1. #51
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,887

    Default

    So just laying out an LDH and gating it back isn't a lot easier,faster and more efficient? It would seem to me that marrying to engines together in tandem pumping evolution could spell trouble if the first engine has a pump issue. But if you use to ports of the hydrant to inividually supply the two engines won't they be fighting for residual pressure? If they don't communicate and one opens their deck gun when the other has less residual wouldn't that cause the other to go to 0 psi quicker?

    Of course I fully support teaching tandem pumping because it goes in the "more you know" category. We as a fire service are letting things go left and right. Someday someone will realize that there may be a need to pump in tandem for what ever reason and most people won't have a clue!

  2. #52
    Banned

    Join Date
    Feb 2007
    Location
    In my house
    Posts
    2,332

    Default

    Quote Originally Posted by RFDACM02 View Post
    So just laying out an LDH and gating it back isn't a lot easier,faster and more efficient? It would seem to me that marrying to engines together in tandem pumping evolution could spell trouble if the first engine has a pump issue. But if you use to ports of the hydrant to inividually supply the two engines won't they be fighting for residual pressure? If they don't communicate and one opens their deck gun when the other has less residual wouldn't that cause the other to go to 0 psi quicker?

    Of course I fully support teaching tandem pumping because it goes in the "more you know" category. We as a fire service are letting things go left and right. Someday someone will realize that there may be a need to pump in tandem for what ever reason and most people won't have a clue!
    That is one way to look at it. The other way is the more useless knowledge I get the higher the likelyhood I will forget something really important.

    And really, how many hydrants have 2 steamer ports on them? Todays trucks can easily handle that capacity. It is a tehnique that had a place when trucks had smaller pumps. It would be crazy in todays environment to buy a truck with a less than 1250 gpm pump. The better method is to use individual feed water mains to feed different hydrants each feeding a different pumper. It is really senseless to put two aparatus at the same hydrant pumping from the same hydrant, unless your trucks only have 300 gpm pumps.

  3. #53
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,887

    Question

    Quote Originally Posted by HotTrotter View Post
    That is one way to look at it. The other way is the more useless knowledge I get the higher the likelyhood I will forget something really important.
    Come on, you don't really expect that we'll beleive you only have some much room in your brain? If you learn something you have to forget something else? I realize tandem pumping might be a stretch for most of us, but nowadays so many firefighters only know how to throttle up until the needle is pointing at the tape! So little understanding of why you can't draft over 22 ft. or that all pressures are equal in a closed system! I don't beleive it can hurt to teach and practice these evolutions as long as you can keep up with the rest which may be the real challenge.
    Quote Originally Posted by HotTrotter View Post
    And really, how many hydrants have 2 steamer ports on them? Todays trucks can easily handle that capacity. It is a tehnique that had a place when trucks had smaller pumps. It would be crazy in todays environment to buy a truck with a less than 1250 gpm pump. The better method is to use individual feed water mains to feed different hydrants each feeding a different pumper. It is really senseless to put two aparatus at the same hydrant pumping from the same hydrant, unless your trucks only have 300 gpm pumps.
    I think HWOODS describes the perfect scenario of why some depts wouldn't waste money on a pump over 1000 gpm. I'd agree individual mains or grids are a better choice, but it depends on hydrant spacing and flow. We have a few places where tandem pumping would be a benefit, though I'd probably opt to just stretch a 5" LDH from the original engine. You do understand that the GPM rating of your pump is meaningless on a big hydrant if you have adequate discharges right? You can use a 1000 gpm pump as a 2500 gpm water manifold. We've flowed around 3000 gpm using a 1500 gpm pump off one of better hyrdants.

    Again, not a high priority in most places but a valid technique that may be of value at some point. I still am not sure why supplying the 5" LDH is not a better option? It seems easier and faster.

