Thread: Direct or Indirect Attacks
02-05-2001, 10:58 PM #1nobull911Firehouse.com Guest
Direct or Indirect Attacks
I was just wondering what you guys thought on the subject. I know that people are starting to focus just on direct attacks and even tossing out their fog nozzles for a solid bore. I am starting to be convinced that the switch to the solid bore is a good one. The only concern I have is that in case of an emergency you don't have that fog pattern to protect you.
02-06-2001, 12:07 AM #2DDFirehouse.com Guest
Get a comb tip with a solid bore slug behind it if you want both.
I have used a solid bore for direct attack for a many years. Now I'll use the Heavy Attack Vindicator on an 1-3/4" line. It flows 250 gpm at 50 pounds nozzle pressure and with less nozzle reaction than the solid bore knob.
02-06-2001, 09:07 AM #3BarndogFirehouse.com Guest
Smooth bore IS th way to go but don't forget stay alert to your surrounding (change in smoke condition, sudden increase in room temp. etc)
02-06-2001, 11:48 AM #4ADSN/WFLDFirehouse.com Guest
What "emergency" are you talking about? It is a myth that a fog stream will portect you from flashover. If you start to notice the danger signs of a flashover. (high heat, rollover) you can hit the ceiling with a smoothbore to cool the room and delay flashover. Or just put the fire out.
The direct attack is the way to go, spraying water on smoke will only increase the damage caused to the building and delay putting the fire out.
A fog nozzle (on straight stream), smooth bore, or vindicator will all work. The higher flow of the Vindicator will just do it faster and beat you up less.
02-07-2001, 04:06 PM #5Paul GrimwoodFirehouse.com Guest
'It is a myth that a fog stream will protect you from flashover'....NO! It is most certainly NOT a myth and the correct use of a fog stream is far more likely to prevent a flashover from occurring when occupying a room/area adjacent to the fire room/area.
'The direct attack is the way to go, spraying water on smoke will only increase the damage caused to the building and delay putting the fire out'....Actually, spraying water into smoke and hot gases is the SAFEST action a firefighter can take!!!!!!!!!!!
Direct attack - excellent and most productive form of attack to deal with room surface and contents fire.
Indirect attack - application of water-fog onto SURFACES of a fire room to create large amounts of WET steam that smothers the fire to extinction....fraught with hazards where the room is occupied, but an excellent method of preventing backdrafts where signs and symptoms are obvious.
3D water-fog attack - used to apply water into superheated gas and smoke layers in rooms and areas adjacent to the fire room/s to create DRY steam to reduce the likelihood of flashovers and backdrafts occurring - excellent tactics!!!
Any firefighter that advances into a fire involved structure without the protection of a combination nozzle is limiting his/her options and may be leaving their survival to chance.......
02-09-2001, 03:30 PM #6TXFIRE6Firehouse.com Guest
We use fog nozzles, and I prefer the straight stream setting. Keep in mind if there are occupants anywhere near the fire with no protection, and you spray into the smoke, you have eliminated any chance for survival of the occupants.The disruption of the thermal balance will increase tempuratures at lower levels, and also decrease visibility to zero. This increase in heat level near the floor, and humidity increase stress on crews inside. Fog streams and indirect attack, have a place, but its not for interior firefighting when the building, is, or could be occupied.
Any Opinion expressed, are my own, and do not reflect my Department...RB
02-09-2001, 06:10 PM #7Paul GrimwoodFirehouse.com Guest
Temperature inversions and upsetting the 'thermal balance' are caused by incorrect use of the fog nozzle. By resorting to 'new-wave' techniques this will NOT happen if application technique is trained and correct. Don't think with tunnel vision here guys..........
02-10-2001, 09:47 PM #8FyredUpFirehouse.com Guest
I have read with interest all of your postings on "New Wave Faog Attacks". I always like to read of different ideas to see if I can incorporate something into our FD.
But I have to correct your terminology. You are using the term THERMAL BALANCE incorrectly.
Thermal balance is when the temperature at the lowest point (floor) in an area is nearly the same as at the highest point (ceiling) in an area.
Thermal imbalance is when the majority of the heat, smoke and fire gasses have accumulated at the highest point (ceiling) in an area and the lowest point (floor) is substantially cooler.
What you don't want to do if you are in the immediate fire area is to disrupt the thermal imbalance and thereby bring the heat and smoke and fire gasses down on you.
The surest and quickest way to disrupt the thermal imbalance is to place too much water into the super heated atmosphere at the ceiling in the form of a fog stream. This type of fire attack is called an indirect attack and should NOT be undertaken if you are in the fire room or if there are possible survivable victims in the fire room. The circumstances where this type of attack works well is in a fairly tight room or area, especially if you can shut the door, with you on the outside of the room and let the steam do its work.
