Research Trends and Results

Full-scale fire experiment of three-story woodenschool building (preparatory experiment)
NARUSE Tomohiro(Ph.D., Engineering), HeadNII Daisaku(Ph.D., Engineering), Senior Researcher
Fire Standards Division, Building Department
FUKAI Atsuo, HeadYOKOTA Yoshihiro, ResearcherStandards and Accreditation System Division(keywords) three-story wooden school building, full-scale fire experiment, fire safety

1.

Introduction

And it was intended to confirm their effectiveness and toThe act concerning promotion of wood utilization ingather data for evaluation of fire spread routes, impacts

public buildings, etc. was enforced in October, 2010.

on surroundings of the building and impacts on main

Therefore, NILIM started to prepare a basic draft byconstruction frames of the test body in case of longcollecting necessary data to review provisions related tocontinuing fire, etc. and accordingly full-scale fire

fire protection of Building Standards Law regarding

experiment (preparatory experiment) was conducted inthree-story wooden schools.

Gero City, Gifu Prefecture on November 25, 2012. The
constructed test building was a quasi-fire resistive2.

Purpose of preparatory experiment
Full-scale fire experiment of three-story wooden

construction for one hour duration with the building areaof about 310m2 and the total area of about 850m2.

school building (preliminary experiment) was conductedin the premises of NILIM on February 22, 2012 and as aresult, the following issues emerged.

3.

Outline of the result of preparatory experiment
In the fire starting room, the fire source grew to limited

・Early spread of fire to upper floors from the room on thepart and did not spread in the whole room and as a result,first floor where a fire occurred through the external

combustibles stored in the fire starting room wereopenings (about four minutes after setting fire to thereignited 50 minutes after setting fire.

second floor and about six minutes after setting fire to

fire source gradually grew and the fire spread to thethe third floor)

whole room about 89 minutes after setting fire and flames

・Early spread of fire through fire walls (about 18 minutes
after setting fire on the first floor)
・Fire walls collapsed without freestanding (96 minutes

After that, thespouted from external openings.
The spread of fire from the fire starting floor (the firstfloor) to the second floor occurred about 129 minutes

after setting fire)after setting fire through the floor of the second floor andIn order to address these issues,

the spread of fire to the third floor occurred about 139

・to make interiors of the building except pillars, beams
and floors resistant to fire,

minutes after setting fire through external openings.
After confirmation of the spread of fire to the third floor,

・to place balconies and eaves to upper part of openings offire extinguishing started at the moment 142 minutes after

outer wall andsetting fire.

・to separate fire walls structurally and change fire-proof

The results indicate the following: firstly, the spread ofdoors and so forthfire from the fire starting room to staircase and the spread

were worked out as countermeasures.

of fire through fire walls did not occur because earlyResearch Trends and Results
spread of fire to upper floors through external openings
was prevented, and secondly, although pillars of the firestarting room carbonized 5~6 cm in-depth from thesurface after completion of the experiment, both of thetest body and fire walls did not collapse. Thereby, effectsof the countermeasures against the issues of thepreparatory experiment were confirmed and various data
were gathered.
4.

Conclusion
Based on the preliminary experiment and thispreparatory experiment, after adjusting specifications andtest methods, it is scheduled to conduct again full-scale
fire experiment with building configuration which issupposed to be standardized and to prepare a basic draft
in 2013.
[ Reference ]As for the results of preliminary experiment andpreparatory experiment and outline of video image, referto the following URL.
http://www.nilim.go.jp/lab/bbg/kasai/h23/top.htm

Photo: The spread of fire to the second floor at the time of
137 minutes after setting fire