  4. #54
    Forum Member
    Rescue101's Avatar
    Join Date
    Jun 2001
    Location
    Bridgton,Me USA
    Posts
    8,162

    Default

    You guys still don't get it. 1 hydrant,two 5(or 6")soft sleeves and marry the intakes of the two pumps together.If pump one fails,the water will still flow to pump two.Both pumps will operate to the capacity of their ratings or the Hydrant whichever occurs first.Needless information? I'd guess that would depend on your hydrant and street layout. I'd add it to my useful to know,not essential file.I think we've used it maybe five times over 38 years I've been here.I regard it as more of a pump operator familiarization/confidence tool than a daily driver.But certainly an important skill that can still have a place in this world. T.C.

  5. #55
    55 Years & Still Rolling
    hwoods's Avatar
    Join Date
    Jun 2002
    Location
    Glenn Dale Md, Heart of the P.G. County Fire Belt....
    Posts
    10,739

    Thumbs up Ron's Got It............

    Quote Originally Posted by FlyingRon View Post
    The scheme we had was to close the hydrant partially so you could hook up the second engine to the other suction port on the first engine without having them stop pumping. To do that you can't use a soft suction (or so they tell me). Got me, like I said, not only has it not been used in recent memory, it's not even been drilled. There just aren't too many places in the district now where you just wouldn't run more line from a different hydrant.

    We did this, from time to time, both in Training and on Fires, as long as I've been around. We do it with Soft Suction Sleeves with no problems. A number of other posters have mentioned LDH, but out of 90 Engines, only about 6 carry LDH. For whatever reasons, folks in this area do not want to use it, preferring 3 inch Suppy line.

    One Station, the Clinton VFD, ( www.clintonvfd.org ) Runs County-wide as the Water Supply Company on Second Alarms. Their Apparatus carries a large amount of LDH, and 2,000 or 2,250 GPM Pumps. They also took a "Utility Body" 4X4 Pickup and set it up with 1,200 feet of 5 inch Hose. This unit can stretch supply lines in to units already working in congested areas much easier than full size Engines.
    Never use Force! Get a Bigger Hammer.
    In memory of
    Chief Earle W. Woods, 1912 - 1997
    Asst. Chief John R. Woods Sr. 1937 - 2006

    IACOJ Budget Analyst

    I Refuse to be a Spectator. If I come to the Game, I'm Playing.

    www.gdvfd18.com

  6. #56
    Forum Member

    Join Date
    Sep 2004
    Posts
    259

    Default

    Quote Originally Posted by Rescue101 View Post
    You guys still don't get it. 1 hydrant,two 5(or 6")soft sleeves and marry the intakes of the two pumps together.If pump one fails,the water will still flow to pump two.Both pumps will operate to the capacity of their ratings or the Hydrant whichever occurs first.Needless information? I'd guess that would depend on your hydrant and street layout. I'd add it to my useful to know,not essential file.I think we've used it maybe five times over 38 years I've been here.I regard it as more of a pump operator familiarization/confidence tool than a daily driver.But certainly an important skill that can still have a place in this world. T.C.
    Thank you...at least I know there is another person out there who is actually talking about dual pumping and not something else. It's kind of entertaining to read an argument about the merrits of an evolution when we haven't all even reached a point of agreement on what the evolution is.

  7. #57
    55 Years & Still Rolling
    hwoods's Avatar
    Join Date
    Jun 2002
    Location
    Glenn Dale Md, Heart of the P.G. County Fire Belt....
    Posts
    10,739

    Thumbs up Yeah................

    Quote Originally Posted by kayakking View Post
    Thank you...at least I know there is another person out there who is actually talking about dual pumping and not something else. It's kind of entertaining to read an argument about the merrits of an evolution when we haven't all even reached a point of agreement on what the evolution is.
    I think that there are only 3 of us......
    Never use Force! Get a Bigger Hammer.
    In memory of
    Chief Earle W. Woods, 1912 - 1997
    Asst. Chief John R. Woods Sr. 1937 - 2006

    IACOJ Budget Analyst

    I Refuse to be a Spectator. If I come to the Game, I'm Playing.

    www.gdvfd18.com

  8. #58
    MembersZone Subscriber

    Join Date
    May 2000
    Location
    SW MO
    Posts
    4,249

    Default

    Quote Originally Posted by Rescue101 View Post
    Needless information? I'd guess that would depend on your hydrant and street layout. I'd add it to my useful to know,not essential file.I think we've used it maybe five times over 38 years I've been here.I regard it as more of a pump operator familiarization/confidence tool than a daily driver.But certainly an important skill that can still have a place in this world. T.C.
    While I tend to agree with what you're saying in regards to the need to know, I do think it's an underused operation. I've been one several scenes in hydranted and rural areas where the practice would have been beneficial. However, like you said, it depends on the department and water supply.