A direct attack uses either a straight stream or a very narrow fog from a fog nozzle or a stream from a smooth bore nozzle. The water is directed at the base of the fire and direct cooling of the burning material extinguishes the fire. Much less steam is developed and the thermal imbalance is usually mostly retained.
An combination attack is where a brief sweep of the ceiling for cooling of the atmosphere or flame extinguishment is followed by direct application of water to the base of the fire. Again, as long as the water application into the overhead is brief the thermal imbalance is maintained for the most part.
I believe you are advocating a combination attack but instead of a constant brief sweep you are saying multiple quick pulses into the overhead. Again, with the intent to cool the overhead, but not disturb the Thermal Imbalance.
I hope you don't think I am nitpicking because I do enjoy your postings.
Take Care and Stay Safe,
02-11-2001, 02:18 PM #9Paul GrimwoodFirehouse.com Guest
Hi Fyred up........and thanks for posting here! I too have enjoyed your many many posts on this excellent forum since 1999.
When I use the term thermal balance - I use it with inverted commas....'thermal balance' (you will note). I am not fond of this terminology and associated definitions used by many firefighters as they vary widely!
I note you bring thermal 'imbalance' into the arena and accept that your definition is perhaps more acceptable.
However, I fully appreciate that advancing firefighters do not want to bring the heat, smoke and superheated gases down to the lower levels of the room and that is always a distinct possibility when utilising an 'over-application' of water - be it water-fog OR straight stream.......been there - done that!!
You are correct (of course) that an effective combination attack can preserve the heat at high levels but no - pulsing water-fog droplets is not the same as a combination approach.
Temperature inversions ARE actually a disruption of the thermal balance (or imbalance) and are caused by over zealous use of water-fog patterns (mainly) - here the temperature at lower levels can soar beyond those encountered near the ceiling and such conditions have been recorded during test burns (in Fairfax for example) when using indirect water-fog applications.
I am sure we are talking in agreement here!
02-13-2001, 02:49 PM #10chiefjay4Firehouse.com Guest
You hit the nail on the head txfire.
02-14-2001, 11:18 PM #11ADSN/WFLDFirehouse.com Guest
Paul, correct me if I'm wrong but it is my understanding that firefighters in England and much of Europe attack fires from outside of the building. The brothers on the other side of the pond are not a tenth as aggressive as firefighters in the USA. When the palace had its fire, we saw a lot of companies spraying water through the windows. It didn't look like many lines were being operated from inside.
If you practice aggressive firefighting then the direct attack is the way to go.
02-16-2001, 07:52 AM #12Paul GrimwoodFirehouse.com Guest
ADSN - Did you really think I would rise to such a stupid remark???!!! I think you have an awful lot to learn about 'aggressive' interior firefighting my friend and I hope it is not at somebody else's cost!
02-23-2001, 02:36 PM #13ADSN/WFLDFirehouse.com Guest
I guess you would since you started an entirely different post on it. Fighting a fire in a ship is considerably different than fighting a house fire.
[This message has been edited by ADSN/WFLD (edited 02-23-2001).]
02-23-2001, 03:41 PM #14Paul GrimwoodFirehouse.com Guest
It may be different in many ways - however, in others it may be very similar. A compartment fire in a ship may present similar heat release rates and conditions where similar fire loads to those found in residential basements are involved.
Moreover, these techniques are aimed at gas-phase cooling........fire gases behave similarly whether on a ship or in a closed structure.
This style of approach was developed for interior structural fire attack and was later adapted by the US Navy and FDNY Marine Division (examples) for ship use.
02-23-2001, 08:02 PM #15ADSN/WFLDFirehouse.com Guest
The big difference between a basement and a ship compartment is how tight the space is. The steam created in a ship's compartment can't go anywhere. That's why that technique works so well for ships. In a house you don't have that tightness. That was the major problem with an indirect attack. The final result was a fire that wasn't completely extinguished and now you have no viability.
In reference to an earlier post if a room has reached flashover a fog nozzle will not protect you. The danger signs of a flashover must be recognized and flashover prevented or you have to leave the area prior to flashover.
I guess I would have to experience this 3D fog attack myself. But I can't see how a fire that almost doesn't back down to 150 GPM directly applied to the burning material would magically go out with several quick bursts into smoke.
02-24-2001, 07:51 AM #16Paul GrimwoodFirehouse.com Guest
ADSN - your points are most valid. I agree about compartment 'tightness' in relation to ships but try to avoid comparisons with 'indirect' applications of water-fog onto heated surfaces. Steam production is most certainly not the objective when applying 'pulses' of 3D fog but inevitably, there is some surface contact (especially in small compartments) and steam becomes a by-product. The main aim is to 'cool' the gases outside of the fire compartment. When this occurs the gases contract and 'dry' steam expansion is nullified by such contraction of the gases. Ideally, under certain circumstances, the existence of steam is not overly apparent.
