05-23-2001, 03:00 PM #51LHS*Firehouse.com Guest
80 psi versus 80 and 50 vs 50 and 100 vs 100 is the proper way. However when the comparison is our 15/16ths out reaches your fog tip then it is a 50 versus 100 and the reach favors the fog in most cases. Smae holds true to a 80 psi SB deck gun versus a 100 psi fog, fog almost always wins. Penetration? The highest NP wins period.
05-23-2001, 04:11 PM #52ChiefMcDFirehouse.com Guest
This is actually a very good thread if you take the garbage out. This is why I read these posts.
You have stooped to a new level insulting an entire department like NYC. THINK BEFORE YOU WRITE!!!
05-23-2001, 04:16 PM #53KEAFirehouse.com Guest
Thanks for posting Larry. Although your post does not point out the error in from Cottrellls web-site you do emphasize proper comparison.
However, I disagree that the highest NP wins when it comes to penetration. What I mean by penetration is the ability of the stream to overcome the thermal currents, gravity etc in order to get to the fire.
I high NP stream may have velocity on its side but depending on the droplet size it may be a loser when it comes to penetration.
Fog nozzles at 100-psi create a much smaller droplet as it rips through the air. THis cuases the mass to decrease which in-turn cuases less penetration. Smaller droplets flash to steam faster and are ate up by the thermal drafts. A great example of this is to take a Low pressure Fog and compare the droplet size of the 100-psi fog. It wont take you long to see which one stands a better chance to penetrate a big fire.
A crosswind will also bring out the truth about penetration. Small droplets are more vulnerable to wind. This being the case they do not reach as far as a big dropplet from a SB or a low pressure fog or a ..........(sorry, not supposed to mention it by name)
If your talking penetration into a pile of ruble at your feet of 10 feet away, I would agree the higher NP wins regardless of the nozzle.
Just adding my two cents.
First Strike Technologies, Inc
05-23-2001, 04:23 PM #54FREDFirehouse.com Guest
-Wouldn't a fog stream, which is made up of smaller water particles have greater surface area than a solid stream?
Yes, all hydraulic books speak of this. This is, as we all know why the stream has lower electrical conductive traits. And also why in a controlled environment it absorbs more heat than other streams. It is designed to perform as such.
-If a certain Stream had greater surface area than lets say another, wouldn't it hold true that the friction of the water and the air be more than that of a solid stream.
-My question is not what the velocity of that water was when it left the nozzle. That is undisputed by the figures...
My question would be what is the rate of deceleration on the streams as they are affected by Gravity, Wind and Friction?
Basically if the fog stream is slowing down at a faster rate than the smoothbore then it wouldn't have the same punch nor would the majority of the stream hold together as well at the end of the stream.
Just as the page says "The basic laws of physics can't be ignored"
[This message has been edited by FRED (edited 05-23-2001).]
05-23-2001, 05:22 PM #55mongofire_99Firehouse.com Guest
Do any of you incorporate a stream straightener into the nozzle?
We have a stream straightner on a 2.5" nozzle we use on a blitz line.
And you are 100% correct, the department should do its own testing.
Why would you reference a web-site that is not comparing "Apples to Apples"? Do you agree with comparing a 50-psi stream to a 80-psi stream?
In this case yes.
I was simply replying to a post stating what I referenced "All you have to do is look at the quality of streams side by side." He references looking at the quality of the streams. There's the pic, which is the better stream?
You have the option of posting a pic with a fog nozzle set to a tight straight stream getting beat by the SB at the same flow. With all these folks saying the smooth is better than the fog, there has to be some out there somewhere...
I have seen first hand that the stream from a fog does have a better straight pattern away from the nozzle than does a smooth bore. I don't have a pic, but I posted a link to one. As far as apples to apples, they are both flowing 180gpm, I could care less what the reaction is, one firefighter can easily handle them both.
To claim that a faster moving stream will go farther and penetrated deeper is not necessarily true.
My point was on quality of stream, not penetration. But I'm not so sure I agree with your hypothesis. If I remember, we've been through this before...
But this has taken an interesting twist, please post references and studies regarding this.
With both flows being equal and teh fog set on its straightest stream, the highest exit pressure wins on the reach and penetration issue.
1500# in a 15/16" stream moving at 60mph has how much KE?
1500# roughly a 1.25" moving at 75mph has how much KE?
