My way is still better than yours :)
Yea i am not a fan of the tft's either but that is what the city put on the rigs.
This thread has got me thinking though.
I wondder what kind of "big" flows we can get out of our new ponn 1 3/4 hose.
I might just have to break out the flow meter and a 1 1/4 tip for the smooth bore
Specifying pipe size and not performance takes the monkey off the manufacturer's back because no matter what the final flow and friction loss are they can sat they met the spec. Specifying flow requirements makes the manufacturer do the engineering to ensure they meet that requirement and not just simply throw in pipe, with 37 elbows in it.
Essentially, we're operating pretty similarly, with a few differences in the details: Our 1 3/4" 200' and 300' crosslays are our equivalent to your 2" crosslays, just with a preference for 250gpm top flow instead of your 300gpm, and our "long line" is basically your "apartment line" except we didn't want a wye (less bulk while stretching, and no risk of it getting kicked or bumped closed) and we chose for the base hose to be 2 1/2" instead of 3" (a bit lighter for minimal staffing).
One thing is for sure: I really can't see justification for flowing 250gpm offensively with anything larger than 2", with the exception of highrises.
Okay I went and checked the pump discharge pressures on our attack engine.
For our 200'-2 inch front bumper crosslays the pressures are:
160 gpm: 75 psi PDP
200 gpm: 125 psi PDP
300 gpm: 150 psi PDP
For our 300'-2 inch over the pump crosslays the pressures are:
160 gpm: 95 psi PDP
200 gpm: 145 psi PDP
300 gpm: 190 psi PDP
Keep in mind these are PUMP DISCHARGE PRESSURES, not simply friction loss figures.
FyredUp: The numbers pretty much agree with the flow tests and your PDP numbers except for the 300 gpm on the 300’ cross lay. I made the following assumptions….
160 & 200 gpm were using a 15/16” slug tip and the 300 gpm was done with a 1 ¼” slug.
15/16” tip at 160 gpm needs a NP of 37 psi.
15/16” tip at 200 gpm needs a NP of 57.5 psi.
1 ¼” tip at 300 gpm needs a NP of 41 psi.
160 GPM Np =37psi Hose Loss = 29psi Piping loss = 9 psi
200 GPM Np = 57psi Hose Loss = 42psi Piping Loss = 14psi
300 GPM Np = 41psi Hose Loss = 80psi Piping Loss = 31psi
Piping losses calculate to an equivalent of 28 feet of 2” iron pipe.
160 GPM Np = 37psi Hose Loss = 44psi Piping Loss = 14psi
200 GPM Np = 57psi Hose Loss = 63psi Piping Loss = 25psi
300 GPM Np = 41psi Hose Loss = 135psi Piping Loss = 14psi *
(*) – Suspect Reading - Based upon the previous two flows, this loss should be around 50 psi. Perhaps these flows were performed on different cross lays with different piping and elbows. Equivalent 2” pipe length for the first two is 50 feet. Equivalent length for last reading is only 12 feet of 2” pipe or 38 feet of 2 ½” pipe. (about 2 elbows and the swivel)
To verify the final (300 gpm) use a pitot gauge on the 1 ¼” slug tip. Raise the PDP until you get 41psi on the pitot. This should be the required PDP for the 300 gpm setting. The darn piping makes a big difference when you are pushing flows that the plumbing wasn’t designed to do.
The flow tests were performed using a calibrated flow meter. The nozzle used for the 160 and 200 gpm flows were the Elkhart Chief Model 4000-24 low pressure combination nozzle tip attached to an Elkhart B375GAT pistol grip shut off with a built in 1 1/4 inch slug. The water way through the ball shut off is 1 3/8 inch.
To be honest we weren't too worried about the nozzle pressure just meeting a specific flow through the desired length of preconnect. The front bumper crosslay was tested by pulling one of the lines and flowing it. The over the pump crosslay beds were tested the same way, one line was pulled and flowed.
I am going to have to borrow a flow meter again to test our second pumper so perhaps I will retest the attack pumper and this time attach a pressure gauge behind the nozzle to get abetter idea of nozzle pressure.
