It's really not that scientific. You need the water to move which creates air movement which will draw the smoke out. We took some footage of this at a recent class, ill try to get it edited together as soon as I can.
I knew this would come up sooner or later. Hose-line advancing, handling, and nozzle techniques seem to be a lost art. As for the venting abilities of a nozzle, I was hoping to find a rotary saw with a booster tank so I can do just the opposite. I have actually witnessed so-called 'training' in which the hose-line crew focused on the search, going room to room with line as their orientation. But like anything else, it all comes down to how the firefighters are trained.
Chris is referring to the effects of water turbulence from a smooth-bore nozzle being half-shut. It works. It makes little sense to base your nozzle selection, and purchase based on it's ability to ventilate. However this started as pistol-grip discussion. It seems like a marketing idea that caught on becouse of the lack of hose-line handling principles. Justify it if you want, have a ball with it. Take your aim and pull the trigger.
Makes as much sense to me as it does putting a 100psi adjustible nozzle on the end of a 2.5". But even that has seem to become the popular, state-of-the-art way to go. Save your breath Chris...I only answered this post to say hi. Be safe.
I have to say that I have never even seen a nozzle on a rig without a pistol grip (I think my college had one 2.5" smooth bore with the circular wing handles for master stream applications). For that matter, I asked for a smooth bore the other day, and not a single department on scene even had one. I think this all comes down to how the dept. extinguishes fire, and how much manpower it has. We usually have only a few FF to extinguish an incipient fire, and pistol grips are awesome for maneuvering a charged line with one person. Also, we have very few deep seated fires, such as hay or piles of paper, so all dept. in our area swear by fog combination nozzles.
Oh and in response to a back-up FF, if I am doing more than holding some of the weight if the hose (as opposed to the back force due to nozzle reaction), I am using my webbing to work smarter, not harder.
Very interesting video, great link. As others have said I believe it all boils down to personal preference (or the personal preferences of the folks who trained you, haha). When I went through Volunteer 160 (Alabama school for volly's) our instructor was big on pistol grips/combination nozzles. When I went through career rookie school it was the same thing mostly, though there were a few of the instructors, officers and old salts who swore by smooth bores.
Personally I like the pistol grips, I like the control you have on the line, though I agree you can be limited in the range of motion you have with it. In regards to position of the backup nozzle guy, we kept about an arm length or two back to help steer and keep situational awareness up.
Hey John I assume you have watched the video, I know I use to use the pistol grip, and all it does do for you is fatigue you a lot faster. If you put the nozzle out like in the video it will save you a lot of your energy and it is easier to spray what you need to sprayed and also advance the hose line. Well expecially advancing the hose line, it is a must to have it out in front of you. Give it a shot, if you use proper technique you will find out that putting the nozzle out in front of you will make your life a lot easier, especially with a 1 3/4 or whatever you might use for a smaller hand line. And it does work the same for a 2 1/2.
Ian, is your department a small department? What I am getting at is, does your search team also serve as the back up line or primary line? If not Chris is right, for a search team to drag a line around isn't helping them at all, they need to go straight to the fire and search their way back from it for victums. Also if you are advancing a line with out spraying water the back up man can be a bit behind the nozzleman they can be farther behind the nozzlemen than an arms length also so he or she can go back and help push the line around corners if need be as long as they keep in voice contact with their partner. What the video shows is that if your nozzlemen is spraying thats when you should be right butted up to him, expecially on a 2 1/2.
We have pistol grips on some of our nozzles, even though we don't use them and would like to take all of them off of our rig, at this point Nick Hintz and I are trying to make changes as we can with out causing to many people to get upset. On our Elkhart Load (400 feet of 2 1/2 dead load with a smoothbore nozzle, connected to a 100' of 1 3/4" with a Cheif combination tip which unless we are doing mop up we will spin off the fog and use the smoothbore, we have the pistol grips off of both nozzles for this load. Pistol grips in my eyes are a waste and like you said earlier $40 can go to buying something else, or if you are buying multiple nozzles you might save enough to get an extra nozzle. But proper technique goes a long way, long long way. Start out with your 1 3/4 or 1 1/2" get down like you would in a fire, put the nozzle out in front of you and give it a shot if you haven't before, you will notice it is a lot easier than having that pistol grip right up on you.