1. #1
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    Question 6" Hard Suction Hose on a 1000 GPM Pumper?

    I've checked around some and haven't found any threads to answer this so...

    Is there any problem using 6" Hard Suction and suction strainers (with a 5" to 6" adapter at the truck) on a 1000GPM pumper?



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    No there is no problem at all.

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    No problem at all.

    Except, once a year when you service test it, you not supposed to use hard suction hose larger than 5" when testing a 1,000 GPM pump.

    Yes, dumb requirement, but it still exists. My Dept breaks that rule everytime they test a pumper, and no one from ISO hardly ever checks records in such detail.

    6" has much less friction loss than 5", so your pumper could likely exceed 1,000 GPM when using it. Although I wouldn't want to use a 5" strainer, go ahead and get a 6" strainer.
    The American people will never knowingly adopt Socialism. But under the name of 'liberalism' they will adopt every fragment of the Socialist program, until one day America will be a Socialist nation, without knowing how it happened. --Norman Mattoon Thomas, 6 time presidential candidate for the Socialist Party of America

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    Quote Originally Posted by txgp17 View Post
    No problem at all.

    Except, once a year when you service test it, you not supposed to use hard suction hose larger than 5" when testing a 1,000 GPM pump.

    Yes, dumb requirement, but it still exists. My Dept breaks that rule everytime they test a pumper, and no one from ISO hardly ever checks records in such detail.

    6" has much less friction loss than 5", so your pumper could likely exceed 1,000 GPM when using it. Although I wouldn't want to use a 5" strainer, go ahead and get a 6" strainer.
    Using 6" has lots of plus sides to it...

    The annual test is trying to recreate the UL test done at the time the apparatus was built and tested for pressure, volume and Engine RPM's. (Plate mounted on panel)

    There are many variables that need to be taken into consideration and the size of the suction and lift is one. I don't think that the friction loss on the hard suction should make that much of a difference (5" to 6") and not have one of the other variables (Pressure/Volume/Engine RPM's) not show the change. Then if there is a change you have to explain it on the test report.

    Also, most strainers just change the intake adaptor but the body of the strainer is the same. Unless it is a high flow strainer where they increase the screen area. Kochek floaters come to mind.

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    Quote Originally Posted by ChiefDog View Post
    I don't think that the friction loss on the hard suction should make that much of a difference (5" to 6") and not have one of the other variables (Pressure/Volume/Engine RPM's) not show the change.
    Actually there is a significant difference between 5" & 6". It might not show itself in a service test, but if you have a robust pump, and an adequate discharge arrangement that can handle the GPM, 6" hose will provide no less than 44% more water than 5" hose, at equal friction loss levels.

    The difference may only be 1 or 2 psi, but that extra 2 psi of intake pressure may translate into another few hundred GPM's in a drafting scenario, making the difference between adequate flow, and cavitatiton.

    When drafting, the intake pressure is always the same. The only losses are that of lift, and friction loss inside the hose.

    If I place any specific pressure on a 5" port, a 6" port will almost always flow 1.44 times the water a 5" port will.
    The American people will never knowingly adopt Socialism. But under the name of 'liberalism' they will adopt every fragment of the Socialist program, until one day America will be a Socialist nation, without knowing how it happened. --Norman Mattoon Thomas, 6 time presidential candidate for the Socialist Party of America

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    Quote Originally Posted by txgp17 View Post
    Actually there is a significant difference between 5" & 6". It might not show itself in a service test, but if you have a robust pump, and an adequate discharge arrangement that can handle the GPM, 6" hose will provide no less than 44% more water than 5" hose, at equal friction loss levels.

    The difference may only be 1 or 2 psi, but that extra 2 psi of intake pressure may translate into another few hundred GPM's in a drafting scenario, making the difference between adequate flow, and cavitatiton.

    When drafting, the intake pressure is always the same. The only losses are that of lift, and friction loss inside the hose.