    We haven't got to try it yet (in a drill, we don't want to do it in a real-life scenerio for the first time), but we've discussed at length of using it while relaying water to a scene. If we place our 1,750 pumper/tanker at a water source close to a fire and can push the 1,750 (or even 1,500 or so) to the scene, we can supply our primary unit flowing it's master stream at 1,000 gpm. We can then hook on ours, or another department's, apparatus in a dual-pumping situation and flow another 500 or so worth of large hoselines or master stream.

    I mentioned a page or two back a scenerio at my career department where it would have been handy to use instead of pumping my stick and four attack lines off of my quint. We could have dual pumped another stick or the hoselines/master stream off an engine off the same hydrant that had plenty of water left even with me pushing upwards of my 1,500 gpm capacity.

  9. #59
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,887

    Default

    So as one of the people that must be "missing something" here? How much water will flow through the first pump if there is a failure and it won't turn? I'm really asking here. There is some mechanical restiction from one side to the other of the pump. Will you only lose one pump? Or will you even temporarily draw a vacuum? Like I said, I think there is value in knowing the evolution, but it seems less practical where LDH lays in the streets. Maybe (probably) many engiens are not capable of discharging more than their capacity?

  10. #60
    MembersZone Subscriber

    Join Date
    May 2000
    Location
    SW MO
    Posts
    4,249

    Default

    Quote Originally Posted by RFDACM02 View Post
    So as one of the people that must be "missing something" here? How much water will flow through the first pump if there is a failure and it won't turn? I'm really asking here. There is some mechanical restiction from one side to the other of the pump. Will you only lose one pump? Or will you even temporarily draw a vacuum? Like I said, I think there is value in knowing the evolution, but it seems less practical where LDH lays in the streets. Maybe (probably) many engiens are not capable of discharging more than their capacity?
    I'm not sure that running water through a non-operating pump is exactly "dual pumping," but I'll try to answer your question (I'm sure someone will correct me if I botch it). The intake manifold has no obstructions within it (other than valves). So, you can supply a helluva lot of water straight through one suction port to the other with only a little friction loss.

    I have had to pump "through" a pump before. Our situation was that we had some icing issues with our first arriving engine. We had already pulled attack lines and were working to resolve the issues when the second due engine arrived. Instead of wasting time trying to get the pump working, we hooked the hydrant to the second arriving engine, hooked in from the discharge on the operating pump to the discharge on the broken pump, and pressurized the discharge side of the malfunctioning pump. Of course, the pressure carries through to the intake side through the impellor, but it's not an issue. One could also hook into the intake side of the malfuctioned pump, but you'll have some friction loss to deal with through the impellor, but I've seen it done several times.

    Dual pumping is when you supply engine 1 with water from the source. You then connect engine 2 to the intake side of engine 1 with hard/soft suction. Both engines get water from the same source. It saves issues with pumping water from engine 1 (through a discharge) to engine 2. "Textbook" says you're not supposed to pump LDH (or master streams) and attack lines from the same pump. Imagine what happens to the guys on the end of a hose if you shut down a discharge flowing 750-1000gpm too fast.

    Is that close guys?

  11. #61
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,887

    Default

    Quote Originally Posted by Catch22 View Post
    I'm not sure that running water through a non-operating pump is exactly "dual pumping," but I'll try to answer your question (I'm sure someone will correct me if I botch it).
    I wasn't calling it dual pumping at all, just wanted to know "what if". I was think if you were correctly dual pumping then the first pump died. Which you answered perfectly!

