|
REDUCING THE RISK OF LANDFILL FIRE
Early Detection
Elevated
temperatures and changes in landfill gas composition provide the
earliest warning signs of a potential landfill fire. The
threshold temperatures leading up to a fire are:
<60°
C Anaerobic Decomposition
<75°
C Aerobic Decomposition
80
°C
Microbes Die-off
93
°C
Pyrolysis Starts
149
°C
Exothermic Oxidation of Wood Starts
315°
C Wood Ignites Spontaneously (Combustion)
As
described in the Vancouver Landfill Fire Case History (MSW Management,
September/October 2001), Carbon Monoxide (CO) can also provide
early warning of a potential landfill fire situation. In
the article the following CO scale was introduced:
No
Fire Indication
0 -
25 ppm
Possible Fire in Area
25 -
100 ppm
Potential Smouldering Nearby
100 - 500
ppm
Fire or Exothermic Reaction Likely
500 - 1000
ppm
Fire in Area
>1000 ppm
Having
monitored for CO on numerous landfill sites since, I have detected
CO concentrations of up to 1,000 ppm at landfill sites where a
fire does not appear to be burning. In these cases, I believe
that the CO is being produced as a by-product of Pyrolysis, the
endothermic breakdown of cellulose into tar, char, CO, CO2,
and water. As Pyrolysis is the precursor to spontaneous
combustion, CO levels above 500 ppm continue to be of concern.
Access
to Funding
Following the extinguishment at Delta Shake and Shingle, the B.C.
Pacific Chapter organized a one day Workshop on landfill fire
in February, 2000 attended by more than 80 landfill operators,
municipal and provincial regulators and fire fighters. A
key conclusion of the workshop was that securing funding to fight
a major fire incident was the biggest hurdle to rapid response.
It was recommended that landfill owners secure insurance or put
in place methods whereby funds for fighting a large landfill fire
can be quickly accessed by the owner/manager if required to deal
with an emergency.
     
next page 
Four Levels of Fire
|
