05-19-2001, 08:05 PM #1Paul GrimwoodFirehouse.com Guest
Texas Firefighters Adopt 'pulsing' Fog Tactics
In the early part of February 2001 the Austin Fire Department in Texas USA completed 146 live training burns in acquired structures and evaluated the 3D water-fog approach in every situation. Over 500 students employed this form of fire attack and noted that the application of 'pulsing' water-fog droplets into the super-heated fire gases 'worked on the great majority of fires'
The 'new-wave' applications developed throughout europe since the 1980s were particularly effective when traversing the approach route to fire-involved compartments. The improvements in visibility and maintaining thermal balance when compared to smooth-bore attack was particularly outstanding.
It was noted that on a few occasions the fire would grow so rapidly that no amount of nozzle 'pulsing' would control it and on these occasions even a smooth-bore application failed to reduce the fire's intensity, causing firefighters to retreat
One Austin Fire Officer stated - 'I believe the 3D attack method worked very well and was the method of choice in the vast majority of the fires we encountered in the training and are likely to encounter in the field. The use of 3D water-fog pulsing streams is the safest and most effective method compared to other applications although it is not suited to all situations. We are now teaching our firefighters these techniques'.
05-24-2001, 11:12 PM #2benson911Firehouse.com Guest
Good for you, Paul!
And great for the FF's in Austin, Texas.
05-25-2001, 03:30 PM #3ADSN/WFLDFirehouse.com Guest
Where was the error that caused the firefighters to retreat? Was it with the size up, application of water (3D Fog), equipment malfunction.
I would prefer to use tactics and equipment that will work when I need it. It doesn't do anyone much good if the fire drives us out of the building. If you plan on bringing enough water with you (flow) to put out the fire you won't get driven out.
I eagerly await your response.
05-25-2001, 06:31 PM #4Paul GrimwoodFirehouse.com Guest
There are times in this job when it is OK to retreat! There will be times when it is nothing to do with 'error' or lack of water. If every fire was that simple then we would be laying nothing but 250 gpm lines - but sometimes, even 250 gpm lines have to retreat!
Be smart ADSN - don't keep opposing techniques you have little or no experience in. The mere fact that a fire department like Austin as well as the US Navy and a large proportion of the world's firefighters have advanced these concepts with success should inform you that they MAY have something worth investigating here!
If a fire is escalating then you can be certain that venting of the structure is playing a major part in that process - maybe that venting was a natural result of fire spread - or perhaps it was initiated by the on scene firefighters. I think you should take a closer look at the openings you are making in a structure when discussing escalating fire-fronts before blaming under-powered lines.
I have advanced hoselines into many major conflagrations alongside some of the world's most professional firefighters - they were professional because they knew when to 'retreat' and back a line out. They were NOT in error because they were hauling a 150 gpm inch and three quarter line in!
Have you ever heard of the Kings Cross underground fire? Our guys were advancing towards a 25 MegaWatt fire - it was bottled in an underground (train) tunnel and 39 people lost their lives, including a firefighter. They retreated a few times as well - nothing to do with a lack of water but more to do with airflows in the tunnels firing the flames up!
When FDNY were fighting a fire in the Empire State building they suddenly had to retreat due to the external windows failing - the wind sent the heat at them like nothing you have ever experienced (if you have never had cause to retreat) and I tell you - Not even a water cannon would enable you to hold your ground in that situation!
05-25-2001, 07:02 PM #5ADSN/WFLDFirehouse.com Guest
I once had to back out due to high winds. It was like being in a blow torch. We reentered with a larger line and took the fire.
Our line had the flow to protect our retreat, then the greater flow did fine in extinguishing the fire. What I am concerned with is not having the flow to begin with.
From what I have read on the topic this tactic is usually preformed with higher pressures and lower flows than the usual line. What are the details from TX I didn't see them at the website you posted.
05-25-2001, 07:47 PM #6Paul GrimwoodFirehouse.com Guest
Remember ADSN - pulsing water-fog is a complementary use of a fire stream to the straight-stream approach. I have never knowingly implied that its an either/or situation.
