- Author
-
Tuomisaari, M.
|
Baroudi, D.
|
Latva, R.
- Title
- Extinguishing Smouldering Fires in Silos.
- Coporate
- VTT-Technical Research Center of Finland, Espoo
- Report
-
VTT Publications 339,
1998,
74 p.
- Contract
- BRANDFORSK-PROJECT-745-961
- Keywords
-
smoldering
|
extinguishing
|
fire detectors
|
fire extinguishers
|
autoignition
|
porous materials
|
containers
|
combustion
|
fire fighting
- Identifiers
- silos
- Abstract
- Combustible, porous materials may self-ignite during their storage time in silos as a result of internal heating. The self-ignition process may be slow, and it results in smoldering fires that are extremely difficult to extinguish. Suitable means to fight the smoldering fire were studied both theoretically and experimentally. General heat and mass transfer equations for porous media subject to fires and suppression were written. The equations together with dimensional analysis revealed critical parameters, like the grain size and moisture content, affecting the combustion and suppression process, but they also revealed the complexity of the problem. Experimental results of over 50 tests with varying combustibles and suppression agents were used as the basis for proposed qualitative guidelines on how to fight a smoldering silo fire. Among the potential gaseous agents, CO₂ was found to be the most efficient one. Low expansion foam was also found to be a potential candidate, but its applicability requires further confirmation. Quantifying the guidelines requires a whole new study on the detection of a smoldering fire. The same detection system should be capable of monitoring the suppression process and - most importantly - verifying the extinguishment.