# Quiz

Discussion in 'Firefighter/EMS Talk' started by DepChief, Jan 2, 2005.

1. ### DepChiefGet Tous's Rope

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You lay 250 feet of 2 1/2 hose from your engine to a dry standpipe on ground level of an apartment building. On the fifth floor you run another 100 feet of 2 1/2 from the standpipe connection, up 2 more flights of stairs to a gated wye. From the wye, you run 150 feet of 1 1/2 hose to a fog nozzle at the fire. To get 100 lbs. pressure at the nozzle, what will your pump pressure be?

2. ### aspartz

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Flow rate?

I'll take the easy answer -- static, flow rate = 0
NP = 100
lift = 7 floors = 70 feet = c. 35 psi.

Pump pressure = 135 psi.

Now if you plan on opening those nozzles and friction becomes an issue and the math gets more complicated...

ARS

3. ### DepChiefGet Tous's Rope

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Well, to be fair, I did say "at the fire", so I did intend this equation to include friction loss.

4. ### keary

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I figure about 225psi PDP. I did not include any FL for the standpipe nor did I figure any FL for the gated wye.

Keary

5. ### aspartz

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Assuming 2 handlines from the wye, 125 gpm each:

All flow loss is from Akrons data sheets -- my slide rule is at the hall:

250' 2.5" hose, 250 GPM total: 13 psi/100' -- 32 psi
50' elevation -- 1 psi/2' -- 25 psi
standpipe friction loss is negligible -- 0 psi
100' 2.5" hose, 250 GPM total: 13 psi/100' -- 13 psi
20' elevation - 1 psi/2' -- 10 psi
Wye -- some say 0 psi if less than 350 gpm, I was taught 5 psi
150' 1/5" hose, 125 GPM: 38 psi/100' -- 57 psi

32
25
0
13
10
5
57
---
147 psi lost

EP = 100 + 147 = 247.

If you use 1.75 handlines the loss drops 21 psi.
If you use only one handline on 1.5" hose the loss drops 35.

ARS

6. ### ARFFormula

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Can I use my cheet-sheet?

7. ### obxprnstarGoth Lover

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I shotgun guessed 190, but I have the fire/rescue field guide in my turnouts, and it is opened to the friction loss cheat sheet. @ my old FD, I printed that thing up along with friction loss formulas and taped it to the inside of the engineer compartment door.

8. ### DepChiefGet Tous's Rope

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Yeah, I think I remember that dept.

9. ### obxemtChaplain of CT

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DC, sometimes you just have to get down to basics first:

"Throttle up upon cavitation. Trying to suck more water through flat 5-inch LDH is extremely effective for water delivery."
-- Avon F.D. SOP Manual

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