zMessages from Departments and Centers of NILIM   Towards the Creation of Safe and SecureCities

Photo—Urban Disaster Prevention Research: Its Past and Future—
YAMASHITA Koichi, Director
Urban Planning Department(Key words) Urban fire, evacuation simulation, densely populated urban area, cooperative reconstruction
1. Introduction
A long time has passed since we recognized just
how susceptible Japan’s cities are to earthquakes, tourban fires in particular. According to a damage
estimate by the Expert Panel on Measures to Prepare
for an Earthquake Directly Under Tokyo of theCentral Disaster Management Council, in the worst
case, of approximately 850,000 homes which would
be damaged, about 80% would be burned down, andof the 12,000 anticipated fatalities, more than half
would be killed by fire.
To plan urban disaster prevention, it is, of course,
essential to consider disasters of many kinds,including flooding caused by torrential concentrated
rainfall which has increased in recent years, storm
surges, strong winds, tornadoes, etc., but the Urban
Planning Department has conducted a series ofresearch projects concerning urban fires. This reportsummarizes past initiatives and considers the future
direction regarding research on urban disasterprevention, including the perspective of densely
populated urban areas where the risk of fire is
extremely high.
2. Evaluating the disaster prevention performanceof urban areas focused on urban fire simulations
A General Technology Development Project
implemented from 1998 to 2002, Development ofDisaster Prevention Assessment and Countermeasure
Technologies for City Planning, was a study of adamage prediction simulation concerning 1) thedanger of fire spreading and the 2) difficulty ofactivities (evacuation, rescue, first-aid, andfire-fighting activities) as a result of road closures.
Specifically, regarding 1), to perform urban fire
simulations, a program which visually represents theway fires spread by elapsed time in the process,outbreak of fire Æ spread of the fire Æ damage tosurroundings Æ ignition of nearby buildings, has beendeveloped based on data concerning the state ofindividual buildings in urban areas, positional
relationships of buildings, and shielding. Concerning2), activity simulations, a study was performed toevaluate the degree of difficulty of evacuation,
fire-fighting, rescue, and first-aid activities according
to the state of the area’s facilities, parks, city streets,etc., under conditions where roads have been closed

following an earthquake.
These studies incorporated knowledge concerning
the situation when many fires broke out
simultaneously in densely populated urban areas andthe effectiveness of fire break belts (wide streets,parks, rows of noncombustible buildings) during the1995 Hanshin-Awaji Earthquake Disaster.
Urban area fire simulations are performed todevelop 1) advanced urban area fire simulation
technology, 2) urban area fire imaging technologies,and 3) urban area data and building data control
technologies as part of Development of Support Tools
for Comprehensive Urban Area Fire Measures (2007
to 2009), in order to continue to improve the precisionof simulations and visualization technologies.
3. Disaster prevention performance evaluations for
densely populated urban areas
The 2002 Urban Recovery Project (Third decision)
stipulated that during the next 10 years, priority
improvement of approximately 8,000 hectares atparticularly high risk of major fires during earthquakes
from among a total of 25,000 hectares of densely
populated urban areas nationwide would beundertaken. And the 2007 Urban Recovery Project(Twelfth decision) stipulated that because, in densely
populated urban areas, there are many bottlenecks,
including numerous lots which cannot be usedeffectively under building regulations, and houses
difficult to reconstruct, it is necessary to accelerate
improvements of such areas.
In response, we tackled disaster prevention
problems in densely urban areas based on the resultsof the General Technology Development Projectreferred to above as part of Research on HumanSuffering During Earthquake Fires Based on theImprovement of Area Facilities in Densely Populated
Urban Areas (2006 to 2008). Specifically, the themeof the study was 1) evacuation simulation technologies
performed to predict the state of evacuation by area
residents incorporating residents’ evacuation site andevacuation route selection actions and obstruction ofroads caused by the collapse of buildings and by fire.
The study also included 2) methods of evaluating theeffectiveness of providing small empty spaces (pocketparks, etc.) to prevent the spread of fire by performing
urban area fire simulations. Based on 1) and 2), azMessages from Departments and Centers of NILIM
technique to clarify methods of effectively improving
area facilities etc. comprehensively considering thecharacteristics of the area was studied and, forexample, a method of clarifying a road project site toeffectively prevent the spread of fire was presented.
And concerning evacuation simulations, Researchon Smoothing Wide Area Evacuation During anEarthquake Fire began in 2009 in order to develop awide-area evacuation multi-agent program which canbe used to deal with a variety of problems encounteredduring wide area evacuation, including the analysis oflocations of evacuation problems and obstructivefactors.
4. Densely populated urban area improvement
promotion policies
And regarding research on improvement promotion
policies for densely populated urban areas, as part ofStudy and Survey of Early Safety Assurance
Promotion Policies for Densely Populated Urban
Areas (2004 2005), studies from the perspective ofreconstructing deteriorated housing etc., were carriedout focused on the use of Special Methods ofCooperative Reconstruction such as special exceptions
to building form restrictions under the Building Codeof Japan, for example, cityscape inducement type areaplans, special approvals of building coverage ratios,
and the special design method for group buildings etc.
The term, Special Methods of Cooperative
Reconstruction used above means effectively linking
individual building plans to reconstruction, byapplying special methods under the Building Standard
Law as reinforcement measures of so-called bean jambuildings inside urban blocks.
And beginning in 2010, the Development of
Cooperative Reconstruction Rule Enactment Support
Technologies for Densely Populated Urban Areas wasstarted in order to construct guidelines to theenactment of cooperative reconstruction rules to

promote the improvement of densely populated urban
areas. And in order to discover reconstruction needs
based on the application of Special Methods ofCooperative Reconstruction, plans call for thedevelopment of area performance prediction andassessment tools which local governments andconsultants can use easily, including environmental
performance items such as access to sunlight andventilation in addition to disaster prevention
performance. (see following figure)5. Conclusions
Disaster prevention research has advanced under themethodology—considering future measures taking
past disasters which have actually occurred as
lessons—but severe disasters which actually occur
usually trigger damage greater than that anticipatedand greatly exceeding past knowledge. In response,
we considered that it might be possible to go beyond
conventional methodology to use simulation
technologies to clarify new forms of disaster damage.
It is assumed that from the macroscopic perspective,
damage hypotheses of earthquakes bear this role to acertain degree, but it might be possible to search forforms of damage which apparently cannot be
imagined applying past knowledge, that related toevacuation after earthquake fires in particular,
according to the specific conditions in various urban
areas.
Resources:
Guidebook to the Operation of Group Regulations toImprove Densely Populated Urban Areas, Technical
Note of the NILIM January 2007.
㧔http://www.nilim.go.jp/lab/bcg/siryou/tnn/tnn0368.
htm㧕

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Sunlight

Access tosunlight

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way 〝㕙
surfaceRoofደᩮ

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AirVentilation

឵᳇

WindVentilation?

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Roofደᩮ
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Integration andsimplification

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Fire prevention