    If I place any specific pressure on a 5" port, a 6" port will almost always flow 1.44 times the water a 5" port will.
    So we agree that the 6" will help and potentially give you more discharge volume if the setup will take it. It is a similar discussion to the difference between 4" ldh and 5"ldh for flow and friction loss or using a larger dump valve size to flow more water quicker.

    The main thing is that the annual pump test is trying to recreate the same results as the test it passed at date of manufacture. That way you are able to detect wear to the pump and drive train components. If it won't duplicate the original test then you have to make the repairs necessary to do so.

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    Default Larry Davis R.I.P.

    Knew I had this somewhere, but it took a while to find it. Table is from Larry Davis' book II "Rural Firefighting Operations" page 176. Minimum Expected
    5" @ 10' lift = 1,000 gpm 6" @ 10' lift = 1170 gpm Table won't upload Probably too large.
    Last edited by KuhShise; 11-09-2008 at 06:25 AM. Reason: Attachment lost

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    Quote Originally Posted by KuhShise View Post
    Knew I had this somewhere, but it took a while to find it. Table is from Larry Davis' book II "Rural Firefighting Operations" page 176. Minimum Expected
    5" @ 10' lift = 1,000 gpm 6" @ 10' lift = 1170 gpm Table won't upload Probably too large.
    Without knowing the details of the pump that Mr. Davis used in that specific test, it's hard to assess his results.

    I've not read his book, and know little about him, and in no way mean to assert that his numbers are wrong. I'm certain there were a few other parameters of his tests that led him to publish the numbers he did.

    For example, my Dept has 10 quints with 1,500 GPM pumps. We service test each one with 6" hose, @ 10' of lift. And I've found cases with at least 3 different trucks that could pump 1,760 GPM (or more) before cavitating while using one 6" intake @ 10" lift.
    The American people will never knowingly adopt Socialism. But under the name of 'liberalism' they will adopt every fragment of the Socialist program, until one day America will be a Socialist nation, without knowing how it happened. --Norman Mattoon Thomas, 6 time presidential candidate for the Socialist Party of America

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    Default 1,000 gpm pump W/ 6" suction

    txgp17:

    Mr. Davis' table referrs specifically to a 1,000 gpm pump that just makes the 1,000 gpm annual service test at a 10' lift using 20' of 5" diameter hard sleeve. That same pump set-up using a 6" hard sleeve and a 6" strainer should be able to pump 1,170 gpm. Assuming that the system followed this 17% increase, then a 1000 gpm pump that moved 1100 gpm from draft should be able to move 1287 gpm using the 6" hose and strainer.

    I would suggest that if you are service testing a 1500 gpm pump, then the goal is to compare the current pump condition at exactly 1500 gpm and noting any change in the specified pump rpm as a measure of the condition of the engine / pump combination. While I agree that a 1500 gpm pump is capable of supplying that amount of water, some pumps of this size and all larger pumps require dual suction sleeves to perform the test properly. There is a finite amount of water that can be moved by 14.7 psi atmospheric pressure through a single 6" strainer and 20' of suction tube. The upper limit for that flow is usually under 1680 gpm. Most pump manufacturers design the castings to meet the NFPA requirements so this upper limit has held more or less constant for the past 80+ years.

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    Thumbs down

    I think any value you get in drafting with 6" instead of 5 is going to be overcome by the fact that you're reducing to 5" going into the truck. On top of that, you haven't mentionned whether or not the actual intake pipe going INTO the pump is 5" or if it too is dummied down to 4 or even 3".

    Drafting up more water and reducing it is going to create more resistance at your pump side intake- whichever size it is... provided it's smaller than 6"- which it is.

    It will also take significantly longer to prime. Also, if lifting- my impression would be that trying to lift more water would take more pumping capacity...? If you're using primers... seems to me it might be awfully hard on them?

    Not to mention the fact that drafting with 6" seems absolutely wasted on a thousand GPM pump. Okay, so you MIGHT squeeze a hundred gallons per minute extra performance out of your pump... 1000gpm is 16 gallons per minute. if you waited 10 seconds you could do the same. In an hour's worth of evolutions that would add, what? 10 minutes?

