As I recall there may have been a 50-50 split between the two. Personally, to get this discussion going, I prefer the combination fog/SS nozzles because of the ability to switch between stream patterns to adapt to different situations.
I feel the combination nozzle offer the best of both worlds....just takes a little knowledge and experience to know when to use what....Cannot beat penetration ability of a smooth bore...but in some instances you might want the protection of a fog.....jus be careful with interruption of the thermal layer or else you are going to get burned....yes water turns to steam and steam burns....knowledge comes from training ....train as you fight...Stay safe and keep the faith....Paul
Copied and pasted from another article. This debate has been going on for years and will probable go on for years to come.
The next tip tested was the 7/8" tip. This tip flowed 160 gallons per minute at 50 pounds nozzle pressure and had a reaction force of 60 to 65 pounds; therefore, we found this reaction force manageable by one firefighter and the window of error for the driver/engineer was larger than with the 15/16" tip. Over-pump this tip or under-pump it a little and it is no big deal. We were getting the same reaction force from the 7/8" tip that was generated from a 100 psi combination nozzle flowing 125 gallons per minute. This size tip proved very effective for quick fire knockdown because of the punch it delivered with its direct attack and added gallons per minute. This is when our firefighters and company officers discovered that the direct attack inside the fire room, or just outside of it, with a 7/8" smooth-bore nozzle proved to be the correct choice for almost every interior structural firefighting operation where the seat of the fire could be reached. Could the same thing be accomplished with a combination nozzle set on straight stream? It certainly could, but not with the reduced reaction force and additional gallons per minute available from the smooth-bore nozzle. Keep in mind, it is gallons per minute that extinguishes fire. Plain and simple, the higher Btu's of today's structure fires requires more water. Did the smooth-bore provide us with any protection inside the structure? If you keep the upper atmosphere from reaching the 1,200 degree mark (the point which flashover occurs). We found that not only did flashover not occur, but we were putting out interior fires with less water than if we were using a combination nozzle set on a narrow angle fog pattern that flowed the same gallons per minute. The theory taught about fog streams went right out the window. There was no protection offered from fog streams inside the structure. The fog stream inside an unventilated structure did not protect the firefighters, it burned them.
My department uses the fully adjustable (fog to straight steam) that has the gpm adjustments on them. I have seen the smooth bore in action and unless you have a CAFS system to get the pressure you need, it would be more efficiant for me to pee on the house and im a girl!!!! And even with the CAFS system, there is no guarentee that the smooth bore is gonna be effective.
We have smooth bores on at least one preconnect on each pump, so we have 15/16" tip with 1 3/4 inch lines. For some time I complained that we were over-pumping these nozzles so we did a test using a pitot gauge.
Turns out, we were in the ballpark with the pump pressure. So, when flowing 180 gpm we have a tremendous fire stream but it takes at least three members to hold onto and advance it. I wonder if there's that much difference between a 7/8 and 15/16 tip in terms of reaction force.
I like the gpm but I hate the fact that I can't hang onto it safely by myself. Does anyone else have this problem? Am I missing something, or just becoming a wimp in my advancing years?
Despite the endless debate this topic brings I will offer my opinion:
Fog nozzles were designed for confined space firefighting, specifically shipboard firefighting. The reason I choose smooth bore (not straight stream) is:
1. a smooth bore does not move air, thus significantly cutting down the ability of the ff to disrupt the stratified gasses and the thermal layer.
2. More water, less pressure. Fact is the only way to put out fire is to stop the BTU production. The only way to do that with water, is to cool the fuel. I love it when people talk about steam "smothering" a fire. Yes water does expand 1700 times at 212 degrees F, however steam rises and being a gas follows the currents of air coming from the fire. Water expanding 1700 times is great when you are in a room with no exit, or ventilation opening...but when was the last time you fought a fire in a locked vault?
With a smooth bore I get better reach, penetration, and more importantly more water on the fire. And before I get a million replies talking about the amount of water on a 50psi smooth bore vs. 100psi combo, know this... I get 125-150psi at my 1.125" smooth bore tip.
"And before I get a million replies talking about the amount of water on a 50psi smooth bore vs. 100psi combo, know this... I get 125-150psi at my 1.125" smooth bore tip."
Sorry, not following ya Jonesy... did you mean 125-150 gpm? And did you really mean 1 1/8 inch tip? 120 psi at a 1 1/8 inch tip is a real MAN'S nozzle, I would think... we call them deck guns where I live.