  12. #62
    MembersZone Subscriber

    Join Date
    May 2000
    Location
    SW MO
    Posts
    4,249

    Default

    Quote Originally Posted by RFDACM02 View Post
    I wasn't calling it dual pumping at all, just wanted to know "what if". I was think if you were correctly dual pumping then the first pump died. Which you answered perfectly!
    OK, I misunderstood what you were asking. But if you got the answer you were looking for, it's all good.

  13. #63
    Banned

    Join Date
    Feb 2007
    Location
    In my house
    Posts
    2,332

    Default

    [QUOTE=RFDACM02;808581]Come on, you don't really expect that we'll beleive you only have some much room in your brain? If you learn something you have to forget something else? I realize tandem pumping might be a stretch for most of us, but nowadays so many firefighters only know how to throttle up until the needle is pointing at the tape! So little understanding of why you can't draft over 22 ft. or that all pressures are equal in a closed system! I don't beleive it can hurt to teach and practice these evolutions as long as you can keep up with the rest which may be the real challenge.{/QUOTE]

    The human brain can only hold and comprehend a finite amount of information. This is why not all people can be engineers, scientists, doctors, lawyers, etc. The total lift that you can draft is limited by atmospheric pressure. Using approximate values of 15 psi Atmosperic and a loss of 5 psi per 10 foot of lift you will see that the amout you can draft is closer to 30. In a closed system with no water flowing the pressures will without a doubt be equal. If you are flowing water the pressures will vary, as will the velocity.

    Quote Originally Posted by RFDACM02 View Post
    I think HWOODS describes the perfect scenario of why some depts wouldn't waste money on a pump over 1000 gpm. I'd agree individual mains or grids are a better choice, but it depends on hydrant spacing and flow. We have a few places where tandem pumping would be a benefit, though I'd probably opt to just stretch a 5" LDH from the original engine. You do understand that the GPM rating of your pump is meaningless on a big hydrant if you have adequate discharges right? You can use a 1000 gpm pump as a 2500 gpm water manifold. We've flowed around 3000 gpm using a 1500 gpm pump off one of better hyrdants.
    WASTE (!! ) money on a 1000 gpm pump. I would say you are crazy to buy anything less than a 1000 gpm. We put 1500 gpm pumps in all of our newer trucks, 1990 and later. Are you worried about the extra weight? And if it is cost, then how do you justify a tandem pumper (an entirely second truck) vs one truck with a bigger pump? The only time I have seen a pump not work is when they freeze up in winter. In that case it would be better to push all of the water through a single pump rather than two pumps. The faste the water flows the less the liklihood anything will freeze.

    Quote Originally Posted by RFDACM02 View Post
    Again, not a high priority in most places but a valid technique that may be of value at some point. I still am not sure why supplying the 5" LDH is not a better option? It seems easier and faster.
    I agree 100% here. Most hydrants in our area will only supply a max of 1500 gpm. And there are many that struggle to get 500 gpm. If I try to hook up to two hydrant on the same line my trucks will be fighting for water, they in essence would split the available supply, with the upstream truck getting more of the water. And I oculd even connect to multiple hydrants on different parts of the same grid and still not be able to pump at full capacity.

    I know of an incident recently where there was a used tire processing facilty that burned. They shredded up old tires for use in other things. Anyway, the local departmetn had their Quint hooked up with it's 2000 gpm pump, and they were feeding it from anohter pump. The gauge on the quint said they were flowing 3500 gpm. Makes you wonder how that is possible. ??

  14. #64
    MembersZone Subscriber

    Join Date
    Sep 2006
    Location
    Northeast Coast
    Posts
    3,887

    Default

    Quote Originally Posted by HotTrotter View Post
    WASTE (!! ) money on a 1000 gpm pump. I would say you are crazy to buy anything less than a 1000 gpm.
    I said HWOODS presented a perfect example of why a dept. would not waste money on a pump greater the 1000 gpm. I think most everyone agree a 1000 gpm is about the minimum. I have a hard time justifying buying a pump over 1250 in my department. Given the hydrant flows average around 1000 gpm and drafting is just about non-existant, we don't need the extra gpm pump at the cost of a larger engine, transmission, dual hard sleeves, etc. Our new engine will have plenty of discharges for those few exceptional hydrants, but the higher GPM just isn't required. Anyway, I'm sticking to my point that I'd like my people to know more, not less when it comes to this job. I'll take my chances with what they'll forget, we do have some control over what is important and routinely practiced.

