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VANCOUVER LANDFILL DEMOLITION FIRE
Fighting The Fire
A case study described by
Hogland et al. (1996) shows very a very similar scenario to the
Vancouver Landfill fire. In a controlled experiment to monitor
self-heating, Hogland et al. constructed a 3.5-4 metre high pile
of demolition material over a 400 m2 area. The pile
was compacted during construction and covered with wood chips.
Hogland et al. monitored a variety of parameters for several months.
Temperatures of around 85 °C
were attained after about two months. Almost no methane was recorded
after two months. Oxygen levels varied as a function of depth
of the pile, but were around 20% in the middle and upper areas
of the pile. A fire occurred after about 6.5 months of storage.
The fire occurred on the windward side of the pile the day after
a strong wind fully oxygenated the pile. In a single day, temperatures
in the pile increased from 85 °C
to approximately 240 °C.
To extinguish the fire, Hogland et al. capped the pile with clay.
After about 2 months, temperatures in the pile dropped from several
hundred degrees to 50 °C.
Similarly,
in a recent fire incident within a 2 million m3 demolition
material cell in Minnesota fire erupted at surface. After
several days of digging, it became apparent that the fire could
not be contained by excavation. Instead, the hot area was
covered with low permeability soil and water was injected into
boreholes drilled into the waste. After several weeks of
monitoring temperatures and gas compositions it appears that the
fire is abating and temperatures are returning to normal levels.
In each of
the Vancouver Landfill fire, the Minnesota landfill case history
and the fire described by Hogland et al., excavation was not chosen
as the preferred method to extinguish the fire. It is difficult
to determine the extend of an underground fire and the risk of
excavating is that additional oxygen will be delivered to the
fire. To minimize oxygen intrusion, any excavations to dig out
burning material or install fireguards should be immediately back-filled
with soil or other inert material.
     
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Monitoring Program
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