    The reduced friction loss achieved by pumping through the larger hose is also going to be exponentially small considering the minute amount of water flowing anyways. 1000gpm is a drop in the bucket for 5" nevermind 6". Are you planning on drafting a mile? No? Maybe 20 feet? I highly doubt that in that much distance you'd even be able to see a measurable difference on your gauge.

    When pumping its maximum volume from a non pressurized source at the ULC stamp rating of 1000kpa or 150 and something psi... frankly... it's only going to be able to pull so much at that pressure. PLUS you have to take into consideration that many of your pumping evolutions are going to be occurring at higher PDPs than 1000 kpa / 150psi... ESPECIALLY if you're using 1.5" with fog nozzles. Automatically, that brings you up to almost 200psi PDP. Remember- I said almost.

    I can't personally see any value at all in it. If you had a 3500 GPM pump... okay- I'm seeing it. With some puny K cranker? Not seeing it.

    Back to the question though- is there a problem with it? Where do you put it on the truck? The americans will think you're storing Russian nuclear missiles on board and will likely blockade your town!
    Last edited by Eno821302; 11-10-2008 at 06:33 AM.
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    Cool Suction Hose Size

    The new 1901-2009 manual, ($44) table 16.13.2.2.1.1 suction hose size and number of suction lines for fire pumps: says:

    1,000 gpm 6" max. hose size, one hose.
    1,250 gpm. 6" max. hose size, one hose
    1,500 gpm. 6" max. hose size. two allowed.
    1,750 gpm. 6" max. hose size, two allowed.
    2,000 gpm. 6" max. hose size, two allowed.

    I have flowed 1,500 gpm. through one 6" hose with a basket strainer many times. Basket strainer has much lower friction loss than a barrel strainer.

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    Quote Originally Posted by Eno821302 View Post
    It will also take significantly longer to prime. Also, if lifting- my impression would be that trying to lift more water would take more pumping capacity...? If you're using primers... seems to me it might be awfully hard on them?
    You are not "lifting" water into your pump. You are creating a lower pressure area inside the pump cavity than the outside atmosphere. The atmospheric pressure on the body of water you are getting water from flows the water up your suction hose to try to equalize the pressure (lack thereof) between the two. You need all the connections tight so you create the negative pressure area where you want it with the least amount of effort and loss due to leakage.

    Primers are usually rotary gear pumps driven by an electric motor similar to a starter. There are some air driven venturi effect primers out now too. Primers may be a little different from one pump to another but should not be designed to break or fail on the difference between 5" and 6" suction lines.

    I am sure that someone like ChiefEngineer11 would be able to explain this better than I did so maybe he could add or correct me if I am wrong.

    I belive that standardization to 6" would be just as important, if not more so, between trucks in the fleet. Allowing to have standard fittings that are interchangable between your 1000 gpm and any larger pumps has it's advantages also.

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    Quote Originally Posted by ChiefDog View Post
    You are not "lifting" water into your pump. You are creating a lower pressure area inside the pump cavity than the outside atmosphere. The atmospheric pressure on the body of water you are getting water from flows the water up your suction hose to try to equalize the pressure (lack thereof) between the two. You need all the connections tight so you create the negative pressure area where you want it with the least amount of effort and loss due to leakage.

    Primers are usually rotary gear pumps driven by an electric motor similar to a starter. There are some air driven venturi effect primers out now too. Primers may be a little different from one pump to another but should not be designed to break or fail on the difference between 5" and 6" suction lines.

    I am sure that someone like ChiefEngineer11 would be able to explain this better than I did so maybe he could add or correct me if I am wrong.

    I belive that standardization to 6" would be just as important, if not more so, between trucks in the fleet. Allowing to have standard fittings that are interchangable between your 1000 gpm and any larger pumps has it's advantages also.
    ChiefDog, your explanation exactly as it was taught to me quite a few years back. By reducing the pressure inside to sleeves and the pump to something below atmospheric (14.7 psia), the atomospheric pressure outside pushes the water up the sleeves and into the pump.