Which one has more KE?
How much is "peeled-off" of each on the way to the other side of a fire maybe thirty to forty feet away?
Here's where the BS in this whole issue comes in.
The smooth bore only fans don't think (or know) that a fog nozzle can be operated on a straight stream without disrupting the thermal balance or pushing air into the room.
Or, they don't think (or know) the fog has enough penetration.
Or, to paraphrase one post, with all the other BS we have to learn and know, we can't be expected to remember how to work a fog in the heat of battle.
If any of these situations were actually true, and fogs were so terrible, they would be outlawed. Instead they are used everyday in some of the busiest and slowest departments in the nation, just like the smooths.
If the smooths were that much better than the fogs or vice-versa, the firefighter advocacy groups would be beating on congress' door to have the fog nozzles outlawed.
And you know what, that ain't happenening.
And don't go nuts because I posted a link to Cottrells web page, its handy place to find a picture.
05-23-2001, 07:23 PM #56KEAFirehouse.com Guest
Mongo: Who's going nuts. I agree there is way to much BS involved in the SB vs fog argument.
/I have seen first hand that the stream from a fog does have a better straight pattern away from the nozzle than does a smooth bore./
I gues that depends on your definiation of a straight stream. Not being sarcastic with that statement in any fasion either. Every one has an opinion as to where you should position the bumper on the fog to give what one wants to call a better looking stream.
Food for though. For the SB, depending on the the type of ball in the ball valve you may see a huge difference in performance. One manufacute makes a cut out ball on the inlet side and the stream from that type of BV sucks. Use a smooth water way ball valve and the results are much different. Also the type of SB makes a difference as well. These stubby tips may flow the water but there is not enough length in them to stabalize the stream. The little things make a big difference.
/I could care less what the reaction is,?
So do I! I didnt mention anything about reaction.
/But I'm not so sure I agree with your hypothesis./
I'm glad to see skepticism. I could post my own testing but all would say those are swayed results. So, try it for yourself.
Pick a good windy day and set up a catch tank. Shooting the water into the tank with a crosswind with like flows, one at 100-psi and one at 50-psi and flow water for the same amount of time. You will find that the low-pressure stream will have a better footprint and provide more water into the catch tank at its farthest point. Why? I believe that its because of the velocity of the stream. The faster it goes the more the droplet gets stripped down in size. Smaller size, less mass to carry it.
/How much is "peeled-off" of each on the way to the other side of a fire maybe thirty to forty feet away?/
Measure what is in you catch tank and you will know the answer to the peel off volume.
Most would agree that the bread and butter jobs seen today are handled within that very 30-40 feet your talking about. Yet when the discussion of penetration comes into the conversation most are talking about a much further distance and the results will be noticable different. My reference to penetration stemmed from Larrys comment.
/The smooth bore only fans don't think (or know) that a fog nozzle can be operated on a straight stream without disrupting the thermal balance or pushing air into the room./
Agreed....although ANY stream does move a small amount of air and the one moving the fastest will move the most. Is it enough to be a problem, not in my opinion as long as the nozzleman knows what he is doing.
/Or, they don't think (or know) the fog has enough penetration./
Interior I dont think it matters much. Exterior I think it does.
/Or, to paraphrase one post, with all the other BS we have to learn and know, we can't be expected to remember how to work a fog in the heat of battle./
I would say that we should be tought how to safely and properly use any type of nozzle. Its unfortunate but most academies I have visited teach what they think is right with no regard to the new rookie that has to go back to a department and use something he may have never been trained on. Our academies and instructors should, in my opinion, instruct on the safe operation of all nozzles.
/If the smooths were that much better than the fogs or vice-versa, the firefighter advocacy groups would be beating on congress' door to have the fog nozzles outlawed./
I dont think its so much a matter of one being better than another as it is recognizing the value of both of them. I must admit it amazes me how heated the nozzle topics are compared to items like SCBA, or TIC. Why is there not the emotional attachement to those types of products?
Understanding we only see words on the screen, rest assured my blood pressure is low, my emotions stable and when it comes to going nuts, I'll go for the cashews.
First Strike Technologies, Inc
05-23-2001, 08:00 PM #57LHS*Firehouse.com Guest
KEA, I was too lazy to look at Cottrells data, but a test should be equal in all terms. Unless the tester is comparing apples to orages like is so often done on these boards, you know...EP is lower with our SB than your fog. It wold be the same if both had low pressure tips, DUH.
