Large naphtha storage tank fire at Tomakomai, Japan (part 2)

National Research Institute of Fire and Disaster,

Japan 　Hiroshi Koseki

Two fires occurred after the eathquake

Crude oil tank　Ｓｅｐｔｅｍｂｅｒ 26, 2003, just after the

earthquake 　 Naphtha tank fire　 September ２８ , １０ : ４９ AM Koseki was asked to help fire-fighting against

the second fire, who was in Tokyo. About 5 hours after fire, he was there.

Summary of Naphtha tank

No.30063 tank, floating roof, single roof Storage volume 　３２，７７９ｋｌ , 　

２６，０００ｋｌ exist （ Fuel height ：about 18 ｍ）

Diameter 　４２．７ｍ　 Height 　２４．4m

Built in 1974 as crude oil tank Then changed for storage of naptha

naphtha No posibility for boilover because of 71

C for 95 ％ distilation Similar to gasoline, but lower boiling poi

nt Flash point 　ー２０℃ Burning rate is very high ； 5-8 mm ／ m

in （ 0.36-0.50m ／ hour ） Due to strong wind, it was higher.

Distilation curves(Naptha, Crude oil and gasoline)

0

50

100

150

200

250

300

0 20 40 60 80 100

( 流出量 Vol.% )

(℃

)温

度

ガソリンナフサMurban

m

Crude oil

Naptha

gasoline

Volume %

Temperature C

Burning rate during the fire

Period Burning rate(m/hr)

Ignition - 4 hr 0.36

4 hr - 8 hr 0.50

These values are very large, normally 0.2-0.4m/hr for gasoline, keroseneBecause naphtha is very light

４ :0 ５ AM, September ２９Start of large fure fighting gun, 17 hours after start of the fire

9:32 AM Sep. 29

1:00 AM, September ２９

Tank Fall down, at 1:23 PM, September

2:06 PM, Sep. 29

2:07 PM September 29

Strong heat flux damaged fire engine

About 6:30 AM September 30

Tanks after the fire

Oil storagety storage base near Idemitsu Refinary, very little damage by the same earthquake

Problems in fire-fightings Not enough extinguish agent,

because two fires occurred after the earthquake

Commanding system is not good, because so many fire departments came

Strong wind, tank height is high, so extinguish agent did not reach inside tank

Problems, use of foam extinguih agent

Each fire fighter group has different agent

Government: synthetic foam Idemitsu: AFFF, Protein Foam National storage base: Protein Foam USA military: AFFF

Conclusion To extinguish we need 44 hours,

and most fuel was burnt out. Naphtha is so difficult to be

extinguished Other problems, strong wind,

height of tank is 24 m However, no human damage