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Can a 2 1/2" hose be used as a hand line for fire attack?
When I first started in the fire department we had two types of hand lines 1 1/2" and 2 1/2". We were taught that when you attack a fire that you always take your first line in, backed up by a 2nd line at least as big or bigger. We were also taught that if you have light fire conditions you can use small (1 1/2") water, but heavy fire conditions require big (2 1/2") water. I know we now have 1 3/4" hand lines, but I did not know that we no longer use 2 1/2" hand lines.
A couple weeks ago I was out drilling with my engine company and was discussing using 1 3/4" and 2 1/2" hand lines, when to my surprise one of my pump operators who has been around 30+ years and happens to be a retired state fire instructor said "you can not use a 2 1/2" house as an attack line it is to big".
What do you think?
Replies to This Discussion
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Permalink Reply by Don Catenacci on
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Actually the real reason is standpipe systems are designed for the use of 2 1/2 inch hose. The friction loss in high rises makes pressures excessive to make the small lines fnction properly, especially if stupid nozzle choices are made like automatics or other 100 psi combination nozzles.
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Permalink Reply by Derek J Sinesi on
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John, The Chittenango Fire Department uses 3" hose instead of 2 1/2" line. We have a couple lengths of 3" ourselves we use to fill tankers that only have 2 1/2" inlets.
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Permalink Reply by captnjak on
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But why do we want the stream to remain cohesive? If the fire is destroying the stream, the stream is also destroying the fire. When the stream breaks up into smaller water particles it is more efficient at absorbing heat. This is one of the reasons why we whip the line around and let water deflect off walls and ceilings; it breaks the stream up and knocks down fire quicker.
Seems to me that 300 GPM's is 300 GPM's regardless of one line or two. Of course, you are correct in that the single line would more easily and quickly be put into operation and any fire company should be able to do it when called for.
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Permalink Reply by John Gallagher on
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Not sure I agree 55, I would think it would depend on the number of lenghts stretched and conditions in which it has to be moved. If stretched from the pumper to the door to the fire on level ground maybe. Throw in a dry stretch of four or five flights of stairs and an occupancy where the charged line has to move room to room and your talking a lot of work for 2 men. I seem to remember reading somewhere, that they now have 1-3/4 in. low friction hose that can flow the same amount of water as the old 2-1/2 in hose. If you can get the same result with less labor, why not? The fire service should evolve as technology evolves, otherwise we'd still be dipping our beards in a water bucket and stuffing it in our mouths instead of using SCBA.
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Permalink Reply by 55 TRUCK on
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John, you need to consider that most Departments don't have the budget to purchase every new tool that comes out. Also I was trying to show that a understaffed Vol. or small paid dept. can pull a 2-1/2" with 2 FF on the line.
I do not know how you fight a high rise fire. Here we get a high rise responce bassicly a 2nd alarm with extra companies on the initial alarm. Most of our high rises have stand pipes. So we carry the load up dry and hook in to the stand pipe. Some of our 5 & 6 story buildings do not have stand pipes. On these we go to the floor below the fire, drop a line a pull a supply line up from the Engine and hook our attack line into it.
You are right about he 1-3/4" line. We used to use them in our high rise packs(regular 1-3/4"). In fact we would like to have the option to use them in those situation where you are first due and need to get some water on the fire rapidly. The next incoming companies can bring the 2-1/2" up.
We have found that the 2-1/2" attack lines hinder the egress of civilians.
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Sorry captnjak, but your thought process couldn't be more wrong.
You want the stream to remain cohesive enough to muscle through the heat to get to the heart of the fire. There if it is used to bounce off the wall or the ceiling and breaks into smaller drops that is fine, but if the flow is inadequate to get through the heat you will never get a chance to bounce it off anything because it turns to steam before it has any extinguishing effect. So in fact 2 - 150 gpm streams do flow 300 gpm together, but if 150 gpm won't penetrate the heat then you aren't really flowing 300 gpm at the fire.
You are FDNY right? Your standard 2 1/2 inch nozzle is a 1 1/8 inch tip flow 265 gpm at 50 psi at the nozzle. 2 1/2 inch hose with that 1 1/8 inch smoothbore, from all I have read, is the standard FDNY highrise hose pack. If 2 lines flowing an equal amount would be equal to that why isn't your standard op to take 2 - 1 3/4 inch lines in instead of a single 2 1/2?
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Yeah, that low friction 1 3/4 inch hose actually is at least 1.88 interior diameter and isn't really 1 3/4 inch hose anymore. It is essentially poor man's 2 inch. I laugh every time I see someone post, or say, LOW FRICTION LOSS 1 3/4, what a joke.
Why not be truly progrssive and go right to 2 inch where you actually can flow up to 300 gpm out to a 300 foot preconnect without making the pump scream like a mad dog? I know that works because we have been doing it for over a decade.
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The stream does not have to get to the seat of the fire initially. You can cool down the fire as you advance TOWARD the seat of the fire. It is not an all or nothing proposition as far as hitting seat of fire immediately upon opening nozzle. There are times where a 2 1/2 or 2-2 1/2's working together would not penetrate to seat of fire. Hitting the outer "edge" of fire area will cool the entire area. Sometimes you have to work your way in to the seat of the fire. We can progressively cool the fire as opposed to penetrating the fire.
The reason we don't use 2-1 3/4's right out of the gate is because it requires more time and manpower to get going. A single 2 1/2 is obviously quicker. The 2-1 3/4's would also require higher pressure into the standpipe system to overcome increased friction loss. The less pressure put into some of these systems, the better off you are.
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The above post was supposed to be in response to 55truck's assertion that 2 men can advance a 2 1/2 line.
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Don, If you can flow the same amount of water thru a smaller hose with less labor, what would be the down side to that? Are those claims false? 1.75in. 1.88 in. or 2 in. if your flowing the same as 2.50in. hose with less effort, why not do it? I think we all agree that 2-1/2in CAN be used as a handline, but if you can get the same result with less effort, wouldn't you do it?
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