FyredUp: Through the years, I've been burned a couple of times using flow meters. A pitot and a properly tapered playpipe and nozzle with a calibrated gauge pitot is an exact way to confirm that the flow meter is properly calibrated. This is the reason that UL runs their annual calibration tests on apparatus flow meters. Also since the present day hose lines expand with internal pressure, they also change friction loss as the diameter changes. I only mentioned the possible problem with the 300 gpm flow on the cross lay because the piping losses seemed to be a little out of whack. We too are fighting operating pressure differences, but are using TFT's so as long as the Wide Open flow is reached, other application rates are controlled by the nozzleman. A gauge behind the nozzle (opening at right angle to flow) can be influenced by the venturi effect and turbulence in the line. Put a wye behind the nozzle and attach a gauge to the other outlet. This way the velocity head developed in the hose line can be "mostly" measured.
I used 2" attack lines on two the departments early in my career back in the mid to late 80's, and I have mixed feelings on it. One used it for all of thier attack lines, and the second used it as a reel line for selected situations where a little more flow was required beyond the standard 1 3/4". On that department, it was discontinued shorly after I arrived and we switched over to all 1 3/4".
While it does provide excellent flows, especially for commercial fires, I found it to be heavy and difficult to move around in a small residental space, such as a trailer or less than 100-1200 sf home with a heavy fire load.
Certainly it is a very good choice for departments where that 3rd man on the hoseline is almost always available, but if you are consistantly operating with 2, I found it to be less than ideal for interior operations.
From what I understand, my previous department (which was the one that got rid of the 2" shortly after I arrived) has switched to 2" as the primary attack line.
For the circumstances that we bought it for it works perfectly for us and I don't figure that we will be changing anytime soon.
My dept has been using 2in handlines since before i became a member 10 years ago....I honestly cant see doing it any other way...ive used 1.5" and 1.75" in training and so forth but actually hated it and couldnt wait to get back to the 2in we have no problem with advancing the line with 2 guys through even the worst cluttered residential structures or commercial structures. We've also changed from dry line to wet line advancement when we changed over to the nitrile rubber hose with smoothbore pistol grip nozzles
Might be a bad time to bring up Paul Grimwood but we have been decreasing line size and increasing training.
Still using 2 inch and 2 1/2 but just another tool in the tool box.
What is encouraging is that individual departments are taking the time to experiment with what they use and what they encounter.
1) What is the relevance of the Paul Grimwood comment?
2) Please explain what you mean by decreasing the line size and increasing training? Fire of a specific size takes a specific flow to cool and effect extinguishment. So unless you are meeting the needed flow all the training in the world won't help.
I think I can maybe shed some light on that for ya. In Canada the "standard" methods of "attacking" a fire are somewhat "different" than in the States. UNFORTUNATELY, MOST Canadian FD's bought into the whole "little drops of water" concept decades ago...we generally canned all the straight bores, and pretty much uniformly opted for 1 1/2" attack lines.
This is essentially Paul's Fog Attack and 3D attack type stuff. AS I view it, it works well in EUROPEAN structures, which are generally much heavier built, AND it can work well in the LARGE Canadian CITIES, where they have Full time FD's and can respond and be on scene with sufficient manpower to mount effective interior attacks on contents or single room fires.
REALITY is in Canada, almost 95% of all FD's are Volunteer or Paid on Call.....many have HUGE coverage areas and are chronically short of volunteers..SO, are often responding to and arriving LONG past the point were it becomes a full involved structure fire, NOT just a room or contents fire, YET many still grab their little 1 1/2" lines with their little automatic fog nozzle and off they go...
SO, in MOST cases this "thinking" is a falicy. Firstly, I can almost gaurentee that these FD's "BELIEVE" they are flowing LOTS OF WATER...cause the lines are hard to control and Nozzle reaction is high...so it must be flowing lots right?...lol...
There ARE more and more Fire Chiefs and senior Officers that are seeing what is wrong...there are movements in effect to return to the tried and tested straight bore nozzles and 2" lines, myself included....
All the Canadian Provinces have seperate levels of training established, some to FF1 and 2 levels, some to higher Provincial standards, regardless, the "fire Marshal's and Fire Colleges have been teaching this outdated Fog and 1 1/2 crap for sooo long, that is almost ingrained now...and is TOTALLY ineffective in tha vast majority of situations....
