1. ## 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. 12

3. I believe D. 16 is the correct answer.

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

5. It's exponential not elementary Watson.

6. 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. 16

8. 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.

9. 16

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

10. 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. 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. 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. 1 pound of ice + 143 BTU =1 pound of water +1150 BTU= steam

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

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

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

Scott

FIRE BOAT!

17. Removes or inhibits two parts of the fire triangle.

18. JerryGarcia.......
Whats in water that puts out fire?

A FIRE BOAT!

Ha,
Scott

19. 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. 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

21. Hmmmmmm.............They are on a tiller and therefore their hoses are the same? A is in the truck and b is on the ladder being pulled by the truck...........but wait....how can they both go east and west? Thinking out loud......ok thought I had it for a second until I started posting.

Scott

22. Scott, I have let you wonder enough.
The 3rd question is a take off on all the IQ/SAT tests, that had a bunch of questions that started:
2 men, A & B, .....

Usually it was: A leaves Chicago on a train going 75 MPH at 3PM, B leaves NY at 4:15 on a bus going 55 MPH, what time will they pass each other."

Maddening, confusing, and widely hated! Particularly when your entire future is at stake.

Have a nice weekend.

23. This is cruel and unusual punishment..........ha! I'll be back on shift Sunday..........between the 5 of us we will figure it out trust me.

If you left us in a room with two ball bearings and came back in an hour, one ball bearing would be broke and the other would be missing. Ha...........but we will get this one.

Scott

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