An 'indirect' injection of water-fog is another technique and we can use this in some situations where warning signs of backdraft are presented.
I agree also that flashover needs to be prevented rather than dealt with as it occurs. If you are occupying the compartment where fire gases are beginning to ignite at the ceiling, quite simply, a range of water droplets pulsed into the overhead will take the heat out of the situation quicker than a straight stream. If the compartment you are occupying is the actual fire compartment and the fire is developing then a straight stream attack may/will prove more effective.
A situation may arise where the fire is developing faster than any water available (in any form) at the nozzle is unable to deal with the increase in heat release. Then it is time to back-up immediately or withdraw your line.
I can think of numerous occasions where we have applied 3D tactics on the approach route - along hallways; in rooms adjacent to the fire room etc to cool and 'inert' gas layers. I can think of others where we have utilised 'indirect' applications into the fire compartment to reduce backdraft potential.......and then more still where we have gone with the all-out direct approach.........different sets of circumstances.......different conditions etc.
All three approaches most definitely have their place on the fireground but may not be suited to every fire.
Be open minded here.........until personal experience of this approach is proven clearly NOT to work.
03-06-2001, 09:01 AM #17FireLt1951Firehouse.com Guest
In my 28 years in the fire service,the best pipe I have ever used was the Rockwood,which the Navy invented years ago.It allows for a solid bore stream but slightly broken and a fog stream.One great pipe.Actually I prefer a slightly broken stream to the solid or the fog.Allows for smaller water droplets than the solid bore straight stream.If you ever get the chance to use a Rockwood nozzel,try it,I think you'll like its effects.One big plus to this nozzel is that it never clogs up on you and you still have your option of fog or straight.
04-03-2001, 06:58 PM #18LadderCappFirehouse.com Guest
Let us keep in mind that the newer automatic fog nozzles flow nearly as high a gpm as the old smooth bore nozzles. The key is to get the water to the seat. With a good nozzle you can get nearly the same effect with a good interior attack with a straight stream as you can with a smooth bore. Smooth bore nozzles are great for hitting it from farther out, but if you gotta get close, any water will do.
04-03-2001, 09:30 PM #19LHS*Firehouse.com Guest
Gee if the Fire LT from Detroit supports Rockwood navy nozzles as the best nozzle he has ever used inside, I guess he'll support me in using 1" hose inside too
04-03-2001, 10:16 PM #20johnusn971Firehouse.com GuestOriginally posted by LHS*:
Gee if the Fire LT from Detroit supports Rockwood navy nozzles as the best nozzle he has ever used inside, I guess he'll support me in using 1" hose inside too
04-14-2001, 10:51 AM #21alaskafiremanFirehouse.com Guest
We use TFT Fog nozzles.....I personnally prefer the TFT so that I have a choice of full fog to a straight stream. I will mostly use a modified (1/4 fog) pattern.
Captain, Seward Fire
04-15-2001, 09:14 PM #22jmichaelFirehouse.com Guest
When I was on an Engine we used smooth bore stream. Not much steam production and water hit the base of the fire and put it out. Some fog nozzles may flow what a smooth bore will, however the for is just that a fog. Lots of surface area absorbs lots of heat and makes steam and doesn't penetrate very well. I think really the best nozzle is the one your department provides, it is just up to you to use it wisely. Fogs streams are great for the application of AFFF and I used them on car and trash fires, any where i was outside.
04-19-2001, 05:14 PM #23GBordasFirehouse.com Guest
All of our hoselines whether it would be a 1-3/4" or 2-1/2" line have a smooth-bore nozzle attached to them. The only line that doesn't have one is the booster line.
A smooth bore nozzle is the only way to go for fire attack. First off the benefits are tremendous such as greater water flow, low operating pressures and less reaction force making engine work and handling the hose less difficult and you more effective at extinguishing the fire.
With that out of the way, let me say that the only way to attack a fire is directly! There are times when indirect attacks work but only if there is an obstacle that prevents you from hitting the fire directly, In that case then you can deflect the water stream off the ceiling or wall to hit the fire. Other than that circumstance, hitting the fire directly is best. I can't believe some of you are just starting to realise this and are just now focusing on direct attacks as if it was some new technique. This should be the primary means of attacking fire unless you're confronted with the situation as mentioned above. This stuff about spraying water above you to cool the ceiling or protecting yourself with the use of a fog pattern is ridiculous. (Obviously some of you haven't spent a lot of time on the nozzle or in a fire). By spraying water at the ceiling with a fog pattern you are going to create a lot of unecessary steam which in turn will get you and other members on the hoseline burned. If you're the nozzleman on the hose all of that water that you hit the ceiling above you with will be coming down as hot water on the guys behind you. And they're not going to like you very much after that.
