Smoothbore Vs Fog/Automatic for Standpipes

Replies to This Discussion

Permalink Reply by George H. Potter on October 22, 2008 at 9:38am

This nozzle debate is like the classic question of "what came first, the chicken or the egg". And it will continue probably well into mid century.

The trash flow through and lower nozzle pressure/reaction features of the smooth bores are indeed well based arguments, and quite acceptable. However, how many of you guys have participated in Flashover training in solid fueled training containers - not those sophisticated gas fueled ones?

To correctly and safely dilute and cool the fire gases accumulated at ceiling level you have to use a 30º fog pattern, "shooting" pulsations into the gas mass. A straight stream
does not work.

I have in my hand right now a manufacturer's tech sheet for a 11/2 constant gallonage variable stream nozzle that can flow up to 210 gpm at 75 psi, and 240 gpm at 100 psi.
Put this nozzle on a 13/4 line and it can be an effective weapon. The same manufacturer also has adjustable flow nozzles with the same top of the line flows.

The combination nozzles can get plugged up, Russ's glove would plug any nozzle.

Permalink Reply by Antiquefirelt on October 22, 2008 at 1:12pm

While I have not participated in a flashover training simulator, I would venture to say that your statement basically reads that a fog nozzle is the only safe one to use? My recollection is that the 3-D firefighting authors advocated a straight stream to "pencil" the gas layer?

I think the key to this issue is that when utilizing standpipes there are many factors that point to solid bore nozzles and larger diameter hoses. Ie: PRV's, older systems designed for 65 psi. max, debris in the standpipe system itself, and the fact that in a standpipe op if you are outgunned to start it's not as easy to just back out and stretch the "big line".

Utilizing low pressure fog nozzles only covers some of the issues found with standpipes, where as other than the perception that smoothbores are somehow not safe to use, there is little down side.

Permalink Reply by Ray on October 22, 2008 at 1:32pm

On thing guys forget is - The fire scene is not a flashover trailer. Hitting a fire in short bursts doesn't put out the burn barrel and it doesn't put the room out either.

Permalink Reply by George H. Potter on October 22, 2008 at 2:49pm

Ray, The short bursts are to reduce the probabilities of a Flashover, thus permitting localization of the fire, attack, containment, control and extinction. If you don't get rid of the flashover threat, you're not going to get in, or if you do
get inside with the flashover potentially still there, you may well not get out.

Permalink Reply by Russ Chapman on October 22, 2008 at 3:31pm

George
I have to agree with Ray on this one. If I am getting flashed on, I will not pulse anything, but put the fire out or do an emergency action drill and back out while flowing. The Swedes came up with this "Penciling" that you are describing. The whole reason for this maneuver was for teaching purposes only, and was not to be used for a tactic. Like all teaching, many a student takes it literally. So, this procedure was taken as gospal. The same thing occured with Loyd Layman and the fog theory. If you read his book, he NEVER said for any firefighter to be inside a burning structure with a fog stream. Then Royer and Nelson took it one step further, and then people took it for gospal.
Six dacades later, we got folks going into burning structures with fog streams. The power of the pen.
I am not a fan of the "breakaways" as who will think to break off the tip when they need it? I will bet you that department will have guys who will leave the fog tip on. Sorry.

Permalink Reply by George H. Potter on October 22, 2008 at 4:16pm

Adam,
The penciling is just one of the many application options within the 3D concept which also includes: pulsing or spotting, bursts or sweeps, painting, straight stream (yes SS) direct attack and the age-old indirect attack.The Swedes have recently introduced what they call the "shark" which also contemplates initial straight stream with the ball (or slide) open partially open and aimed directly at the seat of the fire, followed by change to fog patterns and fully opening the shut-off.
However, the principal technique used to penetrate into the gas mass is using the 30 to 60 degree fog pattern to break up the stream into individual water droplets to absorb more heat in less time as well as diluting the concentrations of the combustable gases to below the lower inflamtion limit. This cannot be done with a smooth bore.
The simulator container is a training tool. The dimensions are reduced and static; 8 feet wide, 8 feet interior height and 40 feet long. It is not meant to accurately copy real structural fire conditions, principally thermal rerlease. It was devised to create an environment SIMILAR to real life fires, with the great advantage over acquired structures that you can repeat drills over and over again without destroying the scenario. Purpose built burn buildings (at training centers) are fine except that they don't retain the heat as the metal containers do (concrete breathes). I strongly reccomend participating in a flashover course in a solid fuel simulator. The experience will add another tool that can be very useful in the real world.