I'm actually glad that you and others posted up on this thread what YOU all are using....let me do some investigating and looking up nozzles and hoses etc......so THANK you all for YOUR input...it is appreciated.
I'm guessing he is refering to Grimwood's push toward 3D firefighting which favors the European style of construction and fire loading.
It revolves around smaller compartments, more natural or fire resistant materials, and smaller required GPMs applied in controlled fog and pencil streams.
It works. Really, it works...under the right conditions.
The opposite end of the spectrum is Ray MacCormack tactics which call for a big hit to get a big knockdown...Lots and lots of water applied in straight streams...
It works. Really, it works...under the right conditions.
I agree with the idea of bringing a big gun and using only as much ammo as needed. Once you are in there, if you drag a small line, you do not have the option to flow more if needed. Just sayin....
As far as training, Grimwood pushes (rightly so) lots of compartment fire training to first understand fire behaviour, and second, recognize violent fire behaviour. The point behind the recognition is that knowing when to go is as important as knowing how to put it out.
Understand that Grimwood himself has stated that one technique does not solve all fire conditions. The construction and fire loading may dictate what you will choose to do.
I've got Grimwood's 3D Firefighting book. That and his articles on his website are where I got this info. I neither endorse nor nay say these theories. I just add them to the tool Box.
Having said that, If I'm told I have one tool for most fires, I choose a medium size hitter (2" or oversize 1 3/4"). Just sayin.
With that being said I have read Paul Grimwood's book 3D firefighter as well as the air track management book that is along the same school of thought. Whilie i struggled to choke through the fire attack portions of the book. I did learn alot of good information on fire behavior and other related stuff. I recommend that people read it with an open mind and take what you can from it as it relates to your department's tactics and building construction.
First off, I should not have mentioned Paul. In retrospect I do realize the controversy that that raises in the forums. My apologies.
Oh and My Name is Bootstraps and I like to go to FIRES!
I dont post here alot but I spend alot of time here. I am Canadian as-well.
What made me post here was Fyredup's thread on how their department did alot of looking at flows and what that meant to them.
I see too many departments, FT, POC and Vollie that do training in the same old way that they have done for the past 30 years without looking outside the box. That's why 6-7 years ago I got interested in what Paul was doing and promoting.
The area that our department covers is a mix of concentrated urban, rural residential and rural industry. Three very distinct areas that have 3 very distinct response needs from our department. We can be on scene in 3 minutes, with a 900 square foot house to a 70,000 square foot warehouse/manufacturing floor in 15 minutes.
As has been pointed out we do things abit different up in the Great White North, but we still carry 1 3/4, 2 and 2 1/2, fog, combination and smooth. Tools in a tool box.
My comment of increased training and decreased size was directed at our approach to training on quick response, low square footage fires. This is where the 3-D method shines in my opinion.
Again, I find it awesome that small and large size departments are experimenting through training to best meet what they are being face with.
We did do a lot of testing, experimenting, and actual in service use testing, before we came to our decision of 2 inch hose, 200 gpm at 75 psi combo nozzle and the 1 1/4 inch slug. We know our area, our daytime staffing, and the reality that in our case the first line 9 times out of 10 make or break us in battling the fire. Because in the first few critical minutes we may not have adequte personnel to pull that second line.
To me I couldn't care less what method of fire attack you use, 3-D, indirect, direct, combination of any of those, the simple fact that cannot be refuted is the application of water must be greater than the heat produced or you will fail at extinguishing the fire. Of course this can be accomplished one of 2 ways: 1) Overwhelm the fire with flow from nozzles, 2) Apply inadequate amounts of water, never extinguishing the fire until it burns down to the rate of flow you are applying. Both work. The first is generally far more satisfying to both the firefighters and the property owner.
One of the FDNY guys said to several people on this forum a while back "Don't do what we do simply because we do it. What we do may not work where you are." That is the truth, no matter who you emulate, differing construction, differing staffing, differing equipment, and more all play into tactics and strategy. Evaluate YOUR area and all of the above and come to the right solution for you.