires in Japan during a 30-year period from 1979 through 2008. The area burnt varied widely from year to year but has gradually diminished since the 1980s. The mean annual area burnt during the period was 1878 ha. The mean annual estimate of direct carbon emissions from forest fires in Japan was 15.8 Gg C year–1 and ranged between 2.7 and 60.4 Gg C year–1. The mean annual trace gas emissions were 49.4 Gg CO2 year–1, 3.4 Gg CO year–1, 0.15 Gg CH4 year–1 and 0.18 Gg NMHC year–1. Although the carbon emissions varied widely from year to year based on the area burnt, they decreased dramatically from the 1980s onward. The interannual variations in trace gases parallel the total carbon emissions. The direct emissions from forest fires in Japan were substantially lower compared with the mean annual net primary production of Japanese forests or the carbon release in other countries and regions. However, the average annual carbon released per unit area burnt was comparable to that estimated in other regions and rose gradually with the increasing age of plantations.

Experimentally Simulating Wind Driven Firebrand Showers in Wildland-urban Interface (WUI) Fires: Overview of the NIST Firebrand Generator (NIST Dragon) Technology

Evidence suggests that wind driven firebrand showers are a major cause of structural ignition in Wildland-Urban Interface (WUI) fires. While firebrands have been researched for over four decades, prior studies have focused mainly on how far firebrands fly and are of limited use to design firebrand resistant structures. The NIST Firebrand Generator (NIST Dragon) is an experimental device that can generate a firebrand shower in a safe and repeatable fashion. Since wind plays a critical role in the spread of WUI fires in the USA and urban fires in Japan, NIST has established collaboration with the Building Research Institute (BRI) in Japan. BRI maintains one of the only full scale wind tunnel facilities in the world designed specifically for fire experimentation; the Fire Research Wind Tunnel Facility (FRWTF). The coupling of the NIST Firebrand Generator and BRI's FRWTF is leading to progress in assessing vulnerabilities of structures to a firebrand attack. A brief summary of key results to date using the NIST Dragon installed in the FRWTF are provided in this paper as well as a description of the NIST Dragon's LAIR (Lofting and Ignition Research) facility. The Dragon's LAIR is the only experimental facility capable of simulating continuous wind driven firebrand showers at bench scale. In addition, a detailed description of a new experimental apparatus is presented here for the first time. This device is known as the NIST full scale continuous feed Firebrand Generator (the NIST continuous feed Dragon).When installed inside BRI's FRWTF, the full scale continuous feed Dragon, an improvement of the NIST Dragon, is the first and only experimental apparatus capable of generating, continuous wind driven, controlled firebrand showers that may be directed onto full scale building elements. This paper closes with a discussion of future research needs and opportunities for collaboration.

Effects of Fire Regulation Revisions on Building Fire Damage

Between 1965 and 1974, there were many large building fires in Japan which resulted in numerous fatalities. In response, several revisions were made to the fire regulations for large buildings in the Building Standard Law and the Fire Service Law, leading to a decrease in such fires until about 1980. Extensive fire damage was frequently seen in old buildings with insufficient fire prevention features, so application of the fire regulation revisions to existing buildings was a crucial problem.This paper compares the content and timing of fire regulation revisions, retroactive application to existing buildings, and time limits for retroactive application of each fire regulation with the average fire burned area of buildings in which fires originated according to usage and construction.I examine the main causes of the sudden decrease in fire damage to large buildings from about 1970 to 1980, and show that the decrease is due to a sharp reduction in the number of large fires, owing to the retroactive installation of automatic fire alarm systems.

Experimental investigation of structure vulnerabilities to firebrand showers

Attempting to experimentally quantify the vulnerabilities of structures to ignition from firebrand showers has remained elusive. The coupling of two facilities has begun to unravel this difficult problem. The NIST Firebrand Generator (NIST Dragon) is an experimental device that can generate a firebrand shower in a safe and repeatable fashion. Since wind plays a critical role in the spread of WUI fires in the USA and urban fires in Japan, NIST has established collaboration with the Building Research Institute (BRI) in Japan. BRI maintains one of the only full scale wind tunnel facilities in the world designed specifically for fire experimentation; the Fire Research Wind Tunnel Facility (FRWTF). The present investigation is aimed at extensively quantifying firebrand penetration through building vents using full scale tests. A structure was placed inside the FRWTF and firebrand showers were directed at the structure using the NIST Dragon. The structure was fitted with a generic building vent, consisting of only a frame fitted with a metal mesh. Six different mesh sizes openings were used for testing. Behind the mesh, four different materials were placed to ascertain whether the firebrands that were able to penetrate the building mesh assembly could ignite these materials. Reduced scale test methods afford the capability to test new vent technologies and may serve as the basis for new standard testing methodologies. As a result, a new experimental facility developed at NIST is presented and is known as the NIST Dragon's LAIR (Lofting and Ignition Research). The NIST Dragon's LAIR has been developed to simulate a wind driven firebrand attack at reduced scale. The facility consists of a reduced scale Firebrand Generator (Baby Dragon) coupled to a bench scale wind tunnel. Finally, a series of full scale experiments were conducted to visualize the flow of firebrands around obstacles placed downstream of the NIST Dragon. Firebrands were observed to accumulate in front of these obstacles at a stagnation plane, as was observed when the structure was used for firebrand penetration through building vent experiments, due to flow recirculation. The accumulation of firebrands at a stagnation plane presents a severe threat to ignitable materials placed near structures.

