Can Fire Suppressant Gels Protect Log Decks? A Case Study to Test the Concept

Transcription

1 Intrductin Can Fire Suppressant Gels Prtect Lg Decks? A Case Study t Test the Cncept Dave Schreder Wildland Fire Operatins Research Grup Frest Engineering Research Institute f Canada As part f its lg deck prtectin prject, FERIC is investigating techniques that may aid in preventing r suppressing fires in lg decks. In 2005, an pprtunity arse t explre the effectiveness f fire suppressant gels at the Cmmunity Prtectin Trials site (frmerly Internatinal Crwn Fire Mdeling Experiment) near Frt Prvidence, NWT. These gels are mixed with water, and absrb many times their weight in water. Because the gelled water adheres t the surface f frest fuels, the gels enhance water s effectives in suppressing fire. FERIC, the Gvernment f the Nrthwest Territries, and Alberta Sustainable Resurce Develpment tk advantage f the pprtunity and cnducted a case study t test the technique. Case study bjective The bjectives were t: Observe/recrd the spread f fire int the lg deck frm an adjacent debris pile. Observe the effect f fire suppressant gel n fire spread thrugh the lg deck. Attempt t suppress the lg deck fire with water. Use results t prvide directin fr future research. Methds The case study utilized a lg deck (Figure 1) cmpsed f jack pine extracted frm an adjacent fuel management plt in 2004 (Figure 2). Wd misture cntent was nt measured, but the deck had dried fr ne year after falling. In additin t the main deck, five small satellite decks were als built. These satellite decks were psitined at different distances frm the main deck t see if they might be affected by heat radiating frm the larger fire. Gel was applied t three sectins f the large deck and t fur f the five small decks (Figures 1 and 2). The gel cntainer was attached t a standard 1.5 inch fire fighting hse and mixed autmatically nce the pump was started (Figure 2). On the tw center sectins f the large deck, gel was nly applied t the tps and the sides facing the satellite decks. Fur f the satellite decks were cmpletely cated while the fifth was left untreated (Figure 1).

2 The fire was ignited in the adjacent debris pile (Figure 1) and allwed t prgress int the deck. Fire behavir was recrded with vide and still phts. During the fire suppressin prtin f the trial, 2200 litres f water were applied t a 6-m sectin f the lg deck using a standard frest fire fighting pump (Mark 3 see- and a 1.5 inch hse with a standard nzzle. Figure 1. Schematic shwing treatments applied t the lg decks. Figure 2. Applying gel t the lg deck.

3 Results and discussin The fire spread frm the debris pile t the deck via surface fire (Figure 3). Sme embers landed n the tp f the deck but they did nt result in ignitin. The fire prgressed alng the back f the deck (the side facing the standing trees) as surface fuels and debris had nt been remved and n gel had been applied t this area. The deck was cmpletely engulfed within 20 minutes after the fire had spread frm the debris pile. Figure 3. Fire spreading frm the debris pile t the lg deck. During the first 1.5 hurs after ignitin, fire behaviur within the three gelled sectins f the large deck was visibly less intense than fr the rest f the deck (Figures 4 and 5). The gelled sectin facing the debris pile did nt prevent the deck frm igniting because the fire spread alng surface fuels and bypassed the gelled area. If mre surface fuels were remved and mre gel was applied t the sectin facing the debris pile, the spread f the fire int the deck may have been slwed.

4 Figure 4. Fire has spread alng the back f the deck. Gelled sectin is in the center f the figure and is nt n fire. Figure 5. After ne hur the entire deck is engulfed, but the gelled sectin (in the centre f the main deck) is nt burning as vigrusly as the rest f the deck. The back side f the deck was nt gelled and is burning vigrusly. The attempt t suppress the fire with water was unsuccessful. Figure 6 shws the water being applied t a 6 m sectin. Althugh the fire appears t be extinguished (Figure 7 - far end f deck) the center f the pile cntinued t burn. Eventually the entire deck burned (Figure 8). All f the satellite decks, except the ne with heavy gel applicatin, were cnsumed. The fire spread frm the large deck t the satellite decks as a creeping surface fire that eventually ignited unprtected wd. The heavy gel applicatin prvided enugh gel n the surface t prevent ignitin.

5 Figure 6. Water applicatin t suppress the deck fire. Figure 7. After 1.5 hurs, the entire deck was engaged and grund fire had engaged 2 f the satellite decks.

6 Figure 8. All f the decks burned, except the ne with the heavy gel applicatin. Summary Fire suppressant gels have ptential t slw the spread f fire thrugh a lg deck and t prevent ignitin. Direct suppressin f fires in lg decks is unlikely, and this has been the experience f frest industry and frest firefighting agencies n large scale deck fires. New questins Hw much gel is needed fr industrial scale lg decks and what is the assciated cst? Hw can the gel be applied t be effective? Timing? Amunt? Penetratin int large decks? Safety issues f accessing a burning lg deck r a deck that is being threatened by wildfire. FERIC will wrk with frest industry and gel vendrs t answer these questins. Hme

7 Cpyright 2006, Wildland Fire Operatins Research Grup (WFORG), FERIC. Fr cmments: web administratr