One simple reach/pentration test, conducted by Mr Shapiro with my specific guidance was point the SB and the fog straight up side by side. Yeah the fog always wins by a bunch. So, there is a good reach and penetration measurement. In the 10 to 30 foot inside a house range penetration is won by a combo nozzle.
05-23-2001, 08:14 PM #58mongofire_99Firehouse.com Guest
Pick a good windy day and set up a catch tank.
We'll try it sometime, but I have to wonder....
When was the last time we had a good windy day INSIDE a burning house?
05-24-2001, 01:06 AM #59Dalmatian90Firehouse.com Guest
From Akron Brass:
( http://www.akronbrass.com/products/flowreach.htm )
7/8" Solid Bore, 50psi, 160gpm. Effective Reach: 130'
15/16" Solid Bore, 50psi, 180gpm. Effective Reach: 142'
Akromatic II (Automatic Combination Nozzle),
100psi, 150gpm. Effective Reach: 122'
100psi, 200gpm. Effective Reach: 142'
TurboJet 1724 (Fixed Gallonage Combination nozzle),
75psi, 150gpm. Effective Reach: 133'
100psi, 150gpm. Effective Reach: 140'
See very many rooms 130' wide? Very many halls 130' long? Heck, cut those reaches by a third. Are we putting water on a fire 45' away very often on the inside of building?
Even using handlines outside, how far away are we using them that wind would become a concern? Master streams, I could see the arguement. I can't see reach being a legitimate arguement for handlines unless your tying them off to protect a tank against a BLEVE!
By the way, I don't mind comparing different nozzles of different psi to each other if what you're comparing is how the nozzles are typically used. 50psi on a SB handline is typical. 100psi on a traditional Auto Combo is typical. Yep, you can compare 50psi SB to 50psi Auto Combo...but then the SB crowd can no longer argue that they have less nozzle reaction, negligent to use it from a standpipe, etc when the nobs are running at the same pressure. Except you still can't pass a mouse through a combo
05-24-2001, 10:37 AM #60KEAFirehouse.com Guest
/15/16" Solid Bore, 50psi, 180gpm. Effective Reach: 142'/
/100psi, 200gpm. Effective Reach: 142'/
If these figures are correct, then are you agreeing that a 50-psi nozzle with less flow reaches the same distance as a 100-psi stream with more flow?
This is a perfect example as to why I say dont believe everythhing you read just because its on a web-site.
Beware of what you believe! Test things for yourself. It takes all the gobbly-gook out of it.
First Strike Technologies, Inc
05-24-2001, 01:55 PM #61ADSN/WFLDFirehouse.com Guest
I think we need to look at this from a slightly different angle. We should be looking at lines with the same flow, and then look at nozzle reaction and ease of handling the line.
Prior posts are correct. How often are you fighting a fire in a 130' room?
If you have a SB flowing 180 GPM and a 100psi fog flowing 180 which one will be easier to move? The Smooth Bore. We have already identified that the fog will be used on straight stream, so why do we want to beat ourselves up fighting the line?
If you want to make life harder than it has to be go back to steel bottles on your scba, they are less expensive and more durable.
When it comes to exterior attacks use whatever will flow the most water onto the seat of the fire. Again the SB would win out. How many pictures have you seen of ladders surrounding a building with nozzles flowing good looking streams out of their fog tips, but with the stream being broken up or turned to steam by thermal updrafts prior to any water hitting the seat of the fire. You need the cohesiveness of the solid stream to hit what is burning. The only other way around this is to flow so much water that the fire can't defeat the stream, but that would certainly lead to a discussion on the Vindicator and our dance card is pretty full to add this to the current post.
05-24-2001, 03:20 PM #62Dalmatian90Firehouse.com Guest
KEA: What I believe from those numbers of most nozzles reaching 120' to 150' range, arguements over reach of one nozzle style to another is irrelevant for interior firefighting.
Rarely will you be trying to apply a stream to a fire more than 40' away from you.
ADSN: You need the cohesiveness of the solid stream to hit what is burning. The only other way around this is to flow so much water that the fire can't defeat the stream
Vividly been there on a barn fire I was assigned to the ladder pipe. If I tried to hit the center of the fire, stream broke up -- and I was taking enough heat I actually got the equivelant of a bad sunburn on my legs from radiant through the 3/4 boots I was wearing (Didn't have bunkers with me that day, so I *thought* the tip of the ladder would be the safe place!)