Detecting long-range correlations in fire sequences with Detrended fluctuation analysis

The spatial–temporal power-law distributions are found in many natural systems, which have self-similarity and fractal behavior. By analyzing the time series of such systems, we could expect to explore and understand the underlying mechanisms. In this paper, the Detrended fluctuation analysis (DFA) is used to analyze the long-range correlations of forest and urban fires in Japan and China. It is found that the interevent time series of both forest and urban fires have the persistent long-range power-law correlations, and they all have two scaling exponents, α 1 and α 2 , which are both bigger than 0.5 and smaller than 1.0, despite the different regions and countries. For forest fires, 0.61 < α 1 < 0.73 , 0.87 < α 2 < 0.98 and for urban fires, 0.52 < α 1 < 0.61 , 0.59 < α 2 < 0.88 . The result suggests that fires have self-similarity characteristics. The occurrence of forest fires may have connection with the weather fluctuations, which have significant effects on the ignition and have the similar temporal correlations. It is shown that the interval sequences of urban fires closely resemble that of white noise in small timescale, and the correlations are weaker than that of forest fires. Human behavior and human density may affect the long-range correlation in some way. This seems to be helpful to understand the complexity of fire system in temporal aspect.

Temporal scaling behavior of human-caused fires and their connection to relative humidity of the atmosphere

It has been found that many natural systems are characterized by scaling behavior. In such systems natural factors dominate the event dynamics. But in countries with high population density such as China and Japan, more than 95% of the forest fire disasters are caused by human activities. Furthermore, with the development of society, the wildland–urban interface (WUI) area is becoming more and more populated, and the forest fire is much connected with urban fire. Therefore exploring the scaling behavior of fires dominated by human-related factors is very challenging. The present paper explores the temporal scaling behavior of forest fires and urban fires in Japan. Our findings point out that although the human factors are the main cause, both the forest fires and urban fires exhibit time-scaling behavior. Similar distribution law characterizes the relative humidity.

Spontaneous ignition of biodiesel: A potential fire risk

The spontaneous ignition of biodiesel was for the first time suspected to be the cause of a recent fire in Japan. We herein present experimental evidence implying this potential risk of biodiesel. Thus, three independent biodiesel samples were subjected to a series of experiments, including a thermogravimetry-differential thermal analysis, a differential scanning calorimetry analysis and a modified wire basket test. The results were comparatively evaluated with reference to vegetable oils, of which spontaneous ignition has been well reported as a cause of fires. The heat onset temperature of biodiesel samples was determined to be ~100 ?C, which was ~45 ?C lower than those of vegetable oils. Furthermore, under the isothermal condition at 100 ?C, the inner temperature of biodiesel samples rose rapidly with the generation of smoke after short induction periods owing to their exothermal decomposition, whereas for vegetable oils neither change in the inside temperature nor generation of smoke was observed even after 10 hours. It was therefore concluded that biodiesel possesses the higher risk of spontaneous ignition than vegetable oils. This is very important information to minimize the fire risk in biodiesel production facilities and so on. .

Targeting Fire Damage Relief

The relationship between human beings and fire is older than legend, making fire the potential disaster closest to men. This makes the mitigation of fire damage an ongoing community concern. The nature of fire risk has been changing with time due to changes in urban structure, the societal environment, and energy consumption. These changes are related to technological progress such as the development of fireproof materials and firefighting techniques. Technological advances such as the development of new materials and huge space may trigger the emergence of the new fire risks. The terrorist-triggered World Trade Center conflagrations in New York and the accident-induced Windsor Building fire in Madrid in 2004 are high-rise examples of this new vulnerability. The subway line fire that broke out in Daegu, Republic of Korea, in 2003 is yet another case -- this one subterranean. An example in new-material risks is the outbreak at solid-waste fuel facilities in Mie, Japan, in 2003. Automobile fuel batteries using hydrogen are yet another case of new risks. Ironically, technology developed to solve global environmental issues such as waste recycling are another example of new fire risks. Advancing hand in hand with these new risks are the age-old examples of housing fires in urban areas and structural blazes in forests and fields. Regional differences are a factor, especially urban fires in Japan's densely populated wooden residential areas and wildfires in populated forests of Australia and Russia. Studies on fire prevention must provide solutions to mitigating such risks -- both old and new. Ambitious research in this field is demonstrated in the papers reported in this special issue - articles that readers are about to find exciting, informative, and endlessly interesting!

Three types of power-law distribution of forest fires in Japan

Study on the forest-fire distribution is not only a phenomenological insight of forest ecological dynamics, but also essential for developing forest-fire danger rating method and system. In this paper, three types of power-law characteristics of forest fires are investigated. The first one is the distribution of fire areas. The frequency–area distribution is found obeying good power-law relation that is invariant with time. The second one is the distribution of fire intervals. It is indicated that the frequency–interval distribution of forest fires in Japan is also accord with power law. What is the most interesting is that the frequency–interval distribution is a power law with periodic change, different to that of frequency–size distribution. The third one is the distribution of fire probability against population density. There is positive-exponent power-law relation between fire probability and population density. The results discussed in this paper are expected to promote the forest-fire danger rating method and are helpful to understand the ecological action of forest fires.