Why register? ...To Enhance Your Experience
+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 20 of 23
  1. #1
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default Test Your Hydraulic Skills

    Got bored and figured I'd throw one out.......its simple but do you know the answer.

    1. When the flow through a hose line increases from 100 gpm to 400 gpm, the friction loss increases _____________ times.

    a. 2
    b. 4
    c. 12
    d. 16

    Good luck!


  2. #2
    Junior Member
    Join Date
    Apr 2005
    Posts
    8

    Default

    12

  3. #3
    MembersZone Subscriber firefighterbeau's Avatar
    Join Date
    Aug 2003
    Location
    Central ND USA
    Posts
    451

    Default

    I believe D. 16 is the correct answer.

  4. #4
    Forum Member MetalMedic's Avatar
    Join Date
    Dec 1999
    Location
    The Home of Smucker's Jelly
    Posts
    1,266

    Default

    Would that be using phosphate ester, mineral oil or diethylene glycol?

    Richard Nester
    Orrville (OH) Fire Dept.

    "People don't care what you know... until they know that you care." - Scott Bolleter

  5. #5
    Forum Member
    Join Date
    Aug 2000
    Location
    South St. Paul, MN
    Posts
    95

    Default

    It's exponential not elementary Watson.

  6. #6
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default

    I have 12 and 16 as answers. Anyone want to defend there answer and how they got the numbers? Are you absolutely sure. Ahhh the fun begins.

    Here is another one for you:
    WHAT IN WATER PUTS OUT FIRES?

    Metalmedic: huh? uh.....what? Ha!

  7. #7
    MembersZone Subscriber
    Join Date
    Aug 2001
    Location
    Franklin, Va.
    Posts
    57

    Default

    16

  8. #8
    Forum Member SpartanGuy's Avatar
    Join Date
    Aug 2004
    Posts
    489

    Default

    I've gotten 14 and 16, so I'm gonna say either 12 or 16 is right

    Water's high latent heat of vaporization is what puts out fires. As we know, whenever something cool and somethind hot come in contact, the temperature tries to equalize. However, water absorbs large amounts of heat to change its phase, thus robbing the burning materials of its ability to burn by absorbing all of the joules of heat in the material.

    This is also what allows water to rapidly cool things that its applied to, such as tanks exposed to fire.
    "Captain 1 to control, retone this as a structure and notify the fire chief...."

    Safety is no accident.

  9. #9
    Forum Member jerrygarcia's Avatar
    Join Date
    Jan 2004
    Location
    KC
    Posts
    630

    Default

    16

    Friction loss will vary approximately with the square of the quantity of flow.


  10. #10
    MembersZone Subscriber firefighterbeau's Avatar
    Join Date
    Aug 2003
    Location
    Central ND USA
    Posts
    451

    Default

    Well I got my answer when using 2.5in hose using the friction loss formulas and coefficents in the Delmar pump book. I double checked my answer with the handy dandy Fire Calc. When I used 1.75in line I got 15.5 psi difference.

  11. #11
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default

    And the correct answer is 16

    the square of 100 is 1
    the square of 200 is 4
    the square of 300 is 9
    the square of 400 is 16

    This one tripped me up for the longest.
    Good job guys

    BUT no one has got the "What's in water that puts out fire" right. One of you gave a good explanation of the science and that is correct, but thats not the answer.
    WHATS IN WATER THAT PUTS FIRE?

    Good luck,

  12. #12
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default

    Sparten guy........nice Law of Latent heat of vaporization....
    How many BTU's does it take to dissipate 1 pound of water to a vapor?
    Thats stuff is very interesting isn't it........
    Scott

  13. #13
    Junior Member
    Join Date
    Apr 2005
    Posts
    8

    Default

    1 pound of ice + 143 BTU =1 pound of water +1150 BTU= steam

  14. #14
    MembersZone Subscriber
    Join Date
    Feb 2003
    Location
    Fairfield, CA
    Posts
    105

    Default

    What in water puts out fire?

    First (and foremost) water does not put a fire out. One does not put a fire out. You “put out a cat” and you “extinguish” a fire.

