water "pushing" fire

Replies to This Discussion

Permalink Reply by Ray McCormack on March 18, 2009 at 10:33am

The act of pushing fire is an act of non extinguishment. Not being able to hit the seat of the fire with your hose stream in a direct manner. This is common when fire starts to wrap around a wall with two entrances. As for your limited staffing example - Maybe we should hand the hoseline to a civilian so that we can put our command, 2in/2out, safety culture vests on while water is sprayed about. While it is true that we can not operate effectively with a couple (2) of firefighters we must also be mindful of moth to flame engine tactics. I know College Park does an outstanding job at fires. I have visited there.

Permalink Reply by Brandon Krause on March 18, 2009 at 10:39am

We run with 3 man engines quiet often in our department and an exterior attack is what we use to darken down the fire. Once the fire is darkend down we now have a fire we can go in and take care of if 2nd due isnt there yet. The most important factor is to make sure that when you attack from the outside, via window or door, make sure to put the water on the seat of the fire.

Permalink Reply by Todd Trudeau on March 18, 2009 at 2:48pm

Dave,
Your question may need to be broken down a little more. What I mean is, size, set back, means of getting to C side, type of occupancy, rescue profile, etc. It's my belief that a fog nozzle on wide fog will bring O2 into the fire area which will inturn, contribute to fire growth aka spread aka push. Concider hydraulic venting technique, fog 'pushes" smoke out by bringing fresh air in from behind. A striaght stream introduces less air if at all.
Side A may be a kitchen fire blowing out the window but still allow an attack from the front door on side A. My home is an example, it's a reverse ranch 24 X 40, LR inside the front door, kitchen to the right through an open doorway. The side entrance is onto the kitchen landing but in the attached garage (and then we'd be "pushing" it into the LR), a backdoor is available but only after stretching 150' hose (just to get to it,not in it), and scaling a 6' privacy fence.
A quick hit from the front door may allow for a quicker search for my kids than the long, cumbersome stretch described above. Judgement call.
I may be off track, so hopefully some guys with experience in making these judgement calls will help me out. Thanks, and 2 on an engine is behind the ball from the start.
KTF
Todd

Permalink Reply by Dave Stacy on March 18, 2009 at 10:27pm

Thanks for the comments and opinions guys. I still just feel that this is one of those topics similar to whether to use smooth bore vs. fog. Eveyone has different opinions and we might not get to an answer for awhile. Todd, I agree with what you say about how the fog nozzle operates during hydraulic ventillation but it would be interesting to see whether that entrainment of air really affects a fire if water is still being applied too. It could depend on many factors including fire load and the condition of the room (if it's close to flashover).

Permalink Reply by Drew Smith on March 21, 2009 at 12:05am

My experience is that nozzle technique and GPM are the key. If the GPM is a lot greater than the BTUs being produced the fire goes out as long as the water reaches the fire. Its not the fog nozzle but the pattern that becomes an issue. Wide fog has less reach and entrains air. Don't think so? Well just go out back of the fire house, pull a line with a fog, flow it with your face aside the nozzle and adjust the pattern-you'll feel the air flow.
Another issue in the discussionis to not use residential tactics in commerical buildings. What works for small rooms in houses does not work in wide open spaces with heavy fire loads: Line placement and GPM are different. Where we get in trouble is using the usual and customary tactic when the fire is not usual and customary.

Permalink Reply by Adam Miceli on March 21, 2009 at 4:35pm

I guess I'd offer that first, it's not the water that's pushing the fire, but more often the air from a fog pattern. Spraying water from the outside will not allow you to effectively operate the stream on the seat as well as the direct attack from inside and depending on your effectiveness you may cause fire and heat that was venting to the outside to find another avenue of travel through the interior.

One other problem I see is the "unburned to burned methodology". I've come to believe this practice has far outlived it's usefulness. The unburned to burned tactic was required when we used to pull 1.5" lines flowing less than 100 gpm on 30-50 degree fog patterns, and pushed the fire either out or to where nothing readily could re-ignite. Eventually this would break down the forward production of heat to the point that the limited GPM would overcome the BTU's. Today, we pull 1.75" lines minimum, flowing 150-180 gpm, with tight patterns or smooth streams and apply an overwhelming amount of GPM to suppress the BTU's. This allows us to kill the fire in place vs. pushing it.

The most significant issue here is that most of us do the majority of our work in PD's and the unburned to burned methods fail to routinely provide the occupants with the best protection. Our SOP is the first line goes through the front door on all private dwellings. Period. This puts the line at the base of the stairs in 95% of our first due (2nd and 3rd due too). This is by far the fastest approach to any interior fire as well. The line at the stairs can be used to protect the vertical ingress/egress for search crews and occupants, and perform fire control on the first floor. Obviously if the fire is above the ground floor, this puts the line at the stairs to advance up as well. Taking lines to other doors can quickly add to the stretch, encounter gates, and add numerous extra bends in the line. Of course there are exceptions to every rule (they prove the rule) such as alternative building styles where the stairs are not near the front door, or those times where the owner blocks the front door for extreme temperature control.