  15. #65
    Forum Member
    Rescue101's Avatar
    Join Date
    Jun 2001
    Location
    Bridgton,Me USA
    Posts
    8,162

    Default

    Trotter,let me simplify your pump dilema a bit.750-1250 pump same impellers,same casting.1500-2000 same impellers same casting.The part that determines whether it's a 750 or a 1250 is the discharges.Same with the big pump.That's oversimplification at it's finest but basically correct.Now as Harve indicated to you earlier the wild card is the hydrant.Catch a good one and that 'lil ol' 1000 can flow half again or even double it's at draft capacity.People make waaaay too much complication in Fire service hydraulics.A wise old fire instructor once told me,"better to figure your FL high and have plenty of water,than figure it low and run out".As far as your little hard drive having space,remember simple formulas that work at high noon or 0 dark thirty.I've used three friction loss formulas for years.30#per 100' small hose,15#100big hose,5#100LDH.Not accurate with todays hose construction but the old Fire instructor was right. T.C.

  16. #66
    Forum Member
    Bones42's Avatar
    Join Date
    Mar 2001
    Location
    Pt. Beach, NJ
    Posts
    10,694

    Default

    Anyway, the local departmetn had their Quint hooked up with it's 2000 gpm pump, and they were feeding it from anohter pump. The gauge on the quint said they were flowing 3500 gpm. Makes you wonder how that is possible. ??
    Quint - 2000gpm. Other pump - 1500gpm. What's the problem?
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  17. #67
    MembersZone Subscriber
    JohnVBFD's Avatar
    Join Date
    Nov 2006
    Location
    Norfolk, Va
    Posts
    1,479

    Default

    Quote Originally Posted by Bones42 View Post
    Quint - 2000gpm. Other pump - 1500gpm. What's the problem?
    It requires thought, thinking and logic to be able to comprehend math.
    Co 11
    Virginia Beach FD

    Amateurs practice until they get it right; professionals practice until they cannot get it wrong. Which one are you?

    'The fire went out and nobody got hurt' is a poor excuse for a fireground critique.

  18. #68
    MembersZone Subscriber
    JohnVBFD's Avatar
    Join Date
    Nov 2006
    Location
    Norfolk, Va
    Posts
    1,479

    Default

    Quote Originally Posted by Rescue101 View Post
    Trotter,let me simplify your pump dilema a bit.750-1250 pump same impellers,same casting.1500-2000 same impellers same casting.The part that determines whether it's a 750 or a 1250 is the discharges.Same with the big pump.That's oversimplification at it's finest but basically correct.Now as Harve indicated to you earlier the wild card is the hydrant.Catch a good one and that 'lil ol' 1000 can flow half again or even double it's at draft capacity.People make waaaay too much complication in Fire service hydraulics.A wise old fire instructor once told me,"better to figure your FL high and have plenty of water,than figure it low and run out".As far as your little hard drive having space,remember simple formulas that work at high noon or 0 dark thirty.I've used three friction loss formulas for years.30#per 100' small hose,15#100big hose,5#100LDH.Not accurate with todays hose construction but the old Fire instructor was right. T.C.

    Please myself and plisken I believe already went over pump basics with him once. We were wrong he was right.

    I will go out on a limb here and say, you are wrong he is right.
    Co 11
    Virginia Beach FD

    Amateurs practice until they get it right; professionals practice until they cannot get it wrong. Which one are you?

    'The fire went out and nobody got hurt' is a poor excuse for a fireground critique.