Even if you have a combination nozzle set for straight stream, the pressure needed to use the nozzle (100psi) is too high and makes handling of the line difficult,(Especially when using a 2-1/2" line). You can operate and effective stream with a sufficient amount of water at half that psi with a smooth-bore.
On a side note: Aside from the nozzle choice, some guys don't think about the skills required of a good nozzleman. Some guys just go in and hit everything with water even if there is no sight of fire, just smoke. What a waste of time, energy and needless damage for nothing. Don't just hit a spot where you think the fire may be. Take a minute and look around at the conditions of the room on fire before making the attack. Remember the basics: LOCATE, CONFINE, then EXTINGUISH.
[This message has been edited by GBordas (edited 04-19-2001).]
04-28-2001, 12:54 AM #24Nate MarshallFirehouse.com Guest
Smooth bores are even better when the insurance adjustor asks the fire department why there is so much water damage.
Combination nozzle, halligan, thermal imager, and axe the best tools for interior attack.
04-29-2001, 12:15 AM #25Dalmatian90Firehouse.com Guest
A smooth bore nozzle is the only way to go for fire attack. First off the benefits are tremendous such as greater water flow
Not neccessarily, and even when it is, it's delivered in a less efficient manner meaning you need to use more water.
low operating pressures
There are automatic combinations that work well at low pressures.
and less reaction force making engine work and handling the hose less difficult
A 7/8ths tip flowing 160gpm has 60lbs of reaction force. An automatic nozzle @ 100psi flowing 160gpm has 81lbs of reaction force, and a lower pressure automatic nozzle @ 75psi flowing 160gpm has 70lbs of reaction force. That's noticeable, maybe, but not much. A 7/8ths tip flowing 195gpm has 90lbs of reaction, and a 100psi automatic has 99lbs.
And the reaction forces quoted for automatics are on straight stream. If your using a narrow fog it's considerably less, and dramatically less on wide fog.
There are times when indirect attacks work but only if there is an obstacle that prevents you from hitting the fire directly, In that case then you can deflect the water stream off the ceiling or wall to hit the fire.
Bouncing the stream off the ceiling (or other surface) is still a direct attack. The goal is to put the water directly on the seat of the fire.
An indirect attack is the application of water remote from the seat of the fire. This most often involves the production of steam which smothers the fire by displacing oxygen, robs it of heat by absorbing it, breaks up any "layers" of heat so that particular areas are no longer at or near auto-ignition temperatures, and disturbs the gas flow breaking up the fire.
Not all fog attacks are indirect attacks.
Let's take two room & contents fires. If the room is vented, the attack team can go in with a narrow (30 degree) fog pattern and directly attack the fire, work the nozzle aggressively and push the fire, unburned products of combustion, and steam out the vent. We've seen pictures of "hydraulic ventilation" using a fog nozzle out the window -- in this attack application, the fog nozzle essentially functions as a positive pressure fan in the hands on the attack team.
Take that same fire, in a non-vented room, perhaps a basement. The attack team can use an indirect attack -- put a strap on the doorknob, open the door, hit the ceiling of the fire room briefly till steam starts to bank down, close door. Let it stew, open and repeat a few times until the fire doesn't try to reignite. The steam generated by the application of fog to the super-heated ceiling has smothered the fire, reduced the overall temp of the room below the auto-ignition level. Such an attack doesn't produce untenable conditions -- since the attack team stays outside of the fire compartment, and uses very little water.
Both direct straight stream/smoothbore and direct or indirect fog tactics can be very effective. The choice of which to use really depends on who they interact with other tactics you use -- obviously generating steam when you conduct very aggressive searches isn't a good thing.
Look at your situation. Do you have a need for very aggressive search & vent tactics? Do you have the manpower arrive in a timely manner to safely conduct aggressive search & vent? For that matter, do you arrive in a timely enough manner that there is viable life in the immediate vicinity of the fire? What is your water supply situation? Brooklyn, CT is not the same as Brooklyn, NY -- while the tactics that work in one will work in the other, it doesn't mean the best tactics for the big city are the best tactics for the small, rural town.
I've taken classes taught by FDNY Officers (including interior firefighting), and learned a lot. But it doesn't mean a wholesale adoption of their tactics is best for us -- but we can learn and add what will work for us to our toolbag. If you put my department down in front of a NYC tenement, we'd put the fire out -- certainly not as well as FDNY, but we'd get it done. Similiarly, drop FDNY in front a 600' long chicken coop 20% involved with the nearest water a mile away, they'd put the fire out -- but certainly not as well as we do.
Look at what you need to do, and how you do it, and choose the weapons that meet that need the best.
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