But that didn't mean I only had one choice, to switch to SB to penetrate it. I simply moved the stream to the front edge of the building where it was cooler, and worked the stream slowly into the middle. Since I started cooling the fire from the coolest part at the edge, I was able to defeat the thermal current and knock down the fire. After a couple passes, I'd signal the turntable operator and he'd rotate the ladder over so I could repeat a yard or so over. Fire went out. Just used some good judgement with situation presented me, and used an appropriate tactic.
I really don't like seeing a ladder pipe operated without someone at the tip most of the time -- you don't know where the stream is going, if it's being effective, if it's even hitting what's burning or should instead be moved, or if some other team working the fire just came into the line of fire of your stream. Those eyes up there are important.
Also, being in a predominantly rural area having to use SB on our aerial would be a major crimp on operations.
Often we'll start flowing water through the aerial once the first round of tankers are in. Then we'll increase the flow as long hose lines are established or a larger tanker shuttle gets going. Say we start at 500gpm for 5 or 10 minutes before having the water to bump up to 1000gpm. That initial stream can often cut off the spread of the fire. The larger flow once we have it kills the fire and accomplishes "hydraulic overhaul."
Let's see, 80psi @ the nozzle, 500gpm we'd have to start off with a 1-3/8" tip. Want to flow 1000gpm through that tip? Gotta shutdown the ladder pipe, unscrew the tips down to the 2", start flowing again. Uh-oh, we don't have the water supply we thought we did. Shut down the aerial, screw the 1-3/8" tip back on, charge it. Hey, OK, we figured out what was wrong, we got the water now. Shut down, unscrew the 1-3/8"...
Put an Automatic Combination tip on there.
Got all the water you need? Pump Operator doesn't need to do anything. Even if you have a 250gpm handline you need 200psi to supply, 200psi sent up to the auto on the tip will still just deliver 1000gpm.
Short on water? You pull out a flow chart you've made up and tested previously on your truck so it's accurate for your plumbing, etc and it says:
100' Extension, 70' Elevation:
Tip Flow = Pump Discharge Pressure
500gpm = 135psi
750gpm = 145psi
1000gpm = 155psi
Only have the water supply established to supply it with 500gpm? Keep the main pump discharge pressure down at 135psi.
Ok Pump Op, we now got 700gpm of water, but we want to run a 200gpm handline over their to cut off fire under the eaves. Ok Chief. Pump Op knows his 150' 1.75" line needs 200psi to deliver 200gpm through it's Auto Combo. Crank up pump to 200psi PDP, and gate back the Ladder Pipe feed to only 135psi when flowing.
Got more water? Crank open the discharge. Running shy on water? Crank it back. No need to change tips or shut down to do so.
I suppose if you run in an area with good, consistent water supplies you can select the right tip from the start and us SB on your aerials.
If you run in an area like mine where we work heavily off of tanker shuttles and/or long laid lines, using SB master streams can be an incredible headache for the Officers, Pump Operators, and Water Supply Officer as the only way to effectively control their flow is changing tips.
Yep, we run SB on our 1st in Engine-Tank. For one special tactical use -- it's rigged to deliver 600gpm fro 2 minutes off our 1200 gallon tank if the ET happens to be in the right place at the right time. All our other master streams are kept with combo fog tips, including the bomb line on the ET (300' 3" with 350gpm-1000gpm master stream).
Actually, Fixed-Gallonage combination nozzles are almost as bad as SB for operations when water supply is or may be limited. You don't have to shut down to change flow, but if the nozzle crew sets it to a certain flow the nozzle will try it darndest to make that flow.
Automatics allow the crew to select the flow up to a limit of either the nozzle, or what the pump operator will allow. I don't like limiting flow to interior teams, but when operating multiple handlines and master streams on the outside, an officer and pump operator can set the discharge pressures so the crews can not flow more than a certain GPM from a central location.
05-24-2001, 05:38 PM #63ADSN/WFLDFirehouse.com Guest
I personally don't like automatics on a ladder pipe because of the chance that the engine pumping your gun isn't pumping what you should have.
Sure, we can talk about an engineer needing to know his job, but with the infrequent use of ladder pipes plus all of the elements involved it is easy to have the incorrect NP.