  19. #69
    MembersZone Subscriber

    Join Date
    May 2000
    Location
    SW MO
    Posts
    4,249

    Default

    Quote Originally Posted by Rescue101 View Post
    Trotter,let me simplify your pump dilema a bit.750-1250 pump same impellers,same casting.1500-2000 same impellers same casting.The part that determines whether it's a 750 or a 1250 is the discharges.Same with the big pump.That's oversimplification at it's finest but basically correct.Now as Harve indicated to you earlier the wild card is the hydrant.Catch a good one and that 'lil ol' 1000 can flow half again or even double it's at draft capacity.People make waaaay too much complication in Fire service hydraulics.A wise old fire instructor once told me,"better to figure your FL high and have plenty of water,than figure it low and run out".As far as your little hard drive having space,remember simple formulas that work at high noon or 0 dark thirty.I've used three friction loss formulas for years.30#per 100' small hose,15#100big hose,5#100LDH.Not accurate with todays hose construction but the old Fire instructor was right. T.C.
    I thought that the impellors were different with each size pump. While they have the same castings, it requires a larger impellor as well as the discharges to push the rated GPM (so I've always been told).

  20. #70
    Forum Member
    Rescue101's Avatar
    Join Date
    Jun 2001
    Location
    Bridgton,Me USA
    Posts
    8,162

    Default

    Catch,Did you catch the standard disclaimer"oversimplifcation"?.You're correct,but different pump mgfs do different things to get the different gallonages.Subtle changes like impeller size or merely "detuning"the bigger ones to accomplish the same end result. Most of my pump universe centers around Hale and those are a "derated" pump.Doc,me wrong? I won't have any feelings left,you guys keep beating me up. Yeah,I went a little overboard but some of these guys make too much work out of some simple hydraulics.One thing I'm pretty sure I'm not wrong on is that some in this post don't know the difference between Dual pumping and RELAY pumping.I'm reasonably sure those two animals have different spots.It's been entertaining though. T.C.
    Last edited by Rescue101; 05-15-2007 at 09:27 AM.

  21. #71
    55 Years & Still Rolling
    hwoods's Avatar
    Join Date
    Jun 2002
    Location
    Glenn Dale Md, Heart of the P.G. County Fire Belt....
    Posts
    10,739

    Thumbs up Yeah!!!!...................... ........

    Quote Originally Posted by Rescue101 View Post
    Catch,Did you catch the standard disclaimer"oversimplifcation"?. Yeah,I went a little overboard but some of these guys make too much work out of some simple hydraulics.

    WHAT HE SAID!!.....
    Never use Force! Get a Bigger Hammer.
    In memory of
    Chief Earle W. Woods, 1912 - 1997
    Asst. Chief John R. Woods Sr. 1937 - 2006

    IACOJ Budget Analyst

    I Refuse to be a Spectator. If I come to the Game, I'm Playing.

    www.gdvfd18.com

  22. #72
    MembersZone Subscriber

    Join Date
    May 2000
    Location
    SW MO
    Posts
    4,249

    Default

    Quote Originally Posted by Rescue101 View Post
    Catch,Did you catch the standard disclaimer"oversimplifcation"?.You're correct,but different pump mgfs do different things to get the different gallonages.Subtle changes like impeller size or merely "detuning"the bigger ones to accomplish the same end result. Most of my pump universe centers around Hale and those are a "derated" pump.
    Actually, I caught it, just missed the context. My apologies.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Did you respond to WTC???
    By E40FDNYL35 in forum Firefighters Forum
    Replies: 197
    Last Post: 04-21-2011, 08:28 PM
  2. Dual Pumping Operations -outdated?
    By training6604 in forum The Engineer
    Replies: 5
    Last Post: 06-14-2007, 07:45 AM
  3. Dual Dumptank Operations?
    By KEEPBACK200FEET in forum Fireground Tactics
    Replies: 41
    Last Post: 08-18-2006, 02:05 PM
  4. Round 4 - Status / News
    By HazMan in forum Federal FIRE ACT Grants & Funding
    Replies: 76
    Last Post: 08-31-2002, 04:45 PM
  5. RFP's
    By D Littrell in forum Apparatus Innovation
    Replies: 1
    Last Post: 09-08-2000, 07:36 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Log in

Click here to log in or register