Permalink Reply by Wesley Stephens on October 22, 2008 at 9:19pm

While it is good to train in flashover simulators I don't think the intention is to make people believe that they will be safe in a flashover if they have a fog nozzle. If this condition is occuring the safest thing to do is to get out. The best way to deal with the super heated gases over your head is proper ventilation. You can drive them back using several techniques with a smooth bore but your wasting time trying to extinguish the flames up at the ceiling. With out getting into the chemistry of fire I believe that the best way to prevent super heated gas from burning over your head is to cool down the fuel source that is producing these gases.

Permalink Reply by Wesley Stephens on October 22, 2008 at 9:49pm

I think the thing that I have a problem with is the idea of using your attack line to control the atmosphere. My theory is that the engine company's job is to put copeous amounts of water on the seat of the fire until it goes out. It is the truck companies job to ventilate the structure and remove the super heated gases to prevent rapid fire progress.

I think simulators and other training tools are great, but we need to emphasize that the techniques we use to control our environments during training are for training purposes. While their basic concept may be utilized in real fire conditions the level of control that we have in these real fire conditions is somewhat limited.

Permalink Reply by Mike Walker on October 22, 2008 at 11:05pm

George,

I am afraid you may be failing to realize many of us use Flashover simulators quite often for training. Though Russ's example about a nozzle clog may see extreme the point I think he was trying to make was fog nozzle tend to clog. In a standpipe situation one can expect brackish water with rust scales from the inside of the standpipe walls for up to forty-five minutes of flow (I've seen it). Those rust scales will very likely clog a fog nozzle. This does not even consider the other likely debris that is inside the standpipe that even a 10 second pre flush of the standpipe connection may fail to clear.

Fog nozzles are just like any other tool we use; For certain applications it is absolutely the best choice. But also like all the other tools we have at our disposal, it may very well be the worst tool. As has been preached to us all over and over again, let the situation dictate the tacics (ergo tools) we use.

Too many times we limit our perception of "acceptable" to only what we have personally experienced. Think about it.

Permalink Reply by Ray on October 23, 2008 at 8:48am

George, My point was that techniques used in flashover containers are being used in the field incorrectly. I understand what the short bursts do in the container. They make sure the show continues. The problem comes when we have firefighters thinking that their nozzle should be shut on and off during fire attack and that has only come from flashover training. Last year in Texas two firefighters were LODD's at a house fire. They replaced the original nozzle team who spent their time in the house "penciling" the fire and claimed it was out. It was not out. What happens is firefighters are getting a bit of information here and there and assuming that it is something they should do every time. I am all for preventing flashover.

Permalink Reply by George H. Potter on October 23, 2008 at 9:22am

Ray, I must ask you and the rest of all of you out there that you do not take what I have been saying as Bible. It is not my intention to say that the flashover training exercises will solve all the situations that could and will quite probably occur in any and all confined space fires. These simulators are exactly that, simulated scenarios with limited dimensions and fire loads that are designed to give participants exposure to confined space fires, IN A REASONABLY SAFE INVIRONMENT. The simulators do have limitations, lots of them, and the training sessions therein should be taken as references and not absolute and total solutions. I once had the good fortune to train a mid size municipal FD in an abandoned (authorized for destruction) fish cannary for an entire week. We had literally dozens of varied sized confined spaces, from 100 sq. feet to nearly 5,000 sq. feet and 30 or so ft. high ceilings. These were real world conditions and the FF's gained tremendous experience that they could relate with other real world situations.

I am not a total and absolute fanatical supporter of exclusive use of the combination nozzle. SS does have its place in the ample spectrum of firefighting tools.

What I am trying to communicate is that SS should not be considered as the only stream for interior firefighting. It is quite probable that one may outweigh the other in a balancing act between the two, but we should all be open minded enough to recognize the virtues as well as the limitations of each. I have used probably every combination of both concepts over the last 50 years, and although I personally prefer combination nozzles I cannot nor will not disregard solid bores as solutiion for a wide variety of situations.

I do feel that I'm on the lighter end of the scale.

Be carfeful out there, everybody,

George

Permalink Reply by Tom Gherman on October 23, 2008 at 10:06am

I see the statistics and they clearly show the lack of fireman looking back into history and learning from others mistakes. I am all for the Smoothbore 1 1/8" tip. It has proven itself time and time agian. People have just relied on the fog for to long, and think it is the cure all. You look up the exact wording from Lloyd Layman and how he discribed the Fire compartment. There is a time and place for everything, the fog or combo/auto is not the correct tool for standpipe operations.

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