    The corollary to this is that the maximum theoretical "lift" as we like to call it is limited to the atomospheric pressure divided by the downward pressure of a column of water, 14.7 / .434 = 31.3 feet. That would assume a perfect vacuum (not achievable outside a lab setting) and zero friction loss in the sleeves. Practical maximum lift is more like 25 feet, with gpm well below the pump's rated capacity.

    Rotary gear primers are not as commonplace as they once were, nor are primers that were driven by an intermediate gear in the transfer case. Both are still available, but have generally been replaced by rotary vane primers (dry or oiled). Electric motor drive is pretty commonplace. Vane primers are less expensive to buy and considerably less expensive to repair. The old time pump repair folks that I talk to quite a lot will tell you, though, that you'll get a quicker prime at higher lift with a gear primer.

    The only difference that I can see with respect to 5" or 6" sleeves is that it takes more gallons of water to fill the 6" sleeves. This could result in a slightly longer time to complete the prime. I don't think that the time would be significant at all. Once the prime is completed and water is flowing, agreed, the friction loss within the sleeves is lower, allowing that 1000 gpm pump to work with less effort.

    It's refreshing to know that physics is the same in Vermont as it is in Penna., and that passing of years has not altered it even a little.

    Stay safe out there, everyone goes home!
    Last edited by chiefengineer11; 11-12-2008 at 02:48 PM.

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    Quote Originally Posted by chiefengineer11 View Post
    The only difference that I can see with respect to 5" or 6" sleeves is that it takes more gallons of water to fill the 6" sleeves. This could result in a slightly longer time to complete the prime. I don't think that the time would be significant at all.
    Well, we can make an estimation......

    6" hose requires 44% more water to fill than 5". But that doesn't mean it would take 44% longer to prime. A significant amount of volume is still inside the pump manifold, and that volume doesn't change when we switch hose sizes.

    I wish we could make a Nationwide push to standardize on 6" hose, with a generous timeline to phase out the smaller stuff. I realize that some smaller pumps and brush units benefit by using 2" or 3", but maybe everything between 3" & 6" could be eliminated.
    The American people will never knowingly adopt Socialism. But under the name of 'liberalism' they will adopt every fragment of the Socialist program, until one day America will be a Socialist nation, without knowing how it happened. --Norman Mattoon Thomas, 6 time presidential candidate for the Socialist Party of America

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    FOUND IT!!!!

    This is a chart from Darley's website, showing the difference in time required to prime 5" hose versus 6" hose. It only times the hose, not the pump.

    Priming_Time_-_c338[1].pdf
    Last edited by txgp17; 11-14-2008 at 01:36 PM.
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    Exclamation

    If I am not mistaken, higher altitudes such as Denver, CO and those cities, towns and burgs that fall into this category, have to use 6 inch suctions on 1000 gpm pumpers, due to the higher altitudes.
    Stay Safe and Well Out There....

    Always remembering 9-11-2001 and 343+ Brothers

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    Eno,the ADAPTER has NO effect on the evolution.As it is 6 going to 5 in about three inches,and the pump neck(original)is the smallest point,you will GAIN capacity.I've done this personally enough times with positive results to make this statement.Our last 5" is going out of service in early 09.then everything will be 6". T.C.

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    I've drafted on a 750 GPM PTO pump before... bumper mounted.
    "I don't wanna hear about it... I wanna see results!!!":-P

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    Cool

    Ouch! Took a beating in this thread! I'll brush up on my hydraulics before I step in next time. Frankly, I didn't know that 6" was as popular as you guys are saying- I thought it was more of an exotic accessory.

    Apparently not!

    So, while I STILL don't see the benefit on such a small pump- I guess I have to agree that there's nothing wrong with doing it.
    Ian "Eno" McLeod
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