Sorry for the long winded post and truly a tip of the helmet to Ray who has written and been published about this very topic. Ray's article in became mandatory reading here and solidified our position enough to write the SOP.

Permalink Reply by Adam Miceli on March 21, 2009 at 4:47pm

Dave Stacy said:

Todd, I agree with what you say about how the fog nozzle operates during hydraulic ventillation but it would be interesting to see whether that entrainment of air really affects a fire if water is still being applied too. It could depend on many factors including fire load and the condition of the room (if it's close to flashover).

We show this very issue in probie school/FF1 with hay/pallet fires. We allow students to use the fog slightly off straight and watch as the hay and fire blows around the room, the smoke drops to the floor and the temperature you feel sharply increases. Then on their next evolution we keep the nozzle on straight stream and show how when properly applied, the fire (even hay) stays in place, the smoke stays up better (less steam) and the heat does not increase much at all. While hay is much lighter than most ordinary combustibles in a home the effects will be the same though not as exaggerated.

Permalink Reply by Matt Carlson on April 27, 2009 at 11:14pm

I had a fire like the one you gave in your example: First in engine, driver/firefighter on engine only, heavy fire showing from the Alpha-side of a 1 story ranch. A Lieutenant happened to be driving near the fire and heard it go out. I arrived with my partner and got the Engine ready to pump. Seeing the amount of flame, I grabbed a 2 1/2" pre-connect with a smoothbore nozzle. My partner met up with another firefighter and they went to search for victims around the C/D sides interior. The Lieutenant took over pumping and I attacked the fire. I started hitting it before I made it inside; it was too big and too hot. I knocked it down while the other two firefighters were inside. The fire wasn't "pushed" a bit and they weren't hit with steam.

Permalink Reply by Wesley Stephens on May 15, 2009 at 11:07am

I think that every situation is different. However every situation has alot of similar elements. You can't make a determination of proper fire attack based off of one of these elements. Sometimes people feel obligated to spray water through a window because the bystanders are expecting us to do something, but we don't have the manpower to safely perform an interior attack at the moment. Well that is why we are the professionals. There are other things to do at a fire besides charging off the truck with a line and assaulting the building.

If it may take a moment for the other companies to get there, do some recon, stretch your line and prepare it, force the door but maintain control, etc. Have everything ready so that when help arrives you can make a coordinated fire attack. If my house catches on fire and you save 90% of it because you sprayed a fog through the window, but in the process disturbed the thermal layer so much that the smoke dropped down and killed my children while they were trying to crawl out then I believe I would have been better off if you would have stayed at the station.

We have to remember that we are here to save lives first, and most of the time in residential dwellings that is our first tactical priority. We also have gear to protect us and with proper ventilation techniques an interior fire attack is the answer most of the time. If there is no survivable areas, then sure go defensive and blast away. Fog attacks will have adverse effects in a structure due to the air that is being moved. I believe it moves between 8,000 and 10,000 cubic feet of air. Water don't push fire, but air can, and if your air track isn't managed then bad things happen.

Permalink Reply by Jason R. Ward on May 15, 2009 at 7:45pm

I agree with LT. Stephens on many of his points. My crew is 3 to 4 members depending on the day. We must do what we can. The last full measure of devotion is often required of us. Solid tip streams seem to be the best tool all around for this task. The low operating pressure allows for ease of manuvering with much GPM. We should realize that the fog is not good for the attack of a structure fire it diturbs too much. Keep your streams straight or solid and you most likely will put out the fire and often that is the very best thing an engine company can do.

Permalink Reply by Jeff Schwering on May 8, 2010 at 12:58pm

On recent job, My company was fourth due, the first line was on a fog stream directed into the attached garage. Result, fire throught the attic, we played catch up, but finally stopped it. If you try and knock it down first, straight or solid stream first, then get in and get it.

Permalink Reply by Dan Rice on May 30, 2010 at 1:43pm

Great point with get in and get it. If you're going to make an attack make it and don't mess around. If you hit it from the outside to knock it then knock it, go in and finish up without waisting time outside. Life safety and property conservation, if you keep those two things in your mind when making the decision then you'll be fine. Know your fire and know what its going to do. Every situation varies and its very easy to say what would be the best way to do it but when it comes to the gold its about knowing your structure, your smoke, and your fire.

Be safe, train hard
D.Rice

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