    Next, The key to water having the ability to extinguish a fire lies in both the molecular structure of water and its thermodynamic interaction with the fuel/oxygen reaction. The Hydrogen-Oxygen-Hydrogen bond (water) is at an angle of 104.5 degrees. Using the H-O-H bond dissociation energy (460 kJ/mol) and comparing it to the bond dissociation energies of common fuel substrates, one can easily calculate the chemical energy (i.e., heat) transferred from the fuel to the water molecule. The heat transfer is facilitated by the physical location of the water molecule with the fuel molecule. Where the bond angles of these molecules are such that the molecules are in close proximity to each other (on the order of 25 to 150 picometers [pm], depending on the fuel involved), the extinguishment mechanism is enhanced. This is due to the H-O bond length (96 pm) being shorter than most of the fuels (perhaps all of the fuels).

    Recently discovered by researchers at the new Fire Research Laboratory in Munich, Germany is a relationship between the H-O-H molecule and a fuel called the endothermic dissipation ratio. For water this value has been determined empirically as 23.72. Therefore, when the water molecule comes in contact with a fuel substrate, it will absorb 23.72 times the exothermic heat energy of the fuel-oxygen reaction provided the fuel/oxygen ratio is less than 0.7 and the fuel bond length is at least 1.14 times that of water. Upon absorbing the heat, the water molecule then expands the H-O-H bond angle until a coordinate covalent bond is formed with the fuel substrate. This is particularly interesting since the H-O-H bond is ionic. This work was published in the journal “Science” about a year ago.

    What has perplexed these researchers is that the thermodynamic relationship between water and the common fuels (i.e., hydrocarbon) does not hold up when analyzing a hydrogen fire in a chlorine atmosphere unless the reaction occurs at a pressure greater than 12 bar (176 psia).

    There is more to this that involves enthalpy changes, molecular dissociation energies and ratios, and arguably the degree to which the chemical equilibrium constant affects the thermochemistry of the oxidation-reduction reactions (redox).

    This is why water is a better extinguishing agent on certain fuels than others.

  15. #15
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default

    FireH2O thanks for your molecular physics explanation but you are wrong! Atleast for this question.

    The answer is:
    WHAT IN WATER PUTS OUT FIRE?

    A FIRE BOAT

    We torture our new guys for weeks with this. They are so eager to please the officer that they really think long and hard on this questions giving us all kinds of answers and believe me I've heard them all. When we are ready for them to know the answer we start hanging pictures inadvertanly around the station and talking about fireboats in front of them. It provides hours of fun and laughter and firefighting requires us to really think out side of the box but it also requires that we laugh and enjoy life. Everyone did a great job.......I definetly know more about molecular physics of water now. Ha!


    Keep it safe,
    Scott
    Last edited by Scottsfire; 04-30-2005 at 09:31 AM.

  16. #16
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default

    Oh I forgot.....
    Pineapples....nice job!

    Scott

    FIRE BOAT!

  17. #17
    Forum Member jerrygarcia's Avatar
    Join Date
    Jan 2004
    Location
    KC
    Posts
    630

    Default

    Removes or inhibits two parts of the fire triangle.


  18. #18
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default

    JerryGarcia.......
    The Answer is:
    Whats in water that puts out fire?

    A FIRE BOAT!

    Ha,
    Scott

  19. #19
    Forum Member
    Join Date
    Jul 2002
    Location
    Arizona
    Posts
    481

    Default

    Scottsfire, for posting such an inane question, I have called the CO State Fire Marshal. Your test has been revised. Expect questions like:

    How many doors were on the truck pictured on page 138?

    How many turns does it take to connect two 2.5" hoses without Higbee indicators?

    Two men, A&B, leave the station at the same time, one in a truck, one on a ladder. If A turns East, and B turns West, how long is the hose on A's truck?

    We'll get even with you for that!


    Fire Boat - HA!

  20. #20
    Forum Member
    Join Date
    Apr 2005
    Posts
    63

    Default

    Sleuth,
    I'm rolling on the floor.........someone actually replied.....I was starting to think Oooops...people are mad.

    Those are easy questions by the way to answer........did you really speak to our fire marshall.........cause the state doesn't have one. Rolling on the floor again.

    As firefighters we sometimes forget to laugh and just have fun. Thanks for engaging.

    You have we stumped with your trivia though........let me chew on it a few days.

    In the mean time care to give this one a go?
    WHAT IS THE ONLY APPARATUS, NO MATTER LIGHTS AND SIREN AND CUE, CAN STILL NOT GO UP A ONE WAY STREET WHILE RESPONDING?

    Scott

Thread Information

Users Browsing this Thread

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

Posting Permissions

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