With anything but an automatic it is obvious that the pressure is low.
Depending on your setup Prepiped VS ladder pipe I also prefer the lower pressure of the SB. (Less nozzle reaction going against the ladder)
05-24-2001, 06:46 PM #64KEAFirehouse.com Guest
Dalmation90: Please help me out on this one.
500gpm = 135psi
100-psi for the tip
35-psi for elevation
That totals 135-psi. Does your rig have some new magical plumbing that eliminated FL?
Sorry for my confusion but the numbers dont make any sense to me.
Just looking for clarification.
First Strike Technologies, Inc
05-24-2001, 06:51 PM #65KEAFirehouse.com Guest
ADSN/WNFLD: It would appear that gating discharges can be done during a fire based on Dalmations explanation. Go figure, they are even able to operate multiple lines by opening and gating them.....and they are using automatics.
Just thought that was interesting considering the last debate you and LHS had on that subject.
First Strike Technologies, Inc
05-24-2001, 07:23 PM #66Dalmatian90Firehouse.com Guest
This post temporarily taken down till I can fix the physics
(For those of you who read, most of it is correct, but I had a problem with some of the math 'cause I had a brain fart and combined benfits of constant flow and constant gallonage nozzles together on one!)
[This message has been edited by Dalmatian90 (edited 05-25-2001).]
05-24-2001, 08:15 PM #67KEAFirehouse.com Guest
/The design of the nozzle limits the volume to 1000gpm, and the design of the nozzle limits the discharge pressure to 100psi. Nozzle reaction doesn't increase on bit./
Please beware if you think this is true. The nozzle does not limit the volume nor does it limit discharge pressure. If you are flowing 1000-gpm with a 100-psi pressure at the nozzle, you can very easily go over the 100-psi NP by simply pumping more. Its called overpressureizing the nozzle and you will be suprised how easy it is to do it.
Dont take my word for it, call the manufacture and ask them if the nozzle limits flow or discharge pressure.
The only way it could limit flow was if it had a relief valve that dumped the excess pressure to it.
Since the automatic works very similar to a relief valve, we know that when it is at its peak flow (1000-gpm) the stem is pushed out all the way. Now that the stem is out all the way the orifice becomes a fixed size. Send to much flow for that size orifice and your NP goes way up while flow only increases marginally.
Try it some time using an inline pressure gauge at the nozzle and a flowmeter. You will see that the nozzle can flow more than 1000-gpm and your NP can go well above 100-psi.
Still curious about your lack of friction loss for your 500-gpm flow.
First Strike Technologies, Inc
05-24-2001, 08:59 PM #68Dalmatian90Firehouse.com Guest
Kirk, I do believe your right about the over pressurization But I'm finally going to dinner so I'll have to redo my math later.
Here's the calc I'm using for the estimate on FL to the tip of the aerial.
30' of 4" piping from midship pump to rearmount turntable. 100' 4" piping up the aerial. 130' 4" using the rubber lined fire hose calculation 'cause I didn't feel like looking up aluminum or stainless steel is 5 psi/100' or 1.3*5=6.5
It's probably close to the actual numbers when you consider new metal pipe will have a lower FL per foot, but I'm not adding in elbows, possibly undersized valves, etc.
70' in elevation gain will cost you 70*0.434psi or 30.4psi.
30.4psi + 6.5psi = 37psi which I rounded off to 35psi.
Because of all the variabilities in materials and design, your best running an actual flow test to build the chart. That also gives you a baseline in case you have a future problem and have to go looking from a clog somewhere in the pipes
05-24-2001, 09:45 PM #69E229LtFirehouse.com Guest
You getting all of this?
05-24-2001, 11:21 PM #70NY SmokeyFirehouse.com Guest
I don't know about the rest of you but my brain hurts from all of this math I am reading!
05-24-2001, 11:34 PM #71NozzleHogFirehouse.com GuestOriginally posted by E229lt:
Your comments about the FDNY,
//"And they knock off more guys too! They just started to provide EMS, wear bunker pants, buy imagers, etc, so they a few decades behind the rest of fire service, let's not hold that against them.
Fire activity isn't something to brag about it is a living example of a failure to perform the whole task of the fire service. Try a few codes and sprinklers. //"
How can you put your foot in your mouth when your head is up your ***?