Having said that they has been much operational and scientific research that attempts to compare smooth-bore .v. straight-stream .v. indirect fog .v. 3D 'pulsing' fogs for fire extinguishment and gas layer cooling to prevent flashover etc.
The truth is - ALL of these differing applications of water streams demonstrate both positive and negative effects under varying fire conditions and situations and no single stream is suited to all the scenarios a firefighter is likely to face.
I feel the best option is to be armed with an attack line that optimises ALL types of stream - ie; a combination nozzle.
Austin used smooth-bores, straight streams and pulsing fog patterns in their burns. They used 125gpm lines and remember - they were not 'trained' specifically in these techniques - they were experimenting, and yet they noted success in the large majority of their burns! Had they have assigned an experienced instructor in 'pulsing' to this project I feel they may have advanced even further and appreciated the benefits to a greater extent.
I have no problem with high-flow lines in direct attack mode flowing a straight stream pattern into a major fire-front. However, on the approach route, the direction of a straight stream into super-heated gas layers forming in corridors and rooms adjacent to the fire compartment is proven ineffective in comparison to pulsing fog patterns.
For me the argument should not be 'high-flow' versus 'pulsing fogs'!
They BOTH have their uses on the fireground. But I feel it is unsafe and ineffective to rely on any single option.
05-25-2001, 08:52 PM #7hfdfaoFirehouse.com Guest
Once again, very well put....
May your vents be leeward, your searches be negative, and your overhaul complete......
05-28-2001, 05:30 PM #8LooperFirehouse.com Guest
I haven't seen the Austin report, but it sounds like the steam conversion method.
We've been using steam conversion techniques for many years, with good success. It offers quick knockdown, with limited water and less disruption of the contents of the room -- important for invetigation afterward. Works best in a room that hasn't vented to the outside yet.
Sometimes a steam conversion isn't appropriate, due to very heavy fire load or if the structure has already vented itself. It also isn't very effective in a large room (warehouse, church, ect) with very high ceilings, where the heat may not have built up enough to convert the water to steam. Thats why its important to use lines that will flow a respectable amount of water so that you can still make a direct attack if needed.
We use either a 1.75" or 2" line with a automatic nozzle (either 200 or 350 gpm)and class A foam. Set the nozzle to a tight "power cone" pattern, and hit the ceiling with a short (3-5 second) burst of water. It turns into steam (1700 to 1 expansion ratio), which displaces the oxygen and snuffs out the fire. Then you can ventilate and mop up the hot spots.
We don't have any basements around here, so I don't know how it would work in that situation.
It works great for us and we have put out many room and contents fires with less than 50 gallons of water.
05-28-2001, 05:42 PM #9Paul GrimwoodFirehouse.com Guest
05-30-2001, 03:01 PM #10LooperFirehouse.com Guest
Good articles...I now remember seeing it demonstrated (in part) during a class at Texas A&M.
We have a house burn next month. Maybe I can convince the white hats to play with this a little.
05-30-2001, 03:24 PM #11Paul GrimwoodFirehouse.com Guest
Good for you Loops - but take care! We have noted that these techniques take from 5-10 attempts for firefighters before they are truly effective, safe and comfortable with them.
I constantly receive e-mails from US firefighters who have tried pulsing fog patterns for the first time during house burns and they generally achieve effective results that make them wanna look a bit deeper into this.
A safer approach is to practise in purpose-built container systems before advancing into 'real' structures or larger compartments.
either way - good luck - practise NFPA safety procedures and let me know how you get on........providing the 'white hats' let you have a play!!
05-30-2001, 07:04 PM #12ADSN/WFLDFirehouse.com Guest
"We have noted that these techniques take from 5-10 attempts for firefighters before they are truly effective, safe and comfortable with them."
I think this sets up many firefighters and departments for failure. This is the first time that I have read about the extensive training and practice required for this technique. The 3D fog method has been mentioned for months on these posts. If someone decided after reading previous posts that they wanted to try this, they probably failed to extinguish the fire. With the lack of fires that we all have I don't feel that this technique should be pushed upon people the way it has in the past.
Too many departments don't train enough on the basics. You are suggesting that we should try a technique that could take 10 live fires to feel comfortable with?
While I still would like to go to a class on this, it is looking much more doubtful that this should be adopted by the masses.
