semi fog vs. strait stream

[Dave1983]

but given the modern construction and the compartmentilization that is present, SOLID streams (not straight) would be first choice.

I spent 3 days last month in a class with Dr. John De Haan, PhD, the author of Kirks Fire Investigation. As part of his over 35 years studying fire behavior, Dr. De Haan has conducted over 600 test burns, and stated specifically that FOG is the better choice in these situations.

Just an FYI.

[FyredUp]

I spent 3 days last month in a class with Dr. John De Haan, PhD, the author of Kirks Fire Investigation. As part of his over 35 years studying fire behavior, Dr. De Haan has conducted over 600 test burns, and stated specifically that FOG is the better choice in these situations.

Just an FYI.

An author of a fire investigation text says that fog is a better choice. Why? Because it leaves evidence undisturbed by fire streams?

It most certainly is not the better choice if there are victims or firefighters in the fire room and there is major involvement. An indirect attack can be a wonderful way to steam the absolute crap out of yourself, your crew and victims if done wrong. Too much water creates too much steam which pushes it all down on you or the victims.

It can be an effective tool in limited circumstances. Such as no victims or firefighters in the room. Entrances and exits are controlled. The fog stream is injected through a doorway or window that is then closed to allow the steam to work. The room is then ventilated at an exit seperate from the one you will enter through. This can be very effective.

I am still of the mind though that a brief sweep of the ceiling, either a pulse from a narrow fog or a shot from a straight or solid stream, and then water applied directly to the fire is a better and less punishing fire attack method for the firefighters.

By the way I am not at all confusing the pulsing of a fog stream like Paul Grimwood advocates and the fog and steam flooding of an area in an indirect attack.

Fog, applied wrongly like it is most often, in interior firefighting is a dangerous thing and the word protection and fog should not be used together referencing interior firefighting.

[crazyaboutEMS17]

I'm curious, why do you guys that think Explorers don't know about this information feel this way? I can't speak for all Explorers, but mine can tell you more about fire streams than a lot of the firefighters that I know. Aside from that, if you're department isn't teaching this information, shame on you. They're supposed to be learning these kinds of things, isn't that the whole point of having an Explorer post?

As far as my opinion on the matter, both have their purpose and a time and place to use them. I have used both a "modified" fog (30-degree) and a straight stream when interior firefighting, it just depends on the fire. But, you must understand how each works in order to decide which circumstances are appropriate for which stream.

A fog is basically scattered droplets of water. This creates a large surface area for that water and allows it to convert to steam more readily than a solid stream of water. The problem with this is that when converting to steam, the water expands about 1,700 times. If you're not careful and use it in the wrong situation or use too much, you can push that steam and/or the smoke and heat right on top of you.

A straight stream is essentially a solid stream of water, with far less surface area. While it allows less steam conversion due to having less surface area, it has better penetrating ability.

Examples of what I use them on are as such: if I'm at the doorway of a heavily involved room that's vented (we use PPA on both my departments), I'll kick the nozzle to a modified fog and knock it down. If I've got a limited amount of fire or I'm inside the compartment, I'll use a straight stream directly on the base of the fire.

I agree with the part about explorers. I'm a jr. ff and even though i don't do interior attack i've learned a lot working on the hoses on exterior attack. i have pretty much the same opinion about which stream to use. i prefer a semi-fog for putting water in a window to knock a fire down. but why tear down explorers for asking questions like this? it's stuff that we need to know and if we've learned it, why can't we share our knowledge amongst ourselves?
Josh

[eng51ine]

Combination vs. Solid stream...never heard this argument before. If I had it my way, my engine company would be running with nothing but smooth bore nozzles. Lloyd Layman brought the fog nozzle theory back from the US Navy after WWII. It worked great for shipboard firefighting...get a compartment fire, few blasts on full fog, shut the door and wait for it to steam itself out. Now go back and read some of Layman's writings. Even he agreed that it isn't something that should be used in interior fire attack if you're going to have people (FD or civilian) in the compartment. Nozzle reaction is another reason...our combination nozzles operate at 100psi vs. smoothbore line which I can pump at 50psi. This is a huge factor when operating on the 10th. floor. Yes, you do have to watch out for more kinks...but the way you deploy your lines helps alot...it's just general firemanship. Another reason is the amount of GPM we can put on a fire in comparison to a combination nozzle...plus if I'm in an enviroment that's getting ready to hit flashover, I want to be dumping as much water into my overhead as I can, not sitting on my back with a full fog going. Now talking about the tactics side...how many people were taught to attack from the unburned side?? Why do we do that?? Because you don't want to push fire, right? Well that's what happens when we go charging into fires with fog streams. We show up with a room off on side A and we have to stretch a line to side C to get in and knock it...it takes a while so you know that fire is now 2-3 rooms. With a smoothbore, I know I can go straight in the front door and put fire out.

These are just my opinions...take it for what it's worth. Realistically, give me a combi nozzle and I'll still put fire out...it'll just be a very tight fog stream =)

Read David Fornell's book "Fire Stream Management". Everything you need to know is in that book.

[jpmaro]

On our nozzles you can turn it left and right to control the water flow. Left is fog and right is the stream. Th saying we use is left to live and right to fight. You use the fog to protect yourself if it gets to hot and the strean the fight. thats the basics

[Natatha]

I was told during a training session one night that straight streams are the ones to use no matter what. However, if you get into a room with lots of smoke, spray at a window and widen it up until you hit all the edges.. And that would clear it out pretty quickly.

I would assume this is true, but I can't remember the exact details on it, but I believe this was it.

[FyredUp]

I was told during a training session one night that straight streams are the ones to use no matter what. However, if you get into a room with lots of smoke, spray at a window and widen it up until you hit all the edges.. And that would clear it out pretty quickly.

I would assume this is true, but I can't remember the exact details on it, but I believe this was it.

Briefly, VERY BRIEFLY sweep the ceiling with your straight stream to cool the overhead. A second or two is enough. Bring that stream down into the heart of the fire. Use the stream to ventilate. If you can't see the window use the straight stream to find it by working the stream across the wall until you hear the sound difference. If the window is already gone the stream will not make the sound of the water hitting something. Now if the window is still there maybe you can blow it out with the stream OR you will have to advance and break it out. If the outside vent crew hasn't done it by now. The fog pattern should just fit inside the window opening. the stream creates a venturi type effect and sucks the smoke out with the water pattern. Very effectivve in one room fires.