The fact that you would knock any department based on the loss of brother firefighters has brought you below any and all of the bean counters, administrators and budget makers of every municipality in the nation.
The very men we choose to never forget for their sacrifices, you have chosen to use in an attempt to place a black mark on one of the finest departments on the planet.
I ask anyone on this forum to support your statement in regards to the FDNY, and I quote "And they knock off more guys too! "
You have shamed our fallen, their families and yourself. I once read your posts with an open mind, I was foolish. You are a hack and have no place in the fire community.
If you want to knock a department, begin with your own. They have placed you among their ranks and for that they should be ashamed.
Thank you! You get two nominations for Best Post in Topic.
[This message has been edited by NozzleHog (edited 05-25-2001).]
05-24-2001, 11:36 PM #72KEAFirehouse.com Guest
/Here's the calc I'm using for the estimate on FL to the tip of the aerial./
Thanks for the update. I was under the impression your numbers were from actual tests and not estimates.
I agree, doing the actual flow test lays a foundation to work from in the future.
05-25-2001, 12:32 AM #73LHS*Firehouse.com Guest
//I personally don't like automatics on a ladder pipe because of the chance that the engine pumping your gun isn't pumping what you should have
Hmm, NFPA does state a flow meter shall be plumbed to the water way? That a pressure gauge shall be plumbed to the water way? Doesn’t state a pressure relief shall be installed? There are three ways to insure proper flow and pressure.
//it is easy to have the incorrect NP.
Especially when you use a smooth bore tip on a ladder pipe. Hmmm, 100 foot ladder flow 1000 gpm at 80 psi tip pressure to a SB tip. What level do you pump to? 33’ high, 66’, 75’, 100’? If you pump for 33 feet and end up supplying the tip at 66 feet 14.3 psi too little. If you pump for 66 feet and have the ladder at 33 you pump 14.3 psi too much. If you pump for 100 and have the ladder at 33 you’ve got 30 psi too much. If you pump for 75 and have the ladder at 100 you end up with 11 pounds too little. If you pump for 100 and use the ladder at zero degrees you’re 44 psi too high.
//With anything but an automatic it is obvious that the pressure is low.
What no smoke at your fires?? With an automatic the pressure isn’t ever low. It is always 100 psi.
//Depending on your setup Prepiped VS ladder pipe I also prefer the lower pressure of the SB. (Less nozzle reaction going against the ladder)
Oh really? No on makes low pressure automatics? How do you get this lower reaction when you are over pumping the ladder by as much as 44 psi? Your 65 to 144 pounds more reaction than the 100 psi automatic and 292 pounds higher compared to a low pressure automatic! That is enough to damage a portable ladder pipe or dump the ladder. Are your hydraulics so good you can be dead on 80 psi?????
Does an automatic limit flow and reaction better than a smooth bore?
A smooth bore tip 2 inch at 1000 gpm 81 psi. Reaction is 486 pounds.
A 1000 gpm automatic 100 psi nozzle 505 lbs.
A low pressure automatic 80 psi at 1000 gpm only 452 lbs reaction.
Now let's increase the nozzle pressure by 44 psi.
2" tip flows 1328 gpm and has reaction of 750 lbs.
1000 automatic 1200 flows gpm and has 727 lbs reaction.
Low pressure auto 1114 gpm and 624 lbs.
Seems to me the automatic always wins and does a much better job of limiting flow than a smoothbore. The calculations above do not take into acount one make of Auto master stream that has a stream straightner built in that costs 100 gpm worth of loss at 1000 gpm. So in reality on that nozzle you'd be looking at 667 and 568 lbs reaction respectively. Gee, evem lower.
Dalmation depending upon the make, or by simply adding a short stream straightener you can pretty much insure you won't exceed 1100 gpm no matter what you do.
//It would appear that gating discharges can be done during a fire based on Dalmations explanation. Go figure, they are even able to operate multiple lines by opening and gating them.....and they are using automatics.
Are you referring to this post? Or Something else? When you said the above?
//Automatics allow the crew to select the flow up to a limit of either the nozzle, or what the pump operator will allow. I don't like limiting flow to interior teams, but when operating multiple handlines and master streams on the outside, an officer and pump operator can set the discharge pressures so the crews can not flow more than a certain GPM from a central location.
[This message has been edited by LHS* (edited 05-25-2001).]