05-30-2001, 08:15 PM #13Paul GrimwoodFirehouse.com Guest
ADSN - Read it again buddy! I never said 5-10 live fires!!!!
I said 5-10 attempts - in a fire simulator (purpose built container) where the gas layers repeatedly ignite these 5-10 attempts would take a few minutes during one single live burn.
Under these conditions, repetitive and safe evolutions are easily achieved - once these skills have been harnessed, its time to move into larger compartments or even 'real' structures.
Like I said before - extinguishing the fire is not the prime objective, as you constantly fail to grasp!
06-01-2001, 12:47 AM #14ADSN/WFLDFirehouse.com Guest
So let me get this straight.
You in a fire building advancing towards the seat of the fire, you deploy tactics that will only delay a flashover. In prior descriptions of this tactic you made reference to this being enough for extinguishment. I'm sorry but you seem to be leaving something out.
What are you doing with the fire once you get to the seat? I'm really not comfortable now with being there with a high pressure low volume line.
What is wrong with just driving the fire back with a SB or straight stream and extinguishing the fire?
I must be missing something here. Give us a step by step description of this tactic. You have a 2 story frame with a second floor bedroom involved and fire advancing down the hallway towards the top of the stairs. (where you are coming up)
Please give us line size, pressure, fog pattern, anything you want to adequately describe this tactic.
Frankly, between your posts and the website you listed it seems that the 3D fog can do less and less each time we read about it.
06-01-2001, 05:45 AM #15Paul GrimwoodFirehouse.com Guest
ADSN - whats up buddy - you don't seem to be getting enough sun!
When did I suggest you should use high-pressure low flow lines? If you were sincerely interested in studying these tactics and methods you would take the time to click on my links and study the extensive research instead of constantly spouting crap!
You are asking questions here that I have answered over and again in threads you have posted on. I would have liked to think you were reading previous posts before posting on a thread yourself.
I only report what other firefighters have stated - if the US Navy, the Austin Texas fire department and over 100 other major fire departments worldwide have evaluated (over years) and approved these techniques then perhaps there is something worth looking at.
My personal experience and committment is based upon inner city firefighting over 26 years in both the USA and England, having used both smooth-bore and combination nozzles on thousands of 'working' fires.
OK - your points!!
I have stated that extinguishing is not the PRIMARY purpose of 'pulsing' fog patterns - it isn't. BUT IT WILL EXTINGUISH FIRE! In terms of gaseous combustion (fire gases burning off inside a compartment) it is a most effective form of fire attack. In comparison I would prefer this over direct (smooth-bore) attack but there are equally good arguments that propose high-flow direct applications may be better......I won't argue the point because if you can see the fire's source then either application is effective!
If you are advancing some way into a ventilation controlled fire with large amounts of super-heated fire gases are transporting throughout the structure then a fog pattern is FAR SUPERIOR (scientific and practical fact) at removing the dangerous heat from the gases. We do this to prevent flashovers, backdrafts and smoke explosions from occurring - the reasoning is lengthy so research my website!
The fire you describe is the sort of fire that firefighters are likely to meet every week - its a classic.....Line size? Thats another debate but I would personally choose an inch and three quarter 'cos its the most manouverable attack line inline with decent flows available (hey there are other options)! Nozzle - any nozzle that provides water droplets that are able to suspend in still air for a few seconds (rule of thumb) - nozzle pressure - anything that gives you the same effect from the droplets, the higher the pressure the finer the droplets (rule of thumb) but lets say 80-100 psi. Fog pattern? in this scenario probably a 20-40 degree cone pattern, lets say 30 degs average.....pulsing brief spurts of droplets into the overhead on the approach route to the fire - from the outside, into the structure, up the stairs, along the hallway.....'pulse and read.......pulse and read'........arrive at the fire, see the flames and change to a straight stream to attack the fire itself (some prefer to maintain a narrowed fog pattern - opinions vary).
You say - '3D fog appears to do less and less each time you read about it'!
Perhaps you are reading but not understanding? or perhaps I am not very good at communicating! Either way, ask the thousands of firefighters (including the hundreds of US firefighters who mail me) about their experiences with this style of approach......98 percent positive, believe me.
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