05-25-2001, 01:27 AM #74KEAFirehouse.com Guest
Larry, I was referencing another post where there was quite a debate over feathering the discharges.
To everyone: I have read these posts with great interest. I wonder out of all those who like the automatic nozzles how many have ever tested them with a pressure gauge and flowmeter year after year.
A recent visit to the Dallas area reflected 9 out of 12 automatics would not regulate pressure properly. Dont take my word for it, ask Big Paulie, he was with us.
Another trip to the LA area offered 5 out of 5 would not regulate pressure properly. 3 out of those 5 would not change flow or pressure even though they were tried in both normal and emergency modes.
Whats my point? No its not to pick on the nozzle type. The automatic nozzle works fine.....when the proper maintenance is done.
What bothered me the most was that in every case everyone was willing to bet their life on the nozzle operating properly.
In some cases we found that when the flows were good (150-200-gpm) the nozzle pressure was 60-75-psi and not the 100-psi it was designed for. Or when the flows sucked (40-90-gpm, the nozzle pressure was 115-125-psi.
I have tested well over a thousand nozzles and just about every configuration you can imagine. The one thing that continues to come to the surface when flows and pressures are not what they think is that none of them are doing the proper maintenance. If they are doing the maintenance the fail to test them with flowmeters and pressure guages to ensure they are working properly.
If you use automatic nozzles, PLEASE test them with pressure gauges and flowmeters and ensure they are working the way they are supposed to. If you live in an area that has hard water, you may find that your maintenance requirements will be much more frequent than those who have softer water.
Again, this is not an attack on the type of nozzle. If anything, its an attack on those who have failed to ensure their equipment is functioning properly.
I have said it before and Ill say it again,
TEST, TEST, TEST!
First Strike Technologies, Inc
05-25-2001, 09:57 AM #75Truckie5553Firehouse.com Guest
Enough with all of this math!!!!!!!!!!! The best thing we can all do is go out and find which nozzle works best with our department and which will set up for the property that you will be protecting in your district.
The next thing everyone should do is go out on the next live burn they can have the chance to and experiment with both nozzles. Do all your math there, use only the water in your booster tank and see how many gallons of water it takes you to successfully knock down the fire. Then take the following readings:
1. Temp at or around helmet level. Record before the water flow begins and then after water flow has ceased.
2. Visibility...how is it? Which can you see. Set up a marker point to use. See how far you can be away from it before you can see it.
3. Set your lines for equal gpm flow and see which line gets deployed faster and how much strain is placed on the crew. How do you do this...baseline vitals. measure baseline and then check the vitals after each attack, (this is supposed to be done anyway in accordance with nfpa)
Let your crews experiment with the attacks and patterns they use. Do this with a one room contents fire and allow the fire to reach the rollover stage just before calling for the crew. I have worked about 50 live burns during my career and have many more planned. Before we began using smoothbore on the initial attack, many of us (instructors) as well as students was receiving steam burns, suffering from heat exhaustion must faster than normal due to the heat caused from the thermal inversion, and $1000's of dollars of equipment being destroyed. This is all in a "controlled" enviroment. Since we have switched over to using SB, the only way a helmet is melted is if a student stands up. Also our helmets have been lasting much longer throughout the training year.
The biggest thing to remember is that if we cant stop getting firefighers burned in a "controlled" enviroment, then how can we keep them from getting burned at the actual fire scene.
My final thought i will make on this post is about LHS's comments about FDNY. How could you stoop so low so make the comments that you made. There is no reason to down grade a department for their methods they do. Yes many die in their organization, but look at the fires they see. Can you say that you have ever seen a 10 alarmer? Most cant. Look at there run totals. 1.5 million last year, with Chicago under 1 million being the closest. When a brother firefighter is lost we should not attack their ways nor their department, but see if there is something we could do to change it. But to attack the FDNY like you have, i think its a horrible act of class on your part. If i had to give you an ISO rating, you would be an 11, because a 10 is even to low for you. If you want to attack a person in the forum with something they said about a procedure or disagree with a comment, be my guest....but if you want to attack a department and try to make them sound like they are nothing but careless, inexperienced, and down right stupid in their ways of fighting fire, do us all a favor, go **** up a tree in somebody else's world, because i wont speak for anyone but myself, but i think you are low life trash for doing such.
Captain James Collier
McMahan Fire Rescue
KCTCS Area 6 Instructor
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